80-110km/h = bad smell and some smoke - 96 Impreza

Dusty_Hermit · Post by **Dusty_Hermit** » Sat Feb 23, 2013 9:14 pm

Hi folks,

I recently obtained a 96 Impreza AWD Sports Wagon. Initially there was a crunch when shifting into third, along with a bad smell at ~80km/h and some intermittent smoke at ~110km/h.

Everything else is good, the engine is sweet, and the temperature never goes over half... performance seems fine.

I fixed the crunch by changing the transmission fluid, and hoped this would fix the smell/smoke, but unfortunately not. The clutch feels okay, and there's hardly a shudder with low RPM take offs.

Google led me to believe it might have been the clutch freeplay. Upon checking, I found there wasn't any freeplay - so I have since adjusted this.

But the problem is still there!

The smell is really acrid - I'm confused as it smells a bit different to a burnt clutch, but not that different [shrug] and it doesn't happen with sustained stop/start driving through heavy traffic in the hills of Hobart.

My mechanical knowledge is somewhat limited - but the problem might be blindingly obvious to someone here.

Any ideas as to what's going on? Is this a big problem? Gearbox maybe?

Thanks in advance.

AlpineRaven · Post by **AlpineRaven** » Sat Feb 23, 2013 9:21 pm

Smell needs to be identified, brakes, clutch, gearbox oil, engine oil and coolant has its own smell if something is going wrong.
Is there any possibility an slow oil leak on the exhaust causing the smell?
Do a test for the clutch - put in 5th gear and try drive it off - if it stalls then the clutch is good, if you're able to rev while not putting your foot on the clutch then the clutch is on its way out.
If the gearbox was damaged - it either would slip, or gear pops out or car wont be able to move.
Cheers
AP

Dusty_Hermit · Post by **Dusty_Hermit** » Sat Feb 23, 2013 9:58 pm

I just did the 5th gear attempted take off - and it stalled with such a sharp jolt that I'd have to say the clutch is excellent. Great information, and thank you.

I did actually wonder if it was oil or transmission fluid leaking onto the exhaust. You're probably right. The amount of transmission fluid that came out when I changed it seems to be the right level (4 litres). I've probably confused the oil smell with transmission fluid.

But then again, if it is just a small oil leak, are these symptoms likely to only occur when driving above 80km/h on the highway?

Apologies for the total-beginner talk.

YouTube · Post by **El_Freddo** » Sat Feb 23, 2013 11:20 pm

I reckon it'll be a brake that's still holding.

Jack up each wheel and see if you can turn it (gearbox in neutral, hand brake off), if one is particularly difficult that'll be the culprit.

It doesn't pull to one side when driving? Odd tyre wear?

If it was oil on the exhaust you're more likely to smell it in traffic rather than at speed

Cheers

Bennie

steptoe · Post by **steptoe** » Sun Feb 24, 2013 12:11 am

a switch leaking box oil from the side to drip on exhaust and it is just at these speeds the exhaust gets to that nice ignition point perhaps? My Brumby with its 4 speed has this

Post by **TOONGA** » Sun Feb 24, 2013 9:42 am

Accumulated oil on the exhaust will heat up at HWY speeds and burn off, causing that burning oil smell that we all love.

The engine areas to look at are the valve covers for the heads, the power steering pump, the sump gasket and the crank and cam seals. the gearbox areas are the switches (thanks Jonno) the front and rear seals, the rear case seal (5th gear and centre) and the axle seals. If you can, degrease the engine and gearbox then get the car to running temperature and look for oil leaks.

TOONGA

Dusty_Hermit · Post by **Dusty_Hermit** » Mon Feb 25, 2013 8:28 pm

Thanks everyone for the help.

Work commitments means the degrease will have to wait a few days.

I'll let you know what I find.

Cheers

WeeGee · Post by **WeeGee** » Tue Feb 26, 2013 9:50 pm

Seems odd that you'd smell oil on the exhaust at such high speeds... Do you smell it still with the a/c fan turned off?

Odor Description
Antifreeze/coolant : Sweet odor
Electrical short : Acrid
Emissions : Sulfur, rotten eggs
Gasoline : Gasoline vapors
Oil : Heavy odor, usually accompanied by smoke
Overheated friction material : Burnt smell (brakes/clutch)
Overheating : Sweet smell accompanied by steam

(This information is entirely stolen from outside sources, i take no credit for it)

Post by **Alex** » Tue Feb 26, 2013 10:05 pm

Exhaust leak perhaps? At speed there's a vacuum created under the car which might cause the smell.

Sent from my Motorola RAZR HD

Post by **yarney** » Fri Mar 01, 2013 4:53 pm

Another thing to think about is a power steering leak down at the steering rack where the hoses go into it. It will drip straight onto the exhaust i noticed mine first on the hwy i would say coming up through the console

Jan

YouTube · Post by **El_Freddo** » Sat Mar 02, 2013 10:29 pm

Or you have a dodgy bonnet seal on top of the firewall so that the smells/fume/gases are being sucked into the cabin through the outside air pickup system...

There could be so many ways this is occurring it's not funny - it only takes a tiny gap in a boot or grommet for these smells to enter a cabin!

I still don't believe that you should be able to smell an oil burning smell when at cruise. I know the liberty I'm currently driving doesn't and it's got so many leaks that I'm about to pull the engine to sort out the issues - yet at low stop/start driving or stopping at the lights I can smell the burning oil - at speed it's a non issue other than wondering about the oil level in the engine...

Cheers

Bennie