Haven't seen this one before - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Brad Roberts · 03-06-2012, 08:04 PM

We are pulling apart a BoxsterS engine for another issue and discovered a new one

I see water in the oil, pull apart engine, I see intermix primarily in the crankcase

How in the heck (say that with a redneck undertone) do we have water in the oil (typically its oil in the water) This means water is leaking into the engine somehow. We have seen in the past casting plugs in the heads fall out and DUMP water into the system, but typically these are engines that have oil in the water also (cracked 3.2/3.4 heads) They like to crack near these casting plugs (most people call them freeze plugs) but the heads looked great!!

Here is why we had water in the oil, but little to no coolant lost in the system:

No bueno

The brown sealant is from Porsche

B

Brad Roberts · 03-06-2012, 08:10 PM

This engine has 62k miles on it. The block/cylinders/pistons are flawless. Everything is really clean.. then you find this...

Every single engine we pull apart, these IMS drive chain guides are JUNK!!!!

san rensho · 03-07-2012, 02:36 AM

So what was the cause?

blue2000s · 03-07-2012, 07:41 AM

Quote:

Originally Posted by Brad Roberts

We are pulling apart a BoxsterS engine for another issue and discovered a new one

I see water in the oil, pull apart engine, I see intermix primarily in the crankcase

How in the heck (say that with a redneck undertone) do we have water in the oil (typically its oil in the water) This means water is leaking into the engine somehow. We have seen in the past casting plugs in the heads fall out and DUMP water into the system, but typically these are engines that have oil in the water also (cracked 3.2/3.4 heads) They like to crack near these casting plugs (most people call them freeze plugs) but the heads looked great!!

Here is why we had water in the oil, but little to no coolant lost in the system:

No bueno

The brown sealant is from Porsche

B

Interesting. I've had sparatically disapearing coolant for a couple of years. I seem to slowly loose coolant sometimes, but not all the time. Coolant level won't drop when you put pressure on the reservior and the cylinders look dry when scoped. There are no signs of a leak and no signs of water in the oil or oil in the water. I wonder if I have this same issue.

BYprodriver · 03-07-2012, 09:52 AM

Is that the correct seal or is that just sealant? In every engine I have disassembled that seal looks like new. Blue 2000S sounds like you have a hairline cracked head that opens up at high temp. Get a oil sample & check for high sodium.

Brad Roberts · 03-08-2012, 02:19 AM

It's the correct seal! This one showed no water in the oil, but the crank carrier area was milky white (oil on the walls)

maj75 · 03-08-2012, 10:38 AM

So what was the mechanism of failure?

It must have been installed correctly at some point, otherwise the engine would not have lasted 62K

What could have caused this seal to deform?

Brad Roberts · 03-08-2012, 11:46 AM

The seal has a metal band inside it for strength. I believe the seal was damaged prior to install and water caused the metal to corrode and eventually weaken.

I'll pull the seal apart today and post a pic.

B

stephen wilson · 03-08-2012, 01:19 PM

I just had a similar failure on my Chevy truck. The seal was supported by a hard plastic "cage", which cracked, letting the seal bulge into the coolant passage.

blue2000s · 03-09-2012, 11:54 AM

Quote:

Originally Posted by BYprodriver

Blue 2000S sounds like you have a hairline cracked head that opens up at high temp. Get a oil sample & check for high sodium.

I'm 80% sure you're right. At least it won't require a full rebuild if that's what it is.

Brad Roberts · 03-09-2012, 12:54 PM

Another shop sent me these pics yesterday asking me if we could fix this 3.4 head.. LOL (yes)

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Brad Roberts · 03-09-2012, 01:07 PM

Blue,

let me know what you need. I have a few orphan heads with no cracks.

B

BYprodriver · 03-09-2012, 01:13 PM

Quote:

Originally Posted by Brad Roberts

Blue,

let me know what you need. I have a few orphan heads with no cracks.

B

A guy on Rennlist is looking for a 4-6 cyl. 3.4 head to replace a cracked 1 also.

Brad Roberts · 03-09-2012, 01:16 PM

The one good 3.4 head I have has damage on the exhaust cam journal (first mounting point) We are working on a honing bar so we can weld up the 4-5 heads we have with damage in this area.

B

Brad Roberts · 03-09-2012, 01:17 PM

He should sell his one good 3.4 head and install 3.2 heads. Same casting, same valves, small combustion chamber. I believe it is 1 point higher on compression (and all these engines read lower than Porsche published) from what I have found..

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Brad Roberts · 03-09-2012, 01:24 PM

See the rust? This is the side that was in the block

Just found out.. this forum software doesn't like iPhones

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BYprodriver · 03-09-2012, 01:29 PM

Quote:

Originally Posted by Brad Roberts

He should sell his one good 3.4 head and install 3.2 heads. Same casting, same valves, small combustion chamber. I believe it is 1 point higher on compression (and all these engines read lower than Porsche published) from what I have found..

B

what about exhaust bolt pattern?

Brad Roberts · 03-09-2012, 01:37 PM

I have to be careful, we make adapters for everything in house, so I don't worry about that stuff, but should be more clear when speaking in public

Like.. CaymanS intake adapters for 3.2 heads

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Brad Roberts · 03-09-2012, 01:42 PM

This was damaged during install...

B

BYprodriver · 03-16-2012, 08:54 AM

Quote:

Originally Posted by BYprodriver

what about exhaust bolt pattern?

Looks like they are the same you just need to drill & tap threads for the heat shield mounting bosses & a few on the intake side too. Thats how they use the same head casting.