Last weekend I got the 05' out and there was a big puddle of coolant under it after storing all winter. I filled the reservoir and after it warmed up it stopped leaking. but when I took it out to drive it after a few minutes the temperature gauge kept rising and wouldn't stop. I pulled it over and loosened the over flow cap,heard a hissing sound ,the fuild almost filled the reservoir ,tightened the cap restarted it and it ran fine with the temp staying at 220. now today I took it out and the same thing happened started to overheat,opened the cap ,restarted and was fine around 220. I haven't had any leaks since it warmed up the first day. any suggestions?

I have a slow leak as well on my '06 (had to add coolent twice in past several months), but no overheating problems. It is scheduled to go in for annual service Friday, so I will be able to let you know what my problem is. Mine is still under factory warranty. Jon

It could be either a water pump failure or the upper hose to the pump.

I had this experience on my 2004. neither is real time consuming to repair.

Please let us know what you find out.

Regards

Last weekend I got the 05' out and there was a big puddle of coolant under it after storing all winter. I filled the reservoir and after it warmed up it stopped leaking. but when I took it out to drive it after a few minutes the temperature gauge kept rising and wouldn't stop. I pulled it over and loosened the over flow cap,heard a hissing sound ,the fuild almost filled the reservoir ,tightened the cap restarted it and it ran fine with the temp staying at 220. now today I took it out and the same thing happened started to overheat,opened the cap ,restarted and was fine around 220. I haven't had any leaks since it warmed up the first day. any suggestions?

Suggests a stuck thermostat to me. I really wouldn't undo (or loosen) that cap with a hot engine.
What happens if you just stop for a few minutes and then start again? If all is well, then that would reinforce a slow or stuck thermostat.

HTHs

the solution is rather simple. Put more antifreeze in over flow tank til it stops taking it as engine warms up. Now runs fine no leaks and stays at 180-190 degrees.

I have a slow leak as well on my '06 (had to add coolent twice in past several months), but no overheating problems. It is scheduled to go in for annual service Friday, so I will be able to let you know what my problem is. Mine is still under factory warranty. Jon

Confirmed that it was the water pump. Replaced under warranty and good to go. However I am curious - this is the third Caddy I have owned with the Northsrar engine and the first with a water pump failure. Is there a weakness with the waterpump in the XLR setup for this engine? ...or have I just been lucky with my other 2 cars (98 Eldorado - driven 40 k+ miles and '00 DTS with 90 k+ miles)? My XLR is at 35 k.:skep

Confirmed that it was the water pump. Replaced under warranty and good to go. However I am curious - this is the third Caddy I have owned with the Northsrar engine and the first with a water pump failure. Is there a weakness with the waterpump in the XLR setup for this engine? ...or have I just been lucky with my other 2 cars (98 Eldorado - driven 40 k+ miles and '00 DTS with 90 k+ miles)? My XLR is at 35 k.:skep

I would say there is. I replace mine last fall. I've heard if a lot of others who have too. The good news is it's a cheap one. $50 for a delco.

I think the water pump and a few other parts--radiator were sub standard initially. When they were replaced with "V" parts the issues went away.

I think the water pump and a few other parts--radiator were sub standard initially. When they were replaced with "V" parts the issues went away.

Any idea when that happened? My understanding is that the 'V' radiator came with the '06 model - is that correct or is mine at risk? Can I assume that the replacement water pump is better than the original?

Yea I think all replacement radiators are now "V" radiators. It is a better product and saves inventory issues and expense for 2 parts.

The water pump is the same--1 part that works for both.

In my experience with my early 2004 XLR once I addressed these issues the car was as good or better than the new ones. I felt that it was the price you have to pay for having the newest and first XLR's.