White exhaust smoke

[Steve007]

Hi everyone,

I have a 1987 TSI turbo (125,000 mi.) that is blowing white smoke. I store it in the winter and this last spring when I started it, thick white smoke poured out of the exhaust. After a while it thinned out but even the next day it stilled smoked but much less so. The car has never done this before, even after storage. If it were condensate, I would think it would disappear after warming up.

The antifreeze level has not dropped one bit. The exhaust does not smell of antifreeze.

Inspection of the interior of the turbo showed no damage at all. I am the original owner and, on the advice of a mechanic when I bought the car, ALWAYS let the turbo cool for a few minutes. I have never driven the car hard. I have a 911 that I use at tracks.

I have added a quart of oil between changes for some time now. I assumed that there would be some ring blowby in a car this old and mileage.

My Porsche mechanic replaced the gasket at the throttle body, thinking that might be allowing coolant into the intake. Upon removal the gasket certainly needed replacing, but it didn't solve the problem.

I know there can be many causes for this but based on these symptoms, can anyone point us in the right direction? I suppose a compression test would rule out the head gasket, but since the antifreeze level has never changed, he was hoping it might be something else.

Thanks for any help.

Steve

[techboy]

I suspect your valve seals. If your car is stored for the winter and not driven a ton, they may have dried out and letting oil slip by - esp since your coolant level isnt changing, id lean more toward oil. 

Check your PCV as well, it might stuck or shot. Itscs cheap easy replace. 

[psu_Crash]

I would absolutely to a compression test. It is quick and then you will know. No cotton candy smelling exhaust really sounds like it's condensation. Does it clear up after a quick drive? 

You said it doesn't smell of anitfreeze so I assume it doesn't smell like oil burning or super rich either? Is there oil in the turbo inlet and/or charge pipng?

I had a similar issue with a smashed valve guide seal. Ran fine and cleaned up a lot after a little drive. Every cold start was smokey and a quick decell also caused a poof. 

Since yours has had no work and it hasn't done this before ... that's the interesting part. My problems are usually self induced 🙂

Edited August 24 by psu_Crash

[1SICDSM]

also check the exhaust side of turbo for oil leaking in from turbo.can also pressure test the coolant system, pull spark plugs, and see if any traces of coolant.and when the smoke was pouring out was it running rough or normal?

[Steve007]

On 8/23/2025 at 8:23 PM, techboy said:

I suspect your valve seals. If your car is stored for the winter and not driven a ton, they may have dried out and letting oil slip by - esp since your coolant level isnt changing, id lean more toward oil. 

Check your PCV as well, it might stuck or shot. Itscs cheap easy replace. 

I appreciate your quick response and input - a valve seal is one of the options we've considered. I will pass your suggestions to my mechanic.

Another fellow, psu_Crash, said he had similar symptoms and that, after storage, the seal may have dried out and driving it for a while made most of it clear up. If not that, the PCV would indeed be an inexpensive fix. 

[Steve007]

On 8/24/2025 at 7:44 PM, psu_Crash said:

I would absolutely to a compression test. It is quick and then you will know. No cotton candy smelling exhaust really sounds like it's condensation. Does it clear up after a quick drive? 

You said it doesn't smell of anitfreeze so I assume it doesn't smell like oil burning or super rich either? Is there oil in the turbo inlet and/or charge pipng?

I had a similar issue with a smashed valve guide seal. Ran fine and cleaned up a lot after a little drive. Every cold start was smokey and a quick decell also caused a poof. 

Since yours has had no work and it hasn't done this before ... that's the interesting part. My problems are usually self induced 🙂

Thanks very much for the suggestions.

I'm going to pass your post on to my mechanic. He did scope the interior of the turbo and it is clean. I know when my 911 has been sitting for a while, there's always a bit of blue smoke from the turbo when I start it, indicating oil, however it clears quickly.

I'll let you guys know what we find. Perhaps it will help someone else. I love my Conquest but it's getting harder and harder to find parts for it!

[Steve007]

On 8/25/2025 at 8:08 AM, 1SICDSM said:

also check the exhaust side of turbo for oil leaking in from turbo.can also pressure test the coolant system, pull spark plugs, and see if any traces of coolant.and when the smoke was pouring out was it running rough or normal?

Thanks for the suggestions. We will check these things.

It runs normal.

[psu_Crash]

On 8/26/2025 at 12:06 PM, Steve007 said:

I love my Conquest but it's getting harder and harder to find parts for it!

Indeed it is. We all love these old beauties and do what we can to keep them on the road

[Steve007]

On 8/23/2025 at 4:45 PM, Steve007 said:

Hi everyone,

I have a 1987 TSI turbo (125,000 mi.) that is blowing white smoke. I store it in the winter and this last spring when I started it, thick white smoke poured out of the exhaust. After a while it thinned out but even the next day it stilled smoked but much less so. The car has never done this before, even after storage. If it were condensate, I would think it would disappear after warming up.

The antifreeze level has not dropped one bit. The exhaust does not smell of antifreeze.

Inspection of the interior of the turbo showed no damage at all. I am the original owner and, on the advice of a mechanic when I bought the car, ALWAYS let the turbo cool for a few minutes. I have never driven the car hard. I have a 911 that I use at tracks.

I have added a quart of oil between changes for some time now. I assumed that there would be some ring blowby in a car this old and mileage.

My Porsche mechanic replaced the gasket at the throttle body, thinking that might be allowing coolant into the intake. Upon removal the gasket certainly needed replacing, but it didn't solve the problem.

I know there can be many causes for this but based on these symptoms, can anyone point us in the right direction? I suppose a compression test would rule out the head gasket, but since the antifreeze level has never changed, he was hoping it might be something else.

Thanks for any help.

Steve

Update,

Thanks for all the suggestions. Apparently, it was the catalytic converter (there are actually 2 of them). Who knew?? After 38 years it was full of debris.

We replaced the whole exhaust system. Now there is only a tinge of blue which I would expect from a car this old, and I've added a quart between oil changes for years.

On 8/25/2025 at 8:08 AM, 1SICDSM said:

also check the exhaust side of turbo for oil leaking in from turbo.can also pressure test the coolant system, pull spark plugs, and see if any traces of coolant.and when the smoke was pouring out was it running rough or normal?

Thanks for the suggestions. We will check these things.

It runs normal.

[Steve007]

Update

I am writing this to add to the possible causes for anyone else with this symptom.

Apparently, it was the catalytic converter. Who knew?? There are actually 2 of them. Since the Cats are 37 years old, they were full of debris. One right after the turbo then the main one before the muffler. I wonder why 2?

We replaced the the whole exhaust system and that cleared up the white smoke. There is now only a tinge of blue which makes sense since I've been adding a quart between oil changes.

Thanks for all the help!