: How soon do you replace oil pan gasket?

03-24-08, 01:16 AM
My brother has an '01 SLS with 94k and the dealership here in Minnesota recently discovered a minor leak in the oil pan gasket. He only notices a drop here and there, every few days at the most. He runs conventional oil, and wanted me to check on a few things, since they estimated nearly $1000 for a replacement, and I know this is very difficult to do.

-Is it a bad idea to not replace this right away, and just monitor it very closely? What are the chances of this leading to something more drastic? I had an '89 deville that dripped for 5 years from the gasket and never led to anything else...not sure about the Northstar though...

-He's been thinking of switching to synthetic oil, but not in hopes of a cure for this problem. What kind of impact could this have on the gasket since I've read that some people notice more "leaks" and "drips" when switching to synthetics? I personally haven't and I run Mobil 1.

Thanks guys,


03-24-08, 01:35 AM
You might try taking out the pan bolts one by one, cleaning the bolts and holes with brakekleen, doctoring the bolts with blue RTV, and putting them back.

03-24-08, 12:46 PM
I the drip marks do not bother him, I suggest you leave it alone - it's a pretty big job, and oil is cheap, right? Don't switch to syn oil - it is not necessary for this engine, and it does frequently cause leaks to get worse

03-24-08, 09:04 PM
$1000 will buy a LOT of oil. It will not lead to something more drastic.

03-24-08, 10:59 PM
Ok thanks a lot guys, I really appreciate it! So I will tell him not to switch to synthetic at this point, but will any of those conventional high mileage oils like valvoline maxlife or mobil clean high mileage/mobil clean 5000 really do what it claims as far as helping seals and gaskets? Or is that just a ripoff...if you're going to run conventional should you just run the cheap stuff? I ran maxlife in my '89 deville for 6 years and I guess I never noticed a difference, although it didn't have the OLM like my STS...or a Northstar! lol


03-25-08, 09:35 AM
He should definitely leave it alone until it starts causing smoke clouds at stop lights or until he cant stand the smell of burning oil. LOL

03-25-08, 10:06 AM
Timo,.....................No need to run "cheap" oil. Run a good name brand in the viscosity recommended by the owner's manual. Synthetic or blends won't hurt anything if that's his bag, and it won't cure or cause leaks any more than any other oil on earth. The OLM uses time, temperature, RPM, and speed to calculate oil life. It cannot and does not actually "measure" anything in the oil: it calculates oil "abuse" from driving conditions. You lose less oil life time on a 1,000 mile road trip than during a week or so of short stop-and-go.

03-25-08, 11:38 AM
I have read that the synthetic oils have more consistent sized molecules and therefore can slip in and through tighter spaces - this is an advantage on an engine that is in good condition, but can be a disadvantage when you have a leaker. I had some small leaks and I switched to syn on the last oil change before my HG blew and the leaks got much worse. After my HG job, I am now running regular oil, and it is fine. BTW, I use Walmart brand oil - I think it is called SUPER-TECH or something like that. It comes in a 5 quart jug, and it is around $8 something for regular oil and $13 something for the synthetic oil. The syn oil is only around $1 per quart more, and I do use it on my other, newer cars, but I will use the regular oil on my N*, I think.

01-14-13, 04:01 PM
Hi. I would be interested in knowing what the result was when changing from syn oil to reg. I have a 2001 Eldo convertible and a 1996 deville that are both leaking at the pan. I use syn on both and I just tightened the pan bolts which slowed the leaks quite a bit. But there is still leaking which I would like to eliminate all together.

Thank you

01-14-13, 04:39 PM
Regular/synthetic has exactly nothing to do with oil weeps.

If you have a Northstar with leaking oil pan or halfcase seals the only total remedy is to remove the engine and open it up - replacing the formed silicone seals in the process.

DO NOT try to pour in so-called HighMileage oils or oil sealant products - they don't work.

FWIW, My 2002.5 was built in 02/02 and used conventional 5W-30 oils until 11/05 - then I changed to exclusively synthetic. The engine is bone dry on the outside to this day.