docmirror

Right, "work" is a relative term. Yes, they can improve cooling efficiency per sq/ft, but in the case of an auto radiator, they have to expect some amount of contamination.

hacker-pschorr

+1
The person who sent me that photo is finding a lot of very new cars not cooling well, most of them producing photos like the one above.

F451

I had good luck with the replacement end tank and gasket. Brought it to a local guy who was very familiar with the Behr radiators with the plastic end tanks and how to replace the end tank. Cost was very reasonable, I think I was in for just under $200 all told so I was happy with that.

It will be interesting to see how long the radiator holds up, but right now I'm loving driving a 928 that does not leak coolant and runs at a nice steady temp!

I am leaking oil and power steering fluid though which is great because it gives me something to look forward to.

taffelman

yes Ed, always a little project to look forward to when owning a 928

Thanks to all for the quick responses, lots of great info surfaced and the writeup is simply excellent

I'll order the tanks/seals and do the dismantling and flushing of the core myself, but I'll probably leave the mounting of the tanks to the shop, since they deal and service similar Behr radiators used by Mercedes.

Now...time to check the PET for other small parts to add to the shipment....

shmark

For me, it was $200-ish to repair the radiator or $700 to replace it. Seemed worth it to me to go with the aluminum radiator and never worry about it again, but many people have repaired the stock and been fine. I will say I'm happy with the result, runs exactly at the designed temp and no issues.

ammonman

I just did this job a few weeks ago on my 1990 S4 and it was a piece of cake. I used the propane torch annealing method described on this forum to prep the tabs for opening. I did break a few tabs, but only on the passenger side that had already been re-tanked. I suspect those tabs were already cracked. The drivers side (where the leak was incidentally) did not have any tabs break. I only opened the tabs enough to get the old tanks out and the new one in. I re-annealed the aluminum before re-seating the tabs and used a SS wire toothbrush to clean the seal groove. I did flush the core while the tanks were off. Every other tube was open end to end with light visible. I used an old hacksaw blade to gently rod these open tubes ou and did get some flakes of scale. I am assuming the tubes I could not see light through have the flat turbulators in them. I was not sure at first, but when the pattern of every other tube being open was verified by free running water and light visible I did not do anything further to the other tubes. I figured there was no way that every other tube was clogged and there must be turbulators of some type in them. I used two ratchet straps to clamp the tanks in place and compressor the gaskets, no load spreader 2x4's needed. With the new T-stat, hoses, and coolant reservoir my temp gauge runs right on the un-numbered line between 170 and the red 210 line. It does fluctuate slightly as the fans cycle on and off. I have verified the temp at the block outlet and inlet using an IR gun as being right in the 185-195 outlet temp range with return temps running 150ish depending on ambient.

If it ever gets to the point of needing a new rad I will spring for the aluminum replacement, but re-tanking at home was easy, cost effective, and so far is performing well.

Mike

ROG100

For those who want the plastic end tanks I stock both and include the seals for $75.
Roger

Landseer

Roger, any more ideas on replacement oil coolers or substitutes?

ROG100

No but I never did ask Mark A if he had any ideas.
Anyone else?

hacker-pschorr

For anyone else confused like me, what's the issue with the oil coolers?

Landseer

My fault again., took the post sideways a bit.

Roger and I had a conversation about end tanks last week:

Replacement of them. With and without coolers. Fact that tanks and gaskets are available, but coolers aren't. Degree of difficulty in replacing the tanks and the coolers.

A few years ago Mark Anderson made a post where he commented that some undefined Chevrolet radiator coolers for oil had the same fittings as those on our cars, and were very close in size, and were available readily, and that a non-cooler end tank could be drilled to accept the slightly different inlet and outlet locations of the Chevy unit. Nobody inquired any further in that post and it was forgotten.

Roger said that since he spoke with Mark fairly often and would ask details of him next time he thought to ask.

Sorry to take this off course.

nsantolick

How long does it take to remove a radiator from an automatic 89 S4?

I probably have a leak and am torn on what to do. I'm leaning towards an aluminum replacement. I'll do the work myself, and want to minimize future hassles...

Do you need to drain the engine oil and the automatic transmission fluid?

If I can replace the side tanks myself, I'd consider that option, but I just don't trust any local shops. Maybe I'm naive, but ordering a new aluminum one and installing it seems to be the best choice, if current and future headaches are a priority.

If reducing future headaches is a priority, should I just do a decent citric acid flush first, put in a new aluminum radiator and replace all cooling hoses now??? I'm not trying to burn money, but I do intend to supercharge as soon as the car is up to specs otherwise. Henceforth, only I touch this car...

I hate the idea of plastic tanks, but like others said, they'll last another 20 years and all. It seems that there's a 2 week waiting period for an aluminum unit anyway, so who knows?







Nick - 89S4



This is my Porsche. There are many others like it, but this one is mine. My Porsche is my best friend. It is my life. I must master it as I must master my life. My Porsche, without me, is useless. Without my Porsche, I am useless. I must drive my Porsche true. I must drive faster than my enemy who is trying to pass me. I must pass him before he passes me. I will...

(roflmao)

ammonman

No need to drain the trans fluid on my '90. You will lose what is in the cooler but it was less than 1/2 quart on mine. Can't say for sure about draining oil as my '90 has the separate external oil cooler I would say total time to drain all coolant and get the radiator out was about 1 hour including getting the car up in the air. One thing that makes it go quickly is a set of large, thin metric open end fitting wrenches from Harbor Freight. They have a set that goes from 24 mm up to 37mm IIRC for about $40. Makes getting the cooler hoses off a cinch. Also handy for removing the fittings from the cooler and removing the cooler retaining nuts prior to removing the cooler core from the tank.

If your hoses are questionable or of unknown age I would spend the money on new hoses, t-stat w/o-rings, coolant reservoir and associated switches as needed instead of dropping $$$ on a new AL radiator. Have you pressure tested your system to pinpoint all leaks? Most major parts chains will loan you a cooling system pressure tester. Hook it up and put 1 bar pressure (15psi) on the entire cooling system. This will let you know real quick if you have a leak and where. Would be a shame to put in a new AL radiator and fresh coolant only to have to drain it out to change the coolant tank and a bunch of other stuff..

Changing the radiator tanks is super simple. There are several methods documented here on the board, all apparently used with equal success. I removed the tanks, flushed the core,and installed new tanks in about 3 hours one evening.

Mike