Not a hotrod, but!

[CR55]

I know this isn't a hotrod, but I need some help with my son's car. Its a 2001 Caddy with a Northstar engine. It runs fine for varying times then it starts running hot. He's had to tow it twice. The dealer checked it over and put in a new thermostat, he couldn't find anything else wrong. It still runs hot once in a while!Any ideas? The hoses are new and the electric fans are working fine. There are no visible leaks or coolant anywhere to be seen. I'm out of ideas...help!!!...CR

 

[Reign]

does that car come with a clutch fan or is that an electric fan?

 

[42chevy]

Maybe it has an air bubble that shows up on occasion? I would drill a small hole in the thermostat and flush the cooling system if it hasn't been. I also would replace coolant if it is that 100k coolant they used around then, I have heard stories of it clogging stuff up.

 

[CR55]

does that car come with a clutch fan or is that an electric fan?

It has 2 electric fans.

The air lock theory is being given consideration, but you need 14" fingers to get to the thermostat!!..CR

 

[42chevy]

I thought they were hard to get to on those. I ALWAYS drill the small hole in the thermostat because I am too lazy to do it twice. I wish I could think of something easier for you, but if it is real hard to get to that is the problem. In my experience with cars whatever is hardest to get to there is my problem. Do you see my logic?

 

[CR55]

I thought they were hard to get to on those. I ALWAYS drill the small hole in the thermostat because I am too lazy to do it twice. I wish I could think of something easier for you, but if it is real hard to get to that is the problem. In my experience with cars whatever is hardest to get to there is my problem. Do you see my logic?

"Murphy's law"!!!

 

[gassersgarage]

GM had problem with their factory coolant turning to sludge and clogging everything. Best bet would probably be to take it to a radiator shop for a complete flush.

 

[Shea Laking]

I've heard of problems with warped heads and head gasket leaks on Northstar engines. Sadly, there are also problems with damaged block threads for the cylinder head bolts/studs and broken bolts/studs. The fix is oversized Helicoils and new bolts.

Not for nothing is that pink $#!t frequently called "DeathCool." Pure madness to expect stuff to last for years and years WITHOUT any additives or breaking down...

Hope you guys can find your problem and get it fixed for less than an arm and a leg.

Regards,
Shea

 

[PA41]

Maybe the temp sensor that controlls the fans, or its plug/harnes has a problem. Replace that sensor and check the wire/plug for a intemitant short?

Just a shot in the dark..

PA41

 

[rockabillyrat]

Head gasket. Its a very common thing on these. Northstars are a horrible engine.

 

[CR55]

Head gasket. Its a very common thing on these. Northstars are a horrible engine.

I've heard the same thing! But the dealer checked the head gasket and its fine.

 

[englishrob]

when dose it overheat in traffic or on the highway maybe blocked radiator which might point to the other suggestions of crappy antifreeze

 

[CR55]

The overheating is not at any particular time. It has overheated when sitting at a light and the last time was driving on a highway. He drove 350 miles between overheatings!!!
This thing is baffling me! I do appreciate all of your input and we're trying everything that was told to me, thanks!!..CR

 

[CR55]

The overheating is not at any particular time. It has overheated when sitting at a light and the last time was driving on a highway. He drove 350 miles between overheatings!!!
This thing is baffling me! I do appreciate all of your input and we're trying everything that was told to me, thanks!!
My son just wants to sell the car, but he won't do it until he gets it straightened out. I'm glad to see he has integrity! I Must have done something right!!!...CR

 

[42chevy]

I am grateful you raised one to do things right. I won't sell a bad car unless I take the loss and the person wants it. Full disclosure. Good luck

 

[Reign]

i know it has already been said, but look into the sensor and the control module for the fans. i know the aftermarket E-fans for the Lightnings were having a problem with the control modules and they were doing the same thing that you are describing. So, i would say to check there first since it might be the easiest to diagnose too.

 

[BigIrish]

The overheating is not at any particular time. It has overheated when sitting at a light and the last time was driving on a highway. He drove 350 miles between overheatings!!!
This thing is baffling me! I do appreciate all of your input and we're trying everything that was told to me, thanks!!..CR

If it's overheating on a highway, then I don't think it is cooling fan related - there will be tons of air moving through the radiator at speed. I had the elec fan crap out on my sh*tbox high school car and it did fine until I got stuck at a light.