It's been a decade since I've done any major engine bay maintenance... Knock on wood.

The passenger side end tank has off an on leaked a little, especially after long periods of inactivity. Mostly just an annoyance. Now it leaks a lot to the point it requires attention. Considering it is the original 1987 radiator, I'm tossed between repair or replacement. What are the current best options? Thinking either repair since everything else is leak-free working well or replace with a Mark/Roger aftermarket unit. Please keep in mind, I have a Murph Vortech supercharger like 2 millimeters from the stock radiator... no rubbing.

Second, it's been 10 years and about 30 k miles on the Gates belt, with Porken tensioner, and I think Lasco pump. Since I have to yank the Murph, is today's conventional wisdom to inspect or just replace. If pump has no leaks and no impeller end play, thinking it should be good. The belt seems to be too cheap not to replace. And hopefully, my 30 K old cam gears are pitting.

Finally, a local ad popped up for cans of R12 at $25 each or 5 for $100. I haven't ever needed any, but would not mind having some nearby if they are really ubertonium. Is R12 super scarce like I used to think it was, or is it available if needed?

Need to get my old girl back on the road, this one or two tanks of gas per year isn't right.

 

I’m not a pro like many others here; but if I’m pulling the water pump and belts off after 10 years....then I’m putting new on.

For r12; that’s a great price if you don’t plan on converting your AC anytime soon.

jmho

 

30 lb cans of virgin R12 are in the $900 range, so if you can get only what you need for ~$30 a pound, that's a good price.

 

I see cans of R12 on Ebay, it's not all that rare. It is, however, quite a bit more than that. If I found that deal I would buy them (my 928 is converted, but I have another car that is not).

 

I recommend buying that R12, that's a good deal.
Good luck get the maintenance caught up and back to great health, your car sounds fantastic with the supercharger!

 

^ +928

I buy every single can I come across. in Canada they are even harder to find.

 

I wish I'd thought to check here, but I just sold off a few 12oz cans and a partial 30lb cylinder.

There is definitely still a demand for it, to the point that there is at least one business offering to buy any (R-12 and R-404 only, I believe) that people are selling, and providing the packing material and haz-mat paperwork already prepared.

 

I have a full 30# cylinder of duPont R12 somewhere. Hoarding the stuff I guess. Sounds like it's worth about the same as a set of tires. Meanwhile, I converted the 928 to R134a in early 1998 and never looked back.

I bought a cylinder of R134a six or seven years ago at Sam's Club for about $75 in Cali, at the same time they were getting $25 for a small can with their crazy deposit plan. Easy choice at the time, looking forward to the time when DIY services would be outlawed completely there. So we moved...

The cost of the freon R12 is incredible, especially when you consider that we typically buy it to "just top off" a system that leaks. Fix The Leaks! By the time you are done with that little effort, there's enough savings just in the cost of refrigerant to refill the system to make the small extra effort for R134a easy to justify. Waste no time thinking that R134a won't be cold enough; mine blows less than 20ºF cruising on 85º days. Freezes fingers if not managed correctly. In our dry climate I keep the freeze switch jumpered. If you have humidity, you can still easily see 35-40º vent temps with freeze protection.

 

I finally made the R134 jump this Spring, but since I wanted frosty front and rear AC, I added GB's second condenser.

Black on Black brings a LOT of energy into the car, but on a hot hot day can pull 40d at the center vent, both AC units operating, with the freeze switch enabled. It cycles a lot not, never did before.

I can see high-teens at the coils directly, which perfectly match the low side pressures present as well.


I do have some other issue, that..I need to start a separate thread on.

 

I now have 5 cans of R12 on my shelf "just in case". Haven't needed any since I had my compressor replaced over 10 years. Feeling pretty cool on this front.

Now how about my first two questions...

Radiators? Repair or replace?

TP/WP inspect or just replace.

 

Unless there is something else wrong with the radiator I would go with sidetank replacement. I've had it done at a local radiator shop. I got the tank and seal from 928 Intl as the shop could not locate the parts themselves. The shop must have experience doing this on Bosch radiators with plastic sidetanks. They should test the radiator for leaks before and after and clean out that tank. Also, I will add that I drove once for a month with a serious sidetank leak by leaving the radiator cap loose until I could get it fixed. Without pressure there was no leak. I thought I might have some boil over at some point, but it never happened and that included mountain driving. I didn't have a super charger at the time and I wasn't doing burnouts, but I was surprised by how well the cooling system did without pressure. The cooling system behavior, at least under moderate conditions, was fine.

As to the timing belt and water pump. Porsche never called for replacing the pump at any service interval. The interval for the belt is 60K miles with no other service interval specified. I have almost always gone by miles, with inspections in the interim. When I bought my car it had been serviced by Porsche and it had been 9 years and 30K miles since the belt had been replaced. The water pump was original. The odometer was at 90K miles. I replaced them because that was the zeitgeist. The belt literally could not be distinguished from new except for some fading of the lettering on the backside. The water pump was still in excellent shape with no bearing slop, the pulley did not freewheel, and the impeller was still in the original spot. Since then i have gone by mileage for the belt and inspection of the pump. Somebody will probably come in and crucify me for being so cavalier. I don't know of any belt failures specifically due to age. I have seen 928s with belts that were 20 years old. That made me a bit nervous and I advised the owners to replace it. I guessling a big factor is exposure to the elements, such as extreme heat, extreme cold, areas with high ozone. You know, things that affect all kinds of things on these cars, such as the electrical system, interior and anything rubber or steel. My car is garage stored, driven frequently, and most of those things are in remarkable original condition. Even my torque tube bearings are original.

Anyway, back to the TB/WP. Conservative owners and at least some specialty shops go with a 5 year interval for both. That was the zeitgeist here for a long while. After a lot of squabbling, many people moved to periodic inspections and a 10 year max on the replacement interval. That's probably most reasonable even if I don't always follow that. I definitely use 60k miles for the belt, as Porsche recommends. I actually had one belt that required changing at 45k miles. it might have even been less than that. It was a Conti belt that stretched out and tripped the low tension warning. I snugged it a couple of faces once and it did it again not long after. No more Conti belts for me. Greg Brown has tested them and considers them essential a stretchy rubber band.

You need to take the belt off to inspect the WP, and you really need to examine all the rollers and bushings, so you might as well replace the belt, despite my meandering notes above. Unless something changed recently, it's remarkable how inexpensive the Gates belt is. The water pump, which I said I inspect, is iffy in your case. It's old enough that it precedes the improvements I believe Lasso made maybe 6 or 7 years ago. It might be fine for quite a while longer. You can inspect the pulley and bearing behavior, but to inspect the impeller you need to remove the pump. So, you could go either way at that point.

 

Kurt,

I know I have new side tanks and seals somewhere. I may be able to locate one for you. However, that new CSF radiator is a nice piece for the price. Could be worth considering if they are in stock.