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Recommended Posts

Posted

This is my first Porsche. I am really excited to have a new to me 996! I've spent months online reading various forums about

what to look for etc.. I purchased an unloved 996 with no history and 98K miles knowing full well that it was going to be a project to

get it up to an acceptable state of maintenance. I had a pre purchase inspection done in LA and drove it back to Arizona.

I didn't have time to have the PPI mechanic do an oil change. Mistake. I drove it home to Arizona, did an oil change and

found bits of hard black plastic, about 6 small aluminum chips and two small ferrous metal chips in the

sump oil and a few aluminum specks in the dissected oil filter.

I immediately thought IMS and have done three weeks of research and parts ordering to prepare for the bearing upgrade while the car

sits unused in my garage. I am at the point where I feel competent to preform this procedure and actually started today. However, I am already doubting my diagnosis.

I pulled the sump cover expecting to find metal filings all over the sump cover. Nope. Not a one. Lots(15?) of hard black plastic and maybe

some (brown?) plastic. Is this consistant with an IMS bearing failure? (picture attached)

post-85317-0-43314800-1352765689_thumb.j

I have cleaned the suction screen and replaced both sump AOSs. I am under the impression from other DIYs that there may be a third AOS in my

engine that sits outside the sump. Would oil contamination be a reason to replace this AOS as well?

Thanks for any help or encouragement you can provide!

Posted

Not the valve guides, which are metal, but the chain advance tensioner rails that are brown plastic. At 98k these probably have quite a bit of wear. Any engine that has not had the pan dropped will usually have some non-ferrous metals in the pan.

What you replaced in the pan were the swirl pots,Nelson referred to as AOS sometimes, but these seldom go bad. It is the large AOS on the too of the engine, drivers side toward the front, that often goes bad.bif you are doing te IMS bearing upgrade then with the trans out it s pretty easy to get at the AOS so do it while you are in there, only about a $125 part.

Don't be surprised if you need a new clutch while you are in there. With 996's 98k is a lot for a clutch. Cost is not too bad if you don't need a new flywheel.

Also consider the three chain tensioners if you are getting clatter on start up. You will have them out to change the bearing. Less than $300 to buy all three.

Posted

Thanks for the advice! I suspect that the clutch was recently replaced because it feels very good. But I have a new clutch disk sitting in my parts box just in case I find out differently. There isn't any chatter on startup but I'll examine the chain tensioners while they are out.

Almost all the plastic is the black color like the oil filler tube or the AOS units (no sign of AOS failure). I have no idea where it might have come from. There is just a little bit of this brown plastic which matches the color of the chain tensioner guides repair kits Pelican Parts sells (same thing as the chain advance tensioner rails?). I am thinking that this repair is beyond my ability. Is the failure mode of the chain tensioner rails as catastrophic as an IMS failure and also without warning?

Thanks.

Devin

Posted

This is my first Porsche. I am really excited to have a new to me 996!

Thanks for any help or encouragement you can provide!

we have our first Carrera as well, a 2000 cab. you have fun with it! and do it right the first time when you do bring it up to par!

Posted

Thanks KTS, Mine is a black 2000 cab as well. I have to admit I'm currently wondering what I have gotten myself into as mine sits unmoved since the drive home. :( I will be really interested to follow your ownership experience as well. I would have liked to have the tan interior instead of the gray but am happy not to have an extra spoiler to remove

Posted (edited)

Thanks KTS, Mine is a black 2000 cab as well. I have to admit I'm currently wondering what I have gotten myself into as mine sits unmoved since the drive home. :( I will be really interested to follow your ownership experience as well. I would have liked to have the tan interior instead of the gray but am happy not to have an extra spoiler to remove

I was not planning on buying a older Porsche for us to use as a driver, but this one just fell into place, it was very clean, 60k miles and at a dealership I seem to trust, they took the car in the back, put it on the lift had a head tech look it over with me, him telling me about this car,

there was no way I could pass it up., I got lucky to find one here this clean at a pretty well trusted dealer from what I ahve read about them online, and one of the best places that have ever treated my wife as the buyer. being a tech for many years, I know alot about cars, just have not touched a porsche in gosh 20 years, and never was a porsche tech, in fact the only water colled porsche I ever touched was the 924/944's which we owned one of each before.

have patience, do each repair carefully, and most off all, keep your work area and parts spotless, clean everything correclty before reassembly do not bevel sealing surface and do not overtorque anything and all will be well, I have known many Porsche owners and they are a very dependable automobile if you take care of it and do the job right.

Edited by kts
Posted

My story is somewhat similar as far as the intent goes. My son just turned 16 and I gave him my well loved and well maintained 99 BMW E46. My plan was to get a cheap Boxster S

that I could use to learn the ins and outs of Porsche ownership and repair before handing it down to my daughter in two years time and buying myself a 997 CS. But I found a car that was crazy cheap although not without risk... Sold by a guy who was moving to Peru, living in an LAX airport hotel, leaving the country tomorrow. When is that not a scam, right?

I did the title research and made sure that was all good and had a PPI done at TRE in Van Nuys, CA. They found some stuff, they missed some stuff, and told me that the car was in really good condition for the year. I was looking for a light project car that I could tune up, redo the interior, do some painting, replace a bad O2 sensor, that sort of thing.

I'm an engineer by training so slow careful and methodical comes pretty easy to me. However I have never been an auto mechanic. Until I build some more experience I really don't want to split the engine so I have my fingers crossed.

  • Admin
Posted

Isn't it possible that the plastic bits (that Deven Wala mentioned in his oil) are bits of an impeller from a blown water pump?

Not unless he also has water in his oil.

The oil system and coolant system should be separate unless something else is wrong.

Posted

Isn't it possible that the plastic bits (that Deven Wala mentioned in his oil) are bits of an impeller from a blown water pump?

Not unless he also has water in his oil.

The oil system and coolant system should be separate unless something else is wrong.

Thankfully there is no detectible intermix. The few small brown bits I see I tend to believe are from the chain guides. These are so few I would tend to take a monitoring approach. Some of back plastic bits are almost the size of a pencil eraser and as thick as a dime and there are many more of these. If these are from the chain guides it scares the heck out of me. I am hoping that I can track the source down to a perished AOS, oil filler tube or some such thing. Other than plastic bits in the oil are there any other signs of chain guides going bad short of catastrophic engine failure?

I know splitting the engine to replace the guides can't be cheap. I paid cash for the car and am already in another 3K so I'm tapped out for a bit. I'd really like to be able to drive the car but I'd also would really like to be able to continue to drive it. Any thoughts or opinions?

Posted

Isn't it possible that the plastic bits (that Deven Wala mentioned in his oil) are bits of an impeller from a blown water pump?

Not unless he also has water in his oil.

The oil system and coolant system should be separate unless something else is wrong.

Thankfully there is no detectible intermix. The few small brown bits I see I tend to believe are from the chain guides. These are so few I would tend to take a monitoring approach. Some of back plastic bits are almost the size of a pencil eraser and as thick as a dime and there are many more of these. If these are from the chain guides it scares the heck out of me. I am hoping that I can track the source down to a perished AOS, oil filler tube or some such thing. Other than plastic bits in the oil are there any other signs of chain guides going bad short of catastrophic engine failure?

I know splitting the engine to replace the guides can't be cheap. I paid cash for the car and am already in another 3K so I'm tapped out for a bit. I'd really like to be able to drive the car but I'd also would really like to be able to continue to drive it. Any thoughts or opinions?

wow that is one thing I did not think about, splitting the engine to do stuff liike that, I just flat forgot all about that. on the advantage side of this, the wife did kind of like my idea of getting a lift to park both of "her" cars in the garage on top each other, which I am going to check into after the 1st of the years, I do only have a 9ft ceiling though, or adding a garage here

Posted

Congratulations on your C4 cab. There is a lot to learn. The few things I've picked up so far are: 1. If you start looking at all the things that could go wrong you will drive yourself crazy. 2. There should be many fluid changes in your future.

I dropped the transmission and replaced the IMS s well as the AOS. The bearing was in perfect shape but now I have piece of mind. I do have a slight start up rattle so I am replacing the chain tensioners this week. I am now relatively sure that the plastic I saw was from my chain guides. They will have to hold on a bit longer until I can scrape together the money or gain enough experience to replace them. I now have three new style chain tensioners sitting in front of me 188-01, 186-01, and 180-56 but I have to do some more research before I know if I should install all, some, or none of them with my old style roller link chains.

Posted

Congratulations on your C4 cab. There is a lot to learn. The few things I've picked up so far are: 1. If you start looking at all the things that could go wrong you will drive yourself crazy. 2. There should be many fluid changes in your future.

I dropped the transmission and replaced the IMS s well as the AOS. The bearing was in perfect shape but now I have piece of mind. I do have a slight start up rattle so I am replacing the chain tensioners this week. I am now relatively sure that the plastic I saw was from my chain guides. They will have to hold on a bit longer until I can scrape together the money or gain enough experience to replace them. I now have three new style chain tensioners sitting in front of me 188-01, 186-01, and 180-56 but I have to do some more research before I know if I should install all, some, or none of them with my old style roller link chains.

Congratulation on your 996. Sounds like you have the problem taken care of. I am glad to hear that you were able to take care of the problem. I too purchase my car in CA (San Diego) and drove 500 miles to Arizona. Loved every minute of the drive back with my 12yr old son beside me! Smiles the whole way! I plan on doing much of any work on my car as well so I like seeing posts like these and I plan on doing it myself as I go.

  • 2 weeks later...
Posted

A belated congrats on your 996. Mine is a 2000 C2 cabrio bought from a TX dealer. Suggest keep a record of all the maintenance/tires/etc., done on the car, no matter DIY or shop. Some porschephiles (myself excluded) even keep records of every gallon of gas. I live in central VA and we have a few gas stations that have nonethenol gas and I buy it when I'm in the area because it's supposed to be good for any internal combustion machine. Enjoy the experience and drive.

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