ped

Here is the article in full. Interesting reading...

With the introduction of the Boxster, Porsche teamed up with Kolbenschmidt to manufacture their new water-cooled engine. These engines were to utilize the newly introduced Lokasil liners. The liners themselves offer a higher friction-free service area. This is most useful in regard to not only the longevity of the cylinder but the ever-growing higher mileage service interval. The cases experienced several issues starting with their porosity. In 1997 many of these newly released engines seeped oil through the cases themselves. This seepage was due to a problem in the manufacturing process. When the cases are made in a high-pressure die-casting, the air in the die has to escape. Should the alloy enter too fast and not let all the air out, trapped air pockets are the result. These pockets produce a porous area. This area would then allow seepage of the oil. The reason it was generally oil and not coolant leakage was due to the casting process. The air was trapped in the bottom to center rear of the castings, which housed the oil.

Another well-known problem was the liner failures in late 1998 to early 1999. This would translate into only the 1999 model year do to production dates.

These failures were also due to a manufacturing process. The cylinder liners are created from an alloy made abrasion resistant by adding silicon. Prior to casting the crankcase, the cylinder liners are fixed in position by an operator, then surrounded by a conventional aluminum alloy casting. This is done by inserting the pre-formed cylinder liners (manufactured by Plochingen-based Ceram Tec AG in a special freeze casting process) into the die. The dies are then closed and a high-pressure die casting (HPDC) and squeeze casting (SC) are utilized to achieve this. Three casting machines with a closing force of 1800 tons are used for this purpose. The advantage of the Lokasil process is that the silicon is applied only where it is needed. Lokasil base material costs less than Alusil and is easier to process. These liners or pre-forms are of high silicon content (20-27 percent) and offer a high reduction of friction. Kolbenschmidt holds the patent to Lokasil and is also known for their Alusil and Galnikal piston liners. Lokasil is a "sacrificial" bore liner comprised of silicon fibers in a binding that, when inserted into the block mold, burns out the fibers, leaving the high-content silicon surface directly in the bores. This actually allows the “sacrificial” liner to become one with the block thus eliminating a separate part in the block.

In 1998 Kolbenschmidt’s casting machine was damaged. The time required to repair the machine could have slowed Boxster production down severely unless a fix was found. The solution was to reline some not-quite-perfect blocks that were on hand. Most of these blocks had a casting defect or a porosity problem in at least one cylinder. The fix was simple and absolutely acceptable to standards when done correctly. Kolbenschmidt began the process of the repairs until the casting machine was fixed. This process started by boring out the failed cylinder to allow for the insertion of the liner. There is also a groove cut around the top of the cylinder to keep the sleeve from dropping. This groove is approximately 2.0mm larger than the size of the cylinder’s width and goes down approximately 4.5mm. The next step was the insertion of these liners. It was decided to press the liners in the blocks. This is where the error occurred. Some of these liners were pressed in at a higher rate than the top retaining ring could handle. This would then fracture the ring at the top of the liner. When this ring failed under operating conditions, it was catastrophic. The ring itself would fall apart inside the combustion chamber. At this time the piston would force this debris up into the cylinder head. The piston rings would grab the liner and pull it down from the momentum of the crankshaft. Some of these engines were replaced from coolant loss before they totally self destructed in this fashion. This was due to the ring starting to come apart but not fully. This would compromise the sealing of the head gasket and cause the coolant to either be burnt or expelled from the combustion pressure.

Porsche has not divulged exactly how many engines this actually occurred in other than a broad range of 2.5 engines in late 1998-early 1999. Nor have they released any engine numbers that have had sleeves installed. Generally speaking, the problem occurred within the first several thousand miles. They have been very good in correcting this for their customers in and out of warranty.

Scott Slauson - PCA WebSite - 6/14/2004

(edit - added quotation designation - Loren)

Just spent the whole weekend working on the roof, AND IT STILL DOESN'T WORK!!!!!

I've followed the advice found on here and the procedure in the workshop manual but after spending TEN HOURS fiddling and scratching my head, my roof is now stuck in the up position.

I bought both the pieces that were broken from my OPC, the push bar spring and the main bow push bar. Following the advice on another thread I disconnected the other (right) main bow push bar, synced both transmissions with a drill, snapped on the new push bar spring and lowered the clamshell to check operation.

As the clamshell closed it made the same popping sound it did before. I'm sure this isn't right, so I then tried to lift the clamshell to have another look. BUT when I pressed the button, instead of raising the clamshell the motor kept turning the opposite way and pulled the clamshell tighter and tighter until the motor couldn't turn any more. With a drill on the cables I managed to release each side in turn and pull the clamshell up manually.

I then thought it may have something to do with operating the clamshell and not the roof, I connected it all up only for the clamshell to get stuck again.

I then took the transmissions out and checked inside to see if I could spot anything, I couldn't. While the transmissions were out I also took the opportunity to shorten the outer caasing on the cables. Before I put the transmissions back in I used the marks on the transmission cases to be double sure that both motors were synched. I put it all back together and tried lowering the clamshell again. Still got the popping noise.

I checked all the micro switches with a test meter. They seem fine.

I got to a point when it seemed to be working but still popping as the clamshell closes. After ten hours I was disappointed but at least it worked. Later in the evening I went to put the car into the garage and thought I'd try the roof one last time. I unhooked the latch (the windows went down), pressed the down button and heard the motor turn. Then it stopped and clicked like it was stuck again. I pressed the button the other way and the motor just clicked again. Now my roof is stuck up.

I lay awake in bed thinking about the problem and the only thing I haven't touched is the relay. Could this be the problem?

Please help. I'm a desperate man. Summer in England is very short.

Pete

The roof on my 98 2.5 has just broken.

I was putting the roof up and there was this loud clunking noise. I looked in the rear view mirror to see the clamshell judder and twist. I stopped to have a look and found an arm in the mechanism had broken at one end. It was just lying in the base of the hood recess. I've since found out this arm is called the push bar spring. It broke by the hole where it fixes to the hinge lever.

On further investigation, I also found the plastic end of main bow push bar is also broken. I've no idea if that was broken already or if it happened at the same time. I understand that it's common for this part to fail but not the push bar spring?

Does anybody know why this happened? Could it happen again?

Any tips for replacing these parts would be greatly appreciated.

thanks

Pete

Thanks fellas,

Got the light to do it again at the weekend. It doesn't flash but stays lit. After restarting it goes out. I think Loren could be right and it's just a bad sender.

Does anyone know how difficult the sender is to change? Can I do it myself?

Ped

I'm in the UK but...

The Traffic Pro, Silverstone changer and installation cost me £700

The Bose Base box and Pioneer door speakers I had fitted a few weeks later. That cost me another £350.

I admit, for that kind of cash you could buy a better sounding system. But I like the standard look.

Also, as none of the louts round my way know what a Becker is, it's less likely to get pinched.

Ped

Thanks loren,

Not sure if it's doing any of those things though. I don't think it flashes at all, just stays lit. The engine is stone cold. I'll double check the next time it happens.

Thanks

Ped

Hi,

Sometimes the tiny red warning light on my temperature gauge doesn't go out after the engine starts. If I turn the engine off and restart, it goes out. All the other lights go out fine. The car is cold.

Anyone know why? Should I worry? Is it easy to fix? Is it a sign of impending doom?

The car is a 98' 2.5

Thanks

Ped

Fred,

I had the Bose base box fitted in my 98' 2.5 a couple of months ago. My car had the sound upgrade package from new, so it already had the amp installed on the bulk head and the door speakers. The amp looks the same as the one in your pics, is it made by Nokia?

I also fitted a new head unit; the Becker traffic pro. The shop who did the install said that when they wired the system up it sounded pretty crappy so they played around with different combinations to get the best sound. They settled on:

The front amp runs the base box only

The amp in the head unit runs the door speakers and the ones on the dash.

The door speakers were junked in favour of some two way Pioneers (sorry don't know the model)

It sounds incredible. An obvious disadvantage is that you cant use the front/rear fader control but I don't find it a problem. Just crystal clear sound at up to 80mph. You could obviously get a better sound system but I like to keep my cars looking standard.

Next step is to upgrade the dash speakers. With the volume wound up they sound a little harsh.

Ped