: 97 DeVille oil leak



ZSKI
12-18-04, 03:00 PM
OK. My friend purchased earlier this year a 1997 DeVille, 4.6 Northstar engine, with 40,000 miles (nice looking car) from a little old lady; who just drove the car 10 miles a day; back and forth to work (city). One month after purchase the water pump started to leak and had to be replaced. A few months later an oil leak developed...a five inch circle on the driveway after sitting overnight. The shop said it was the oil-pan gasket. This was changed...still leaking. Now the shop says it is the rear seal and the engine will have to be pulled. A different mechanic has advised that it may not be the rear seal but another gasket on the bottom of this engine...and the engine will have to be pulled. Also, my 1999 Deville with 45,000 miles is also showing some oily moisture on the bottom of the oil pan (but as yet no dripping). Can anyone comment on this as to experience with these engines and oil leaks? Can anything be or should be added to stop this leaking (E.G. RISLONE)? Thanks.

BeelzeBob
12-19-04, 02:25 AM
OK. My friend purchased earlier this year a 1997 DeVille, 4.6 Northstar engine, with 40,000 miles (nice looking car) from a little old lady; who just drove the car 10 miles a day; back and forth to work (city). One month after purchase the water pump started to leak and had to be replaced. A few months later an oil leak developed...a five inch circle on the driveway after sitting overnight. The shop said it was the oil-pan gasket. This was changed...still leaking. Now the shop says it is the rear seal and the engine will have to be pulled. A different mechanic has advised that it may not be the rear seal but another gasket on the bottom of this engine...and the engine will have to be pulled. Also, my 1999 Deville with 45,000 miles is also showing some oily moisture on the bottom of the oil pan (but as yet no dripping). Can anyone comment on this as to experience with these engines and oil leaks? Can anything be or should be added to stop this leaking (E.G. RISLONE)? Thanks.


As per the answers on the other posts you made for this....crawl under there and see what is leaking....only way to tell. A case half leak or an oil pan leak would not leave a 5 inch puddle on the driveway in all likely hood. A rear main seal is pretty robust on a Northstar and is unlikely to suddenly fail and start leaking.

I would suspect the oil filter adapter, an oil filter itself or an oil cooler line...any of which is very easy to repair.

Understand that when the engine is sitting and not running the LCC seal, the oil manifold plate seals and the oil pan seal are all above the level of the oil. so...why would oil leak past those seals with the car sitting still and not running. An oil pan drain plug could do this and if it was damaged or cross threaded at the last oil change it could certainly cause a puddle.

Pjs
12-19-04, 11:38 AM
When my oil pan and oil manifold were leaking, I would have at least a 4-5" spot of oil inder the car in the morning, and in the garage where I park at work. If I completely cleaned my oil pan as best I could with carb cleaner and then started the car, a sheet of oil would literaly run down all sides of the oil pan. When I changed my oil pan gasket and put everything back together, the oil leaked a lot more, from the oil manifold plate. Since changing that AND the 1/2 case seals my engine is now leak free :)

ZSKI
12-19-04, 01:32 PM
We are in the process of checking the oil leak source now. Thanks, what you say makes sense (bbob)...we shall see.