heinrich

Post your thoughts in this thread, let's beat this one together.

I think if we took a copper tube and coiled it so ti fit neatly inside the rad end tank, and brazed it at the top and bottom to the existing fittings, we would have an oil cooler that would never leak again.

So .... maybe Dave and Garrity or some other industrious fellow could do this for us and sell them at a good price? Better than buying a new rad, right? And it will happen to you, at soem time in your car's life, because I believe the fittings start leaking oil into the coolant because they are frail.

Mark Anderson

Actually the solution is quite simple. There is a Chevy cooler that has the same treads but the center to center spacing is slightly off but just a few mm. If you buy a new end tank with no cooler holes you can put them in the appropiate location and use the inexpensive Chevy cooler.

heinrich

Mark did I tell you you're like a brother to me?

mark kibort

when the oil gets into the water via the oil cooler, if you removed the oil, wouldnt the water then leak into the now , unused oil cooler if you didnt fix the original oil cooler leak?

anyway, the after market oil cooler seems to be a good idea. certainly would provide much better cooling vs a using 190 F water to cool 250F oil temps as in the stock system.

MK

heinrich

MarkK, the cooler is a little evaporator-like thin inside the end tank. You take it out, remove its fittings and weld between them, a length of copper tube which you coil, or trumpet (911 style). You then insert that assembly into the end tank, bolt the two fittings through the holes in the end tank, and attach the end tank to the radiator. VOILA!

But, Mark Anderson's tip above gives me new hope. I will find that cooler, and replace mine with it, and buy a couple of end tanks from Mark in the process. MarkA ... better start stocking up on end tanks, and maybe the coolers too

Heinrich

Jim bailey - 928 International

Liquids are far better at transferring heat than gases like air. If you were to stand naked in a 55 degree room you could survive for a rather long time but immersed in a 55 degree ocean is quite another story. So even though the coolant might be at 190 it can be more efficient than air at much lower temperatures in sucking out the heat. The other aspect for street driven cars is that the coolant helps heat up the cold oil on start up and stabilize the operating temperature to the range that Porsche designed it to be. The 928 did change to an external oil to air cooler on the 1990 > for reasons know only to Porsche At least that way when the cooler fails it is more obvious ...like 9 quarts of oil on the ground and zero oil pressure !

John Veninger

I know, I know!

To sell more oil coolers

Normy

That's all good and true Jim, but you're forgetting one variable: age-

Our cars are old now, even the last GTS's. Age causes problems, and one of them is the situation where oil mixes with the coolant from a failed cooler. I guess a better idea than some brazed tube would probably to use a cooler from another company, since the Porsche cooler is difficult to get. A radiator shop in Orlando tried to build for me an oil cooler based upon parts from general motors, but we just couldn't get the item to fit in the tank.

I wound up mounting a Hayden air-to-oil cooler in my grill, which cools the oil via sandwich plate. I don't know how effective it is- I'm still in the process of mounting an oil temp gauge, but this cheap fix [found the Hayden system at Pep-Boys....] allowed me to run a late model, easily available GT/GTS non-cooler radiator.

N!

Ketchmi

I hate to pop your bubble Jim but the oil cooler in the radiator doesn't assist in warming the oil quicker. There is a thermostat in the oiling system that doesn't allow oil through the cooler until it's up to temp. This is another one of the reasons we are working on a solution.............

Normy

The oil cooler that I installed.

N!

heinrich

Norm that looks good if a little on the small side for an air-cooler? Btw, if some years never had a cooler .... one wonders if a cooler is even needed.

Jim bailey - 928 International

Dave the heat exchanger in the radiator is always full of oil and it sees pressure all the time but you are correct that oil is only FORCED to flow through it when the oil thermostat closes starting at about 87 C and when there is less than 1/2 bar of pressure differential or the internal bypass valve (pre 1990 or so) opens. The coolant in the radiator will in fact heat the oil inside the heat exchanger which will allow it to flow more freely (lower pressure) as the oil thermostat closes. Porsche did state that the external oil to air cooler that they fitted in 1990 had more cooling capacity. The coolant thermostat at 85 C ,the radiator aux fan switch at 92 C (78-86 )and the oil cooler thermostat at 87 C is perhaps a good indication of what Porsche intended as a normal operating temperature. My point was really about Porsche wanting the engine to operate in a given temperature range. I still vividly remember the 1969 Mustang Mach 1 with the 428 big block Cobrajet with drag pack option ....430 rear gears and a front oil cooler ..brand new car belonged to the Ford store , I drove it home and on start-up the next morning (cold night in northern Indiana) it blew off the oil cooler line and dumped the oil in the street. Perhaps one reason why POC and PCA do not allow oil lines with barbed fittings and hose clamps on any car participating in the track events. This comment has me puzzled.."...allow oil through the cooler until it's up to temp. This is another one of the reasons we are working on a solution." if the oil is NOT HOT or even "up to temp". why would you want it to flow through a cooler ? or was that not exactly what you meant to say ? In my opinion no one person knows everything about 928s and the purpose of a forum like this is to discuss points and issues. Thanks for pointing out that I overstated the warm up effect , I am probably delusional enough as it is

docmirror

1990 model air cooler on mine with no front spoiler. A recipe for disaster. It's been whacked several times, and the bottom of the frame looks like a skid plate. We have two conflicting constrains, frontal area, and cooling requirements. I agree that the oil/water cooler system is crap. It was a bad idea and was executed poorly. The only thing worse was the Ford setup Jim mentioned. This goes all the way back to type I VW days, with the oil cooler in the doghouse, causing the #3 cylinder to run hotter than all the rest. They even have a special distributor lobe to retard #3 on an air cooled VW because of this. Baaaad Engineer!

I line the out front setup that's right in the slipstream of fresh air, but partially blocks the radiator. Sometimes ya can't win, at least it's simple, low tech and effective.

heinrich

Any progress on this? Does anyone know if the MoPart piece looks any different from our stockers?