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No Smoke, No Check Engine Light, No Leak but smells like burning

I have a 2006 SAAB 9-2X, that I just bough used with 116k. The car rides great and I am really enjoying it. The one problem is that there is an intermittent smell of burning. Some days its strong, some days there is no smell at all. It is really weird. I took it to my mechanic for its inspection and he passed it and said that the care looked great. I havent seen a leak, the check engine light is not on and there is no smoke. Any thoughts?

I would check the oil pressure sending unit for leaking. A few drops of oil dripping onto a hot manifold can make a stink.

Ed B.

thanks Ed. I am schdeuled to bring the car in for an oil change this weekend. can i still drive it around with that or no? thanks again.

Because your car is really a Subaru Impreza with Saab badges, you should make sure that you are using a mechanic who is familiar with Subarus.

That being said, a very common problem on Subaru engines as they age is seepage from the valve cover gaskets. Because of the design of the horizontally-opposed Subaru engine, at least one (possibly both) of the exhaust headers is directly below the valve cover. A slight amount of seepage–so little that you wouldn’t see leakage on the pavement below the car–is enough to produce a burning smell when that small amount of oil drips on the exhaust header and is vaporized.

A mechanic who knows Subarus should be aware of this, and would know that simply retorqueing the bolts holding the valve covers usually cures the problem. The worst case scenario is replacement of the valve cover gaskets.

Incidentally, I hope that you have confirmed that the timing belt was already replaced.
The maintenance schedule calls for this procedure at 105k or 8 years, whichever comes first, so you are overdue on the basis of odometer mileage. Many owners of cars that are due for this service simply sell the car, rather than spending the money for this vital maintenance.

When the timing belt snaps (with no warning of any type) it will result in valves and pistons colliding, and internal engine damage that will cost ~$1,500-2,000, over and above the cost of the timing belt. Don’t take the previous owner’s word for anything. Only accept printed invoices as proof of the timing belt having been replaced.

It is very wise if you also have the water pump, serpentine belts, and all belt tensioners replaced at the same time as the timing belt. This is a proactive move, as replacing these items later will essentially result in having to pay for the timing belt labor a second time.

Thanks VDC. great advice. The one question i have is that the mechanic who i trust is not available until tomorrow. with what you think it may be can i drive it today or should i keep it off the road until then? i wont hold you liable with the answer as you have not seen the car just gone off of assumption

also is there a way the mechanic can check and see if the timing belt has been changed?

He could visually inspect it, I guess. If it was done recently, it will look new. If it has been around a while, it will look kinda dirty so it will be harder to tell. There’s a very good chance he replaced the water pump and an idler/tensioner pulley assembly for the timing belt as well, if he did the job right. While you’re there, you replace those things because they are relatively cheap and are cheap insurance.
Those tend to look nice and shiny when new.

What does it smell like?

I don’t think we can tell you whether it is okay to drive. That smell could be anything. Maybe electrical, maybe oil, maybe coolant, etc. If it were me and you have another means to getting around, go on the side of caution, until you can get it looked at.
It may not be serious, but why risk doing damage, right?

its smells like burning plastic sort of? it doesnt have that burning oil smell. im not running “hot” on my temp gauge. and there is no smoke.

Look under the car. Maybe your ran over a plastic bag and it is now stuck to the muffler. It could easily be something like that.
Under what circumstances does it smell most? Driving at night with lights on, by chance?
If so, look at the connections to your head light. Not sure about the more modern Saabs but if they use the same three prong connector Subaru uses, those things tend to get hot and will eventually melt the connector’s plastic. They get hot because it eventually makes a bad connection. Its resistance is higher than it should be and it heats up.
That’s a very common Subaru issue. Maybe the same is true of the Saabaru?

Honestly, it is so intermittent, I cant even pinpoint it. So when it does smell, it smells for about 5-10 minutes then it goes away. Sometimes i jump in the car drive it and nothing. sometimes i drive it for 2 minutes it starts to smell and then goes away. My wife drove it on a 4.5 hours two weeks ago intermittent smell when she got to her destination but no check engine light, smoke, leak etc…

If it smells like burned plastic, it may be some sort of electrical issue.
Are you running the heater and fans when it smells?

Sometimes yes

If you said “always yes” I would suspect these resistors they use to vary the speed of the fan. They sometimes smell, right before they are about to fail. That’s not likely because you would never smell that plastic burning with the fan off.

Look at the cables around your engine. They are normally contained such that they are not allowed to touch hot parts of the engine and radiator. It could be one wire moved and is now touching or near touching.

let me pay more attention to it… maybe that is the case. you have been most helpful. thank you so much. will keep you updated

Sounds good. It may be electrical in nature so it is probably a good idea to get to the bottom of it before you drive it because having to replace a burned out wiring harness can be really time consuming and expensive.
Good luck.

if you are ready for a good laugh i drove the car for about an hour just now. No smell at all!