Why Replace a Good Dual Row IMSB? Advice
 

Hello, I have not seen this exact IMSB question before.

I am aware of all the different IMSBings out there and the discussions about what's better, not asking that question. I have my 1999, 996 engine apart because it was making non magnetic metal at a decent rate. I believe that problem is solved and I am reassembling it at the moment.

My question is this:
My dual row IMSB seems to be in perfect condition. Seal looks good and it turns smoothly, no play. I am thinking of just putting the IMS back in the car as is. Then replacing the bearing at 60k (32k now) when I do my clutch. I can't think of any reason to put in a non sealed bearing now with engines history of making metal even if it may be solved. I plan on having two magnetic drain plugs and just swapping them out every 2k miles or so to check for any ferrous metal particles just in case. Replace bearing? Remove the seal? Leave as is?

Any thoughts?

Joel

Same car (99 C2)interested in a response, using a magnetic drain plug and filter dissection every 5000 miles. 90K on the ODO

Why replace it? Sounds like you would be doing it yourself? To me, that would be a no-brainer. It is a real crap shoot, whether the original ims will fail...and I know that the original dual row bearings were less prone to failure. If you were going to do it anyway at 60k, it sounds like you have some level of concern...why not just do it now and eliminate the concern?

Of all three bearings that were designed from the factory for the M96 and M97, the dual row is the most robust and durable, but as the experts have mentioned, the dual row bearing can fail over time and a preventive approach (swapping out the bearing at clutch replacement time) is the best option to getting the most out of your engine and avoiding catastrophic failure. If it's shredding metal that shows in the filter, then it's too late.

Worth a view if not seen it yet from PCA.

Understand the speaker is selling a solution, he puts the entire IMS mystery into prospective.

short version his recommendation oil change every 5000 miles or 6 months will keep the oil from attacking the bearing seal.

Yep... you nailed it Jay. Good advice. I can't tell you how many people I've talked to that believed that since they're using "10,000 mile synthetic oil", they don't need change their oil twice a year or even annually, but would rather wait until they get near the mileage mark. 10,000 miles for many Porsche owners could mean 2+ years. Yikes!

yes if you are going to re-install the original bearing, remove the seals,and change oil every 6 months or 5000 miles. When you run the engine, run it long enough to get the oil temp up to boil off any condensation to retard the formation of acids in your oil. This requires driving the car. It is practically impossible to warm the oil enough by letting the car idle.

"yes if you are going to re-install the original bearing"

If you already removed the bearing, DO NOT RE-INSTALL IT ! You'll need to get a new bearing, because removing it ruins it (regardless of whether it feels smooth now). When you remove the bearing, you're pulling on the inner race only... If you didn't remove the bearing, remove the outer seal and put the flange back on. Hopefully it'll make it until your clutch change.

Exactly! Hit the nail on the head. If I've learned anything from the experts, is that when you remove an older IMS bearing from these cars, it's always best to install a new bearing.