Smoke Offside exhaust on 993

[SJSlack]

Have only just put very low mileage (17000) 993 aircooled turbo back on road but getting black/blueish smoke with oil residue in offside exhaust pipe which has not gone away with long/varied driving.

Any ideas on what simple things to tackle before worst is assumed?

Performance seems fine but fumes not!

 

[Gordon Attar]

It's very hard to define from symptoms with that mileage has it been regularily started to keep all the seals lubricated so good be anything.

I would hazard a guess at looking into oil seepage into the turbo it's a well known 993 tt issue.

Please visit a specialist that look after 993 tt's like Northways near Reading.

 

[911 targa]

Sounds like oil passing through valve guides

 

[IndischRot]

A few questions:

1. when was the oil last changed?

2. what weight oil was used?

3. Is the oil overfilled?

4. what brand of oil filter was used?

Might sound like obscure questions but the answers could reveal the source of the problem.

 

[John_Ward]

Oil seeping past seals somewhere.......

If you post this in the 993 section I'm sure that you'll

get a helpful response from Maurice or Christian

 

[John_Ward]

This makes for interesting reading

https://parts.turbokraft....harger-oil-line-update

 

[SJSlack]

Would that only be the case if this were a worn out engine, which this is not - we are the second only owners and knew the original ones. Your input is greatly appreciated, as we would like to nail this problem asap so we are less embarassed as we sit in traffic!

 

[IndischRot]

As I asked it would be useful to know the recent maintenance history. I'll venture a guess that the oil was changed recently?

It's important not to overfill the oil tank. About 1/3 above minimum is ideal and then check it regularly. If a non-Porsche filter (even Mahle) filter was used it may well not have the anti-siphon valve that's within the genuine Porsche filter (only relevant to the 993tt, not NA 993s). But even the Porsche filter needs to be installed carefully; if it's over tightened the valve can be damaged. And the oil weight should ideally be something like 15W50, not a 0W30 or 0W40 weight.

Those oil lines can help on higher mileage cars but with only 17K miles they shouldn't be needed.

The cause is usually a combination of too light an oil, the wrong and/or a damaged oil filter and/or an overfilled oil tank.

The 993tt is rare enough that even usually well meaning and knowledgeable specialists can use the wrong oil, wrong filter and/or over-tighten the filter. A certain otherwise very competent specialist located near to J20 on the M25 did this to my 993tt - used too light an oil and overtightened the filter and damaged the valve. The car smoked very heavily out of both exhausts and oil dripped from one or perhaps both of the turbos. I changed the oil and filter and all was well. In the photo you can see part of the anti-siphon valve that fell out of the filter when I shook it after removal and you can see the spring lying sideways.

 

[SJSlack]

Thanks for this support. Oil used in last fill up was Mobil 10W/40 at 10000 on the clock. I cannot detect on the service bill any oil filters (could not believe that as it was an official Porsche dealer?) Will check oil level (and colour) issues, and probably then get the oil properly changed. The oil seemed to comply with the book, but things have moved on and note your comment on too light oil, as I notice we have a bottle of Mobile 1 5W/40 in the garage for top ups. Get back shortly.

 

[SJSlack]

Hello John Have now posted on the other thread. Novice to the posting codes I am afraid.

 

[Gordon Attar]

How long ago was the last service ? It is meant to be annually! I'm getting the impression from the current mileage and opening post ref putting back on the road it was a while ago?

The filter are part of the ."service kit"

 

[IndischRot]

And worth noting there *2* filters - can't see why any specialist would change just one or worse yet, neither. Unless they didn't have them in stock in preparation for your car. In which case I would vote with my right foot and drive elsewhere.

 

[IndischRot]

Agree with Gordon, like usual .. [8|] .. lots of warnings about infrequent use in the buyer's guide etc.

Probably oil getting into that side's turbo. Bringing a car back from disuse requires re-commissioning by a marque expert ..

cheers, Maurice

It'll be the turbo on the opposite side of the smoking exhaust...

 

[IndischRot]

I beg to differ with the right honourable 993 register secretary... it's likely to very much be oil spec or maintenance related. The wrong oil or filter choice doesn't always manifest itself immediately.

You don't state what your appetite for DIY is? Or where you're located?

That only one side is smoking is symptomatic of the oil sump for the nearside turbo being filled by oil being siphoned out of the main oil tank. This oil is then getting past the seal on the hot side of the nearside turbo and getting burned off within the turbo itself.

In the photo below I've circled the sump plugs on each of the turbos. If you have the appetite for it remove the sump plug on the nearside turbo (6 or 7mm hex key) and drain the oil that's in the sump until it just drips slowly. Then reinstall the plug, take the car for a drive and get the engine hot and check the oil level (engine running as required by a dry sump system).

If you look at the exhaust system in the photo you'll see why the problematic turbo is on the opposite of the smoking exhaust tip.

If you bring the car to a specialist they may simply say that your turbos have failed and that they need to be rebuilt. IMHO that could be a four figure mistake and you could well end up with a smoking engine in a year or two because the root cause was not addressed. Start from a known baseline - the right oil, the right oil level and the right oil filter. Even Porsche now recommends their 10W60 oil for the aircooled cars!

 

[Gordon Attar]

Guys until the owner tells us the following we are wasting our time. As it could be any of the above responses.....

1 - car has been in storage, for how long?

2 - car has done 17k last serviced at 10k when was this. Could be 5 years 10 years ago!?

3 - Roughly where they live so we can point them at an experienced 993 Turbo specialist

 

[SJSlack]

DIY yes is possible and of great interest, even as a mere girl!! The car was last serviced 10 years ago thereabouts with 10K on the clock. The oil has now been dipped per the instructions and the level is at the full rather than the much lower level suggested. I have noted the point about the crossing over of the turbos from the excellent photograph which is there, so can see why I need to use a particular drain to draw off surplus oil, and then go for a drive. I am still getting the smoking, so if we can get some oil out of the correct plug that may answer everything!! First I will tackle the how to remove the plate under the car that gives me access to them but may have to go to someone with a hoist as this is definitely a tight fit job. Thank you everyone for your support - I know we will get the answer from your combined expertise.

 

[Gordon Attar]

Please please please dont drive it until you get a major service including spark plugs and have all the belts changed before you do some serious damage. The smoke could be down to something as simple as the oil or petrol breaking down

 

[Pierrealinoor]

We are discussing a complex car whose value is well into 6 figures .. please get it serviced by someone really knowledgeable ASAP ..

BTW, will you marry me ? ... [&o][8|][] ..

cheers, Maurice

haha - that made me chuckle! I totally agree that a service by a good independent sounds key - a +1 vote for Northway if you're in Berkshire area.

 

[Ray]

We are discussing a complex car whose value is well into 6 figures .. please get it serviced by someone really knowledgeable ASAP ..

BTW, will you marry me ? ... [&o][8|][] ..

cheers, Maurice

Take a ticket and stand in line Maurice.

Ray