2004 Tahoe operating temp issue.

[93M6Formula]

So i've had my tahoe for just over a year, it has 107K now. Ever since i've had it, it has trouble warming up. Anything starting around 40 degrees or lower, it takes about 5 miles to get to operating temp, and this is also letting it warm up for at least 5 minutes. At idle it will never get to temp on it's own like any other gassers i've had or like my 08 escalade which sucks because it takes forever to get heat, I pretty much just freeze for most of my commute, it already does terrible on fuel so I don't want to idle it forever either. I replaced the thermostat last winter with a genuine GM to see if it would help and it didn't. It also cools off at idle if you leave it sit for a few minutes. Goes from operating temp (210 on the gauge) to around 170. I see it's had a waterpump at one point and look aftermarket but not sure if that's the cause? If your driving it's fine and stays at temp and heat is great, it just takes forever to get there and won't maintain it at idle. It's bad when my 6.5 diesel pickup warms up faster and holds heat... I would like to get rid of the clutch fan for an 05+ electric setup but I know that's not the root cause here, any ideas??

 

[93M6Formula]

Cools down to this from "210" at idle.

 

[Fless]

Is the radiator the original, or has it been replaced? If replaced, do you know what mfr and when it was done?

 

[Joseph Garcia]

As @Fless suggested, could it be that a replacement radiator does not have a restrictor within the nipple in the line that goes to the reservoir?

 

[rockola1971]

There is only 3 causes that I know of that could lead to "overcooling" of the engine. (1) Thermostat stuck partially open or wrong temp (2) Thermostatic Clutch fan stuck engaged (they tend to fail the opposite of that) (3) Someone put in an oversized radiator for the application.

 

[93M6Formula]

Is the radiator the original, or has it been replaced? If replaced, do you know what mfr and when it was done?

Radiator looks to be original.

 

[93M6Formula]

I replaced the fan clutch also because funny enough the a/c also sucks when not moving, it didn't help anything either.

 

[93M6Formula]

As @Fless suggested, could it be that a replacement radiator does not have a restrictor within the nipple in the line that goes to the reservoir?

Any pics of that restrictor by chance? i'll have to check that out.

 

[rockola1971]

I replaced the fan clutch also because funny enough the a/c also sucks when not moving, it didn't help anything either.

An A/C wont work correctly when idling but works much better or fine when moving IF the refrigerant level is low.

 

[Scottydoggs]

sounds like a stuck open t stat. id just replace it. i got full heat in less then 2 miles of hwy driving and just a few minutes of idle warm up time. love them heated seats too lol

could also drop some cardboard across 1/2 the rad. that should help it warm up some.

im surprised you dont have a code set for cold temp. not reaching 210º will def hurt your mpg.

 

[Joseph Garcia]

Any pics of that restrictor by chance? i'll have to check that out.

@iamdub , @swathdiver , @wjburken , @Doubeleive - Any suggestions for finding a pic or more details regarding that restrictor in the radiator nipple for the hose going to the reservoir tank?

 

[Doubeleive]

there really isn't a restrictor per say, it's just that the inner diameter of the pipe is smaller inside, the repops often have a larger diameter return line

 

[wjburken]

@iamdub , @swathdiver , @wjburken , @Doubeleive - Any suggestions for finding a pic or more details regarding that restrictor in the radiator nipple for the hose going to the reservoir tank?

People have posted various solutions they have tried. One guy used a 45acp casing and removed the primer. Another put a small pipe nipple in there. Someone else simply took a piece of round rod and pipe clamped it parallel to the hose to squish it down.

Never had to deal with it myself…..yet.

 

[Doubeleive]

whatever you use make sure it is clamped on/in tight if it makes into the system then it's bad news.

 

[Fless]

@Charlie207 posted a few pics in this thread. The restrictor is a small orifice built into the radiator fitting for the small return hose going to the surge tank.

Cold Case radiator

Somewhere in these threads a 45 cal Brass without primer installed was cited as a "perfect"fit restrictor. Is there a quick DIU for this? My aftermarket radiator ( Champion) also cools too well on cool mornings, and causes the same dash error. I have a zillion .45 brass laying around, and...

www.tahoeyukonforum.com

 

[Fless]

As a temporary test, put some kind of clamp on the return hose that goes into the surge tank. Don't restrict it completely, but see if that helps.

 

[93M6Formula]

As a temporary test, put some kind of clamp on the return hose that goes into the surge tank. Don't restrict it completely, but see if that helps.

Tried this today, really didn't notice much change in warming up faster, and it still cooled down when I idled it for a bit. I don't know what else to try other than maybe a new GM waterpump and stat, not sure what brand is on it. Radiator is 100% original.

To be clear, yes it does get up to temp, it just takes longer than it should and it doesn't hold that temp if you let it idle. Also is my lower radiator hose supposed to be cool to the touch?

 

[93M6Formula]

It sits here when driving.

 

[Donal]

Sounds like you have a problem with the blend doors out of calibration, stuck, actuators broke or some thing in the duct. The engine cooling system is functioning. Use the search function and find more threads on the engine cooling and cabin cooling/heating and how to calibrate the air flow doors. I recongize the my ecperience is limited and my spelling is varied.

 

[Fless]

Sounds like you have a problem with the blend doors out of calibration, stuck, actuators broke or some thing in the duct. The engine cooling system is functioning. Use the search function and find more threads on the engine cooling and cabin cooling/heating and how to calibrate the air flow doors. I recongize the my ecperience is limited and my spelling is varied.

I would add that the HVAC system will have a negligible affect, if any, on the engine temp. @Scottydoggs' suggestion to replace the thermostat is a good one.