What causes loss of coolant in a Northstar engine (does not run hot)
Lots of things. Same as in any other engine - leaks, bad hoses, engine burning it, a whole host of things.
Cylinder head gasket failure. Trade it in while it still runs. But first check the “normal” failures such as radiators and hoses and such. Good luck.
Head gasket failures are very common on these engines. They are also oil burners. (you probably know that already)
Thanks for your reply. It doesn’t burn oil yet (I only have 39k miles). The coolant loss started last year. I noticed in rush hour traffic the car would run warmer than normal (never ran hot). I took it to the dealer and they discovered the coolant was low. They flushed the system, added new coolant and did a pressure test but no leaks were found. A few months after that the computer displayed low coolant and I had to add almost a gallon. Took the car to the dealer again and this time they kept it for a couple of days doing all types of testing in all conditions and still found no leaks. One of my friends recommended I check it often and keep a log. About every 2 weeks I had to add 8 oz. of water/coolant (would alternate). In July I did a long road trip and there has been no loss since (then again there is no way to check the actual coolant in the radiator). I know these cars are good for blowing head gaskets. Do you have any tips for me, I still have 2 more years on the warranty but intend to start looking for places now that replaces head gaskets for future reference if needed (I tend to keep cars for at least 10 years).
I would keep pushing the dealer to get a handle on this problem. Also save any documentation that indicated that you are losing coolant. Some dealers will stonewall you on the problem until after the warranty is up, then suddenly realize that you need an expensive repair. (The service writers don’t make commission on warranty work.)
You may be OK in terms of oil burning. My father-in-law had a 2000 Cadillac that burned about 1 quart in 800 miles when he bought it used. It was about 1 year old with 8000 miles. I think Cadillac fixed the problem on later models.
Actually one of the common areas for leaks is the water pump. Its tucked in and hard to see. Not cheap to replace but if not the head gasket, or other common leak areas like the radiator, hoses, etc., I’d bet the water pump. I had a leak in mine and never could see it coming out, just a loss in the over flow tank.
GM has had major problems with Intake Manifold gaskets.
Thanks for all the good responses. I took all of the advice, kept a log of my coolant loss and maintained pressure on the dealer. Recently a technical bullentin came out about a crossover leak. The dealer replaced the manifold gaskets, water pump, thermostat and housing as well as something a called a plenum to solve the problem.