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Discussion Starter #1
Just picked up a 2002 e39 M5 with 48k miles. I’ve noticed getting out of the car after a drive that there is a noticeable “old engine” smell...little motor oil and and a touch of gasoline. Occasionally get a whiff inside the car when it has been sitting for a while of through the AC (usually on a cold start).

Search results indicate failed valve cover gaskets are the leading cause and I will check them but there was also quite a few folks who have mentioned their cars just had these smells from time to time. That being said, I wanted to ask the community...do these cars just have a bit more engine smell to them on a normal basis?
 

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Congrats on finding a 48K mile E39 M5!

Yes some of my E39 M5's do have a bit of an oily smell to them at times. I attribute it to one of the following:

Possible valve cover gasket leak as you mentioned.

Leaking diff input shaft seal, the CV joint flange then slings diff oil on the resonator and then the hot exhaust pipe helps to vaporize the oil and generate the aroma. I think this one is the most noticeable by far.

Power Steering fluid leaks as they all seem to seep a little from the hoses in various places, and then dripping on a hot part? (A lot of times can be just fixed by cutting back the hose ~20mm and a fresh tight hose clamp)

The gasoline smell may just be from driving it spiritedly, some of them run a little rich at times especially when cold. Or if MAF's are old?
 

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My 2002 with 86k does not have any noticeable engine smells. Mainly the smell of leather associated with the "Luxury" interior.
 

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Discussion Starter #4
Congrats on finding a 48K mile E39 M5!

Yes some of my E39 M5's do have a bit of an oily smell to them at times. I attribute it to one of the following:

Possible valve cover gasket leak as you mentioned.

Leaking diff input shaft seal, the CV joint flange then slings diff oil on the resonator and then the hot exhaust pipe helps to vaporize the oil and generate the aroma. I think this one is the most noticeable by far.

Power Steering fluid leaks as they all seem to seep a little from the hoses in various places, and then dripping on a hot part? (A lot of times can be just fixed by cutting back the hose ~20mm and a fresh tight hose clamp)

The gasoline smell may just be from driving it spiritedly, some of them run a little rich at times especially when cold. Or if MAF's are old?
Thanks - loving it so far! Also appreciate the feedback! Sounds like some level of smell is normal but I’ll be sure to check those items out to make sure there are no leaks.

The rich/gasoline smell I usually only pick with a cold start. Slightly disconcerting that it comes through the AC but it is usually brief - that just a factor of the air inlets and cabin filter design in the engine bay?
 

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I would check for an exhaust leak as well.. my car only has 47k and does have those symptoms other than a leaky diff that I will address next year.
 

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I would check for an exhaust leak as well.. my car only has 47k and does have those symptoms other than a leaky diff that I will address next year.
Thanks - the exhaust is stock with exception of Dinan mufflers. The cabin air intake runner on the driver’s side was recently replaced so I’m planning on checking that it’s tight when I get back to the car.
 

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+2 on exhaust leak.
 

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Could be anywhere, obviously around the flanges is one place to check.
 
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