Cadillac Deville - Vacuum leak
babelfish69
Member Posts: 2
I recently acquired a Cadillac from a friend. It’s a nice car, but the catch is it will run but it barely idles. If you step on the gas the engine dies. He gave up on it after a guy he knew “fixed” it for cheap. They had a sharp dispute and parted company on bad terms. My friend shelled out several hundred dollars for a car that was useless to him. This supposedly knowledgeable car person, who isn’t part of any auto repair outfit, offered to put new intake manifold gaskets on to fix a coolant leak. That doesn’t quite make sense to me. What does the intake manifold have to do with the cooling system? This is my first Cadillac, so maybe there’s something I don’t know yet. Also my friend said the car ran perfectly before this guy got his hands on it. I checked and re-checked all the vacuum connections around the throttle body and followed the lines to their connections. Everything was fine. I hooked up a vacuum gauge and fuel pressure gauge. The fuel pressure was fine, but the vacuum gauge barely registered any vacuum while idling. I made sure the gauge was working by hooking it up to another automobile, and it was. So it seems to me that the guy must have messed something up putting the manifold back on. My question is if there is any way of isolating the vacuum leak, or do I just have to take the intake manifold off and replace the gaskets again? And am I right to assume it’s a leak somewhere around the manifold? Or is there any other area I should check? The guy also was supposed to put valve cover gaskets on and change spark plugs. I found three new gaskets in the trunk. By looking at a parts supplier online I see that two of them would be from the intake manifold gasket kit. One is squareish, about 3” by 3” with three bolt holes. The other is round with a projection, and has nine bolt holes. The last gasket looks like it comes from a valve cover gasket kit. It has eight circular holes, and four bolt holes. I’m not sure what these gaskets are for until I start taking things apart. I’m not sure why he didn’t put these in. Anyway, any suggestions about if I’m on the right track would be appreciated. I don’t want to tear things apart unless absolutely necessary.
0
This discussion has been closed.
Comments
Spray starter fluid or carb cleaner around the edges of the intake, or any other hose or area thought to have a vacumn leak. If the idle changes, increases, there is a leak there.
This motor has a complicated 'idle speed motor' and maybe another idle controller. And they are hard to 'set up', per what I have read. I don't think there is a timing problem (save your money on a timing light), I think most timing is controlled by the computer by 1993.
You need a service manual. A Haynes or other cheep one might have the needed steps to set this up, and then maybe not.
The price for a head gasket job on a Northstar is very expensive. The motor must be pulled to get to ther rear head. The heads removed, the bolt holes bored out and then re-threaded and steel inserts screwed in. The head, with new gaskets are then reinstalled, with the new head bolts screwing into the inserts. This usually stops any future head gasket problems. The cost for all of this is probably $3,000, more or less.
Have you just been driving 'easy'? Slow accelerations and not been driving very fast? This might keep it from overheating, especially on short trips.
Take the car out and accelerate it hard a few times. Find the steepest hill and run it up the hill, fast. It will probably overheat.
If the car overheats and is not then totally abused by continuing to drive it, the Northstar motor is usually not hurt by a head gasket failure. Pull the car over and let it cool and refill the fluid to get the car home, slowly. It it overheats almost instantly, the car probably should be towed. The heads usually are fine, and the block does not warp. You just have the huge expense of having the bolt holes fixed up. That and new gaskets, other misc parts, and the motors are usually fine.
It's just when you need $3,000 or so to fix a $6,000 car (or less), it just is not worth it.
Drive it until it seizes. Then you've driven it too far. This is the best answer I can give.
-A correct 'Timesert' installation (overboring of bolt holes and steel inserts) is supposed to pretty much cure the head bolt problem.
-Don't know about 'skip'.
Is your motor overheating or not? If you are just losing coolant and it is not overheating, you have a leak somewhere. Unless your are in the early stages of a head gasket failure.
2) If it's not running hot, I would look for a leak.
Prepare to spend big money or send the car to salvage.