Herman K

Mine was still holding pressure and after I removed it for a regular check of the coolant fluid (I remove the cap to check for color changes of the fluid and to observe the water surface) I decided to do a close-up examination of the rubber seal and you can see from the pictures it's time to replace this one.

It's been on the car for about 3 years, many years ago I read one of Gene O'Rourke episode on how he got stranded due to a failed radiator cap and ever since I've kept a close look on mine.

Gene is no longer with us but if you have never heard of him you may want to go here and read some great 928 stories. http://www.928s4.com/GeneO.htm

Thank you Gene.

danglerb

Cap fit is I think generic USA style in 12 psi. I think I have a Behr on both of mine, but I bought a funky one to try from Mr Gasket with a temperature gauge built in.

Herman K

Reprint from Gene

16th September 1997

Subject: 928 Radiators

With all the talk of cooling systems going on I think I should relate what happened to me in July. I was a few miles north of Wilmington, Delaware heading north at about 85 mph. The outside temperature when I passed through Washington was 105. I had the AC on max and the heat gauge was running a little over normal but not up to the first white mark. The car which has 96K on it was running smooth as grease. Suddenly the heat gauge literally shot up into the red zone and smoke started pouring out of the AC vents. I immediately pulled off onto the shoulder but the engine died before I even rolled to a stop.
Lots of smoke, not steam, poured off the engine. At first I thought that the engine was on fire and naturally, I had moved my extinguisher to one of my other cars and had forgotten about it. Fortunately, after a few minutes, the smoke died down. Meanwhile, I was on my phone, to AAA and shortly a wrecker arrived. The guy wanter to shove a hydraulic ram six inches high under my brand new front air dam. I told him that I needed a flatbed and explained why.
His grandson arrived with one a short while later and I had to show him how to winch it up on the truck by putting wooden blocks under the front tires etc. As he was winching it up he said; "Don't worry mister, we'll fix it up for you. Does this one have the engine in the front or the back?" As he said that, I was talking to my mechanic in Pompano Beach and after he stopped laughing he said, "Don't let them touch that car! So I had it flatbedded eleven hundred miles back to Florida. End result? The spring in the pressure cap on the radiator broke and fell into the resevoir below. The water pump immediately pumped all the water out of the radiator and the left hand cylinder head cracked and the gasket for same blew. The head had to be welded by an aircraft repair shop that does a lot of aluminum welding.
Two months later, I'm just getting the car back. While the head was off, the mechanic discovered that one of the cam bearing caps had a hunk broken out of it around one of the screw holes. A two dollar part right? All the Porsche dealers in Florida said the the cap was made of unobtainium and could only be purchased as an integral part of an entire head assembly for approximately $1500.00. So my mechanic had a local machine shop make a new one out of a block of aluminum for $150.00. After driving 928s over three hundred thousand miles since 1978 I thought that I had experienced every thing that could happen to them. I was wrong. My advice? All members of this group invest five dollars or whatever and replace your radiator caps. Mine was obviously a ten year old original.

Gene O'Rourke

Herman K

Did you try it on yet?

danglerb

I have a water bridge leak to sort first, so its still sitting in its box, but soon as in next couple weeks.

Arnoud

Thanks to Herman for reminding us all on this very cheap pre-maintenance fix that is at the same time very easily overlooked.

At least I did not do this super simple check when doing my full coolant flush and refill a few months ago, I will check (and most likely replace) the radiator cap as soon as my car is "back in business" again.

steve322s

I have been using this one for a month now. i see no problems.

i decieded to use it for fear my temp gauge might not be working correctly. it must be cause everytime i check temp on cap its always in the green
Steve

Herman K

What's the part # for the one you have?

SMTCapeCod

Thanks for keeping/refering to the GeneO archive.
One of his 928s was being passed around for a little while, couple years ago. Wonder where it ended up.

steve322s

not sure of the part # it is a 13lbs i purchased from advanced auto. if i remember nxt time i'm at advanced i'll get the part #

dr bob

The original Behr caps are relatively cheap from our regular suppliers. Mine gets changed every couple years just because. Hoses get renewed every other timing belt change. ALL the coolant hoses, by the way. Like replacing the cap, it's cheap insurance agains getting stranded for something stupid. Or having to pay for the 1100-mile flatbed ride as Geno related.

Rob Edwards

Looking at that Mr Gasket stop sign shaped cap, my kneejerk thought is whether it fits? Even a stock, lower profile cap can be kind of a PITA to get on and off under the fender lip. That cap looks taller than stock, but looks like Steve is using it without problems.

Thing is, as Bob says, the stock Behr is cheap. Like $8 cheap, and they're good for 10-20 years. More, on some cars

http://www.mailordercentral.com/928i...106%20257%2003

Arnoud

Now "done" (yesterday evening, as part as many small replacements everywhere), and mine was most likely never changed before. New one is tight to put on and off (good workout ), when compared with my old one.

Thanks once again to Herman for reminding all of this cheap preventive maintenance.