I'm having troubles removing both the oil cooler and transmission cooler lines from my radiator so I can pull it out and replace it. I was able to remove the lower transmission line, but the rest don't seem to want to budge.

I can get the overall nut removed from the radiator (or at least loose), but then the outer nut simply wants to turn with the oil cooler lines, etc. I've sprayed it a million times with penetrating oil, but it's still stuck. The lower trans line turned just fine.

Any tips or tricks?

 

Are you holding one with a wrench while turning the outer nut with a wrench?

 

Yeah, what he said. The big nut is really the fitting that stays with the radiator. The smaller one is the actual one that will turn and stay with the hose when it's disconnected. A 10" and a 12" adjustable wrench work great. I just did this job 2 weeks ago. Not hard at all. Are you putting in one of the new all Aluminium rad. form 928 Spec., or Devek?- Ruf

 

It is really important that the nut on the radiator tank does not move or you will break the oil cooler.

One trick is to use 2 wrenches whose handles form a sort of V so you can get both hands on the V and squeeze them together,

Myself, to shift the bottom connector I bought some thick steel gas pipe and extended the wrenches by about 2 foot.

Marton

 

If I recall I used a 1 1/16" and a 1 1/8" wrench. Not sure what the metric would be but I don't have any metric wrenches that big.

 

The wrench sizes are 32mm and 27mm ( 1 1/4" & 1 1/16"): you MUST counterhold the 27mm flange to keep it from moving. The 32mm gland nut ( captive on the line) is the part that must yield ....

edit: ** reversed the two numbers above ... the gland nut is 32mm, and is the one that loosens

 

Thanks, Garth. That's the information I needed. I wasn't positive which nut needed to do the moving. I'll give it another shot tonight.

 

The inner jam nut only serves to compress the gasket between the tank and cooler. So counter holding not possible or necessary.

Make sure you have a long enough wrench (no cresent wrenches) with enough leverage (15" minimum) to break it loose easily, as the accessibility of the nut is quite limited.

 

It may not be necessary to counterhold the 27 mm nut ... but IMHO, it is a wise thing to do: the plastic end tanks that are on all but the few aftermarket aluminium rads are not overly robust.
Counterholding this fixture stabilizes the heat exchanger inside and consequently minimizes torque transfer to the aged plastic when cranking on the 32mm gland nut: It is reasonably easy to do so with a thin faced 27mm wrench, so however wrong it may be, it remains something that I would advise doing.

edit: corrected the gland nut size (32mm)

 

Garth,

I highly recommend counter holding fittings where possible, however I only pointed that out because unfortunately, and counter to what first appears to be the case, it is not possible to counter hold this particular set of fittings.

 

Borland, I was able to counter hold it. Your wrenches may be too wide. Mine are a cheap set of harbor freight, 14 wrenches up to 1 1/4" that cost all of $13 but they work great.

 

I did the exact same thing. Think about it........... why is it shaped like a nut if it wasn't ment to be counter held? Porsche could have easily left is to look like a round disk.

 

Maybe the radiator on my 90' S4 is different?

It looks like a nut because that's just what it is. Like I said before, this jam nuts sole purpose is to compress the gasket inside the tank.

Since it's threaded to the cooler nipple, it can't counter hold the cooler nipple while loosening or tightening the nut on the oil hose fitting.

Just look at one of the fuel hose union fittings... the aposing nut there is integral to the barbed fitting half so that it can be used to counter hold the union nut.

 

Understood ...

 

I still can't seem to break it loose. I've tried all directions. It's either really stuck, or I'm trying to turn the wrong nut. I've uploaded an illustration for reference.