993 - Smokey startup?
Discussion
Hi guys
When I start up from cold there is no smoke to speak of, but when I have taken it out for a few miles then leave it for a couple of hours and then startup there seems to be a fair bit of smoke coming from the exhaust for a few seconds then it dies down to normal, any ideas? or is this fairly normal of 993's.
Many thanks for any replies..
oil gets nice and thin at operating temperature. Switch off, leave for a couple of hours and a little may be remaining in the cylinders behind the pistons. This can seep passed the pistons into the combustion chamber (being a flat configuration). Start up and hey presto, a puff or two of blue smoke.
I believe many 993s have this 'feature'. Some get it at cold startup after sitting for a while.
My Boxster S used to do it every now and again.
I believe many 993s have this 'feature'. Some get it at cold startup after sitting for a while.
My Boxster S used to do it every now and again.
This is a common issue and its due to flat six engine layout as Silver993tt mentioned. I have to say that I'm aware of it only on cold start-ups but you seem to be getting it with warm start-ups and this may suggest that the oil you are using is too thin.
Many of the modern oils such as Mobil 1 are 0w/40 and you may need something thicker. I use Castrol Formula RS 10w/60 but I have also heard good things about Mobil 1 Motorsport 15w/50. Do you know which grade of oil you are using? If its 0w/40 I would think about switching to something thicker at the next service.
Many of the modern oils such as Mobil 1 are 0w/40 and you may need something thicker. I use Castrol Formula RS 10w/60 but I have also heard good things about Mobil 1 Motorsport 15w/50. Do you know which grade of oil you are using? If its 0w/40 I would think about switching to something thicker at the next service.
A little bit of smoke is certainly normal in my experience of starting my 993 after a bit of rest.
As long as it goes away after a few minutes and you are not using masses of oil, I wouldn't worry too much.
If you are seeing huge clouds of smoke under heavy acceleration and you haven't overfilled with oil so it has overflowed down the inlet tracts and is getting burned off, I would certainly seek the advice of your friendly local independent Porsche garage.
As an aside , an interesting quick and dirty way of checking cylinder leakage (according to Chris @ G-Force) is to pop out the dipstick on your 993 while the engine is running and look for distinct puffs of smoke.
I don't think this is definitive as oil gets a bit of moisture in it if you do lots of short runs and the oil will get hot enough to evaporate it off, which could confuse the issue a bit, but a helpful tip nonetheless.
Ian D
As long as it goes away after a few minutes and you are not using masses of oil, I wouldn't worry too much.
If you are seeing huge clouds of smoke under heavy acceleration and you haven't overfilled with oil so it has overflowed down the inlet tracts and is getting burned off, I would certainly seek the advice of your friendly local independent Porsche garage.
As an aside , an interesting quick and dirty way of checking cylinder leakage (according to Chris @ G-Force) is to pop out the dipstick on your 993 while the engine is running and look for distinct puffs of smoke.
I don't think this is definitive as oil gets a bit of moisture in it if you do lots of short runs and the oil will get hot enough to evaporate it off, which could confuse the issue a bit, but a helpful tip nonetheless.
Ian D
ian_dorrian said:
A little bit of smoke is certainly normal in my experience of starting my 993 after a bit of rest.
As long as it goes away after a few minutes and you are not using masses of oil, I wouldn't worry too much.
If you are seeing huge clouds of smoke under heavy acceleration and you haven't overfilled with oil so it has overflowed down the inlet tracts and is getting burned off, I would certainly seek the advice of your friendly local independent Porsche garage.
As an aside , an interesting quick and dirty way of checking cylinder leakage (according to Chris @ G-Force) is to pop out the dipstick on your 993 while the engine is running and look for distinct puffs of smoke.
I don't think this is definitive as oil gets a bit of moisture in it if you do lots of short runs and the oil will get hot enough to evaporate it off, which could confuse the issue a bit, but a helpful tip nonetheless.
Ian D
Interesting tip Ian, where are the puffs of smoke coming from? I am confused as i thought the dipestick went into the oil tank. I am not following how removing it would result in puffs of smoke. Any clarification would helpful..cheers.
I don't know how you could get oil mist coming out of the dipstick, unless there was no oil in the oil tank. However, worn valves could conceivably cause oil to be found in the air filter. This certainly happens with Land Rover engines, when the valve stem oil seals are knackered.
Back to the original question, mine issues a puff of blue smoke on startup maybe once or twice a month. It seems completely random, and I don't think it's anything to worry about. When I first got the car, it did it more regularly, but I've been filling it with Mobil 1 Motorsport which is quite thick, so perhaps that's why it happens less now.
Back to the original question, mine issues a puff of blue smoke on startup maybe once or twice a month. It seems completely random, and I don't think it's anything to worry about. When I first got the car, it did it more regularly, but I've been filling it with Mobil 1 Motorsport which is quite thick, so perhaps that's why it happens less now.
MR DVD said:
Many thanks for your replies guys, Barryj, I am currently using OW40, think I'll take your advice and try different oil at next service.. feel happier now, thought it may be the start of something serious..
When I was using 0w/40, I used to get a puff of smoke on every cold start-up and after switching to 10w/60 it happens probably once a month. Its definitely worth changing your oil before paying up for someone to investigate a potential problem that may not even be there.
When you check your oil level before topping up, are you doing so (a) when your oil temperature meter pointer is horizontal (b) when the car has been allowed to idle for a minute? If not, you may be over-filling and this is a common mistaka to maka!
>> Edited by barryj on Friday 4th June 08:35
ian_dorrian said:
Chris said the dipstick tube would puff smoke that had blown past the piston rings.
Seemed plausible to me at the time, but you are certainly right about the dipstick going into the oil tank.
Hmmm...needs further investigation
Anybody else shed any light on this?
I was there when Chris said this and I don't recall him saying that smoke would come from the dipstick; I thought that he said puffs of air would come from the dipstick. Of course, I may be wrong so it might be worth putting and call into Chris and checking?
Also worth remembering that 911s overfuel quite significantly on start up so you're likely to get a puff of (black) fuel smoke too. This mixed with a tad of oil from sitting for a while and overnight crap in the exhaust is always likely to cause a small puff of smoke - IMO as long as it is ONLY a puff there's nothing to worry about. All my 911s have done this.
steve-p said:
Back to the original question, mine issues a puff of blue smoke on startup maybe once or twice a month. It seems completely random, and I don't think it's anything to worry about. When I first got the car, it did it more regularly, but I've been filling it with Mobil 1 Motorsport which is quite thick, so perhaps that's why it happens less now.
Same here!! You should have seen the smoke screen after I'd left it for a month....
Been running Mobil Motorsport in 964's for some years. It favours the bigger oilways and bores of 'older' engines. Keep the 0-40 for the new ones...
But tell that to the guy that blew up his 993 at Combe yesterday....lots of smoke from the right exhaust on start up. Trailing a haze of smoke all day and a puff on change up (many told him -he knew!!) -garage had checked levels and said it was all OK........
Mel
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