: 1994 Deville oil pan gasket leak

02-18-04, 07:20 PM
1994 DEVILLE, 86000 miles like new, one owner, very good condition. runs great. Just purchased this car and the oil pan gasket leaks like a strainer. Tightened the bolts and one broke. (darn the luck) I figured no problem I have replaced oil pan gaskets before. I then purchased a helm service manual (Great). Everthing I have read tells me I am screwed and will be working my butt off to pull the trans and/or engine to replace the gasket and fix the bolt. I have called cadillac dealers and they have quoted me a price of $1800 to $2400. What should I do?

Now I have owned the car for a little over a week. To make things worse there was poping an electrical short sound under the dash. I first smelled the smoke then saw it coming out of the air vents. I turned the AC and key off. I then turned the key and started the car. I turned on the AC on and the fan would run a few seconds then turn off then come on and then turn off again. Now the fan does not come on at all. I think the fan motor shorted out?
Should I sell the car?

02-18-04, 07:29 PM
which motor?
I have just got a 94 northstar eldo coupe with a oil pan leak also. Not going to a dealer for that kind of bill. Ouch

02-19-04, 09:49 AM
The 4.6 northstar.

02-19-04, 10:31 AM
Yes, the engine or transaxle must be removed to R&R the oil pan. A lot of work and $$$$.

First I would recommend that you verify that the oil pan is really the leak source.

Wash the engine down thoroughly, top to bottom.

Get under the car and use spray brake cleaner around the oil filter adapter, the oil pan and front engine cover.

Check the oil filter for tightness.

Wipe the general underside of the engine area with paper towels or rags till clean.

Now drive around for an hour or so, get under the car and CAREFULLY look for an oil leak. Often the oil leak is from the oil filter adapter and/or the oil cooler lines and is blown around under the engine and it looks like the oil pan is leaking.

If the adapter is leaking, get new O-Rings seals from the dealer; they are special (square cut) seals.

If the oil-return lines are leaking, test for tightness, do not over tighten. These lines seal with O-Rings and if they are tight and still leak, you must replace the O-Rings, again a dealer item.

If the leak is coming through the oil pan by metal porosity, there are various methods to seal aluminum, do some research on external metal sealers.

If the leak turns out to really be a small leak that has accumulated over time ignore it and clean up when necessary.

Find the electrical problem before it does more damage.


02-19-04, 10:40 AM
One more note on Northstar oil leaks.

Excessive tightening will not help stop oil leaks and in fact can make the problem worse by distorting the aluminum pan or cover. The seals used on this engine swell when exposed to oil so normally they work pretty good.

A careful check for bolt or screw tightness will let you know if the fastener has loosened over time. As you found out you can break the fastener and cause a worse problem.


02-19-04, 01:50 PM
First, sounds like the HVAC blower speed control just died...that was the smoke and smell from the vents. Replace the HVAC blower speed control. See similar posts from Raven in the STS/Seville section. In Raven's case the blower motor itself had to be replaced. In your case, the 94 has a separate blower speed control module. Look under the hood on the HVAC case on the firewall. About the middle of the car there is a module mounted in the HVAC duct with a group of wires coming out of it. Trace the wire from the blower motor back and you will find the module. That is the blower speed control and it is very simple to replace.

First, diagnose the oil leak. DO NOT assume it is the pan/lower crankcase/etc... Get under there, clean up the oil with spray cans of degreaser/brakeclean and start the engine and locate the oil leak. It may be a very simple fix like an oil cooler line fitting , an oil cooler line hose or the seals between the oil filter adapter and the block.

Regarding your broken oil pan bolt....leave it alone. No need to pull the engine or do anything crazy because of one missing oil pan bolt. It is possible, if you are patient and carefull, to loosen all the oil pan bolts, thoroughly clean the gap at the oil pan to the lower crankcase and pack a little silicone seal/RTV into the gap around the perimeter of the pan. You can try this, especially at the area around the broken bolt. First drain the oil and leave the drain plug out so that any solvent that you spray into the gap or joint will drain out of the drain plug port. Just gently pry the pan down to get a small gap, pack the RTV into the gap after cleaning with spray degreaser/brakeclean and retighten the adjacent bolts. Let the RTV and the joint sit for 24 hours for the RTV to cure and then refill the oil and drive it.

02-22-04, 07:18 PM

I will let you know the rest of the story.