Oil Smells Burnt

[KLowD9x]

I noticed yesterday, while making sure my oil is still topped up after 5000 miles, that the oil smells burnt.

I do nothing but highway, I have no turbo, and there is a coolant-oil heat exchanger. The engine is immaculate and runs perfectly.

Does good combustion make oil smell burnt?

 

[ctc]

If you have to top off and you have no leaks, then wouldn't you be burning oil?

 

[KLowD9x]

Originally Posted By: ctc
If you have to top off and you have no leaks, then wouldn't you be burning oil?


I never said I had to top off. I said I was checking to make sure the level was still perfect.

 

[ARCOgraphite]

Funny you should mention this as I had a similar experience this week. I notice the oil in my wifes 09 Forester smelled "burnt", this is with Rotella 10w30Cj4 (4700mi on the Oil. Odor was like burnt trans fluid. Never had this smell with Mobil clean 5000.

 

[jdeare]

Mine also smells burnt, but then again it is burning oil, so I also can see the level go down. What does the oil smell like new?

 

[froggy81500]

how is the cooling system? have you overheated it recently or is the cooling system running hotter than normal?

 

[Bryanccfshr]

I wouldn't put to much thought into the odour of the in use oil. Like colour it is not a good indicator of oil condition. It is simply the way the oil and additives react to use.

I doubt in your use you are severely oxidizing the oil. If you arein doubt get a UOA to confirm the condition of the oil and its fitness for continued service.

 

[KLowD9x]

Nope, this car has an immaculate cooling system. Coolant is replaced every 50K miles and the water pump is done every 100K miles. No overheating, [censored], it doesn't even get enough of a load put on it to come close to overheating.

That's good that it means nothing. I might do some UOAs and see how long I can take my interval out, but I wasn't sure if the burnt smell had anything to do with anything.

 

[Bryanccfshr]

All it means to me is that is what your used oil smells like,... BTW.. Don't let the neighbors see you sniffing the dipstick.

 

[KLowD9x]

Originally Posted By: Bryanccfshr
All it means to me is that is what your used oil smells like,... BTW.. Don't let the neighbors see you sniffing the dipstick.


I'm sure my neighbors don't care. I sniff my transaxle dipstick every time I check the fluid. Not because the fluid could be burnt, but JWS 3309 fluid smells GOOD!

 

[froggy81500]

Originally Posted By: Bryanccfshr
I wouldn't put to much thought into the odour of the in use oil. Like colour it is not a good indicator of oil condition. It is simply the way the oil and additives react to use.

.


not always true. sometimes you can pick up no other issues by the smell of oil, like a strong smell of fuel in the oil can point to a fuel system issue (like a leaky injector).

 

[Bryanccfshr]

Or not. I have smelled heavy fuel and it does not turn out to be so on the UOA. Sometimes aromatic hydrocarbon odours stick around long after the mass that contaminated the oil has flashed off.

I get this all the time in hydrocarbon facilities. Odour and and photoionization detectors detect that there are hydrocarbons in the area but there are not enough to even register as a percent of the lower explosive limit using the wheatstone bridge LEL monitor. The fact that the engine oil is a heavy hydrocarbon itself will be read through a PID.
Fuel in oil in a laberatory environment must be hard to measure as the fuel will polymerise with the oil and the more volatile componets will flash off and be emitted throgh the crankcase ventilation. Ever notice how hard it is to get the gasoline smell off of you if you accidently spill some on your person or clothing? That is washing with soap and water. Engine oil is going to bond with that odour quickly.

 

[360kid]

If you have any doubts about the oil, then I would just change it. You already got 5000 miles out of it, so a change certainly wouldn't be a waste. I would change mine if it smelled burnt and had a significant amount of miles on it. Could there still be some life left in the oil??? You bet. Would I want it in my car??? No way.

Don't waste money on a UOA unless you suspect a real problem. You can save yourself a lot of time and just change the oil for less than the cost of a UOA anyways.

 

[KLowD9x]

Originally Posted By: 360kid
If you have any doubts about the oil, then I would just change it. You already got 5000 miles out of it, so a change certainly wouldn't be a waste. I would change mine if it smelled burnt and had a significant amount of miles on it. Could there still be some life left in the oil??? You bet. Would I want it in my car??? No way.

Don't waste money on a UOA unless you suspect a real problem. You can save yourself a lot of time and just change the oil for less than the cost of a UOA anyways.


Well, I was going to do just a couple UOAs with my normal drive cycle to see if I could extend my oil change interval to 15K miles.

I will change it at 7500 miles, not much longer.

 

[440Magnum]

Every piston engine pumps its oil full of combustion by-products, so of course there's a "burnt" smell to it after a few hundred miles. "Burnt" might not be the best description, to me it smells like engine exhaust from the days before catalysts.

 

[ARCOgraphite]

Originally Posted By: Bryanccfshr


I doubt in your use you are severely oxidizing the oil. If you are in doubt, get a UOA to confirm the condition of the oil and its fitness for continued service.
I'm running 5K oci so I will assume its serviceable to this point - smelly or not. I am putting GTX(on sale) in there this weekend; If I was continuing to run the RT1030 HDEO I might get a TBN home test kit to push OCI to the allowed 7500 mile non-severe service interval on our NON-turbo motor. OTW Id rather spend the money for a "casual" UOA on an oil change instead. Bet the car would like it better

 

[ARCOgraphite]

Originally Posted By: 440Magnum
Every piston engine pumps its oil full of combustion by-products, so of course there's a "burnt" smell to it after a few hundred miles. "Burnt" might not be the best description, to me it smells like engine exhaust from the days before catalysts.
But this was very strong and an off scent. It had floral notes of sweaty armpit on top of a burnt dexron base odour. "Jimmy, that's sniffin your dipstick rag!"