h20boy,

Dick Maury at Coventry West gets the credit for solving my problem. In a nutshell when the S/C is underload it creates additional heat which doesn't get cooled enough via the intercoolers. The intercoolers has its own electrically driven coolant pump which sends the coolant to a dedicated radiator on the front of the car. If the pump isn't working this heat transfer doesn't take place which will set off restricted performance. I only had this situation when I was climbing a mountain at freeway speeds for 20 min. or so. This situation never occured just tooling around town because the S/C wasn't under increased load. The first step in solving the problem was checking the fuse on the I/C pump circuit. If the fuse is blown then you proceed to checking the wiring which in most cases will not be a problem. The second step is the pump itself which in my experience in the power electrical industry is due to a motor winding failure (short to ground inside the motor). I replaced the std. factory pump (Hella) with a Bosch I/C pump # 0 392 022 002 which is around $115 versus $300 from Jaguar. I did have to make some wiring modifications as well as the pump mounting bracket (removed rubber mounting from clamp). It's unbeliveable how cool the top of of the I/C is as compared to before I discovered a bad pump. I mean I can put my hand over the word "supercharger" after driving several hours. It's just luke warm as compared to blazing hot. I'll also mention there were no OBD II codes thrown by this situation which I can't explain.

 

very good explanation...and I'm going to link your individual post to the FAQ, so it doesn't get lost in history. I think that issue will be cropping up more frequently as the xkr's continue to age. thanks a bunch!

 

Thanks. I purchased the Bosch pump on line thru Siliconeintakes.com and can say everything was delivered in a timely fashion. I also used a discount code (link987) for a 10% discount. The reason I chose these guys is that the pump came with a plug connector which was 16 ga wire. I will say it appears that the wire coming from the fuse box is probably more like 18 ga. The toughest part of the job was getting the air box removed---finally figured out that the rubber mount under the air box has a thin hex head nut molded into the top of the rubber isolation mount. Other than that the JTIS is a good reference for the R&R procedure.