Hello, I'm hoping someone can point me in the right direction... 

 

I've owned my mk1 VRS for a couple of years now and had the odd problem here and there but this I can't seem to find what's causing it. 

 

Only when driving, occasionally the exhaust spits out white smoke. It never does this when idling and doesn't always do it when driving. It's usually one biggish plume of white smoke and then disappears within a few seconds, (happens more under harder driving) it's getting more frequent now than it used to (once every week or so) and is worrying me as I can't seem to find what's causing it. Doesn't lose water or oil, no mayo under the cap etc. As it doesn't happen when idling, I can't get a whiff of the smoke to give any more details on that! Can anyone help??? 

Is this "on power", or lifting off throttle when you get the plume of smoke?.

 

Is the car fully warmed up when it occurs or does it make no difference?.

 

Roughly what sort of mileage has tghe car done?.

Both when on power and off, it's like one cloud that then disappears. The car sometimes makes a slight cough when this happens but not always. Yea it's normally when it's warmed up but I can't be certain it's fully up to temperature. Temp gauge stays at 90 degrees, and it's on 116k miles, fully serviced with all stamps etc been looked after and not a ****ter lol really has me stumped 

Is the exhaust system just gathering H20 and blowing it out?

If you are not having any movement in coolant / not using any that is the only source of Antifreeze / H20 other than condensation in the engine 

or moisture coming in the air intake or breathers.

 

Is the air filter perfectly dry?

Yea I think it's completely dry, I've not checked having said that but I will to make sure, to me it's more like smoke than steam. Coolant never goes down, no oil in the expansion tank, nk may under the cap so, to me, no signs of head gasket 🤷‍♂️ thought it may be the turbo? Or oil gathering in the intercooler? 

If it is oil then it is not 'Smoke' anymore than it is Steam or water vapour. 

It will be Scotch Oil Mist... a haar even.

I was initially thinking along the lines of valve guide seals, but they normally manifest themselves as smoke on the overun and initial power takeup after the overun, rather than continued on power acceleration.

 

As you are getting it all the time, I would be inclined to check the PCV valve in the breather pipe - they are about £10 for a new one, as consistent breathing of crankcase fumes could be filling the intercooler with oil. Having said that, it would have to be fairly extreme to fill the intercooler without you noticing any loss of oil. It is highly possible it is just rebeathing a higher than normal amout of crankcase fumes due to a geriatric PCV valve.

 

I would check your pcv valve and also check the throttle body for excess oil contamination, - you can check the throttle body easily by just dropping off the intake hose and having a brief look with a good light source.

 

Just my thoughts at the moment, hope it helps

 

 

8 minutes ago, kentphil1 said:

I was initially thinking along the lines of valve guide seals, but they normally manifest themselves as smoke on the overun and initial power takeup after the overun, rather than continued on power acceleration.

 

As you are getting it all the time, I would be inclined to check the PCV valve in the breather pipe - they are about £10 for a new one, as consistent breathing of crankcase fumes could be filling the intercooler with oil. Having said that, it would have to be fairly extreme to fill the intercooler without you noticing any loss of oil. It is highly possible it is just rebeathing a higher than normal amout of crankcase fumes due to a geriatric PCV valve.

 

I would check your pcv valve and also check the throttle body for excess oil contamination, - you can check the throttle body easily by just dropping off the intake hose and having a brief look with a good light source.

 

Just my thoughts at the moment, hope it helps

 

 

Thank you for your reply. It's hard to give you accurate information as your not always looking in the rear view mirror to see the smoke! It's not all the time, its probably 1 in 10 drives or maybe slightly more that it tends to give off the smoke. If I think about it I would tend to say its more when I let off the throttle or when it's above 3k-3. 5k revs when accelerating hard. I've owned the car for a couple of years and serviced it last year, since the service I've topped the oil up once a couple of weeks ago when the light popped on so I wouldn't say it uses much oil at all really. I did pass it by my local mechanic before this corona virus came about and his initial thought was head gasket, (no signs of it on the way out) possibly the turbo or maybe oil getting into the intercooler. Apart from that I'm clueless! I will definitely have a look at the throttle body and pcv valve and check back my findings, thanks again! 

When you remove the intake pipe from the throttle body on a fairly new car you would normally see a very light almost non existant mist coating on the throttle body butterfly, but as the car ages, it rebreathes fumes more, which tends to get more noticeable.

 

It should really be more of a case of feeling the oil coating if you just rub you finger around the throttle body entrance rather than seeing full blown streams of droplets of oil in the intake. The thing is, as I said, you have to allow for age passing more fumes, the trick is when to decide what is too much.

 

Best plan at the moment is to have a look in there, if there is visible oil rather than mist, take a photo, post it up and we can give you an opinion as to whether is in line with the expected age of the car and mileage or whether it needs a bit of tlc. Just out of interest, to the best of your knowledge, when was the throttle body last cleaned?.

 

When I first had my vrs, it had just over 85k on the clock, and most of the breather hoses were either split, or parts of the hose lining had degraded and blocked the PCV vavle from sealing shut. it would use a pint of oil in about 6000 miles until I renewed the pipes and a new valve, which reduced futher oil usage to almost zero between services. It now has 150k on the clock, and still only uses just under half a pint between intervals, so I may check the valve again at service time as I've the car 9 years now.

That all makes perfect sense, il have a crack at it after work tomorrow. Since I've owned the car the throttle body hasn't been cleaned at all, just over 2 years. I bought it on 99k miles and it's around 116500 miles now. I would like to add, incase its relevant, that the smoke has come more frequently since I had the car fitted with a 3" downpipe and decat. I had this done around Feb this year along with a new clutch and other bits. I have had a little look online about the pcv valve and so far everything points in that direction. Thanks again and il be back on tomorrow with what I can find!