Coolant system problems

[Wingsfan19]

Hey guys,

I have had my LS for 2 years and have had continual problems with the coolant system. Recently it has gotten so bad that I cannot drive it anywhere without it overheating. I have had the system fully bled 3 times by 2 different mechanics, each time it works fine for the duration of the drive, but the next time I turn the car on after going cold, it overheats and there is a new air pocket in the system. There doesn't appear to be any leaks anywhere. I had the water pump replaced and radiator flushed, but neither seemed to do the trick. At this point I am wondering if it might be a head gasket, in which case I will have to say goodbye to the car, which I do not want to do.

Although I trust the one I have my car with now, I'm not convinced that either of the mechanics have much experience working on this car, so I thought I would ask here. Any ideas?

Thanks!

 

[cobey]

I would probably start looking at all of the plastic components of the cooling system. Thermo housing, any of the plastic Rad hoses and the Degas bottle. Cracks may appear strictly during changes of pressure and maybe small enough that they may not be super obvious. I have yet to deal with this headache personally, but I believe that what most people here would do is to replace all at once, since when one fails, others aren't far behind. There is a relatively recent post here started by SoalSoak that has all of the necessary parts listed with part numbers.

 

[cobey]

http://www.lincolnvscadillac.com/forum/showthread.php?91092-GenII-LS8-Cooling-System-Overhaul

This is the thread that I referenced earlier. It would be a pretty good start for you. This is for a Gen II (2003-06), not sure which year you have. Only go with Motorcraft for Degas bottle for sure

 

[joegr]

...each time it works fine for the duration of the drive, but the next time I turn the car on after going cold, it overheats and there is a new air pocket in the system. There doesn't appear to be any leaks anywhere. ...

This is exactly the symptoms of tiny cracks in the plastic parts of the cooling system. They are too small to lose much coolant from, but when the engine cools down, air is sucked into the system through those tiny cracks. It can be hard to locate them, but the good news is that you don't have to. We have enough experience to know that all the plastic parts will get these cracks within a month or two of the first one getting one. You need to replace them all.
What year is your LS? V8, I assume?