I have a 2001 Deville, I am having serious overheating issues. I have replaced the coolant cap, the thermostat, the sensors. I

[momyeroc94]

I am having weird coolant issues with my 2001 Cadillac Deville. I have replaced sensors, surge/coolant tank cap, had it pressure tested, no leaks. It runs great when in park, even while pushing on gas for periods of time but as soon as I get it in gear and on the rd it will overheat within 3-4 miles and I will have to pull over and let it cool down. I bought the car 15 months ago and take very good care of it. I bought it with round 51000 miles on it and only have round 57000 miles on it now. I did replace the cad converter and all the sensors and therms, also the one in the surge/overflow tank as well as the cap. When I put the computer on it it comes up with no codes now that sensors r replaced but still overheats when driving. It has been off the rd since Turkey day. I'm a single mom who needs my car so I am desperate and stumped. Any help would be great. Please tell me there is someone out there who can help. Thank you in advance

 

[wip99gt]

It sounds like you have a flow issue. The first 3 things to check is if you thermostat is opening, is your radiator is plugged, or is the belt slipping. To check the thermostat see if your upper rad hose gets hot. If it stays cold while your engine is overheating then it's not opening. If it get hot then it's opening, now it might still be an isue but there are other easy things to check before removing and testing it. With checking the radiaitor look with a flash light to see if the fins on the radiator are plugged with debris, if so get it washed out. You can do it easily yourself it's just you need to be careful not to bend all the fins as that will severely restrict airflow. The next thing is internal blockage on the radiator. A rad has passages in which the coolant flows through it which can plug over time. How to test that is by looking for cold spots on the radiator, a cold spot means that no hot coolant is passing through that part of the radiator. If the rad gets warm throughout than the radiator is not plugged. The belt is pretty straight forward and you will usually hear a squeal from a loose or slipping belt. These are the simple checks to go over. Now if these things check out then we now have to dig in deeper. The next step is to remove the themostat. Get a pot of boiling water and submerge the thermostat in it. You're looking to see how much it opens. If it opens crooked or just a fraction the it's not working correctly so replace it and see. I've had new ones not work right before so even if it has been replaced I'd check it. Now I'd remove the belt and see if the waterpump turns freely. If it does then the next step is removing the waterpump to see if there is a problem with it. A waterpump has impellers that are usually pressed on to a shaft. There might be a problem with broken impellers or they are just slipping on the shaft, while not too common it can happen.

 

[momyeroc94]

Thanks so much, I am going to try all those things and will let u know how it turns out.

 

[momyeroc94]

We replaced the thermostat for the second time, it was all black after 2 weeks. We replaced the waterpump just because and completely flushed the coolant and used cleaner and it seemed to work better but overheated again after about 10 miles instead of 3. Now we are replacing the radiator and praying this fixes it. The head gaskets looked good and no cracked block so that's good. No idea what to do if replacing the radiator doesn't work. Any other ideas?

 

[wip99gt]

With the thermostat being black that means there is something in the cooling system. I hope the radiator will fix it. If not there is always a chance that the temperature sensor is no good as well. This is getting to be an expensive repair for you.

 

[momyeroc94]

With the thermostat being black that means there is something in the cooling system. I hope the radiator will fix it. If not there is always a chance that the temperature sensor is no good as well. This is getting to be an expensive repair for you.

 

[momyeroc94]

Already replaced the temp sensor..the norstar engine is called the deathstar on most sites I have seen. Talked to a friend who works on caddys, he says to drain the radiator and fill it with water and add this stiff sealant and run it for an hr, then drain it and let it sit for a day and then put coolant back in. Says he thinks its a gasket and said that they won't leak or code when tested but that he thinks that's what is wrong. Says ifthat fixes it then I should trade the car in and get something else. I'm pretty discouraged.

 

[wip99gt]

Yeah the Northstar was not a good engine. They have a lot of big problems. If the car runs good after this then trade it in like he said. Your friend sounds pretty honest to you so when you do trade it get his advise or mine on any car you're looking at.

 

[momyeroc94]

Yeah the Northstar was not a good engine. They have a lot of big problems. If the car runs good after this then trade it in like he said. Your friend sounds pretty honest to you so when you do trade it get his advise or mine on any car you're looking at.

 

[momyeroc94]

Absolutely I will get advice before I buy another vehicle. I would not advise anyone to get a vehicle with this engine, EVER. I am a woman and have done more work on this car then any other car I have owned. I know more then any woman should about an engine. Lol. Thanks for your help. I will let you know if this works. Thanks again.

 

[wip99gt]

Hey no problem. By the way one of my mechanics is a woman and does quite well.

 

[momyeroc94]

Hey no problem. By the way one of my mechanics is a woman and does quite well.

 

[momyeroc94]

Oh I wasn't saying woman can't be great mechanics I am saying I an not one lol. I might become one now though, I am not so bad at it. Thanks to your stellar suggestions I was able to do way more then I thought I could. Just wish it wasn't my car. Thanks again. You are awesome!