[SOLVED] 2001 Tahoe heating issues

[outdoorsman388]

Hello, I have a 2001 Tahoe. I have owned it for 17 years with 307000 on it. I need some ideas on a very wierd heating/cooling issue. I'm in International Falls MN. It's fairly chilly here. If I let the rig idle for 30 to 40 minutes I have good heat coming out of the vents. I will not come up to operational temp. After driving for a little while, the temp gauge starts to drop and so does the temp of the heat out of the vents. I have replaced the thermostat twice in one week. I replaced the pressure cap on the reservoir. I have now replaced the water pump and thermostat. I'm having the same issue. The symptems to me scream stuck open thermostat. I have tried to burp the system by leaving the cap off and running if for up to an hour. When I replaced the pump, I cut in a flushing tee it the heater hose to try and remove more air as I filled the coolant. Any assistance would be greatly appreciated. Thank You, Scott.

 

[justirv]

Hello, I have a 2001 Tahoe. I have owned it for 17 years with 307000 on it. I need some ideas on a very wierd heating/cooling issue. I'm in International Falls MN. It's fairly chilly here. If I let the rig idle for 30 to 40 minutes I have good heat coming out of the vents. I will not come up to operational temp. After driving for a little while, the temp gauge starts to drop and so does the temp of the heat out of the vents. I have replaced the thermostat twice in one week. I replaced the pressure cap on the reservoir. I have now replaced the water pump and thermostat. I'm having the same issue. The symptems to me scream stuck open thermostat. I have tried to burp the system by leaving the cap off and running if for up to an hour. When I replaced the pump, I cut in a flushing tee it the heater hose to try and remove more air as I filled the coolant. Any assistance would be greatly appreciated. Thank You, Scott.

I have a newer Audi, along with my old '02 Tahoe Z71. Having this car I needed to get a Vacuum Coolant Fill device. It's the only way to get that dang car properly full of coolant. Bonus feature, creating and holding that inital vacuum is a great test of the system, then, after 20-30mins, turn a valve and fill the system. Amazing results. I have used it on my Tahoe, and other vehicles, and it never fails to get all the air out of the system. You may have other issues, but this will get it "burped"... You may need to physically block off some airflow to your radiator as well.

 

[outdoorsman388]

Thank you. I have read that to burp these newer engines you have to elevate the front of the vehicle. Have you heard of that? Did you just purchase the vacuum filler at a auto parts store?

 

[Fless]

Did this happen recently, perhaps after a radiator change?

Any other work done right before this started?

Aftermarket radiators don't always have the correct size orifice for the small hose that goes to the surge tank. A restriction might be needed in that hose, but let's hear answers first.

Recommend you read this short thread:

Problem after installing upgraded radiator

Now that winter time has come I’m needing to defrost the windows in the morning. and the truck barely wants to warm up at all with the radiator upgrade I changed the thermostat for a 187* factory spec and it’s barely warm at all. I’m thinking I need electric fans to keep the truck at temp at...

www.tahoeyukonforum.com

 

[outdoorsman388]

Yes, the radiator has been replaced. Also, intake manifold, knock sensors, ops, tps, iac, injectors, and a used (cleaned up) throttle body. I had a very high idle. The throttle body finale fixed it.

 

[outdoorsman388]

Yes, the radiator has been replaced. Also, intake manifold, knock sensors, ops, tps, iac, injectors, and a used (cleaned up) throttle body. I had a very high idle. The throttle body finale fixed it.

And the small bypass tube for the intake.

 

[Joseph Garcia]

I have a newer Audi, along with my old '02 Tahoe Z71. Having this car I needed to get a Vacuum Coolant Fill device. It's the only way to get that dang car properly full of coolant. Bonus feature, creating and holding that inital vacuum is a great test of the system, then, after 20-30mins, turn a valve and fill the system. Amazing results. I have used it on my Tahoe, and other vehicles, and it never fails to get all the air out of the system. You may have other issues, but this will get it "burped"... You may need to physically block off some airflow to your radiator as well.

Product name, model, specs?

 

[Joseph Garcia]

If you did not replace the radiator with a stock OEM radiator, your issue may be what folks above are implying. The stock radiator has a fixed orifice in the return line to the reservoir, and if your replacement radiator does not have this fixed orifice, that is most likely the source of your issue. Please take a look inside the nipple for the hose that goes to the reservoir and see if there is a significant restriction inside. If not, folks here can give you suggestions on how to resolve the issue and still keep your aftermarket radiator.

 

[Fless]

The thread linked in Post #4 shows a quick and easy test to see if the lack of a proper orifice in that hose is the issue. All that's needed is some kind of clamp to pinch it off partway and a run up to temp.

Post #27 in that thread has great info with pics.

 

[outdoorsman388]

Did this happen recently, perhaps after a radiator change?

Any other work done right before this started?

Aftermarket radiators don't always have the correct size orifice for the small hose that goes to the surge tank. A restriction might be needed in that hose, but let's hear answers first.

Recommend you read this short thread:

Problem after installing upgraded radiator

Now that winter time has come I’m needing to defrost the windows in the morning. and the truck barely wants to warm up at all with the radiator upgrade I changed the thermostat for a 187* factory spec and it’s barely warm at all. I’m thinking I need electric fans to keep the truck at temp at...

www.tahoeyukonforum.com

I'll give that a try, I have a hose pinch plyers. I have noticed when cold starting, that small hose flows quite a bit into the reservoir. Thank you.

 

[outdoorsman388]

I'll give that a try, I have a hose pinch plyers. I have noticed when cold starting, that small hose flows quite a bit into the reservoir. Thank you.

 

[outdoorsman388]

I'll give that a try, I have a hose pinch plyers. I have noticed when cold starting, that small hose flows quite a bit into the reservoir. Thank you.

The thread linked in Post #4 shows a quick and easy test to see if the lack of a proper orifice in that hose is the issue. All that's needed is some kind of clamp to pinch it off partway and a run up to temp.

Post #27 in that thread has great info with pics.

It worked awesome. I've been trying to get some pics from my phone to the laptop with no avail. The other day when I was driving, I had to turn the heat down. Thank you all very much. I will get the pics up. I have the temperary solution and the permanent solution.