IMS Inquiry
 

I own a 2002 Porsche Boxster S. It is in good condition with only 35,000 miles. It has the original IMS bearing, which has caused me some concern.

I want to know if, given the age of the car, should I go to the expense of having the IMS bearing replaced. If so, what should that cost be if done by a Porsche dealer? I live in the U.S.

If I go through having the IMS bearing replaced, what other work should I do at that time (new clutch, new rear main seal, etc.) and what cost should I expect?

TIA.

As has often been said... it depends on your tolerance of risk. Probably your IMSB will last a long time. Perhaps wait till you need a clutch.
I can't tell you what it would cost if you decide to go ahead with replacing the IMSB... but the last place I would take it is a Porsche dealer. You will pay away more than at a good independent garage that specializes in Porsches and... how many Porsche dealer's mechanics know their way around a 21 year old engine? While you are in there the normal things to look at are the clutch and RMS seal. Since the half shafts have to be disconnected from the transmission check the rubber boots for cracks and verify that the wheel bearings are tight. Others will have more suggestions I am sure.

There are many IMS bearings to choose from, some with a good track record of support and many sold, some not so much. And they come in at wildly varying prices for the parts.

You want to pick your mechanic first (second the indy choice above) and ask him what he recommends and how many he has done. If he has done a lot, he will have the tools to do it right and efficiently. Is he going to do it or have a new guy do it?

The RMS is a no brainer. You have the rear of the engine exposed, put in the improved RMS. They leak, prevent it.

As to if you should do it, the bearing is 20+ years old. What kind of oil has it been sitting in? It doesn't have many miles and that is actually not a good thing. Did it got its oil changed on a mileage basis as opposed to a more regular basis? Was it driven short distances or long? Did it hibernate for the winter with fresh oil or old? All factor into what kind of oil could be leaking into the bearing. You want clean oil without acid buildup.

Good read...
https://lnengineering.com/products/t...-bearings.html


Lots of good information within these videos:



https://www.youtube.com/watch?v=WNGsyFnv7uQ&list=PLKNhSePDKmOw8GkY69Gxm01dXbjv4X0m3&index=5

https://www.youtube.com/watch?v=goJYLxt-Peg&list=PLKNhSePDKmOw8GkY69Gxm01dXbjv4X0m3&index=7

Considering the age of the vehicle, while doing the IMS, it's best to also do the clutch, flywheel (if needed - need to check for allowable deflection to make sure it's still serviceable), water pump (with low temp thermostat and expansion tank), and AOS and associated vent lines. It would be best to take your car to an independent that is thoroughly versed in these models and can identify any other components that need to be changed based on time. It's going to be a sizable bill but the car should be good for quite a few years within nothing more than oil changes and basic maintenance.

https://lnengineering.com/products/p...1-engines.html

I just picked up a '99 base with 151k miles that I got for cheap because the variocam guides on the outsides were toast (bank 2 was metal to metal). I luckily just found that likely caused a major crack but not explosion in a camshaft sprocket.

Of course it costs a valve cover removal to do it, but if you are all the way to the IMS and RMS you could dig a bit further and have those guides inspected, not sure how age affects the guides like it might a IMS bearing although I suspect it might. I know it can be done in the car but I yanked my engine being the first time tearing into a M96. If I were to venture a guess on what a Porsche dealership would charge for IMS, RMS, and chain guide check it would be $15k. I imagine a indy would be more around $5k-8k. It can be done DIY much cheaper of course. CHeers!

Personally I think that those cam chain pads or guides are a more important problem than the IMSB when engines approach 100K miles, or less. You were lucky that pieces of the pads didn't lodge somewhere that would block a chain and cause an engine failure.