Dear muskox27,

Hope you're well. The brass nipple, to which the steel ATF (automatic transmission fluid) pipe attaches, is braze-welded to the in-radiator ATF cooler. The cooler is a double-wall copper tube, with a hollow core.

To remove the ATF pipe from the ATF cooler's nipple, you'll need two wrenches. One wrench is used to hold the large brass hex nut that is directly against the radiator's plastic side tank wall and the other wrench (15mm, if I recall corrctly) is used to turn the steel hex fitting on the ATF line.

The large brass hex nut should NOT be moved AT ALL. The steel hex fitting on the ATF pipe should be turned, to loosen it.

While holding stock still the wrench on the large brass hex nut, push on the wrench on the steel hex fitting. Apply pressure until: (a) the steel hex fitting moves or (b) the steel pipe seems to twist.

If (b) occurs, apply more PB blaster and wait. It can take a long time for PB Blaster (or any other penetrating oil) to work its way through micro-channels in the corrosion and so to weaken the corrosion bond.

Were you to loosen the large brass hex nut and push on the ATF cooler's brass nipple, you'd break the seal between the inner surface of the ATF cooler's nipple and the inner wall of the plastic side tank. This won't allow coolant to enter the ATF. But breaking that seal will likely mean a bleed leak of coolant from the radiator and so a rad replacement.

Be advised that one or both of the ATF coolant pipes are no longer available from Volvo.

In short, use two wrenchs, turning only the smaller of the two wrenches.

Hope this helps.

Yours faithfully,

Spook