Standard or hiflow thermostat for 02 gu td42t

[Robo]

Had a cooling issue towing and have now upgraded to a ARE alloy twin core rad.
I'm looking at the thermostat now.
daily, with towing duties big van.
Iv'e been a little unlucky in the past prior to upgrade imo with temps getting to 105 C in cool weather on a long-ish approx 1k but low grade climbs, and want to stop this sort of problem before the hot weather turns up.

I've read n read and it seems common for 100+ deg c to be seen as ok, but this is around boiling point and not ok imo.
so little perplexed on which thermostat to use.

Thermostats listed for said car.
Std is set at ----76.5 deg.
aftermarket-----80.0 deg.
a/m hiflow also-80.0 deg.

things floating around inside the little mussel.
Should I be fitting say hi flow 76 deg c ?
Is hiflow a good thing as it will allow more flow partially open, and then open more when pushed to keep things under control when hills appear?
Or just stick with a std oem unit ?

oh and egt's are good, large t/m so that's not the issue or part the problem.

Note- hi flow is recommended for towing according to it's packaging.
69151
thoughts please.

Update as the aftermarket temps were quoted wrong they should be 70deg c

[mudski]

Certainly worth a shot. Its not a big cost so I would give it a go for sure.
I think I will be doing the same to mine soon. I also have a hi flow water pump. I have just fitted a UFI radiator, larger 2 core copper jobbies, added more oil into the viscous fan clutch so it engages earlier, and change my fan to an Infinity G35 fan. Haven't taken it for a test but I might do today...
Air flow is paramount of these motors. See the big gap you have between the top of the rad and the support panel? This needs to be blocked up. Same goes for the sides. Otherwise at high speed, where mine usually gets hotter, the fast moving air just hits the rad and goes out the top and sides, and not through the rad.

[Robo]

Certainly worth a shot. Its not a big cost so I would give it a go for sure.
I think I will be doing the same to mine soon. I also have a hi flow water pump. I have just fitted a UFI radiator, larger 2 core copper jobbies, added more oil into the viscous fan clutch so it engages earlier, and change my fan to an Infinity G35 fan. Haven't taken it for a test but I might do today...
Air flow is paramount of these motors. See the big gap you have between the top of the rad and the support panel? This needs to be blocked up. Same goes for the sides. Otherwise at high speed, where mine usually gets hotter, the fast moving air just hits the rad and goes out the top and sides, and not through the rad.

Yeah I was looking at the gap all the way round also thinking the same thing.
How much oil did you add?.
I haven't pulled a viscus hub apart before, but I have some fluid in the draw ready to top up or refill.
That said its still fairly tight, I got the oil with the intention of replacing but it still only turns very minimal by hand.

Humm g35 fan, I have a gt35 skyline, same car I thought, and it runs all electric fans, so which fan are you talking about.

And the ARE rad is more open to allow better air flow so, yeah off to see if I have some stick on foam or buy some.

[nissannewby]

Whichever way you go you need to make sure that the thermostat will close the bypass port in the thermostat housing. This helps a lot. If the thermostat does not close the bypass port when it opens then temps will rise and could be a problem.

[jff45]

Mark, how much space do you have between rad & fan with the G35? I have a 52mm 3 core rad and my G35 fan only has 15 mm space at the bottom. I moved the rad top further forward to have a bit more there.
I also put 3 x 18ml into my hub but it's never been hot enough to lock it.

Edit: forgot to add I use a 77 degree Tridon thermostat.

[Robo]

Whichever way you go you need to make sure that the thermostat will close the bypass port in the thermostat housing. This helps a lot. If the thermostat does not close the bypass port when it opens then temps will rise and could be a problem.

How much should the bypass valve extend when at full opening temp?
More than the seat depth to put some pressure on seat to ensure a good seal?

But hoping problem was only lack of decent radiator.
will know more next week when I get our van back from the annex man and give it the business with new parts, fingers crossed.

I have an idea my right foot has something to do with it.
but when it first happened in cool weather something had to be done before summer.

[nissannewby]

Yes it needs to close the port. I have even seen people put a small spacer on the bottom to make sure it closes.

[Robo]

Well the after market thermostat supplied was the wrong one.
80 deg c is for zd30 not td42t.
Went back into ask if they had one cooler, wasn't happy with the one supplied , consulted catalog noticed the discrepancy.
Going by the catalog 70 deg is for td engine.
swap out n see what happens now.
didn't go hiflow just std.

ggrrrr doing things over n over.

thinking lol, mill 2mm from top of housing and thermostat seat to remedy by pass issue.

[mudski]

Mark, how much space do you have between rad & fan with the G35? I have a 52mm 3 core rad and my G35 fan only has 15 mm space at the bottom. I moved the rad top further forward to have a bit more there.
I also put 3 x 18ml into my hub but it's never been hot enough to lock it.

Edit: forgot to add I use a 77 degree Tridon thermostat.
Sorry mate for the late reply....
About 30mm gap there is.
One thing i have noticed with the new fan is the amount of air it moves. Upon start up when the fan is engaged you can really feel the air being pulled through when you have the bonnet open.
I just got a hi flow thermostat. Ill get that in soon. Hopefully i have enough oil in teh viscous hub. It will be a pain to just remove the fan and hub without taking the radiator out...
Sent from my GT-N7105T using Tapatalk

[Robo]

Certainly worth a shot. Its not a big cost so I would give it a go for sure.
I think I will be doing the same to mine soon. I also have a hi flow water pump. I have just fitted a UFI radiator, larger 2 core copper jobbies, added more oil into the viscous fan clutch so it engages earlier, and change my fan to an Infinity G35 fan. Haven't taken it for a test but I might do today...
Air flow is paramount of these motors. See the big gap you have between the top of the rad and the support panel? This needs to be blocked up. Same goes for the sides. Otherwise at high speed, where mine usually gets hotter, the fast moving air just hits the rad and goes out the top and sides, and not through the rad.

You replaced only the fan as the G35 fan fits the TD viscus correct?

[mudski]

You replaced only the fan as the G35 fan fits the TD viscus correct?

Hey Robo. I replaced the fan with the G35 fan, it fits the GU hub, not the GQ hub, added more oil in the viscous hub, and put in a UFI radiator. I also put in a high flow thermostat. Not sure if any of this has helped yet as its still too cold here to tell. One thing though is the fan certainly pulls more air than the OEM fan. As on start up when the fan is engaged, with the bonnet open you can really feel the air from the fan. One thing I am not sure of too is whether I have put enough oil in the hub, as this is supposed to make the hub engage earlier, being so cold here at the moment it hasn't engaged any earlier. Plenty of other people who have done this have said their fan is engaged pretty much all the time, mine isn't so I am assuming it just needs more oil. So I might have to take it off and put more oil in it. But I will wait until its warmer here first.
After speaking with a few radiator mobs and a couple of mechanics that do a lot of TD's, air flow is more important than coolant capacity. Sure capacity helps but they need more air flow. Also I will add just adding the fan and not modding the hub you will more than likely just be wasting your time. Because when the hub disengages the fan won't do anything. So you need to do both, or just the hub in my opinion if you want to see any gains.

Cheers.
Mark.

[Robo]

Hey Robo. I replaced the fan with the G35 fan, it fits the GU hub, not the GQ hub, added more oil in the viscous hub, and put in a UFI radiator. I also put in a high flow thermostat. Not sure if any of this has helped yet as its still too cold here to tell. One thing though is the fan certainly pulls more air than the OEM fan. As on start up when the fan is engaged, with the bonnet open you can really feel the air from the fan. One thing I am not sure of too is whether I have put enough oil in the hub, as this is supposed to make the hub engage earlier, being so cold here at the moment it hasn't engaged any earlier. Plenty of other people who have done this have said their fan is engaged pretty much all the time, mine isn't so I am assuming it just needs more oil. So I might have to take it off and put more oil in it. But I will wait until its warmer here first.
After speaking with a few radiator mobs and a couple of mechanics that do a lot of TD's, air flow is more important than coolant capacity. Sure capacity helps but they need more air flow. Also I will add just adding the fan and not modding the hub you will more than likely just be wasting your time. Because when the hub disengages the fan won't do anything. So you need to do both, or just the hub in my opinion if you want to see any gains.

Cheers.
Mark.

All good info, thanks.
I'll try adding some oil to the hub.
As a matter of interest the (toyo) oil comes in 3 different grades,
to lock the hub up at different temps I presume.
Is the g35 fan the type on ebay listed to suit 02/03 models?.
cheers

[mudski]

All good info, thanks.
I'll try adding some oil to the hub.
As a matter of interest the (toyo) oil comes in 3 different grades,
to lock the hub up at different temps I presume.
Is the g35 fan the type on ebay listed to suit 02/03 models?.
cheers

Got a link for the fan? As for the oil, not sure of the grades, I just bought two bottles off the one that everyone uses part number 08816-10001, 18ml bottle, and used 1 and a half of it. I did drain out what was in there, albeit not much but I think i need to add the rest. Just not looking forward to removing the fan and hub with the rad in.

[Robo]

http://www.kewengineering.co.uk/Auto_oils/images/Table_5_viscosity_comparison_chart.jpg
a link, table on various grading indexes and compares them @ 40 & 100 deg C.

toyo oils available.
08816-03001 = 3000cst.
08816-06001= 6000cst.
08816-10000= 10 000cst.
web search, apparently 3000cst is used in cooler environments.
and from what I've found the consensuses is to drain, clean & replace with fresh stuff, as the oil will lose it cst rating with use.

cant bring myself to type that word toyo@#, like swearing isn't it !


GENUINE INFINITI 03-04 G35 FAN BLADE OEM 21060-AG202.

http://www.ebay.com/itm/GENUINE-INFINITI-03-04-G35-FAN-BLADE-OEM-21060-AG202-/122099469409?fits=Make%3AInfiniti%7CModel%3AG35&hash=item1c6db20c61:g:bL4AAOSwJcZWcEET&vxp=mtr

[mudski]

http://www.kewengineering.co.uk/Auto_oils/images/Table_5_viscosity_comparison_chart.jpg
a link, table on various grading indexes and compares them @ 40 & 100 deg C.

toyo oils available.
08816-03001 = 3000cst.
08816-06001= 6000cst.
08816-10000= 10 000cst.
web search, apparently 3000cst is used in cooler environments.
and from what I've found the consensuses is to drain, clean & replace with fresh stuff, as the oil will lose it cst rating with use.

cant bring myself to type that word toyo@#, like swearing isn't it !


GENUINE INFINITI 03-04 G35 FAN BLADE OEM 21060-AG202.

http://www.ebay.com/itm/GENUINE-INFINITI-03-04-G35-FAN-BLADE-OEM-21060-AG202-/122099469409?fits=Make%3AInfiniti%7CModel%3AG35&hash=item1c6db20c61:g:bL4AAOSwJcZWcEET&vxp=mtr

This seems to be the oil to use according to many other users on the interwebs. I did drain my hub out first, but I still think I need to add more. Time will tell....
And thats the fan I used.....

[jay see]

I've always thought that you needed to use two full bottles.

Why didn't you, playing it safe or won't it fit.

[jff45]

This seems to be the oil to use according to many other users on the interwebs. I did drain my hub out first, but I still think I need to add more. Time will tell....
And thats the fan I used.....

I bought 3 x 18ml 10000cst and only initially used 2 but didn't feel any difference. I recently had my engine out to fix a coolant leak so I redrained the hub and put 50ml in. Seems a bit stiffer but it's not hot enough yet to really test.

[Robo]

This seems to be the oil to use according to many other users on the interwebs. I did drain my hub out first, but I still think I need to add more. Time will tell....
And thats the fan I used.....

The G35 fan is the same outer diameter as the std TD fan ??.

[mudski]

The G35 fan is the same outer diameter as the std TD fan ??.
Slightly smaller in diameter by a poofteenth. Thicker and larger blades though.

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[Robo]

08816-10001 $11 at local toyo dealer, ebay over double the price, if the missus doesn't want car will do this arvo.

[Robo]

Completely drain and cleaned out old oil.
Recon 50 mls is more like what came out, so in with near 3 bottles.

It's now a bit harder to turn by hand than it was before.
I recon it now a little louder cruising so presume bit more air being worked by fan.
Ambient air temp to cool to tell if its made any difference but next time vans hooked up will be the real test.

[mudski]

Completely drain and cleaned out old oil.
Recon 50 mls is more like what came out, so in with near 3 bottles.

It's now a bit harder to turn by hand than it was before.
I recon it now a little louder cruising so presume bit more air being worked by fan.
Ambient air temp to cool to tell if its made any difference but next time vans hooked up will be the real test.

Yeah I reckon I need to put more in mine. I got more oil. I might even think about doing it next week maybe. I'll have to think about it though. Looks like too much hard work to remove the hub and fan with the rad still in.

[jay see]

Looks like too much hard work to remove the hub and fan with the rad still in.

Ponder on it with a glass of red..

[jff45]

Mine is definitely louder now with 50mls in the hub. Also looking forward to seeing what temps it runs when I work it a bit.

If I need to modify it, there's just no room to get the G35 off without taking the rad out.

[Makka]

Hey did not read all of this but one thing to remember with a diesel and temp riseing

if you lift your foot so your not pushing fuel into the pots it will stay cooler both egt oil temp and water

dont lift compleately just lift your foot enough so your still makeing power but not over fueling

[Robo]

Mine is definitely louder now with 50mls in the hub. Also looking forward to seeing what temps it runs when I work it a bit.

If I need to modify it, there's just no room to get the G35 off without taking the rad out.

How I went about it, remembering I only have the std fan.
I never loos-send the belts off at all, saved some time and hangs onto the pulley ok.
You may want to line up the viscus/water pump nuts on each side so you can see them easily this helps alot removing and replacing them .
Also using a ring spanner for replacing said nuts helps alot especially if the nuts incorporate a washer they can only fall out of the spanner one way.

Remove cowling.
Take rad top support brackets off.
Siphon radiator top tank into a clean bucket.
Remove top hose from rad only, raise & lift it backwards over the top hose cradle/retainer, this holds it out of the way & retains fluid in the hose & thermostat housing.

Clamp rad forward to rad support panel this will give you much more work space to remove the fan.
I used a slide adjustable, rubber foot, G clamp to hold the rad, and that worked fantastic.
I lost very very little coolant onto the ground this way.

Crack the 4 fan bolts firstly then crack the pulley nuts.
Then finish removing the fan then the viscus hub.

When replacing the viscus and fan--
Assembly the fan to viscus out of the car but leave the fan bolts very loose.
This saves alot of time as you will no longer have to line these bolts up blind and then leaves you enough room to work on the hub nuts.

tighten up replace hose and refill radiator etc finished.

[jff45]

Trust me, with a G35 fan and 52mm thick 3 core rad, there's no way of doing it without taking the rad out.
I have about 15-20mm space between the fan and rad.

[mudski]

Ponder on it with a glass of red..
Haha yeah i did. But it ended up being the entire bottle.


Trust me, with a G35 fan and 52mm thick 3 core rad, there's no way of doing it without taking the rad out.
I have about 15-20mm space between the fan and rad.

Yeah i have around 30mm. I really dont want to remove the rad.
Im hoping i an get the fan and hub off without taking to much skin off my hands.
I think ill put in another whole bottle maybe. So its 2.5 bottles in total.

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[jay see]

Haha yeah i did. But it ended up being the entire bottle.[QUOTE]

That doesn't surprise me.


I think ill put in another whole bottle maybe. So its 2.5 bottles in total.


Yeah, that would made it look like a easy job.

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[Robo]

Trust me, with a G35 fan and 52mm thick 3 core rad, there's no way of doing it without taking the rad out.
I have about 15-20mm space between the fan and rad.

I to have thicker52 mm radiator
By clamping the rad forward as described you gain approx 20mm I recon.
I'd be trying my way but skip removing the fan from viscus, and remove fan & viscus as an assembly.
I recon it may just come out that way, can't hurt to try.
Pulley studs are only about 20mm long.

[jff45]

You need to see what a G35 fan is to understand the issue..

[Robo]

You need to see what a G35 fan is to understand the issue..

Point taken,
just going off the clearance available + the extra that can be gained by moving rad forward that's all.

Getting back to hi flow vers std ,
As yet,?? not answered.
what's the difference hi flow will actually make.
yeah, more water through the rad faster thats a given.
but what does that equate to-- in different driving conditions.
eg- off rd & towing on rd?.
And when Australian summer gets here?? Is it still suited to towing?

[mudski]

The little flap on the bottom of the high flow stats lifts up higher than the oem stats. I recently changed over to a high flow but its not hot here to see any diff.

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[Robo]

ummm I thought the lower valve on the thermostat was for engine warm up only.

While engine is cold it's open to bypass coolant internally inside the engine only, and the top valve to radiator is closed.
Lower valve then closes once engine has warmed up.
Then top opens for coolant to flow to radiator.

hence, cooling problems previously mentioned by others arise when lower valve isn't close fully once engine has warmed up.
as some coolant then isn't' making it to the rad to be cooled off, and a coolant heat soak problem has begun

Or I'm wrong.


Anyway, don't bother putting more than 2 bottles of silicon oil into hub as it doesn't seem to help.
I think to much silicon oil acts like coolant and actually prevents the hub locking up.
Last weekend "towing" gave very poor results, as in higher engine temps.

[jff45]

Too much silicone doesn't prevent the hub from "locking up". Actually, the hub never locks up. It just turns at an increasingly greater % of engine speed as the bimetal spring opens the valve further.
Increasing the amount of silicone will make the fan spin faster than normal because of the greater shear it needs to overcome, hence the increased fan noise.
I'm currently trying to decide whether I accept that noise level while waiting for the hotter weather.
My temps rarely get above 80. Usually fluctuates between 77-79 with a 77 degree thermostat.

[Robo]

Realize viscus hub doesn't actually lock up, I'll rephrase, engage more.
After chewing it over some more--
last outing towing I couldn't hear the fan engage earlier, or increase airflow noise after more of the silicon was added.
I did state I could hear more previously, but realy so slight at idle, willing to admit ,may of even just about imagined it after going to all the effort.
Driving home towing it did seem a little better temp wise, maybe the silicon needed time to settle internally, but again fan noise hasn't increased enough for me to realy claim an improvement, therefore can't recommend it as an upgrade .

A twist,
I was checking windscreen water bottle yesterday in Mav, the TB's airflow caught my attention as it was pulling alot more air at idle than TD42T, "alot more air".
Is the TB42 viscus & fan a better setup?.
It has a h/dty copper brass adra radiator fitted.
Again thinking back, TD never pulled much air realy, especially compared to the TB.
Any ideas?.

[mudski]

Realize viscus hub doesn't actually lock up, I'll rephrase, engage more.
After chewing it over some more--
last outing towing I couldn't hear the fan engage earlier, or increase airflow noise after more of the silicon was added.
I did state I could hear more previously, but realy so slight at idle, willing to admit ,may of even just about imagined it after going to all the effort.
Driving home towing it did seem a little better temp wise, maybe the silicon needed time to settle internally, but again fan noise hasn't increased enough for me to realy claim an improvement, therefore can't recommend it as an upgrade .

A twist,
I was checking windscreen water bottle yesterday in Mav, the TB's airflow caught my attention as it was pulling alot more air at idle than TD42T, "alot more air".
Is the TB42 viscus & fan a better setup?.
It has a h/dty copper brass adra radiator fitted.
Again thinking back, TD never pulled much air realy, especially compared to the TB.
Any ideas?.

Yeah not sure tbh. Unless the td hub was not working right????

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[mudski]

Just thought to bring this discussion back up, particularly about the Infinity fan and re oiled OEM hub. Yesterday we Melbournians were treated to a 30 degree day. It only took 270 days for this to happen but hey, we got one. Anyhoo, yesterday I got to actually see if any difference was made, from the 1.5 bottles of silicone fluid in the hub and the infinity fan. The answer is yes. For the better? Slightly. My temps usually sit or around 85-90c at 100k's. And easily climbs to around 100c when I sit at around 110k's.
Well it still did this, but I did notice as the day was hotter, when slowing the temps would drop fast, and when driving around at 80ks I could hear the fan had engaged and where I would be sitting on 85'c it was now at 80c. Funny this about this, I drove the exact same road today, it was a cool day, and the engine fan wasn't engaged and the water temps was 85'c. And when I heard the fan go off, the temp would go back up to 85c. So what I have done has helped. No question. But I think I still need more oil in the hub. So I will be doing this soon, I hope. But radiator removal is needed for this, so its atelast a 12 stubby job. I have also heard good results from using a Colorado 4JJ1 engine hub and fan, bolts straight on too. But since I have more oil here, and no funds left :(, I will do this instead.

[jff45]

I took mine out last Sunday for a run up to the Sunshine Coast. 37C outside temp, briefly saw 38 for a few seconds. The factory Ti outside temp readings have always been pretty accurate. It was a really hot day..
My usual, around town, 78-80 temps moved up to 82-83. Ran it a little harder in the 110 km/h zone and got it to 85.
Always had the A/C on including the rear evaporator.

This is with the G35 fan and 50ml of Toyota 10000 cst silicone in the TD42T original hub. I've decided to live with the additional engine noise and my wife agrees it's not too invasive.

[mudski]

I took mine out last Sunday for a run up to the Sunshine Coast. 37C outside temp, briefly saw 38 for a few seconds. The factory Ti outside temp readings have always been pretty accurate. It was a really hot day..
My usual, around town, 78-80 temps moved up to 82-83. Ran it a little harder in the 110 km/h zone and got it to 85.
Always had the A/C on including the rear evaporator.

This is with the G35 fan and 50ml of Toyota 10000 cst silicone in the TD42T original hub. I've decided to live with the additional engine noise and my wife agrees it's not too invasive.
Ok. So yesterday arvo i decided to remove the radiator and remove the hub and add more oil. Took way longer than expected as upon putting the hub back on with new nuts on the water pump studs, one of the studs decided to strip and i couldn't even undo the nut as it was just spinning on the stud. So out came the Dremel, and i finally got the nut off. Thank god for a bloke i know who stocks the studs and nuts and was open after hours. Lol. Now i have 2.5 bottles in it. It was hot today but didnt get a chance to go for a spin. I did go wrou d the block yesterday arvo, once warmed up, and the fan was engaged the entire time. So we'll see tomorrow.

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[jff45]

2.5 bottles, so 45ml..

[mudski]

2.5 bottles, so 45ml..

Yes. Even though its a right PIA to do this procedure. I want to go in smaller increments to see the differences. As even with the 1.5 bottles in there was a difference once the weather was warm enough.
When I worked in the transport industry, I used to sell a air operated clutch fan for the prime movers called a Horton fan. They pretty much engaged and disengaged using air and a clutch plate type setup in the hub, all controlled via a water temp switch and a manual override switch.
This would be ideal for our TD's I reckon.

[mudski]

So yesterday was pretty hot here, around 36c or so. The hub was engaged the entire time whilst driving. while I didn't get a chance to get onto the freeway to really test it, I did push it a bit on some hills and the temps seem to be a bit more stable. 75-80c they were. I now have to wait a while until it warms up again here, bloody Melbourne weather, so I can really try it out on the freeway.
Not sure if I'm liking the hub engaged all the time though, its quite noisy, if theres a power loss, its ain't a lot. Time will tell. I still need to wire in my two a/c thermo's on an override switch so I can put them on aswell without the a/c coming on...

[Robo]

Hi flow ordered, tridant tt2028-170.
Will now compare this to a std flow -170.

[mudski]

Tbh I didn't notice any difference from std to high flow, but each motor will have varied results. Just did a good arvo's drive doing deliveries etc etc. Pretty cold here today, around 18c and the temps didn't get over 80c at all. I did find that whilst stationary the water temp would go up about 5c, lol, then once I was moving it would drop. Never did that before. Buuuut, I'm not so sure I'm liking the fan noise. As the hub is now fully engaged. I will wait for another hot day, when ever that may be, go for a highway run and see then. I'm thinking maybe to take the hub off again and remove about 9-10ml of oil from the hub. Just so its not locked entirely. I still have to wire in the two thermo's, which I prolly shoulda done first...

[jff45]

I'm kind of forcing myself to accept the noise because I'm confident it will be good when it gets really hot and I really don't want to empty rad, redo coolant, etc again.
It also makes me drive it a little more gently because the noise makes you think you're revving it out but it hasn't gone past 2000 rpm :)
To remove my rad I also have to remove all the 3mm protection/deflector plates underneath..

[Robo]

Ok, fitted the hiflow Tridant TT2028-170 thermostat yesterday arvo, drove to work back rd 10k@ 90kph then freeway another 10k@ 110kph.
Sat constantly on 77 deg C, Yahooo.
where as before it would of sat min 80c up to 85c.

It was a cooler evening, but that didn't change the previous behavior of 80 + with fluctuating temps.
Also noticed that engine warm up time increased so slightly with new stat but right boot wasn't being pushed at all.

This tridant thermostat is physically the same lengths etc as the std tridant thermostat,
Except for the sensors are a slimmer build, thus allowing greater flow.

From upper base of thermostat frame to lower valve is 35mm & the distance to housing bypass seat is 40mm.
So the lower valve needs to extend 5mm to reduce/cut off the bypass flow.
If this was reduced further by a washer/shim one would expect temps to maybe stabilize further, but engine warm up time would increase.

Chewing it over, over thinking it again lol.
"OVER" reducing the size of bypass passage, even blocking it off altogether may cause a problem, unstable water temps through the engine @ each cold start.
Engine warms as normal, then only cold water from rad is introduced & not a mix of radiator and some recycled warm via bypass.
Is it possible bypass mods cause an undesired increase in temp cycling hot/cold and damage the block or head somehow over the long term?.
Just maybe leaving the bypass alone or minimum mods here is not a bad idea.
I say that as why else would the engineers include a bypass in the first place if it weren't realy needed.
Or is the bypass just a feature for colder climates that upsets the apple cart here in OZ more so when we up power limits?.
That said,
when the injector pump upgrade was done, the mechanic mentioned to me he plugs off the bypass altogether as an fix for TD's over heating issues.

Time for a towing test.

[Robo]

"Tridon" hi flow thermostat update.

Caravan 2.5t on, Held speed at 90 Kph 4th gear M1 Ourimbah hill.
Which is a about 2.5k climb, loaded & you'll know about it and be down shifting, a descent hill to gauge things off.
held speed well, enough right boot only to hold speed @ 90k.
Outside temp was about 27c

Temp climbed to 105 C fairly quickly and settled there.
It took a little while to recover on the flat cruising again in 5th.

Humm----more stable than a std thermostat,
rose a bit slower but not that much slower, think it would give you a bit more confidence.
Biggest improvement (not that big) was cruising.

Cruising 5th gear 100 Kph on the flat sat about 82-93 C depending on grade.
OEM cluster gauge sat in the middle "the whole time" didn't realy move.
forgot to look at pyro (dumb ass) watching time also had to start work, went out of way for the test.

Going to either remove the last 2 lower outer bars on bull bar to open up air flow more & or spotties.
spots & winch have reduced air flow (derr) way more than I like, always learning.
may sound fussy, want a keeper and maintain good travel times.
Caravan is large compared to car and provides alot of wind resistance over n above the 2.5t load.

just want the best out come possible.
yeah yeah lift the boot, last resort.

[nissannewby]

Good on you robo. Always good to see people keeping the threads going with good feedback.

[Robo]

Removed the outer bars this arvo (grrrr camera flat cant find charger lead).
think it came up ok for a bloke with no sheet metal work skills.

70746

air flow has improved a littlebit, small improvement in cooling.