djceri_g

Hi guys. I have a 2005 Subaru impreza gx sport.. Now Im concerned about the amount of oil it's burning! I’ve had it checked out and There are no leaks, actually very clean and dry underneath. No visible black smoke but inside the exhaust is very black sutty (thinking this is normal?) No engine knocking..

My question is how much oil consumption is normal for these cars? Also Does it depend on the type of oil? At last oil change I only bought some normal cheapish stuff. Nothing like Castrol etc. I think It's running on 5w x30w. Also the last oil change was a bit of an eye opener. Unfortunately due to my ignorance maybe, but the car was nearly dry!!! I only owned it a few months and hadnt checked the oil (stupid I know but ive never had to worry about oil in previous cars) but hardly no oil came out..but no light came on previously... I obviously took the car straight to be looked at..car has no knocking...mechanic said I was lucky.

eljay

It shouldnt really burn any oil if everything is as it should be.
Oil smoke will be a blue/grey.

I would look for a puff of smoke at cold startup first thing (get some one else to start it while you stand at back watching exhaust.
Also look for smoke from exhaust under heavy engine breaking.
Also look for smoke from exhaust when throttle is blipped after car has idled for 5mins orso.

It might be a good idea to have a friend follow you while you drive and have them look for any smoke whilst youre driving (small amount of oil could be burning off without you even noticing whilst moving).

If these all return a negative then I would be inclined to look for a rocker cover leak thats dripping down onto manifold and burning off - hiding the fact theres a leak (this could be smelled inside the car as a faint oil wiff - usually when coming to rest at a junction).

eljay

Oh and get some millers(?) 10 40 oil or equivalent in it. Crappy oil can cause problems for piston oil control rings.

djceri_g

The only smoke I see is the usual cold start up..condensation so its like white/grey? once it warms up I dont see anything. But thats a good idea, thanks! I will get someone to follow me and inspect! I dont smell any burning..I think I did once but I figured out it was just after I topped up the oil and i must have missed my aim and spilled some.
Regarding the rocker cover leak..I told the mechanic about this when I took the car to be checked..he went round all underneach the car with a torch and said that he could not see any leaks and the car was very dry.

If it is smoking..does this mean theres an issue with the engine I'm one of these that worry loads and thats why i got 3 mechanics to look at it..even though they have told me its okay..I still worrry

bustaMOVEs

iTrader: (31)

Valve stem seals?

djceri_g

im lost *opens google page* LOL

eljay

Yeah if it is burning the oil it will likely be an engine out job - either valve stem oil seals in the cylinder heads (unusual for boxer engine) or piston rings in the block (more likely). There is the chance it could be a breather system problem but again unlikely to cause massive use of oil. You dont have a turbo on that could have a blown seal so only rings or valve stem seals IMO.

After the visual checks I said in first post I would be getting your mechanics to do cylinder compression test and cylinder leak down tests.

I've just been through a big hassle with oil burning myself which resulted in a full rebuild + turbo so I feel your pain. Good luck mate.

djceri_g

I hear lots of people saying that the boxter engines do burn more oil than other cars..but what is acceptable?

djceri_g

can you tell me more about the breather system? sorry, im just not mechnically minded
ohh sorry to hear! least I havent got that turbo worry...but if my engine goes..what cost am I looking at to wither re-build or get another . I was told thta the non tubos were bulletproof..starting to regret buying one now

eljay

Technically no standard engine should burn oil unless something is worn.....but (and its a big butt) I have heard people say that 0.5L to 1L every couple of thousand miles is acceptable (to them!).

Mine was doing 1L every 100miles at its worst before rebuild and now its burnt nothing in 1000 miles after rebuild.

eljay

Rough breather description: It takes crankcase fumes and recycles them into your inlet to try and burn them off.

The main culprit of a dodgy breather system is the PCV valve (Positive Crankcase Ventilation). They can become stuck in the open or closed position which causes increased pressure in the crankcase causing oil to blow by the piston rings and get burnt.

djceri_g

ohh gosh..thats a lot of oil! I opened a 1L bottle 5 weeks ago and have only used less than a quarter of that bottle..Ive done approx 900 miles since...but its still an issue imo compated to the other cars Ive had in the past..I never had to check the oil..which was a bad thing really!

If this anything to do with EGR? I'll ask the mechanic to check this! HUGE thanks for all your help..thinking of it, I sometimes smell light fumes on startup? could this be linked or another issue completely lol

eljay

EGR takes exhaust gases and recycles them to intake. This is more of an emissions control system. A fault on this could cause you to fail MOT emissions test but isnt really linked to burning oil.

The amount of oil you seem to be burning is minimal IMO and nothing massive to worry about. As I said above, I have heard others say that a small top up every couple of thousand miles is fairly normal on boxer engines.

I would just keep topping up and watch how it goes for a while. If it seems to be burning more and more then it would suggest a bigger problem like those mentioned - valve stem seals, piston rings etc.

Be careful not to overfill.

johned

900 miles on a quarter of a litre of oil? and what mileage has the car done and what grade oil is now in the engine?

djceri_g

yeahh..its not too bad compared to the threads ive read on here and elsewhere since posting this lol..the car has done approx 76000,oil I used @last change comma xtech fully synthetic 5w-30. Since last oil chance ive done approx 1600 miles and topped up approx half litre of oil

djceri_g

ahh It passed mot last month only one recommendation - non standard exhaust fitted lol. yes Im keeping an eye..Ive noted down when I opened this 1 Liter bottle so see how long this lasts...ahh about overfilling...I had a panic once thinking I had because when I topped it up the engine was cold (morning) and it was bang on F...but I checked it again after being out and letting the engine cool for 5 min..oddly the oil level was well above the F :O ..I find it hard reading the dipstik on this subaru properly! often get different readings