puff of smoke on startup when cold
 

Hi all, my Hawk wagon has started doing something a bit odd of late. First thing in the morning with engine cold it will give a puff of smoke. Does not appear to do it when the engine is warm however.
It runs fine, sounds the same as it always has and boosts fine. no EMLs etc. No smoke under boost so I don't think it is the turbo?! It has a very low mileage VF28 fitted but I’m not ruling it out.

I was thinking valve stem seals maybe? But head gasket went about 2 years ago, these were changed to a RCM gaskets and heads refurbished at same time. I think these seals were done at this point as well. Be unlucky if they have gone in such a short space of time..

I do have an Air Oil Separator much like the Grimspeed one. I’m starting to wonder if the breather hoses have been accumulating oil for the last year it has been on now collected a fair amount causing it to do this?

I plan to take the intercooler off at the weekend to see if that has oil in it, and enough to be causing this. But any other suggestions (apart from ringland scaremongering lol) are welcome.

Many thanks,
Rob

im interested in hearing about this. Mine gives off a cloud of smoke on start-up on the very rare occasion and it scares me to death. I've been looking at AOS for a year now but just never bothered. I'm surprised to hear yours still does it with one fitted.

I reckon it's likely valve stem oil seals.
Mine occasionally does it too.

well. I just contacted the company who done the head gasket work. They advised me valve stem oil seals are not normally an issue on Subaru’s due to the boxer engine configuration and oil doesn’t tend to sit in them and weep down into the bores.Usually a sign of turbo or pistons/rings. I’ll get the intercooler off over the weekend and see if any oil is sat in the throttle body. My thinking is the butterfly being closed if it is the turbo there will be a small puddle of oil in there?! Then starting the car would let that drop into the intake.If it’s that then I’ll look at a new turbo. If not then I’ll do a compression test and see what happens. I’ll keep you posted.

If its not using any oil forget about it some do and some don't. It'll let you know when it's poorly. What boost are you running vf turbos don't like being over spooled they tend to loose compressor tips and snap shafts.

My old blob wrx did this, turned out my turbo seals were on the way out.

It didn't use any oil but recently it has started to a bit (since it started vaping). Is without doubt oil coming out of the exhaust I can smell it.
It's away having some paint sorted atm. But as soon as I get it back I'll have a look in the intercooler. I think as it does it when cold I'll take intercooler off without starting it to see if a puddle has accumulated in the throttle body. That I think will be a good sign as it will be turbo related in my logic.


I’ll probably look at a recon turbo. Something a bit bigger than the VF28 (running around 18/19psi btw) I’m thinking VF43 or VF48.
Just hope it is turbo….

some good investigation today. intercooler off and sure enough fair amount of oil in there.
I then decided to go a bit further and done a compression test. lowest 124psi and highest 127psi. On a (2.5 litre) engine with near 80,000 miles I think that's ok? I think I'd be rather unlucky if all the pistons have gone bad at the same time.
I do think this points me back towards the turbo seals. Anything else to look at or do I look at replacing the turbo?

cheers.

Sounds like Turbo to me. If it were pistons you'd notice it sounding a bit uneven when you start it up, as well as low compression.

Another quick check is to see If it smokes on boost, either in your rear view mirror when you give it some right foot, or have someone watch the exhaust when you rev the car while stationary.

You could pull the down pipe and check for shaft play or oil, but by that point your as well pulling the turbo off completely.

Next job is to figure out why the turbo failed. Is it just age/usage related or is there something else at play? Could be a current or historic oil contamination issue so worth checking that. Also boost leaks are known to cause premature failure through overspeeding and oil dilution. A turbo specialist will be able to shed some light on the failure mode when they strip it down.

Read this before taking it apart...

https://www.scoobynet.com/general-technical-10/1031319-3-port-catch-can-install-with-sump-return.html

Chris.

According to a friend it does smoke a bit on boost. He said it gives a puff when I change gear and/or accelerate. This I think now has turbo written all over it.

As for the turbo itself, I was advised it was low mileage but used. I think around 40,000 miles (I have no proof of this). I've had it on for about 3 years and done about 15,000 miles on it and it's running 320bhp and 350lbft. I change oil every 5000 miles with Shell helix ultra 5w40. When the head gasket was done I had uprated oil pump fitted and only use the Subaru black oil filters.

I've found a 'hybrid' VF28 with a larger compressor wheel. that is tempting me but might need a remap. so if it needs a remap anyway tempted with the cheaper option of a VF43/VF48

The new turbo has been on a few weeks. Apart from one of the coolant hoses weeping a bit all appears to be well. no smoke on start up. :)
The intercooler was rather full of oil. I ran loads of carb cleaner through it before putting it back on.

Annoyingly the VF28 feels to have next to no shaft play. Appears to have just blown the seals. I was considering having the seals done but if taking it apart to do the seals I guess you might as well go the whole hog and have it rebuilt?

Next task is to try and get it mapped. It seems to be running ok but want a map to be sure. Any recommendations around the Milton Keynes area? Ideally I'd like it mapped on a rolling road as I will probably be looking to sell the car next year. Nice to have a print out to go in the paperwork.

Thanks,
Rob

Just a thought that car didn't come with a vf28 have you made sure you have the correct banjo (oil feed) bolt in it as the td turbos have a larger orifice.

Yep. I went back to the same banjo bolt from the original TD04L (1.8mm hole from memory!?) I had a 1.2mm banjo on the VF28 as it is a ball bearing turbo.
thanks for caring though ;)