I have an 04 Bonneville SE 3.8. yesterday (Oct.5th) I took it to the dealership for a maintenance inspection. They found that my coolant overflow was empty and the rad was about half full. Back in June of this year, the engine was removed to replace a main seal.

The temp light has never came on, the engine temp has always been at 90 and the engine runs smooth. The dealer wants to charge me $900 to fix the problem. I told them to just fill the coolant up and I will keep an eye on it. The level in the overflow has gone down about a 1/4 inch since yesterday.

I am thinking that the people in June, forgot to refill my rad and overflow.

Any suggestions would be appreciated, I don't want my engine to seize up.

Thanks

The 3800 has a common issue with the lower intake manifold gaskets. These gaskets get really nasty really often, and they break up to allow coolant to flow into the cylinders and even into the oil. Check your oil level.

What the dealership wanted to charge $900 for is to take off your upper and lower intake manifolds and then replace the gaskets so that coolant stops leaking. It'* expensive, and you can get it done elsewhere or do it yourself for less, but it is an essential repair.

Fill it and watch. If it keeps going down you have a leak. Watch for pools on the floor. If none found the most likely area is your EGR stove pipe on the upper intake manifold. Changing UIM gaskets is a fairly easy task. Although the lower intake manifold gaskets don't often fail to the point of draining the coolant, changing them to aluminum frame gaskets is a good idea considering you are about one step away from getting those as well. While at it, change the coolant elbow. All in all, 4 hours for the job is easy. Takes me 2 hours. Cost, about $100 for gaskets. Does that sound a little better then what the stealership wants? There is a write up in tech info on how to do this job. And we can walk you threw it no problem.

Thanks for the feedback.

I forgot to mention that the dealership did an oil change and did not see any coolant with the oil.

Kevin

Dan.. you are definately not feeling up to par today. UIM, not gaskets.

I see a couple possibilities. Air bubble in the system that burped after the engine pull and since you've had "enough" coolant there hasn't been an overheating situation. If you fill it up and see it disappearing, I'd hop on the upper intake right away and do the LIM'* with the GM aluminum framed gaskets at the same time. Well worth the time/investment.

If the level doesn't move...smile and drive on

Thanks Bill, my head is a bit fuzzy today.

The EGR tube gets hot and cracks the plastic UIM. The UIM has a coolant passage that runs along both sides of the EGR tube. Those cracks let coolant enter the intake. it'* easy to check, just remove the throttle body and look. If it'* wet, then it'* leaking.

Eventually this problem will leave you stranded. The water is being burned thru the cylinder and is exhausted out your muffler. Pretty soon the engine is going to run rough and develop a hydro lock.