993TT (1996) - Possible Purchase - Need Advice Please.
08-17-2009, 10:40 PM
#1
993TT (1996) - Possible Purchase - Need Advice Please.
- hi.
- have looked at a 993TT , year 1996.
- a couple of issues :-
(a) start from cold , there is pronounced whitish smoking from the engine (more from left bank exhaust , less from the right). The smoke clears quickly in about 30 seconds. Then the exhaust is clear. Is it something that needs more inquiry/attention ? The seller says that its a common issue with the flat-6 , ie , oil accumulates in the cylinders and is fired out and burned during start up.
(b) the blower is constantly on. The switch unit does not/cannot control the blower fan anymore. Seller says that the circuit board for the blower needs to be replaced (but seller wants to sell the car "as is" , and any repairs are to be done by me). Is this a known issue ?
(c) the right side door window switch does not work. Seller thinks that it is the switch. Could it be the motor ? Or is there a common relay fault ?
(d) clutch is heavy. Are 993TT clutches v.heavy ?
(e) she comes with HID lights. Were these even available in 1996 ?
(f) the hydraulic struts for the front bonnet and the engine lid are all dead. Is this common ? A simple fix ?
(g) car has been sitting for a substantial period of time. Is this a negative ? Mileage is v.low ( something like 26K miles ).
- thanks in advance for your help.
.
- have looked at a 993TT , year 1996.
- a couple of issues :-
(a) start from cold , there is pronounced whitish smoking from the engine (more from left bank exhaust , less from the right). The smoke clears quickly in about 30 seconds. Then the exhaust is clear. Is it something that needs more inquiry/attention ? The seller says that its a common issue with the flat-6 , ie , oil accumulates in the cylinders and is fired out and burned during start up.
(b) the blower is constantly on. The switch unit does not/cannot control the blower fan anymore. Seller says that the circuit board for the blower needs to be replaced (but seller wants to sell the car "as is" , and any repairs are to be done by me). Is this a known issue ?
(c) the right side door window switch does not work. Seller thinks that it is the switch. Could it be the motor ? Or is there a common relay fault ?
(d) clutch is heavy. Are 993TT clutches v.heavy ?
(e) she comes with HID lights. Were these even available in 1996 ?
(f) the hydraulic struts for the front bonnet and the engine lid are all dead. Is this common ? A simple fix ?
(g) car has been sitting for a substantial period of time. Is this a negative ? Mileage is v.low ( something like 26K miles ).
- thanks in advance for your help.
.
08-17-2009, 10:51 PM
#2
Banned
I'll field a few and defer to the others.
(a) Smoke - defer to others, mine has never smoked. Could be BIG beer.
(b) The relay switch may simply need to be replaced or cleaned. I just had that issue. Very small beer.
(c) Window switch - unknown, but probably small beer.
(d) My clutch is far from heavy especially when compared with the non-hydraulic clutch in my 964 turbo.
(e) HID lights are fine. First year in the car was 1996.
(f) Struts are a simple fix.
(g) low mileage is not necessarily bad as long as the usual stuff (oil and fluids, etc.) are kept current. And that the car is driven a bit to prevent dry rot. May potentially explain the smoke.
Good luck and get a good PPI. What color is she?
Cheers,
Greg
(a) Smoke - defer to others, mine has never smoked. Could be BIG beer.
(b) The relay switch may simply need to be replaced or cleaned. I just had that issue. Very small beer.
(c) Window switch - unknown, but probably small beer.
(d) My clutch is far from heavy especially when compared with the non-hydraulic clutch in my 964 turbo.
(e) HID lights are fine. First year in the car was 1996.
(f) Struts are a simple fix.
(g) low mileage is not necessarily bad as long as the usual stuff (oil and fluids, etc.) are kept current. And that the car is driven a bit to prevent dry rot. May potentially explain the smoke.
Good luck and get a good PPI. What color is she?
Cheers,
Greg
08-18-2009, 12:04 AM
#3
- thanks for the reply.
- as regards the smoking , just caught this post by "tsmathers" where he says :-
" BTW: in case I am not the last person on the planet to learn about it, the only other problem I have had w/this car was after ~20k miles, I would get lots of smoking at startup that would go away after 10-20 secs. All the dealers acted like they never heard of the word "turbo" so I lived with it until I discovered the turbo oil line check valve retro-kit from Turbo Kraft. This absolutely eliminated the problem entirely. Pretty painful to install w/the engine in the car but worth the effort. "
- post is here :
https://rennlist.com/forums/993-turb...ng-shimmy.html
- thanks.
.
- EDIT : and from more reading here , there is an issue with (of all things) oil-filters causing smoking ?
.
- as regards the smoking , just caught this post by "tsmathers" where he says :-
" BTW: in case I am not the last person on the planet to learn about it, the only other problem I have had w/this car was after ~20k miles, I would get lots of smoking at startup that would go away after 10-20 secs. All the dealers acted like they never heard of the word "turbo" so I lived with it until I discovered the turbo oil line check valve retro-kit from Turbo Kraft. This absolutely eliminated the problem entirely. Pretty painful to install w/the engine in the car but worth the effort. "
- post is here :
https://rennlist.com/forums/993-turb...ng-shimmy.html
- thanks.
.
- EDIT : and from more reading here , there is an issue with (of all things) oil-filters causing smoking ?
.
08-18-2009, 12:13 AM
#4
- and this post as well by "jmreiser"
"They all do this sooner or later. The car has a design flaw, fortunately they are relatively easy to fix. They all seem to have lots of motor oil in the throttle body, in the intercooler, etc. The more you have, the more readily it will smoke on startup.
The cause is too much oil going into the turbo oil sumps, more than it can return via the scavenge pump. NGoldrich helped me figure this out at MidOhio last year. What a mess I made. Anyway you can either rework the breathers (plumbing project), or you can do what Porsche did with the 996 turbo, which is to install check valves where the oil lines feed the Turbos. Tony Callas came up with this one. I think the reason it works is by acting as a restrictor, but I don't really know. I would check the intercooler to see if its dry after the mod, after cleaning it, and running it awhile.
The oil is not actually coming through the turbos, but everyone's first thought is to rebuild them. There are good reasons & benefits to that, but this is what has been going on in the cars I've seen. When the oil fills up the turbo sumps, it overflows back up the breather line, where it is inhaled right into the intake system. It is sucked in by the turbos, and blown into the intercooler. Check engine lights will eventually come on from this if you run it long enough. "
- post is here :
https://rennlist.com/forums/993-turb...il-leak-3.html
.
"They all do this sooner or later. The car has a design flaw, fortunately they are relatively easy to fix. They all seem to have lots of motor oil in the throttle body, in the intercooler, etc. The more you have, the more readily it will smoke on startup.
The cause is too much oil going into the turbo oil sumps, more than it can return via the scavenge pump. NGoldrich helped me figure this out at MidOhio last year. What a mess I made. Anyway you can either rework the breathers (plumbing project), or you can do what Porsche did with the 996 turbo, which is to install check valves where the oil lines feed the Turbos. Tony Callas came up with this one. I think the reason it works is by acting as a restrictor, but I don't really know. I would check the intercooler to see if its dry after the mod, after cleaning it, and running it awhile.
The oil is not actually coming through the turbos, but everyone's first thought is to rebuild them. There are good reasons & benefits to that, but this is what has been going on in the cars I've seen. When the oil fills up the turbo sumps, it overflows back up the breather line, where it is inhaled right into the intake system. It is sucked in by the turbos, and blown into the intercooler. Check engine lights will eventually come on from this if you run it long enough. "
- post is here :
https://rennlist.com/forums/993-turb...il-leak-3.html
.
08-18-2009, 12:17 AM
#5
- and this post by "kevin"
" The angle on the oil consumption that is based on the fact that there is to much oil flowing through the bearing housing is wrong.. The K16's or K24 turbochargers needs oil flow to reduce the amount of heat built up from the turbine housing. Another words the turbo need the given amount of oil that is flowing through the turbo to provide lubrication AND heat tranfer.. thus oil is used to reduce the heat by cooling the turbine wheel. Infact I wish that there was more flow to the bearings, and on my higher stage turbochargers I drill the orfice diameter larger this supplies more cooling oil to the turbine wheel and seal area. The 996TT check valve does not reduce the flow, I have pulled one apart and the design basically has a check ball to reduce the oil from siphoning back up the oil supply line once the car has been shut off.. Another words the ball is forced against it's seat only when the car is shut off, and closes the transfer of oil back up into the cam housings. Again we have two seperate topics and two seperate views.. The position or view that the vent line is filling up as a excape route due to the lack of scavenge from the scavenge pump is incorrect.. The size of the 3 gears and volume that this little pump can handle exceeds the oil coming into the very small inlet oil lines.. The most crutial time is a idle and when the oil is cold.. I have taken the vent lines off the sump pumps on many cars including my own!! I installed a bent standpipe with 2.5 inches of height to simulate the oil level of the turbo turbine housing. Guess what, there is/was no oil flowing out of the sump Vent line at any time when these lines are removed.. As I have mentioned in earlier posts, if a race engine has blow by of any sort, you will have a situation of High base pressure.. Many PCA racers will accept higher leakdown numbers and run the car, vs a scheduled rebuild. This will definately cause oil to blow through the vent lines. feels that the oil is being overflowed while the car is running!!
Most Rennlister's have complained about startup smoke, on either tail pipe.. If oil was in the center plenum (alledged vent line problems), Your engine will be smoking from both tailpipes because oil will be entering both sides of each engine bank. The oil isn't going to say, well I just run down on the left bank of the engine and then smoke out the right tailpipe.. Also, you will not see oil puddling under your engine, specifically under the turbochargers. The Porsche scavenge pump is not at fault.. Many owners have emailed me and told me that there mechanics have wanted to replace the Pcar scavenge pump... because they have read the it is a scavenge issue.. This is NOT the case for a street 993TT.. If someone is using Garrett turbochargers, Garrett's do not like the volume of oil & Pressure that the Pcar supplies.. A restriction is often advised, however, again I do not recommend this.. Instead I install KKK style bearings in the Garrett's to make them live..
If scavenging was the issue these cars would have never made it 5000 miles back in 1996 when new.. I'm stating for the record that the scavenge pump is not the issue, nor the vent lines, for a street 993TT, this includes 99% of cars driven at DE events. The oil is coming from only 2 issues.. Faulty turbocharger seals, or high oil levels that occur in the sumps. This is caused by oil siphoning back up the oil supply/feed lines. This can be solved by installing the 996TT check valves. However, this isn't the root cause.. The cause is the sump tanks to sump pump oil lines.. These lines backfill oil from the engine to the sump tanks, the oil level increases above the turbo seals.. And since the seals have been worn through mileage and abuse (hot shutdowns).. oil passes through these seals.. On start up the oil that is in the turbine housing immediately appears as smoke on start up. The oil that has leaked out of the compressor wheels gets pushed from boost pressure into the intercooler and into the center plenum and back into the engine..
Again oil is migrating from the engine case to the turbo's.. I was at Andial this week, and they have a good solution to stop this oil transfer.. However, I recommend both options, the 996TT check valves and the sump-sump pump lines (these are not vent lines) I must strongly state that none of these fixes will hold the oil level in check if you have a faulty oil filter!! and or high oil levels.. "
- it is here :
https://rennlist.com/forums/993-turb...il-leak-4.html
.
" The angle on the oil consumption that is based on the fact that there is to much oil flowing through the bearing housing is wrong.. The K16's or K24 turbochargers needs oil flow to reduce the amount of heat built up from the turbine housing. Another words the turbo need the given amount of oil that is flowing through the turbo to provide lubrication AND heat tranfer.. thus oil is used to reduce the heat by cooling the turbine wheel. Infact I wish that there was more flow to the bearings, and on my higher stage turbochargers I drill the orfice diameter larger this supplies more cooling oil to the turbine wheel and seal area. The 996TT check valve does not reduce the flow, I have pulled one apart and the design basically has a check ball to reduce the oil from siphoning back up the oil supply line once the car has been shut off.. Another words the ball is forced against it's seat only when the car is shut off, and closes the transfer of oil back up into the cam housings. Again we have two seperate topics and two seperate views.. The position or view that the vent line is filling up as a excape route due to the lack of scavenge from the scavenge pump is incorrect.. The size of the 3 gears and volume that this little pump can handle exceeds the oil coming into the very small inlet oil lines.. The most crutial time is a idle and when the oil is cold.. I have taken the vent lines off the sump pumps on many cars including my own!! I installed a bent standpipe with 2.5 inches of height to simulate the oil level of the turbo turbine housing. Guess what, there is/was no oil flowing out of the sump Vent line at any time when these lines are removed.. As I have mentioned in earlier posts, if a race engine has blow by of any sort, you will have a situation of High base pressure.. Many PCA racers will accept higher leakdown numbers and run the car, vs a scheduled rebuild. This will definately cause oil to blow through the vent lines. feels that the oil is being overflowed while the car is running!!
Most Rennlister's have complained about startup smoke, on either tail pipe.. If oil was in the center plenum (alledged vent line problems), Your engine will be smoking from both tailpipes because oil will be entering both sides of each engine bank. The oil isn't going to say, well I just run down on the left bank of the engine and then smoke out the right tailpipe.. Also, you will not see oil puddling under your engine, specifically under the turbochargers. The Porsche scavenge pump is not at fault.. Many owners have emailed me and told me that there mechanics have wanted to replace the Pcar scavenge pump... because they have read the it is a scavenge issue.. This is NOT the case for a street 993TT.. If someone is using Garrett turbochargers, Garrett's do not like the volume of oil & Pressure that the Pcar supplies.. A restriction is often advised, however, again I do not recommend this.. Instead I install KKK style bearings in the Garrett's to make them live..
If scavenging was the issue these cars would have never made it 5000 miles back in 1996 when new.. I'm stating for the record that the scavenge pump is not the issue, nor the vent lines, for a street 993TT, this includes 99% of cars driven at DE events. The oil is coming from only 2 issues.. Faulty turbocharger seals, or high oil levels that occur in the sumps. This is caused by oil siphoning back up the oil supply/feed lines. This can be solved by installing the 996TT check valves. However, this isn't the root cause.. The cause is the sump tanks to sump pump oil lines.. These lines backfill oil from the engine to the sump tanks, the oil level increases above the turbo seals.. And since the seals have been worn through mileage and abuse (hot shutdowns).. oil passes through these seals.. On start up the oil that is in the turbine housing immediately appears as smoke on start up. The oil that has leaked out of the compressor wheels gets pushed from boost pressure into the intercooler and into the center plenum and back into the engine..
Again oil is migrating from the engine case to the turbo's.. I was at Andial this week, and they have a good solution to stop this oil transfer.. However, I recommend both options, the 996TT check valves and the sump-sump pump lines (these are not vent lines) I must strongly state that none of these fixes will hold the oil level in check if you have a faulty oil filter!! and or high oil levels.. "
- it is here :
https://rennlist.com/forums/993-turb...il-leak-4.html
.
08-18-2009, 12:21 AM
#6
- and this very interesting thread about how the turbos were replaced with new ones and the smoking became WORSE , but was resolved with some sort of turbo oil feed piping ?
https://rennlist.com/forums/993-turb...996-993tt.html
.
https://rennlist.com/forums/993-turb...996-993tt.html
.
08-18-2009, 12:25 AM
#7
- and this post by "mindovermotors" :
" Hello,
I will share some personal expierence that we have had at our shop. We had four different 993 twin turbos come in our shop in the last year with excessive oil smoking on start up. All with different mileage, turbos, horsepower, etc.. In all four cases we installed "new dealer purchased porsche oil filters", and all four cars have never had a problem with smoking again.
I do believe the Andial oil lines can solve the problem but they are not addressing the problem correctly. The Porsche oil filters have a check valve in them to prevent the oil from draining back into the turbos while the car is sitting. The check valve in a mahle oil filter or a mann oil filter is not the same or sufficient to prevent the oil from draining back into the turbos.
Please note that Porsche oil filters can fail or even have the same problem out of the box new.
I have seen many porsche oil filters fail after six monthes , But it is still cheaper to replace oil filters, than turbos, oil lines, etc...
I have worked on cars that a delership has preformed thousands of dollar worth of unneeded repairs only to have an oil filter fix the problem.
When a turbocharger fails more often than not, the car smokes while running. not just on startup.
I believe that a lot of people have had turbo's replaced when there was nothing wrong at all.
Play in the turbine shaft is normal and not a sign of needed replacement.
There is specific max radial play numbers, and max end play numbers. that can be tested.
Many shops love to throw turbos on cars, good money job, or maybe lack of knowledge.
I had two of my customers come back from the race track this week with worries that they needed new turbos. Mechanics at the track had told them they probably needed turbos. Neither car has a turbo problem.
Hopefully that this will save you some timely and costly repairs.
Thanks for your time,
Chris Shaffer "
- it is here :
https://rennlist.com/forums/993-turb...6-993tt-2.html
- thanks and sorry for info-overload. Am learning as typing now !
.
" Hello,
I will share some personal expierence that we have had at our shop. We had four different 993 twin turbos come in our shop in the last year with excessive oil smoking on start up. All with different mileage, turbos, horsepower, etc.. In all four cases we installed "new dealer purchased porsche oil filters", and all four cars have never had a problem with smoking again.
I do believe the Andial oil lines can solve the problem but they are not addressing the problem correctly. The Porsche oil filters have a check valve in them to prevent the oil from draining back into the turbos while the car is sitting. The check valve in a mahle oil filter or a mann oil filter is not the same or sufficient to prevent the oil from draining back into the turbos.
Please note that Porsche oil filters can fail or even have the same problem out of the box new.
I have seen many porsche oil filters fail after six monthes , But it is still cheaper to replace oil filters, than turbos, oil lines, etc...
I have worked on cars that a delership has preformed thousands of dollar worth of unneeded repairs only to have an oil filter fix the problem.
When a turbocharger fails more often than not, the car smokes while running. not just on startup.
I believe that a lot of people have had turbo's replaced when there was nothing wrong at all.
Play in the turbine shaft is normal and not a sign of needed replacement.
There is specific max radial play numbers, and max end play numbers. that can be tested.
Many shops love to throw turbos on cars, good money job, or maybe lack of knowledge.
I had two of my customers come back from the race track this week with worries that they needed new turbos. Mechanics at the track had told them they probably needed turbos. Neither car has a turbo problem.
Hopefully that this will save you some timely and costly repairs.
Thanks for your time,
Chris Shaffer "
- it is here :
https://rennlist.com/forums/993-turb...6-993tt-2.html
- thanks and sorry for info-overload. Am learning as typing now !
.
Trending Topics
08-18-2009, 01:21 AM
#9
Intermediate
Pistole,
What they all said.
Is the unit the metalllic Schwarz advertised in MT?
Clutch is heavy compared to your Coupe (akin to a 164 manual kinda level) but that's the norm. Kurt at Carrera or Jeffrey of JT Cars for PPI. Check mana dia bikin service for provenance.
Congrats. 993 turbo rocks
.
What they all said.
Is the unit the metalllic Schwarz advertised in MT?
Clutch is heavy compared to your Coupe (akin to a 164 manual kinda level) but that's the norm. Kurt at Carrera or Jeffrey of JT Cars for PPI. Check mana dia bikin service for provenance.
Congrats. 993 turbo rocks
.
08-18-2009, 03:15 AM
#11
Intermediate
Me fine. Danke Schoen. 
Take the car for an extended drive, one of the best route is the backroads of Glenmarie. Many turns and twists and listen for funny clinks and clonks tho' be careful on the sharpies since the 993 can bite hard if the rear alignment is outta whack. Stop after a 20min. hard drive that spooled the turbos and check for smoke again on start-up. If it does, mintak discount lah....( Pre-SOP same as buying a used Coupe or any turbo-ed car )
Note : Exiting Glenmarie to get to Subang Airport...you can whack hard. By the time yer reaching Hyatt Saujana, 200klicks should register on the speedo....
Take the car for an extended drive, one of the best route is the backroads of Glenmarie. Many turns and twists and listen for funny clinks and clonks tho' be careful on the sharpies since the 993 can bite hard if the rear alignment is outta whack. Stop after a 20min. hard drive that spooled the turbos and check for smoke again on start-up. If it does, mintak discount lah....( Pre-SOP same as buying a used Coupe or any turbo-ed car )
Note : Exiting Glenmarie to get to Subang Airport...you can whack hard. By the time yer reaching Hyatt Saujana, 200klicks should register on the speedo....
08-18-2009, 01:08 PM
#12
I'm probably one of the least mechanically qualified to answer your questions, but I have experience with a couple of these issues.
With regard to the smoking on start up, between Kevin, Joel Reiser, etc. you have already found the experts.
The window switch is likely a $40ish part, and an easy fix. I have had to replace one.
The hood struts are slightly more expensive but also a relatively easy DIY. I have replaced the hood struts and the engine struts just went.
As One of Twenty mentioned, the 993 turbo clutch is assisted and should be light, particularly as compared to a normally aspirated 993 clutch. If it engages very high in the pedal travel or chatters in first or reverse, it may need to be replaced. Do a search for degree of difficulty and cost.
The best advice I can offer is to spend a lot of time searching Rennlist for any questions you have, and make sure you get a thorough PPI from someone very familiar with these cars.
With regard to the smoking on start up, between Kevin, Joel Reiser, etc. you have already found the experts.
The window switch is likely a $40ish part, and an easy fix. I have had to replace one.
The hood struts are slightly more expensive but also a relatively easy DIY. I have replaced the hood struts and the engine struts just went.
As One of Twenty mentioned, the 993 turbo clutch is assisted and should be light, particularly as compared to a normally aspirated 993 clutch. If it engages very high in the pedal travel or chatters in first or reverse, it may need to be replaced. Do a search for degree of difficulty and cost.
The best advice I can offer is to spend a lot of time searching Rennlist for any questions you have, and make sure you get a thorough PPI from someone very familiar with these cars.
08-19-2009, 11:00 AM
#14
Guru
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Look at the Hyd fluid reservoir just ahead of the steering wheel in the trunk, its a small reservoir. If its overflowing with the green sticky fluid (Pentosin), then you know the slave cylinder is also bad. Both the accumulator and slave are often times replaced at the same time. Common.
