: '99 STS Oil Smell?

04-15-09, 12:00 AM
Well on my way home from work tonight I noticed a burning oil smell, but the smell was only appearing when the car was on a forward or backward incline. When I got home my dad and I took a quick look at the engine for any signs of leaks, nothing that we can really see for sure. However, we did see below the master cylinder that there seemed to be what looked like a gasket of some sort that obviously had some oil on it. Not sure if this is something that should or should not have oil on it.

Is this a big problem? Where should I start to try and fix this issue? Before I bought this car the Cadillac mechanic I bought it from resealed one half of the oil pan I think he called it? Not quite sure, but could it be the other half of that gasket that's going bad? My dad said he thinks it might be a valve cover, which judging by some responses in this thread I don't doubt his judgment.

Oh and despite this minor problem (I am hoping it is only minor) I am loving the car, and driving it like I stole it! :p

Thanks for the help guys!

04-15-09, 12:19 AM
It's probably oil collecting around or leaking out of the half main seal (or whatever it's called that causes N*s to leak oil). My ETC does the same thing.

N*s leak oil and it costs a fortune to fix; N*s burn oil and it's not really a problem; and some blow their headgaskets -- also a fortune to fix.

All part of the love.....

04-15-09, 12:23 AM
Well is this something that can cause big problems down the road or something that I should just really ignore?

The Cadillac Mechanic I bought it from said that he would fix anything that happened INCLUDING HG's for 6 months and after that he would do the labor for free and we would have to pay for parts only.

Ranger? Sub? Your expertise please? Others inputs greatly appreciated!

04-15-09, 12:59 AM
The rear main (or half main, I've heard it referred to both ways -- unless it's 2 different parts, and they both leak...) are to my understanding an annoyance and a slight mess. Hey, if your guy will fix them for free, go for it. The dealer here charges about $2500...

04-15-09, 02:05 AM
Yeah I agree if the guy said he'll fix anything for 6 months take it to the dealer have them look it over and give you a print out of everything the car needs then take it to your guy. Hell why turn down free service!

04-15-09, 09:16 AM
The best way to pin down an oil leak is to get the car up on a lift, and if you can't readily identify the leak point, thoroughly clean the lower half of the engine with Gunk Foaming Engine Cleaner and a low pressure (pistol grip) hose spray. Stay away from all those wonderful connectors and ignition packs. Just get the crud off the pan and lower block.

Drive around for a couple of days and back up in the air. Things are much easier to find while the car is up in the air - you miss a lot if you have to roll around on the ground, and it sounds as if your mechanic is open for suggestion.......

The common leak points are the oil pan gasket itself, and above that, the half-case seal. (The Northstar has no main bearing caps per se: the entire middle section of the block - the half case - is the bearing caps, girdle, structural member, oil distribution plate retainer, etc. It comes off as an entire unit, so it requires a shaped O-ring type seal.) Others are the engine crankshaft transmission end seal, the cam cover seals, the oil filter adapter O-rings, and possibly a transmission output shaft seal. The only right and proper way to cure a half case seal or oil pan gasket is to remove the engine from the car. Yes, you could put some goop on the outside of the leaky gasket, but that's not a cure, it's a patch.

04-15-09, 09:49 AM
I see, is this in any way detrimental to my engine/car in anyway, or is it just something that's a slight annoyance?

I really want to keep this car running as long as possible, which means doing whatever it needs to keep it running well. (Within my power at least)

The mechanic did replace half of the oil pan gasket, saying that it was bad but the other half looked good to him. Is it possible the other half went and thats whats causing it?

The smell was coming from the right part of the engine, under the master cylinder. That an indication of anything? Its only when the engine is on a incline too, that mean anything?

If this is something to seriously worry about I'll make a call over to the mechanic and ask him about it. He said he could take it to the dealership he works at for repairs.

Your opinion Sub?

04-15-09, 09:53 AM
This is a SWAG (Scientific Wild-Ass Guess).......but if the smell only occurs on an incline, make sure that the metal guard for the exhaust crossover pipe under the transmission/engine joint is not full of oil. If it is, that's either oil pan, half case or rear crankshaft seal(s).

04-15-09, 10:20 AM
K, at school right now but I will check when I get home. Is this something serious that I should be worried about or is it just something I could live with.

But judging from the information given its probably not the valve covers?

04-15-09, 12:22 PM
The mechanic did replace half of the oil pan gasket, saying that it was bad but the other half looked good to him. Is it possible the other half went and thats whats causing it?

No such thing as "half of the oil pan gasket". Maybe he meant halfcase. Cam covers are the least likely. More likely one of the things that Sub mentioned. All are something that you can live with if you are willing to put up with a little smoke and oil smell.

04-15-09, 12:28 PM
Alright thanks Ranger, Happy B-Day by the way.

Anyone have an idea of how much it would cost for any of the given things that Sub has listed? (If the mechanic goes against his word when I call him up.)

04-15-09, 12:38 PM
I don't know, but they are all expensive, major jobs.

Thanks for the B'day wishes.

04-15-09, 12:41 PM
I'm guessing the only thing that it will do is cause a bad oil smell sometimes and cause me to go through oil faster than normal? Or will my oil consumption stay the same? Either way, as long as its not something that's going to cause major problems later on I'm a happy camper!

04-15-09, 01:29 PM
Mine never leaks enough to account for the consumption -- maybe 2-3 drops over a couple week time period.

04-15-09, 01:45 PM
I'm not sure if its accounting for consumption I have to go home and check.

I'm hoping its just drips like you are saying yours does.

04-15-09, 02:46 PM
Well if its leaking oil then yes it will require some top offs throughout your oil change intervals. Most N* consume oil anyway so yours will probably need a little more considering the leak. Just keep an eye on your oil level, try to pin point the leak and go from there. And as Ranger said you cant replace HALF of the oil pan gasket. He may have patched it up with some sort of sealant, but thats only a bandaid. Just take it to your mechanic and have him look it over at the dealership. Make him value his word and fix it.

04-15-09, 03:02 PM
That's probably what I am going to do. Id rather not damage a car that can be fixed at basically no charge to me.

04-15-09, 07:25 PM
Anyone have an idea of how much it would cost for any of the given things that Sub has listed? (If the mechanic goes against his word when I call him up.)

Best price I've seen anyone post here for the lower case half job was $1200. My lower case half reseal cost ~$900 (the gasket set was ~$350) after the motor was already out for HGs. I told the mechanic that GM used the squirt goop seal now but he was old school and wanted to use gaskets. Took some time to find an OEM set.