Question for people with rear mounted radiators

[You Get That]

Rear mounted the radiator on my truck it's a big 6cyl commy one with twin fans it's only for my 1.7 td motor and I've used small rad hose between motor and rad to keep pressure up its probley 1inch tube about 1.5m long. Truck gets up to 110c when driving hard and slowly cools down to just under 100c
Do people run thermostats with rear mounts? I would like to keep it but thinking it would help stop air locks because rad is bit high compared to engine.

[Big]

More flow will mean better cooling.. also thermostat will keep the motor running at it's peak temperature.. SO I'd say bigger hoses and piping from motor to the radiator.. The last thing you want it any restrictions..
My 2 cents worth..

[derk]

the thermostat wont create air locks it only controls the coolant flow, I've done a couple of rear rads and only one of them ran better without a thermostat, if your using it on the road its hard to get enough airflow to keep it cool at highway speeds they work better at lower speeds/loads. Its also pretty subjective to the engine your running (ie: a dirty big V8 will produce a lot more heat and require a lot more cooling), the size of your rad, fans, airflow etc. If you use rubber hoses for your feed/return they are an insulatant that retains the heat in the coolant as opposed to steel tube with rubber elbows that can assist cooling by releasing heat on your feed/return to the rad/engine

[kbushnz]

I haven't done mine yet but have been advised to put a bleeder port above the head height. To make sure all the air in the motor is bleed out when you fill it...

[You Get That]

Might change the return to a bigger diameter steel pipe then, and try find a bleeder valve so I can bleed it before I drive each time easy, and it's only a bush truck doesn't sit at height speeds for long

[3VILC]

The other trick I was told was if you can park on a steep hill or jack the back up to make the rad the highest point when filling.

[Crash bandicoot]

was going to say if the rads on the back it will be the highest point anyway.

[3VILC]

Good point haha. I think more what it was meaning was to try eliminate air from the inevitable dips and rises in the pipes. Mine run under the passenger seat and thru firewall where heater hoses were and I don't seem to get any trouble

[suzolla]

I would think that your biggest problem is the size of your hoses, should be at least the same size as the connections on the engine, or bigger if possible.
Metal pipes will have small cooling effect compared to radiator but will assist a bit if cooling is marginal.
Cheers
Tim

[mercutio]

i used to own a little rear engined suzuki car that had a front mounted radiator it had the radiator hoses that ran through the cabin to the radiator up front but it also had a hose running from the top of the thermostat housing which was the highest part of the cooling system up through the roof and down to the header tank i assume it was there to prevent airlocks

[meatc]

Having actual experience with rear mounted radiators and other coolers

Keep the pipes the same size, ads capacity and lowers flow restriction on pump. (same volume pumped through smaller pipe equal greater pressure) Air can be an issue with the up and down nature of the plumbing, a bleed at the highest point of the engine helps.

Biggest issue as mentioned above is air flow at speed. The aerodynamics of a vehicle reek havoc on air pressure around a vehicle and at speed you can end up with no air to move past the radiator, trial and error and lots of wool tell tales is about the only way to accurately gauge where the air is.

An example of the air flow thing is Darinz new truck, trans coolers work mint at 100kph even in soft sand etc, easy gravel road running with no trans load at 200kph temps climb because there is no air where the coolers are, scoops are being looked at to solve the problem.

For what is worth

[You Get That]

after market temp gauge wired into the factory sender may give out a false reading.....
bought a sca infared temp gun and measured temps at inlet and outlet of the engine at idle temp about 50° going out and 40° comming in.
and after driveing for a bit about 70°going out and 60° comming back in so its runnibg pretty good!

rad gets no air flow from driveing only from twin fans, truck only does 70kmh anyway but it gets there fast

cheers for the ideas guys

[S1V8]

been running rear mounted radiator for couple years now, great off road not much cop on open road unless you have airflow thru them even with extra large radiator, not to bad if you can take roof off. All my pipe work is in stainless and done in one section with mandral bends,also have air scoops to direct the air into radiator when tops on.