I have a 1997 XK8 that is running hot so I bought a new radiator for it. I ordered a Nissens 66700 from FCP Euro , but received a 66701. The transmission cooling lines on my XK8 do not fit this radiator. I contacted Fcp and they replied that this radiator should work. But it does not. The 66701 has 2 brass adapters - they also don't fit my cooling lines. The American companies selling Nissens radiators say that the 66701 is for 1998 -2002 XK8s. I checked the Nissens online catalog and it claims that the 66701 will fit my 1997. As far as I can tell I have stock cooling lines. The lines fit my original radiator. Has anyone else had this problem? Any suggestions? Thank you for your help. Melvin Hoormann

 

Check the connectors and fittings again. On the 2001 I had previously I installed the "correct" Nissen radiator from Rockauto and had the same issue. They were very helpful and quickly sent me a replacement unit that did work. However once installed, I noticed the connectors on my original unit would easily screw into the radiator I was returning. It made it identical to what they had just sent me and would have been fine to use.

Wish I had seen that before I pulled the radiator out and put back in twice.

It's worth a look before you go any further.

 

I believe some of the nissens come with adapters in place, unscrewing them gives a slightly different size fitting.
l think it covers M20 and M18. on 66701.
The 66700 M18/24

 

Is the pressure in transmission cooling lines very high ? It looks like I need to use short hoses to connect my transmission cooling lines to the new radiator I bought. Looks like I'm going to use 12mm high temperature hose to connect the 2 together. With 2 or 3 hose clamps. Thanks for your help. Mel H