All Things Chev

[nissannewby]

Sorry Matt, I'll have to get an accurate description to answer that with confidence. Unless someone else knows the layout... I just know that the flow is directed across the top half, then drops down and runs back through the lower half to the outlet.

If is just a baffle then what the water will actually do is just find the easiest path which will be straight across the top tank down to the lower half and out the outlet so only cooling a fraction of the water.

When the inlet and outlet are diagonally opposed then the cooling can be far more efficient due to pressure/temp differentials.

[Nightjar]

Do you have bash plates installed below engine, if so are they perforated?

[FNQGU]

Thanks Matt, this is the same advice I am getting up here.

Nightjar - I have a Bushskins steering guard and the standard Nissan front radiator guard thing, that yes has big holes in it.

[FNQGU]

Ok, it's been a while and I've made some changes and am still experiencing engine temperatures that are high. Frustratingly high.

In summary - I have the Chev 6.5TD with a modified Nissan Auto (fully rebuilt with HD friction plates and Nomad valve body by Wholesale Automatics), twin transmission coolers with electric fan on them, and an oil cooler also (recently) with an added electric fan on it. I spent a lot of time talking with Richard at ARE out of Brisbane and with a Cairns radiator specialist (who knows 4wdrives on the Cape) and eventually i forked out $1300 to change to a 3-core Copper/Brass dimpled tube radiator, and....it made no difference at all.

This setup will overheat on the first big hill IF it is run with the normal viscous coupling on the radiator fan. If I put a solid block spacer in place instead of the viscous coupling (an expensive Brunswick bandaid), then it will usually run at quite good temperatures (78' - 85'C), UNTIL the ambient air temp rises to about 34'C - 35'C, which it does right through summer up here. At this point it will get hot if working the engine hard, or towing a load up a reasonable hill with the airconditioning on. If I switch the aircon off, it will drop 7 to 8 degrees C on average and working it hard up that same hill won't be an issue. Try that with the viscous coupling back in place and I'd get a quarter of the way up the hill before the temp needle starts climbing dangerously towards the red.

I've also pulled the radiator twice and backflushed the engine block each time with no real improvement. Coolant mix ratio's are correct and coolants haven't been mixed.

I recently moved the oil cooler (ADRAD plate and bar type) out from in front of the condenser and put it lower down behind the bull-bar with an electric fan on it. I did this because temps on the oil cooler were in the mid-90's (temp gun reading) and it had to be sending hot air straight back into the radiator. Basically, just trying to eliminate another factor i suppose. I then stuck a 12" electric fan in front of the condenser (where the oil cooler had been) and it made no difference, although I didn't expect it to.

I then removed the bullbar and winch and front grille completely and ran it up the same hill, and BINGO - no overheating! This was with the viscous coupling on of course. Stick the bullbar and winch back on, and straight back to the redline! It appears that airflow through the radiator is the overall issue right? I don't have a big-arse set of spot lights in the way either. Besides the winch control box, it is as open as it can be, with only a lightbar level with the top of the bullbar.

So, I have had numerous calls with Brunswick Diesel over the last xx months/years and they advise that they fit this solid spacer to ALL the automatic versions of this conversion that they do to Nissan Patrols. Mine is nothing special. Really??!! I am struggling with that concept. My small brain does not comprehend why such a band-aid fix is the recommended answer to this problem. I was told that I'd just have to live with it, as the cost to try and rectify it is simply going to grow and might not make any difference anyway. Gryphon engineering here in Cairns who also do these conversions, have also run out of ideas and are basically going along with it, although they were one of several who recommended the radiator change...

The downside of this solid spacer is that my fuel economy since fitting it has risen from 14.5/100 to 19.3/100 or worse. I'm also nervous about every puddle I drive through on the Cape as I don't want the fan to drive itself into the back of the radiator, and, it just seems ridiculous that this is the answer.

My transmission temps are great by the way, usually in the high 70's, but will climb into the late 80's if the engine is running hot. i had considered that the coolers in front of the condenser were my main problem, but compared to the oil cooler temps, they run cold. Besides that, I am out of ideas as to where else I could put them anyway.

I also have considered the option of spending another grand or more and going to twin thermo fans and a custom shroud. Funny this, but some recommend it and others are dead against it. Brunswick said it wouldn't help and so did Gryphon Engineering, basically saying that the fan already in place pulls more air than the electric system would. I would however 'like' to be able to turn them off for water crossings, but that is just a 'nice to have' I suppose.

Should I be looking at the Water Pump? I'm told it is the High Flow version that was the 'fix' to this original overheating issue but haven't yet pulled it off.

Both Thermostat's are brand new also, and are rated to 71'C.

So, before i start cutting holes in the bonnet and fitting the vents I had been previously investigating, can anyone else point me at a solution?

[nissannewby]

I think you have sussed it ben when you said removing everything from the front equalled no cooling problems. So you need to increase surface area that sees airflow.

Is the radiator your using just a wide style patrol item?

The earlier style systems seem to be prone to heating problems in the patrol. The chevs are a hotter engine as such.

Im surprised the thermostats are the same temp setting. I would have thought a staggered setup would be much more stable.

Do no cut holes in the bonnet. I dont believe it will solve your problem. As in the first paragraph mate you need more surface area for the air flow to act on.

Can you post a few detailed pics of your setup please?

[FNQGU]

The radiator WAS the standard Brunswick custom install, which is pretty bloody huge. I replaced the core in it with the above mentioned version for no real improvement.

Previous thermostats were rated higher. Low 80's C from memory. I replaced both when I found one was not opening properly. Pics to come... thanks Matt.

[FNQGU]

Ok, a couple of the front BEFORE I moved the Oil Cooler.

Drivers side


The oil cooler has been removed and relocated. The P/S cooler is still in the same place now.


Passengers side.

Below is Drivers side NOW. I even temporarily hooked up a 12" electric fan here to blow onto the condenser, but it really made no difference whether it was there or not. Wiring hasn't yet been tidied up...


This is where I dropped the oil cooler down to. Passengers side, behind the bullbar. More just an experiment really and probably not where I would like to leave it as it is still likely susceptible to damage if I hit a roo or something.



Beneath...

[nissannewby]

You certianly dont have a lot of room for free air to the radiator.

[the evil twin]

I have a '99 Ute and it seems to run with no overheating issues at all.
Brunnies did the 6.5TD in Dec 2012 for prev owner
I got them to convert the 5 speed to a crate 4L85 auto (Chevy Suburban et al) in early 2014.
It still has the viscous fan and the 'original' Brunnies Rad (huge Mofo) and thermostats (temp unknown)
The twin tranny coolers are under the tray
Twin IPF spotties on a custom bar in front of the standard series 1 grille

[nissannewby]

Is the front bar a little more forgiving in the flow department than what ben has pictured.