Why Can I Smell Oil?

[CheyneX5]

Over the past couple of months, i have noticed the smell of hot oil coming from my engine bay. I'm not sure if this is normal for the cars age or anything like that but i will list a few things that i think that maybe causing it. Correct me if i am wrong...

1. There was a small oil leak from the CAS "O Ring" a couple of months ago when i adjusted the timing, this ring was since changed but there is still oil sitting at the bottom of the sump/motor that i can see when the car is on a hoist. This oil leak is still there i beleive, i check under the car every few days to see if there is oil leaking, it never drops any oil, there are no spots in any place i park for long amounts of time but my front subframe brace always has a thin glaze of oil

2. The little rubber tube running from the right hand side of the rocker cover to the intake pipe is slightly split at the rocker cover joint.

3. The leaking oil at the bottom of the bottom of the motor gets hot everytime i drive and creates the smell? (this is a guess)

There is no loss in performance as far as i know and the temp gauge sits happily where it should normally be all the time, the oil pressure gauge is correct and normal and oil levels are fine. I cant think of anything that could be causing this...

The car in question is a 1989 NA6 with a B6 Longnose motor in it with around 60,xxx kms.

Thanks Guys, I hope this isnt anything serious....

[Steampunk]

2) is your PCV (positive crankcase ventilation). Virtually no oil should come out of that. Even if it did, it will be very very small amount and you will certainly see it.

some guesses would be:
- oil filter not done up properly
- CAS O ring not installed properly
- cam cover gasket not sealing/installed properly
- sump plug a bit loose

perhaps the oil is coming out of your gearbox?

and just thinking laterally, are you sure it's oil that is coating your subframe? could be coolant.

[Old Dude]

Hi Cheyne

See if any oil is around your exhaust manifold, normally if you can smell hot oil its sitting on something that gets pretty warm and not just leaking out and hanging around the bottom of the motor. I would look higher up.

Regards
Old Dude

[rascal]

I agree. Even very small amounts of oil on exhausts smell bad. I fitted extractors to my prev race car with greasy hands and it stunk for days afterwards until it burnt off, and there was no leaks at all, just the oily fingerprints..

[bruce]

Run a rag around your engine and see if you can find patches of oil (and a possible leak). Wipe everything up. Watchout for hot components and sharp edges.

[CheyneX5]

Thanks for the quick reply fellars.

I know that it is not coolant on the brace, it's definatly oil.

I am starting to thing that we did a dodgy job on the CAS O Ring change. I will check that tonight, last time we checked before it was changed there was oil under the CAS.

It could also be that there is oil on the headers or rocker cover, i usually spill a tiny bit when i do an oil change

Any other suggestions?

[hks_kansei]

Cheyne, if you spill oil when topping it up it often smells, my 626 used to all the time, even when you wipe it up it leaves a film which burns off.

have a look around the bay, you might have a leaking rocker cover (have you ever removed the rocker cover? gasket may be split)


can you smell it from inside the car? or is it just when the bonnet's open?

to smell from inside the car it would need to be more than a few drops burning, even when I spilled oil on my 626's exhaust and didnt wipe it up I couldnt smell it inside the car. Granted it also had an exhaust leak into the cabin which made it hard to smell anything.

[Alex]

I think the oil on the brace could just be from normal oil changes, when you pull out the oil filter some runs down into the brace.

[bensale]

Great advice!

I doubt its the rocker cover as I've done the same and have no smell. Although you could use clean it if you want to be sure. I think the gasket is fine, also you'd see the leak if it was coming from there. Check it closely anyway.

Check the CAS. I'm not sure how old the seal Bruce had is. It still felt soft though. I think as far as actually fitting the CAS it a part that is either in right or in wrong (not in). There can't really be a middle ground as the car wouldn't run without it installed correctly.

Check there is no oil down where the filter is. It possible there is a little pool from when the filter was last done. This could be resonably easy mistake to make.

Have you been keeping an eye on the oil level, is the motor using much or any? Especially compared to before you noticed the smell? If you have a leak somewhere then you must loose some oil on the distick, I'd check it everyday when you're leaving for work for the next week. If its not using any oil then I would say its likely there is oil hiding somewhere in your engine bay. I would also check any area the oil from the inital CAS leak could have gotten too.

Have fun

[manga_blue]

The symptons are right for a leaking CAS seal. I'd say you just used a bad mechanic to do the first seal change. I know for a fact that his last seal change failed after a few months too. Replacement with a new seal worked fine.

You might also check that there's nothing letting excess pressure build up within the crankcase to push oil out through the seals. Your PCV valve should suck easily under light vacuum and lock under heavy vacuum. The hose that runs from the cam cover to the inlet pipe should also be free of leaks and blockages. There should be a small nylon restrictor hiding somewhere inside that hose, usually just before the connection into the air inlet pipe. Make sure it's clear. If the motor is old and letting a bit of gas down past the rings then removing that restrictor can help cut down oil leaks without any really noticeable effect on running.