I searched the past posts for this but haven't noticed an answer. My original radiator has been leaking for about a year. I thought it was something else. But climbing under there and pulling the belly pan, I found the source which appears to be the plastic side tank on the passenger's side right where it meets the metal main body of the radiator. #$^%&#^@!!!***@!! Bummer!
I notice several posts on here saying the plastic sides can be repaired or replaced without needing a new radiator. But I favor an all new radiator. My bank account says otherwise. Anyone know how much longer I can make it until disaster? I lose about a third of a gallon in three weeks, unless I drive alot.

 

Ron--

The car will tell you when it's having a problem. There's a dash gauge if it gets severe.

Having a system that won't old pressure means it will come up way short when weather gets hot. Simple as that. I'll also suggest that you very carefully inspect the hose connection at the top of that tank for leakage. I used aftermarket hoses at the last replacement, and the wall thickness is somewhat less than the original hoses. Using the factory clamps, the clamp would bottom before the hose was sealed. Took a while to figure it out since it's all hidden somewhat there in the fan console. Ultimately I made some shims to get it all to seal correctly but that's a different story. In the meanwhile, look and see if that's really where the coolant is leaking. Gravity carries coolant down from the top hose nozzle there, and it looks just like a tank leak.

928 Int'l has the end tanks and the o-ring seal available. Your local San Carlos radiator shop is familiar with the assembly, so no worries there. If the core is in good shape, it can usually be cleaned and put back in almost-new condition. Better to do it as soon as the budget allows, on your own schedule, rather than waiting for an overheat on a hot day when you just have to get somewhere in a hurry. Edsel Murphy is your co-pilot on this one.

 

The most common problem is a crack in the side tank under the upper hose attachment.

We - and the other vendors - sell the side tanks and seals. Replacing a side tank is usually better left to a radiator shop, but you will usually have to carry them the tank and seal.

If you really, really need to drive the car with the tank leaking, you can run the cap tightened only to the first notch. This will lower the system pressure enough to reduce the leakage to some extent. You MUST keep a careful eye on the temp, as the coolant will boil at a lower temp, but this is not often a problem. Keeping the coolant at or near a 50/50 mix becomes more important at the lowered pressure.

 

Ron,

I'm in the same boat. I tried to get the local repair shop to do the work last week and got some major attitude. Apparently because either a) I brought them the radiator, side tank and gasket so I was 'stepping on their toes' for the diagnosis or b) because it's a Porsche and that means I must be a rich a-hole.

I don't know which one it was and I don't care, I'm not going back there for any of my cars again after that.

I think I may have to take a shot at replacing it myself in the garage and see how it turns out.

There is a way to pressure test it yourself that Adam G. told me about the other day, it will confirm where your leak is (or leaks are) before taking it to the shop.

Here's how I did it:
1) get a bicycle inner tube and cut it and put one end over each of the large radiator hose connections, clamp it down. Also put a piece of 3/8" *(?) hose on the nipple that is on the top of the driver's side tank and plug the other end (I used a drill bit). Now you've got a good seal.
2) pump up the inner tube until it's good and bloated (15psi or so).
3) At this point you'll probably hear a hissing leak if it's the side tanks, or at least I did.
4) You can plug the oil and (if you have an auto) trans cooler holes and submerge it in a tank of water and look for bubbles.
5) If, like me, you don't have a tank big enough, go to the plumbing supply place and get a spray bottle of 'leak detect'. The stuff I got is blue and it's used for finding leaks in natural gas lines pressurized with air. It's non-corrosive and rinses off with water, but if there's a leak, you will see it bubbling up and foaming right on the leak.

If it's in the core, you're screwed, but if the only leaks are around the side tanks, your fix is just to get the side tank and gasket you need and figure out how to bend the tabs out and back without breaking them all.

Good luck, if I have any success with mine I'll do a write-up. If not, I probably won't be at SITM because I'll be saving up the $1g that I need for a new rad.

 

I have several radiators here ... not sure which are good, but can check if nudged hard enough

 

Well, this is Ron's thread, but if he passes, I might take you up on that Heinrich. I've got mine and one used one that Adam hooked me up with as well as a new side tank and 1 gasket. If I can't make one good rad out of these parts by the end of the weekend I'll drop you a line.

Did you get a chance to check out those fog housings? Were they even the right part?

 

I think you have very little to lose in trying to buy the end tank and seal and doing it yourself - other than the requirement that if you screw up you would have to buy a used or new radiator - which are plentiful.

 

Thanks for all the informative replies. I think the leak, thought getting a little worse than a year ago, is not critical at the moment. (Optimistic) I like the idea of sealing the radiator and using a leak detector fluid. I will soon need to do my TB/WP and that seems like the best time to do this repair. Heinrich, if you have spare radiators, I'll pass for now and let Mike take one, and hopefully you will still have one good one left when I get this resolved. I have been carrying around a gallon of distilled water but otherwise I have no temperature problems so far. Guess I'll have to get another ride insured so I can have wheels to get to San Carlos Radiator. I trust that guy who has been the only person able to properly repair my AC system so far. And thanks to Dr. Bob for reminding me of him.

 

Ron, sorry to hear about your radiator. FYI, the guys at San Carlos Radiator wll happily shuttle you to/from the CalTrain station if you're dropping your car off. If you're looking to just drop the radiator off... that's a different issue.

 

Thankks Dave. They did that for me when they had the car to rebuild the AC system. Very convenient. Just a quick bus ride from the train station in Sunnyvale to my office. This time I think I'll drive the radiator up there with my trusty Rabbit. I left it parked outside the garage but no one stole it, so I guess I'm stuck with it for awhile longer.

 

Hi Ron:

I've had my passenger side sidetank replaced twice by a local radiator shop in Concord (Mel and Sons). First time was because of a crack in the original tank after 15 years. The second was a few years later when the tank warped due to overheating (WOT switch not working while trying to cruise at 155+ in desert heat) and the seal began to leak.

The tabs that hold the tank are rather fragile and the new tank and seal must be compressed in a jig while the tabs are bent back into place. The shop has the tools to do this right and reduce the risk of breaking tabs. The shop I used, although very familiar with Behre radiators and plastic sidetanks, was happy I provided the new tank and seal. The shop will pressure test the radiator to verify the leak source, "rod" or otherwise clean the radiator once they remove the bad sidetank, and pressure test the repaired radiator. I think I paid $95 labor charge.

 

Throw that crappy stock radiator away. I changed mine to the c&r aluminum radiator and have never looked back. My car runs cooler and no leaks to worry about in the future. Spend it now or many times later.

 

Ron
Two solutions to this problem.....

#1 get a new end tank seal for your existing radiator....Bills place seems quite reasonable
#2 Buy a new C&R from 928intl.....I have one in the widow and really like it...nice and cool even at track pace....however I have heard of slight fit issues with automatics?

 

OK, just got back in from the garage. I decided that two radiators on the bench isn't worth crap if my car doesn't have one, so I took a shot at replacing the gasket and end tank on my original.

I took a paint can lid remover and ground it down with my dremel so it had a lip that would dig under the tabs but was still beefy enough to bend them up.

Then I went around to each one and bent it up just enough to clear the plastic of the tank, and pried the tank out.

Next took a pick and pulled out the old gasket (it's MUCH thinner than the new one ).

Then I took some q-tips and cleaned the area where the gasket needs to sit, cleaned again, and then a third time with mineral spirits. It was pretty cruddy.

When it was clean and dry, I used a thin film of hondabond on it (I know it's supposed to be dry. but I made sure there was no squeeze out and just the thinnest film on the gasket). I pressed it in, put the new side tank on (It was tight and popped back in when it was seated).

Then the tricky part: Getting the tabs back in place without snapping them off.

I decided to use my vice grips to pull them back in so I picked a setting that felt tight but not too tight, I dialed it in on the handle of the vice grips so that all the tabs would be bent to exactly the same place (if you know what I mean). Only two tabs snapped off and they weren't next to each other. I'd noticed that near the cooler ports the tabs aren't bent down either, so I figure one or two off is OK.

Next I pressurized it with my inner-tube test jig and voila! No leaks!!!

I started about 8:00 and I was on the road by 10:30 including putting my spare computer brains and torquing my new wheels on (pics to follow in another thread ).

It's in the car right now and I'm back on the road! (I'll post if I spring any leaks in the coming weeks).

PS- I only did this to make it to 'upgrade time' next spring. Then I'm going all new aluminum welded tank.

 

Mike:

Good work. So, you didn't need to compress the sidetank gasket? Some people use large pipe clamps or furniture clamps to hold the sidetank firmly against the gasket while they re-bend the tabs.