[Westy]

Been away a while, but now there's a slight problem.  The radiator has a weep.  Not terrible, but a pint or so every 50-60 miles.  These radiators are quite expensive.  Can a radiator guy fix this by boiling the tanks a re-solder the core?  Or do I bust leather and buy a new one?  I was wondering if Alumiseal would be a good alternative to get me thru summer, or would that gum up the works?  No pun intended.

 

Thanx.....Brian

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[J.Elenbaas]

In my opinion repairing an old radiator is just waiting for the next leakage to happen.

I know the're not cheap, recently replaced mine too.

I paid around € 350,00 for the radiator, but there are cheaper aftermarket ones to buy too.

 

It will last for a few decades again!! 

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[94SilverCab]

Have to agree that a new radiator is money well spent. Too many REALLY expensive parts to replace with a major overheat.

 

JMHO,

 

Jay

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[Waylander]

can you see where its comming from,

 

you get leaks in a few places that may not be the rad,

 

thermal switch under the top hose,

drain plug rubber disintigrated

the take off from the water pump with the little plastic part, O ring fails

and last but not least, the header tank cracks at the top of the support leg, if the leg mounting bolt is missing or loose

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[Roboman]

Is the alu radiator for reduced weight or better heat dissipation??


My 968 was in sad condition when I got it, I've previously mentioned the cam belt was already shredding, but it also was running fairly warm. However, given I was in the Middle East running hot was not unexpected. A new Alu radiator wasn't available and nobody did alu welding, so I had a radiator made up with standard components.


When I removed the original radiator I noticed the water channels were coated with a white, smooth, coating. Id not previously seen that and I've seen the insides of many a cooling system, any ideas... egg white maybe? I wondered if the white coating was affecting cooling, but after exchanging the radiator I think maybe not.


I'm aware the 968 is maxing the ponies out of the original design and that each increase of hp comes with an increase of heat.


I'm now in average ambient temperature driving, i.e. neither the extremes of the Middle East or Alaska, Under normal driving I'm around midpoint..... but if I stay in 3rd and enjoy a bit of yeeha around our country roads then I'm up to the 3/4 mark.

where is everyone else's temp gauge sitting, is this the same for everybody?


This is definitely where chatting with other 968 drivers comes to the fore.


Have a good weekend.

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[Westy]

Some good info here.  I didn't discover the leak.  When I took it in for inspection/maintenance, They advised there was a small leak.  As I said, it does lose a little fluid, but not much.  Just got back from a 220 mile road trip and the temp (with AC running) never got much over the first mark.  I'm gonna try and inspect those areas pointed out by Booster.  It would be good to isolate where it is.  The shop could have seen some fluid and assumed the radiator, or they may be right.  Wherever it is, it can't be much.  I guess that's why I wondered if Alumiseal would hurt anything internally.

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[ds968]

This is interesting and inexplicable to me ; in the summer, and when it rained ( this is the inexplicable part ) my 944s always ran with the temp indicator above the last white line ( 2/3 ) and more often than not almost touching the red mark .  But never boiled over ..it’s just unnerving to see it like that .  My 968s however, have never had that issue, the needle usually stays between the 1/3 and the 2/3 white lines, never exceeding that 2/3 one no matter how hot it’s outside or how hard I drive the car .  And this m.o. stayed the same even after the cars were supercharged.   But I have ( one of the first things I had changed in the cars ) the low temp thermoswitch which activates the fans earlier than the standard switch that comes with the car.  

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[Roboman]

Thanks DS, I think my fans are operating correctly but should test them and also check the switch installed. (Mine too doesn't boil, but I agree it's uncomfortable seeing the needle up near the red line)

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[Waylander]

The thermo switches go pop quite often, especially when the fans are getting a bit sluggish and full of dirt


The load at switch on welds the contacts together, and then the fans will run till the battery goes flat


The fans always benefit from a good clean out and a lube,


The temp gauge is a bit of a hit and miss affair, if your really concerned about temps I would install a real temp sensor


With the rad cap hold the system under pressure at 13-15 psi, this increases boiling point to about 110c


But I would definitely check the stat and switch are the correct ones if your temp is up near the red, should never get that high

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[Roboman]

Thanks guys, as always good stuff to mull over.  Westy, my apologies for hogging your thread 

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[Westy]

Nope.  I always learn stuff.  Fortunately I already dealt with the failed thermo switch.  Replaced it, and the fans work perfectly.

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[J.Elenbaas]

My temp needle usually stays steady in the middle, unless on a hot day you have to wait for trafficlights it will go up.

I guess around the 2/3 white needle the fans go full blast.

 

The same happens when i park my car in the garage after a ride, but i suppose that's all normal as at those moments there is no cool air passing through the radiator. 

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[Roboman]

J... but the fans stay on even though you take the keys out .. yes?

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[Westy]

I've decided to just swap out the radiator.  The one in there is old, and I don't have much info about this car's life B4 me.

 

1986-1991 Porsche 944 Turbo (wizardcooling.com)

 

And I don't want to start an argument over antifreeze, but the stuff in there is over 4 years old, too.  It's the pinkish colored fluid.  What antifreeze should I throw in there?  I want to get this job done B4 it gets too hot out here, cause if it heats up too much, then the car will sit for months until it cools down.  Besides, the stereo never worked, and I'm tired of using the JBL Charge 3.  I gotta get the stereo and speakers swapped out.  So in another thread I'm gonna ask some questions that will really make me sound like a..........well, you get the idea.  

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[ds968]

I have always used Prestone Orange  Dex-cool  ( no phosphate coolant / anti freeze ) in my 968s .  I also pour a bottle of Water Wetter in there .   Never had a problem. 

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[Waylander]

If you follow the manual from back in the day it requires 3M G48 based antifreeze,


But times have moved on, and Prestone now seems to be the weapon of choice for a lot of folks

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[J.Elenbaas]

Roboman, correct the fans keep running untill things cooled down a bit even with key removed.

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[Westy]

Thanx for all the good info.  I now know what I'm gonna do.  Stand by for my stereo question thread.  Fun times!  

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[MCL968]

Must be a astrological or geographical issue at work here. My fan switch just failed and welded itself in the on position, so back to the parts store we go.

 

As for repairing the radiator, we nave a shop in town that will pressure test them and weld up cracks for a good price. I replaced mine around 6 years ago, and I went with a lower (85c) switch at the same time. I plan to have my old one cleaned and repaired one of these days for a backup.

 

3 Cautions when you are doing the job.

 

1) BE CAREFUL tightening the fan switch. There is a torque spec that you need to follow, and it's surprisingly low.

 

2) make sure you get a 968 radiator, or a 944 radiator WITH the little cover for the line that goes to the turbo. The 968 radiator has the tube for the turbo, but it's not drilled out. The 944 one is open and thus requires the little cap and a clamp to block off the line that is supposed to cool the turbo.

 

3) Be sure to burp the system after it is up and running. Get it hot to the point the thermostat opens, raise the front wheels a bit, and release the trapped air using the bleeder bolt on the top radiator hose gooseneck. If you have an early 92 you will need to remove the injector cover to access the bleeder, all later models have it exposed which makes it much easier.

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[Westy]

What sucks is I already replaced the switch, removed the pans and installed a new alternator, put in a new grill, cleaned the fans, filled and burped the system, THEN found out there's  a weep in the left seam.  If it had just leaked when I wass in there...............................................

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