964s are infamous for being one of Porsche's leaky 911s. One of the many things that can leak oil are the lower valve covers which are known to warp over, time with the result that the rubber gaskets let oil out even when they are new. The valve covers were originally made of magnesium but these were changed to aluminum at the end of the model line. Even so, the price of Porsche replacement valve covers are nearly £500 a pair plus the the rubber gaskets. Luckily, there are some aftermarket covers available from the USA so I bought a pair direct from the USA that even after shipping, came out to £218.
Newly purchased valve covers below and one of the old magnesiums covers:
Seeing as this was a going to a big job I took the opportunity to replace some of the rusty tinware that fits just above the covers. The tinware has a dual role of shielding the engine from exhaust heat and is vital for directing the air flow produced by the cooling fan. The only place to buy new tinware is directly from Porsche. This little lot, including a few extra bolts came to £147!
Starting on the right side of the engine the first job was to remove the final silencer which exposed a heat shield and a piece of rusty tin:
Once the heat shield and tin were removed removed, the original valve covers were exposed. The upper one is dry (as expected) but there's plenty of oil smeared over the lower one.
Lower valve cover removed:
The old rusty piece of tin and the new piece is shown below. On close inspection it's actually all in tact so could be shot blasted and powder coated so I'll keep it as a spare or stick it on ebay when it's freshened up:
All the old oil that had been seeping out over many years cleaned away and new valve cover and tin fitted:
That side was relatively easy but moving over to the other side the job got a lot bigger because the catalytic converter needed to be removed and since this had not been taken off for some time, there were going to be a lot of siezed nuts and bolts. Here's what I faced:
With the cat eventually out of the way (it took a while to get off) and the lower heat shield removed, you can see that the tin on this side was in a shocking state:
A close up of the valve cover showing just how leaky this one was:
Old and new tin. I didn't bother keeping the old one this time!
Here's a pic of the big cat off the car. Seeing as it was off, I put in a new O2 sensor as there's no record of it ever being changed:
New valve cover and tin fitted and now looking a lot more presentable:
Although I took a few hours off to watch the Spanish GP, this ended up being a full two days work. Although I could have done all the main work quicker, I took the opportunity to give everything I took off a thorough wash with degreaser (Swarfeger solution) which I think is one of the benefits of doing these jobs yourself as a garage wouldn't bother with this bit.
The only downside of the weekend was that removing the cat has now caused me a headache because I found that the flange that connects the headers to the cat has corroded very badly. Since the headers are an integral part of the heat exchangers (produce heat for the air vents) this could mean I'm in for a lot of ££££s to fix it: