Truck won't come up to operating temp after rad install
 

I'm currently trying to understand why my truck will not come up to operating temp. I recently installed a griffin rad (1st gen s10) The original rad was a dual core and quite small. This griffin rad is much larger, aluminum and a triple core I believe. Ever since the install my truck will not come up to full operating temperature when I'm driving. If it's sitting there idling in the driveway it will very slow come up to 190-200F and then the electric fans come on. When I'm driving it will barely ever creep over 160F. I've replaced the thermostat twice (third on now) and that is definitely not the problem. The current thermostat is rated at 192F. I've tried blocking off the rad almost entirely with cardboard just to test it and the temperature will not rise above 160 while driving. I'm kind of at a loss at the moment. The engine is a roots blown 3.2, if that makes any difference. I feel like I'm having a can't see the forest for the trees moment here and would love some input/suggestions.

Have you verified the coolant temp with a gun? Stock thermostat or aftermarket? Some aftermarkets flow before they open. You may have over done it with that radiator.

What is responsible for your temperature readings?

As Todd noted you may have went overkill on radiator size.

Would it be possible to slow or reduce flow to the radiator via water pump speed, impeller design, inlet/outlet reducers?

They do make flow restricters that go inline transfer hoses.

Andrew, Ain't broke why fix it?

Unless I am missing something,
Regardless of radiator size, water temp inside engine should be at the temp that the thermostat is rated for. It will not open until temp reaches that value. The thermostat is your flow reducer.

my apologies for the lack of information.

I have shot the thermostat housing and also just below the thermostat on the intake with an infrared thermometer. Temp reads 169-172 f. I really appreciate the input.

Vegas, it's a stock replacement thermostat but I'm leaning towards that possibility or that coolant may be seeping around the outside of the thermostat? It seems unlikely but I'm at a loss.

Sieg, I have a gauge in the dash that takes a reading of the coolant in the head. I have verified this reading with an infrared thermometer. When cruising or driving at any speed the truck will not get up to anything more then 170ish. Thermostat is rated for 192.

Vince, I'm not quite sure what you mean. Why go to a bigger rad? or ?


Samckitt, this is what I always thought. So I'm pretty stumped at the moment.




I have a 180f thermostat made by STC, going to try that just to see if anything changes. Will report with the results.

Thanks again for the input.

Just installed the 180 for curiousities sake. Drove it around a bit brought it up to temp, then got out and shot the thermostat housing. Gauge in the truck reads 160. Infrared thermometer reads 158-163 on the thermostat housing. So I'm consistantly running 20f cooler then I should be with the 180 and the 192.

Both thermostats have the same profile sitting in the intake. It appears there is maybe 1/32 or slightly more of a gap between the housing and thermostat. My next train of thought is put a thin rubber gasket under the thermostat and try and space it up to close that gap?
Please if I'm missing something here, don't hesitate to point it out to me.

http://i223.photobucket.com/albums/d...h/IMG_5904.jpg

This is the recess I'm talking about. I just don't see how coolant could work it's way around it unless it was floating up.

http://i223.photobucket.com/albums/d...h/IMG_5908.jpg


So to reiterate.
With a 192F thermostat I'm only reaching an operating temp of 170.
With a 180F thermostat I'm only reaching an operating temp of 160.

stumped at the moment...

Going to pressure test the system tomorrow. Nothing to lose. I remember reading that every psi loss is 3* temp loss as well? find out tomorrow.

Pressurized rad to 16 psi, let it sit for 15 mins no pressure loss at all. I just tried changing rad caps to confirm the rad cap hasn't failed. No change in temperature at all.

At a total loss at the moment.

How about a picture of the engine compartment. Just because. It's acting like the thermostat is being bypassed. :headscratch: