03-01-05, 08:48 PM
N* 98 Deville Vin Y 87K. runs rough and exhaust is white and smells like coolant. Oil is very good with NO milk shake and no rod knocks. I pulled the plugs and shot air into the cylinders and coolant shot out of 3-4-5. I would like to know if anyone has seen this before. Not sure if I have 2 bad head gaskets, cracked block, 2 cracked heads. I have been told the intake does not pass coolant through it, so a bad intake gasket would not cause this problem. Any help would be appreciated.
You are correct on the intake. Also it is my understanding that the Northstar will not leak coolant into the oil with a bad had gasket. Coolant in the cylinders is not good. I can't imagine what, other than a head gasket failure would put it there.
03-01-05, 10:35 PM
what about 2 cracked heads??..is it possible both head gaskets are blown. Even the darg race stuff I see never launches both head gaskets...it usually takes one out. I wish I had more experience with the N*'s :-(
03-02-05, 12:56 AM
Most likely you have two bad head gaskets. Since the N* runs well even with a bad head gasket people tend to drive them, and drive them, and drive them until the leaks are so bad they can't drive them very far anymore. By this time both of the gaskets are blown.
Another factor is the gaskets seem to fail from corrosion more than any other factor. So if one is corroded the other will soon be.
Look in the Cadillac tech tips section for info on replacing the head gaskets.
And Ranger is right. THe N* does not put coolant into the oil until the gaskets are totally failed...
It is not likely that the heads are cracked. The engineers did a great job in some areas and the heads are one of them.
03-02-05, 10:09 PM
thanks zonie...looks like I have plenty of work ahead of me!!
03-03-05, 10:09 AM
It is a lot of work but none of it is too hard. Are youu gonna do it yourself?
03-03-05, 10:44 PM
not sure, it is also leaking oil on the passenger side...I assume it the crank seal. I may just drop the motor and replace all the gaskets, or swap the motor. It depends if I keep the car or not...I really like the car. I am a computer nerd during the day, but a gearhead the rest of the time, so I can do the work myself.
03-03-05, 11:53 PM
You can take care of all of it at once. I would pull tht engine apart and check the cyl walls and heads. If the walls look good and there is nothing obvious wrong with the heads I'd just timert the block and replace the gaskets. Don't change engines unless there's something wrong with yours.
What kind of computer job?
03-05-05, 07:38 PM
I was a sysadmin working on Unix systems, but now I am working on IT projects aka IT project manager. Lately, I have been so busy, I have had little time to work in the garage. In a few weeks, I am going install a new custom aluminum fuel cell in my Pro Street Monte Carlo. I need more fuel so I can get around town easier...5 miles to a gallon stinks, but 500Hp is nice!!. What do you do for a living??