Oil smell when hot
 

Hi guys

Just done a oil change recently and now I have a smell of burnt oil coming out of exhaust, it doesn't smell when cold only after cars warmed up.

It never done it before the oil change only thing different I've gone from 10/60 to 5/40 oil grade

The smells definitely coming out of exhaust and not engine bay.

Any reason why you changed?
The latter is a thinner oil so I could only imagine it's molecules are getting pulverised much sooner ,, keep a close eye on your readings & if indeed it is using more I'd say that was your answer ... Oil breakdown in performance cars ( the oil literally get's the sh$te beating out of it & if it is thinner then that will only make the job easier for the engine

This in a classic?

If so way to thin 5/40 oil grade

Bugeye running 400bhp

It could be due to going thinner. I'd personally never use a 5 in my Impreza. Stick with the 10w50 or the 60 you had in previously. If it ain't broke don't fix it.

b0llocks.

its the correct weight of oil.

It may be in the book but it's not recommended by most engine builders.

For once I agree with Thomas.

5w is the winter(cold) weight so makes no difference really
the 40w is the weight at 100c

sadly like above people have no fecking idea what the numbers mean

OP drop the 5w 40 oil and replace with 10w 60. If it cures the issue then you've got your answer, if not then take it to a garage and get it further investigated. None of the respected engine builders are keen on a 5w oil in an Impreza. It's common knowledge.

5 is the COLD weight it makes no difference when warm.
60w oil is too thick for standard internals.
builder dont use standard internals ;)

40 or 50w is fine

too thick oil is as damaging as too thin oil.

bear in mind that modern oil recommends from a manufacturer are pretty much solely based on fuel economy and reducing fleet costs - not engine life

the OP's symptoms sound very strange and not something i would suggest is solely a grade issue although it wouldn't have been my choice

as a rule i wouldn't use less than a 10w40 oil in a classic or a 5w40 in new-age in general use and would move up grades depending on exact use/mods/etc.

and despite what certain "experts" state a *w60 oil is NOT too thick albeit i wouldn't use it in a std car normally...........same experts even suggest using winter and summer grades????

Alyn, bearing in mind the 60w part relates to the warm weight anyway why do we have this fallacy that it's 'too thick'? In my opinion a newage sti running around 300 bhp is a fairly stressed engine, therefore would benefit from having an overall thicker weight. Moreover if you like to use the power. I'd favour a 10/15w 50/60 over a 5w 30/40.

would normally recommend oil weights based on use rather spec as a 215bhp UK Turbo abused on track will have a far harder life than a mapped 350bhp STi pottered to the shops and back most days.......

Stop talking rubbish dan