Help! Blue smoke from exhaust

[dom069]

Hello all,

I'm in need of some help. I've got an 05 plate Gti (AXX) with 70k on the clock. I went and had my wheel alignment done this morning, and on my way home noticed quite a lot of blue smoke coming out of the exhaust.

It is intermittent but fairly frequent, fluid levels are fine, no lights on dash and the car drives ok. I have an oil leak from the top of the engine, which I looked at last weekend and it looks like the oil filler cap was leaking and causing oil to run down the back of the engine.

The car has a BSH PCV revamp which was fitted by the previous owner, a bit of searching on here suggests that smoke and oil from the filler cap can both be caused by a faulty PCV. Does anyone know if the BSH revamp can be fitted incorrectly?

Any other suggestions for cause? Initial thoughts are potentially turbo seals? I'm hoping it's nothing too serious because I'm skint and need the car for work next week.

Cheers

Dom

[th3_f15t]

If you've got oil coming out the exhausts, you definitely have a leak internally and need to check things out. Monitor oil levels very closely but best advice is get it into a specialist ASAP.

I've heard rumours that PCV removal kits can cause excessive pressure within the engine and cause problems. Most VW Cup racing engines use the stock PCV system as it's fine. Possibly worth grabbing a stock PCV and re-fitting it to see how things go.

[MJGib]

Blue smoke is normally means you're burning oil... But also I would get an original PCV them delete things are poo

Does it smoke once the cars warmed up? Or only when it's cold?

[dom069]

Thanks for the replies so far

It's also worth mentioning that oil is being forced from the filler cap so much that it's on the sound deadening on the underside of the bonnet. I've refitted the standard PCV and it's still smoking but I've not taken it for a drive, just gently revved it on my drive.

Should I take it for a short drive to get it up to temperature and see if it still smokes with the standard PCV? The issues is clearly excessive crankcase pressure, I just hope it's not anything too serious that's causing it.

[th3_f15t]

Was it a brand new PCV you fitted? Have you done the standard tests/diagnostics since fitting it?

You'll want to take it for a gental drive to let any oil residue left in the combusion system/exhaust to be fully burned off before saying whether it's a success or not.

[dom069]

It was the original pcv that came with the car.

I unscrewed the filler cap with the engine idling and it started spluttering, as far as I'm aware this suggests it's working?

I'll take it out for a steady drive now and report back.

[th3_f15t]

Yeah, although in future I'd recommend removing the dipstick instead, less chance of damaging something that way.

[dom069]

I didn't even think to do it using the dipstick. I only released the pressure for a few seconds and tightened it back up again.

I've just taken it out for a 3-4 mile drive, there was a small amount of smoke when pulling off my drive and up the road.

I drove a couple of miles off boost until the engine was up to temp then drove it gently with a bit of boost and couldn't see any smoke at all.

The roads were pretty wet so there was a fair amount of spray though. I'll take it for a longer drive tomorrow, but hopefully it was an easy fix.

Thanks again for the help 

[Dan_FR]

PCV delete severely restricts the engines breathing, more than a catch can setup and signifincatly more than the OEM PCV, due to the way the delete restricts the passage for air/vapours in the cam cover, and both the catch can and delete remove the syphoning under vacuum.

Sounds like your pressure was excessively restricted if you were leaking oil from the filler cap. Fingers crossed it's all sorted

[th3_f15t]

As mentioned, you'll probably have some residue to burn off over the next few weeks, but it'll hopefully behave itself now. You might want to look at getting the inlet professionally stripped down and cleaned as it'll be caped in oil and burnt carbon.

AKS Tuning quote about £200 for a strip down and clean.

[dom069]

Thanks again, a good friend of mine owns Only Charged Dubs which is just up the road from me. Under his close supervision I'll probably have a go at giving the inlet a clean out myself.

I've heard nothing but outstanding things about Alex though 

[th3_f15t]

Thanks again, a good friend of mine owns Only Charged Dubs which is just up the road from me. Under his close supervision I'll probably have a go at giving the inlet a clean out myself.

I've heard nothing but outstanding things about Alex though 

You've just become my best friend on this forum... You won't go wrong with those boys, highly rated by Performance VW and other magazines. Would love to let them loose on my engine one day with one instruction: "Make it 300bhp+."

[dom069]

Matt certainly knows his stuff, I've known him for years. Spent many a day lying under cars on his drive before he set the business up!

I set up his first website for him and do some work on his current one in return for use of a corner of the unit, his tools and a bit of advice

I'm still struggling to get my head around how the pcv being restrictive was causing oil to get into the exhaust. I get that it is restrictive, causing a build up of pressure, but how is it entering the exhaust?

[th3_f15t]

I would assume that due to the large increase in internal pressure, the oil vapour was forced though oil seals and gaskets and into the exhaust. I would ask OCD as they'll know. Do you happen to get things done for mates rates?

[dom069]

I would assume that due to the large increase in internal pressure, the oil vapour was forced though oil seals and gaskets and into the exhaust. I would ask OCD as they'll know. Do you happen to get things done for mates rates?

Yeah, I've spoken to Matt and he said it was plausible, he just didn't explain why. They're completely flat out at the moment with other jobs. I get well looked after whenever I have anything done