Td42t thermostat housing modifcation.

[Robo]

Recently Heard of a mod to the housing and doing away with the oem thermostat for generic instead.
There is a hole in the bottom of the housing that can be tapped & plugged off.
This is done to stop the leak/flow of coolant via this port and force all fluid directly via top port of the fitting.

apparantly this mod stops fluid bypassing the thermostat, thus allowing coolant to spend more time undisturbed in the radiator to cool before thermostat opens again.
housing .JPG
Your thoughts please.

[my third 256]

sounds like an expensive job justso you can use a generic thermostat
not much difference in price

[jff45]

If you're referring to the bypass hole, it should be closed by the thermostat when the thermostat is fully open.

It's easy to test if you do a depth measurement from the thermostat housing surface then measure the thermostat when it's open.

[Robo]

Yes,
If the thermostat is weak and or open slightly there's the potential for problems.
I'm trying to gauge if the bypass is a known problem?,
and or the remedy corrects this, works well, or causes other issues.

Plan to tow large van in hot weather and looking for preventive measures to potential problems that's all.
The other potential fix is a $1k+ radiator, but this may get around that!.

Told this helps correct overheating problems, "when all else is working as it should be".
Its a little like the old days of removing the thermostat to make engine run cooler.
Only to find in hot weather the coolant doesn't spend sufficient time in the rad to cool,
so the radiator is eventually over powered and boils the coolant.
And I know that problem because I had it happen as a kid yrs ago ( not that long ago lol), in the middle of nowhere 200k from the nearest town.
new 2nd hand HQ that some idiot played around with.
opps I said that word well nearly somebody slap me!!

[Bigcol]

I found that by using genuine parts
mine was a heck of a lot cooler

I replaced the
Thermostat
Viscus hub
water pump
hoses
Fan

I had already replaced my Rad with a new OEM one

then run it all with Nissan coolant

towing my 2.5T van unless its a real hot day (45* outside temp - 70* under bonnet temp) mine sits on 105* no worries

[Robo]

I found that by using genuine parts
mine was a heck of a lot cooler

I replaced the
Thermostat
Viscus hub
water pump
hoses
Fan

I had already replaced my Rad with a new OEM one

then run it all with Nissan coolant

towing my 2.5T van unless its a real hot day (45* outside temp - 70* under bonnet temp) mine sits on 105* no worries

Ok I'm with you on good maintenance, You'll never get me to sway about that.
105 deg is getting close to the point of boiling isn't it?.

[Ropetangler]

Its a little like the old days of removing the thermostat to make engine run cooler.
Only to find in hot weather the coolant doesn't spend sufficient time in the rad to cool,
so the radiator is eventually over powered and boils the coolant.

I know that this is a very old posting, well 2 years old anyway, and I have seen similar comments in the past in various places, but to me it just doesn't add up. If the coolant passes through the radiator quickly, it also passes through the water jacket of the engine quickly. It may not have as much time to cool while in the radiator, but it also has less time to pick up heat from the engine as well, so in any single pass, not as much heat will be transferred. However by moving quickly, it will circulate more frequently, and the end result should result in similar cooling capacity. It is not like the coolant can sit for ages in the engine getting hotter and hotter, and then do a fast pass through the radiator, without having enough time to transfer the heat to the airstream.
I can see that if you slow the passage of the coolant sufficiently, it could remain in the engine water jackets long enough to boil, before having the opportunity to cool during a slow passage through the radiator, but its hard to see that a fast moving coolant stream would be less effective than a slower moving stream.
This is of interest to me as I have a 99 GU TD42 ute, with original turbo, no intercooler but a propensity to overheat on towing a camper trailer up long climbs. We now have a small off road caravan (Track Trailer Topaz), which will be heavier and have more drag than the TVan it replaces, and although I have made some progress with this issue, I am not home free yet.
the ute has a 3" exhaust from the turbo back, rebuilt injector pump and injectors and dyno tuned by ProDyno Tune at Rockhampton, boost raised to 14-15psi at that time, 4row heavy duty radiator, full shrouds, but does not have all of the foam bits directing air through the a/c condenser and power steering cooler, or the side shield/sealing strips between radiator and radiator support bulkhead. It does have a duct floor between the bull-bar bottom edge and the base of the radiator. cooling system hoses have all been changed in the last 3 years, viscous coupling renewed with a new Dayco unit, Fan is standard, thermostat is genuine Nissan. It has been suggested when I inquired about an intercooler to assist in engine cooling, that a heavy duty fan hub and fan assy would be the first thing to try, but that $650 item is out of stock ATM, with a possible 5 week delay for new stock. I have about 6 weeks before we head off to The Kimberley area, so both the initial cost of this item and the time delay are of concern.
Anyone got any clues as to what may be the best and most cost effective option, and does anyone have experience with the bigger fan and hub combination?

[TDsooter]

I would source a genuine fan hub, re oil it and fit that, a Nissan Infiniti fan draws a hell of a lot more air than standard, ensure your radiator is thoroughly cleaned between the fins, (removal from the vehicle is required) an intercooler will help reduce your EGT temps. Very close friend of mine runs a 300hp 800nm 38psi TD, never gets hot even with a load on the back. Standard rad, re oiled genuine fan hub, Infiniti fan, quality coolant and a healthy tune.


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[outbacktruckn]

Thanks for the tips, will try a few things you suggest.