3.2 L Oil Cooler Thermostat Horror

[dkirk]

Gentlemen,

The top-end overhaul on my 1988 3.2L engine is progressing well. Heads were sent out to Anchor Atlantic for reconditioning. As engine performance, oil pressure, and oil cleanliness were all up to par, I elected not to split the case and get into the bottom end. All rods feel equal and correct regarding bearing end play with no rocking nor radial play on their respective crankpins.

This engine has approximately 110,000 miles on it therefore it was time for a top-end freshening. There is one thing that has always bothered me a bit though, and that is slightly high oil temperature that this engine has always exhibited when compared to other 3.2-engined 911’s. My oil temperature would consistently run a needle width above the 8-o’clock located white block on the oil temp gauge, whereas friends 911’s would always be below this white block, all run on the same day. While I have the engine down, I decided to investigate.

Pulling the engine oil cooler thermostat, I discovered something rather disconcerting. Viewing in the uppermost rectangular port of the thermostat, there was a metallic chard between the spring and the inner cylindrical piece. This object was too big to be removed through the coils of the spring without breaking it. Using needle nose pliers, I was able to extract it. It was very brittle and broke easily. It is also non-magnetic, and quite hard. The picture shows the entire piece after removal.

This is not bearing material. I’m thinking it was either scrap that entered during the manufacturing of the thermostat, or it is part of the inner workings of the thermostat that is in process of failing. Have any of you seen anything like this? If so, what is it?

Also, the inner metal cup has some scoring that bothers me a bit. This is shown in the second photo. I’m new to 911 engines and don’t know if this is typical or reason to be alarmed. In any event, I’m replacing this thermostat with a new part.

Any comments or observations would be greatly appreciated.

Dave

[billybek]

Interesting.
Is it aluminum or does it look more like bearing babbitt material?
Could have been some slag from manufacturing the case.

[dkirk]

Bill,

Thanks for your observations. I tend to agree, it was something that entered the thermostat during manufacture. It is not bearing material as it's very hard and brittle. Being non-magnetic, it resembles a chunk of thin stainless steel. After seeing this, the thermostat will be replaced. At $157.50, it's the most expensive thermostat I've ever purchased.

I'll keep having fun as long as the money holds out.

Dave

[SuperOldSchool]

Hello, I have just pulled my tstat to replace a leaky o-ring....I did not not which way it was in the hole. Does its orientation matter at all...meaning the upper opening needs to be on left side (driver side). Does it matter?


Thanks guys

[MBruns]

It will only go one way with the offset bolt pattern by design

Mike Bruns JBRacing.com

[ninesixfour]

Originally Posted by SuperOldSchool

Hello, I have just pulled my tstat to replace a leaky o-ring....I did not not which way it was in the hole. Does its orientation matter at all...meaning the upper opening needs to be on left side (driver side). Does it matter?


Thanks guys

What Mike said, and also, look down into the case and you can see the passages that correspond with the openings in the thermostat.

[SuperOldSchool]

Thanks to everyone! The engine is in the car, so I cannot see in the hole, but I can feel in there to align holes....