[sp4149]

Our 1995 968 Cabriolet has developed a loud clatter at starting, that gets quieter as the engine warms up, disappears above 1500 rpm, returns when stopped. The car has the Tiptronic with 86,000 miles. I feel an occasional slight lurch when letting up on the throttle when driving (sort of like a locking automatic transmission locking and unlocking). I had loose heat shields around the catalytic converter that rattled badly, but with these secured the clatter continues. I haven't found any other heat shields which might be rattling. The noise is coming from under the car, under the doors and under the front end and still fairly loud from the rear. The car struggles a little on a cold start, but runs and accelerates smoothly after warming up for 60 seconds. This has probably been slowly developing over many months. The car has vibrated when at idle in Drive, much less vibration when in park of neutral. At times it was so bad that I would shift into Neutral when stopped at lights. From other posts it seemed that was not uncommon with the Tiptronic; at the time I was thinking bad motor mounts.

Now I'm thinking the problem is a torn, damaged damper plate at the rear of the engine. Around $2200 to replace ($1100 labor) at my local shop. I inspected under the car and did not find any rubber debris in the viewing port next to the starter. I looked in and did not see any cracks in the rubber and the rubber felt smooth to the touch. I did not remove the starter to look in the port covered by the starter. With my luck I was probably looking at the one section of the damper without cracks. Looks like a real pain to get to without a lift, or a pit, to aid in dropping the exhaust and drive train.

Any suggestions to confirm the diagnosis before spending the bucks, or selling the car? The gate guards really don't like the sound of an approaching tracked vehicle.

-sp4149

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[PorscheDude]

My post from RL



Maybe someone can chime in with better info.



Sounds like you may several problems.



Does your clatter sound like it may be the lifters?

When cold they sometimes clatter and quite down as the oil comes up to temp.



Those damper plates can found for under $900.



Also check your motor mounts, there is a spec to measure for the height.



When is the last time the belts were done?

You may have jumped a tooth on the balance shaft belt.

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[RS Barn]

When starting cold does it sound like Diesel clatter until actually gets to a stable idle?

Pete

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[sp4149]

[quote name='RS Barn' post='47330' date='Feb 11 2008, 04:56 PM']When starting cold does it sound like Diesel clatter until actually gets to a stable idle?

Pete[/quote]



Thats a pretty good description, although a diesel clatter may be more evenly spaced. But it continues even when idle is stable and engine is warming up.



-sp4149

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[sp4149]

[quote name='smokiemon968' post='47328' date='Feb 11 2008, 04:44 PM']Does your clatter sound like it may be the lifters?

When cold they sometimes clatter and quite down as the oil comes up to temp.



Those damper plates can found for under $900.





When is the last time the belts were done?

You may have jumped a tooth on the balance shaft belt.[/quote]



The Clatter is from the bottom, under the car, not the top where the lifters are.



The shop will only waranty their work if they supply the parts. Pelican has it for under $900, but I don't have the setup to do it myself. Removing the exhaust system would be a major job for me with the car on jackstands, and then there is the drive train above.



Belts were done about 3,000 miles ago and checked about 1500 miles ago. If I jumped a tooth on the balance shaft belt, wouldn't it be felt at all speeds? The clatter and vibration disappear above 1500 rpm.



There was a post on Rennlist last November with similar symptoms and a nice photo of a cracked damper.



http://forums.rennlist.com/rennforums/show...idle&page=2





I'm not anxious to spend the money if there are other possibilities. Evidently the damper is the same on 924s and 944s; one 924 owner reported bits of rubber debris on the floor under the car when his failed; I haven't seen that yet.



-sp4149

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[968rz]

[quote name='sp4149' post='47338' date='Feb 11 2008, 07:43 PM']one 924 owner reported bits of rubber debris on the floor under the car when his failed; I haven't seen that yet.

-sp4149[/quote]

That may have been me, Mine failed on the 924 but with out warning. One day after work it just wouldn't move and that’s when I saw the rubber. At the time I was an auto tech so doing it myself was nothing (but that was a 24 not a 68 <img src="/forum/images/smilies/968/unsure.gif" class="smilie" alt="" /> ) I pulled everything from the trans to the fly wheel off (including exhaust). Not really bad, but if you have doubts I would say let them do it.



I now check mine at least once a year (both the 24 and 68). I use a starter button to kick the motor over while looking thru the inspection hole but a second set of hands tapping the key would work.

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[RS Barn]

The clatter is really a Diesel/shudder clunk under startup. It subsides to a steady clatter at idle unless you raise idle a bit. When you put in gear and have foot on brake it has a slight knocky sound. When you accelerate in gear it almost completely goes away.

This isn't lifters

The rubber center of the damper has sheared. Even when you pull it apart the two pieces can fit beautifully together

Pete

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[sp4149]

[quote name='RS Barn' post='47395' date='Feb 12 2008, 05:22 PM']The clatter is really a Diesel/shudder clunk under startup. It subsides to a steady clatter at idle unless you raise idle a bit. When you put in gear and have foot on brake it has a slight knocky sound. When you accelerate in gear it almost completely goes away.

This isn't lifters

The rubber center of the damper has sheared. Even when you pull it apart the two pieces can fit beautifully together

Pete[/quote]



Is this a reasonable DIY project? I know the shop was figuring around 12 hours. The pain in the ass tasks seem to be removing the exhaust system, then disconnecting the drive train. Other than working on my back more than I prefer; are there any special requirements, tools or?



Seems like if I can figure out the drive train disassembly and I've had the starter off before, then it seems straight forward. I don't see anything challenging like tensioning timing belts or trying to remove the thermostat on the 944. I've done a variety of repairs on other cars, however not much with drive trains. I tried to change pinion seals on a 64 GMC truck but couldn't break the nut free with a six foot breaker bar. Needed an impact wrench. The one I have is good for tires and not much else.



Pete,

I am starting to think that if I go to the trouble to drop the exhaust, then would this be the time to change the exhaust system? I think Bob mentioned that his new catylitic converter wasn't as good on California emissions as OEM. When I had the PPI the shop said that the Cat had been replaced. The heat shields have been falling off the Cat causing a hot spot next to the driver seat and a rattling noise. I have another year until smog check time, but the last time I barely passed on Hydrocarbons and was 2-3 times the average readings on CO% and NO (ppm). If it made sense, I would prefer to spend the labor savings on improving the exhaust system. On the other hand the damper is a $1100 part and I don't want to screw it up either.

-sp4149

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[PorscheDude]

I did the clutch in my 944 (which is a PITA) and the clutch in my 968 (easy)

I did it using a floor jack and 4 jack stands. It really is not to bad.



Buy all the parts first even ones you may not need. This will save time if you run into problems. Most suppliers will take the unused items in return.

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[968rz]

DIY? I would say yes. That 12hr is book time and may not take that long.

Referencing the time I did my 924 it's really not that bad, the 968 could be worse as it probably has more connections but shouldn't be that bad.

Smokie mentioned getting all the parts you need but other than miscellaneous nuts/bolts that may break, the damper is the only part you need for this job.

It's really up to you, is $1000 worth being on your back for 8-12hrs? (plus you get bragging rights with your friends <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> )

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[PorscheDude]

you will get more "street cred".

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[MATTS92]

[quote name='smokiemon968' post='47422' date='Feb 13 2008, 09:49 AM']you will get more "street cred".[/quote]

My 92 has a similar sound. I thought it was a small exhaust leak. Fortunately i have my own lift. The search lead to some kind of a valve on the rear of the oil filter assembly. When i checked it out in a parts manual it appears to have a spring in back of the part . I guess when the spring gets tired the valve rattles. I have been meaning to ask about it in forums. Check and see if this is the same on your car. <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" />

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[RS Barn]

This is a real pain job. The trans has oil lines that are hard to get to and can easily break. They are above trans front and rear and are hard to see anyway.

There are a few hardcore DIY guys who would tackle this. My advise is to work some OT and pay someone to do this job. That way if there are complications/issues you may have some help from shop.

Pete

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[968Z]

I agree with Pete, and let a professional handle it. Mine failed around the same mileage, and while they were in there, they noticed the the coupler at the back of the torque tube near the axle was going as well. I got both parts from Sunset for around $800.00, and the shop installed them without hesitation. It would have been another 6-8 hours if they had not noticed.

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[968rz]

Well there you go, I would trust Pete when it comes to these cars. As I said, I was basing my comments off the 924 which had only axles and torque tube attached to it (no cooler lines or wires at all). Still when my time comes I'll do it myself (I just love doing that stuff).

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[flash]

lol- ok - you're coming over here for my next clutch job - i hate doing repair stuff - that's why i closed my shop

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[968rz]

[quote name='flash' post='47450' date='Feb 13 2008, 04:10 PM']lol- ok - you're coming over here for my next clutch job - i hate doing repair stuff - that's why i closed my shop[/quote]

HA, I work on cars every chance I get. About 12 years ago the Doctors said quit wrenching or live with bad shoulders forever (I miss working on cars everyday <img src="/forum/images/smilies/968/angry.gif" class="smilie" alt="" /> ). So I nice easy computer job it is, at least I can still reach above my head <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> .

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[sp4149]

[quote name='RS Barn' post='47434' date='Feb 13 2008, 09:49 AM']This is a real pain job. The trans has oil lines that are hard to get to and can easily break. They are above trans front and rear and are hard to see anyway.

There are a few hardcore DIY guys who would tackle this. My advise is to work some OT and pay someone to do this job. That way if there are complications/issues you may have some help from shop.

Pete[/quote]



Following Pete's advice and others, I took the car to the shop yesterday. It's a new shop for me, closer to home and my new job than the other shops I have used. They got a good price on a damper from Porsche, cheaper than Sunset and it was in stock. They also had done the repair before. They said that the dampers last about 80,000 miles (our 95 Cab has 86,000).

I guess I was getting used to the clatter as the car seemed to be pretty smooth on the drive to the shop. I was having self doubts about the need for the repair until the mechanic asked if I had a bucket of rocks in the engine. Last night I was sweeping out the garage where the Cab sleeps and I noticed rubber debris on the floor, directly under where the damper would be when parked. Mostly sawdust size bits of black rubber but also a couple of bigger chunks including one over a half inch across. I had been looking for rubber fragments before, but these were the first I found. Looks like it was time for the repair.



-sp4149

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[sp4149]

[quote name='sp4149' post='48340' date='Feb 28 2008, 07:15 AM']Following Pete's advice and others, I took the car to the shop yesterday. It's a new shop for me, closer to home and my new job than the other shops I have used. They got a good price on a damper from Porsche, cheaper than Sunset and it was in stock. They also had done the repair before. They said that the dampers last about 80,000 miles (our 95 Cab has 86,000).

-sp4149[/quote]



The Cab has been a shop over a week now. They're having trouble removing the old damper. It is held on by a metric allen head bolt that is stripped. Limited amount of space to work, even with a lift. They say that it's a replacement damper in there and whoever installed it used the wrong Allen wrench when installing the bolt and stripped out the hex pattern. Kind of bummed since that means this car has been chewing up a damper every 40K miles or so.

Any thoughts on what kind of abuse can lead to early failure of these things? I wonder what else is destined to fail because of PO abuse.

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[PorscheDude]

Power breaking (ie. burn outs)

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