993RS

I forgot an option to choose from, so here is version 2.... Sorry guys...

Figures are all in miles

nrubenstein

I replaced them preventatively at 98k while I had the engine out. The car was clacking, but it wasn't clear whether that was actually a lifter, or slightly low oil pressure on the right head due to spraying it out the turbo.

EVERY SINGLE ONE had either a failed o-ring, or an o-ring that failed on removal. At least one o-ring was missing completely.

Turbo motor, fwiw. For $400 and a little time, it's a pretty easy and inexpensive thing to do while the engine is out. I wouldn't touch them without an actual problem unless the engine was already out,though.

NP993

137K on original lifters, still going strong. Car spent most of its life in a cool climate and with an oil cooler fan switch keeping temps around 180F.

bcameron59

Replaced at 123K miles as preventative maintenance during top end rebuild.

So I guess they would have fallen into category "100k and still going strong", because they were still working OK ie not making any significant noise, except for about 2 minutes during startup after winter storage.

However, all seals were toast, or broke apart on removal, so I'm glad I did them.

JB 911

Very interesting NP993.

So you leave the fan on always and it stays around 180? That's interesting. According to p-car the 'low speed' fan doesn't kick in until 230F SO you are able to keep your car quite a bit cooler by doing that.

http://p-car.com/diy/fan/

I am curious what the ideal temperature for engine oil is? I would really be interested to hear from engine guru's on that one. I know too cool and it's not as effective. Obviously Porsche feels 230F is too hot or the low speed fan wouldn't kick on. After I replaced my oil fan resistor, I did notice that even on hot days 90F+ the low speed fan doesn't stay on - it cycles. I noticed that if you keep moving, like a shark, it doesn't come on at all as the car speed forces enough flow over the front oil cooler.

Hmmm... good food for thought. Another mod could be in my future....


PS Good move for changing the poll - I voted

NP993

I don't leave the fan on, I just switch it on when the temps start to climb. 230F is just too hot for an air-cooled motor, or any motor really. 911 motors like to be in the 180-190F range. I believe the factory set the fan thermostat so high for emissions reasons, but I can't remember where I read that.

DiegoR

Poll is in miles or KMS?

JB 911

got it, that makes sense.

I do notice that if it is 90+F here and I'm on the highway, the temp won't get hot enough for the fan to turn on. I'm guessing, it stays in the low 200's. But within a couple minutes of pulling off the highway go thru a few lights it will spike up to 230, fast.

Can you keep it at 180 when it's 90+F outside? I'm being lazy now, but when you do the switch does it keep the fan on low or high speed or choice?

993RS

Miles. Thanks Diego, I made the correction...

NP993

The switch turns the fan on its high speed setting, and it does a fantastic job of cooling. I've only ever seen temps crack 200F with the fan on when sitting in lengthy traffic jams on 95F+ summer days, when the air the engine is sucking in off the pavement is into triple digits, and that's only happened a couple of times.