heating

[ko66]

High all i have a strange issue going on. I have a 2002 gmc envoy 4x4 and she is running warm during the day only.
My trans temps are getting up to 226 and engine 215, If i park and let it idle engine will drop down to 206 but tansmisson will no cool off.
This is all with the A/C running and 108 temp outside. If i spray water on the radiator both trans and engine cool off immediately. Heres where it gets really strange, i took off the front grill, the upper portion is cool you can feel the air being pulled threw. Half way down the radiator it gets hot and i feel hot air coming threw. I do not know how to explain this or why, maybe you guys have an idea.

 

[mrrsm]

With a 16 Year Old Vehicle... As long as your EV Fan is turning on properly... The chances are that you have TWO (or perhaps a Third as well) distinct CLOGGED UP issues involved here:

(1) A Clogged Radiator Core (and/or A Clogged HEATER CORE). Both need to be Well Flushed or the Radiator Replaced if the Flush Method does not clear out the problem.

(2) A Clogged Transmission Cooler... Needs to be Well Flushed with Transmission Flush AND A/T Fluid and then have a Fresh Transmission Fluid Change.

There are several excellent Threads here on GMT Nation and there are many Youtube Videos on How To Do these Jobs.

 

[Sparky]

I'd flush out your radiator.

 

[ko66]

ok got it, but what would make hot air come back threw the lower portion of the radiator? and at night the engine runs about 188 with a 192 thermostat.

 

[Sparky]

You will always have warm air coming off the radiator, but when you have "cold zones" that's a classic sign of a blockage, which causes all the heat load to be only in part of the radiator and result in hotter spots. And down there you do have the AC coil and stuff, airflow could be getting disrupted if there is blockage from grit and grime. Spray out that whole area with a hose and clean out any leaves etc that may be collected.

I do not think your transmission cooler is clogged because if it was your trans wouldn't be working right as the fluid wouldn't even be flowing properly. (The trans cooler is inside the radiator, by the way.) And there are more things that would get clogged up in your trans sooner than the trans cooler.

 

[Mooseman]

Although your EV fan clutch might be pulling some air, it might not be enough. You should check it:
How to test the electro-viscous fan clutch

 

[ko66]

Just an update, added a Hayden trans cooler now the transmission only gets to 184f in 104 degree weather. Engine temp is 215f in 104f degree weather, turn off A/C engine temp drop to 204F. Thermostat is 192f, coming home in 87f weather dark A/C off engine temp 190F constant transmission 163F did not flush radiator or anything.