Cadillac Repair: oil leak, razor blade knife, harley engines

Question
1998 seville, mileage around 82,232.  just bought this car, and changed the oil.  over the last two weeks there has been oil leakage.  crawled under the car checked for leaks, cleaned off everything, hand tightened oil filter, and it is still leaking.  took to repair shop where they tightened the bolts on the oil pan.  i watched them, and some of the bolts needed tightened 1/2 turn.  it is still leaking.  went to dealer, and ask them how much a gasket would be and the person told me there was not a gasket on the oil pan, that they used atv sealant, and i could get that at any supply store a litte cheaper.  my question...is there no gasket?  maybe they can just re-seal with atv sealant, and this will possibly correct the problem??  thank you, for your time

Answer
Hi Barry,

Cadillac engines are like Harley engines--they always leak.

Going back on my rusty memory, most GM engines since the early 80's have not used oil pan gaskets.

Permatex red, orange or black sealant was used. The only real way to temporarily fix your problem is to remove the oil pan, clean both surfaces with a razor blade knife install new sealer. Tighten evenly from center to center going towards end of pan on each side. Retighten to factory specs.

You also need to know that almost all GM engines were notorious for leakage at the rear main seals as well and you may want to change the rear main when you have the oil pan off. Both of my Caddy engines leak. I too have to retighten the bolts, and they leak.

The reason for the bolts to come loose is because of expansion and contraction due to heat and cold and not having a solid gasket.

You could put lock tight on the bolts, but eventually the seal will give way and if you try to tighten or loosen the bolts, because they are small, will possibly break off giving you more problems.

One of the biggest leakers I ran across was the 3.1 (3100) V-6 used in so many GM cars. We were repairing oil leaks in these things under warranty on a daily basis.

I know that you probably are not happy to hear there is no gasket, but GM has been doing this for 30 years.

You can check at an auto parts store to see if Fel-Pro makes an after market oil pan gasket for your car. As for factory design though, it is sealer only. Very common, for not only oil pans, but valve covers, thermostats and just about everything else these days on engines.

Rob