Just cause it's new, doesn't mean it's good! Some of you may remember I fitted a new-from-dealer-stock radiator to Precious' 3.0L a mere 6 or 7 weeks ago:

https://www.jaguarforums.com/forum/s...nt-leak-81519/

While at it, I replaced the DCCV as a pre-emptive measure, using a Four Seasons unit from Rock Auto under their listing for 3.0L Lincoln LS.

This arrangement worked fine for the 6 hr drive back to University and oh, let's say at LEAST 3 or 4 days' worth of shuttle-driving on-campus. Then the return of the low-coolant light. "Not to worry, babe, probably a latent air bubble has burped".....anticipating this, I'd shown Precious how to achieve synergies with distilled water and a cold engine to drive results for a topped up coolant system.....but when she exceeded 3 occurrences I realized we had another leak. Hauled it home again the day before Thanksgiving and found leakage in the vicinity of the DCCV. Unsure whether hoses or valve, but seemed to be the valve. I swapped back to the old one, previously removed (it was not leaking, only a precautionary change as we've had the car since 08 and no svc record of a prior change) For giggles, I called Joe at the local dealership parts counter to enquire after the three hoses and a valve? $63, $63, $94, $307 and only one $63 hose in stock the rest would need be ordered. So no laughs to be had there, I elected to wait til the hoses actually leak to make a replacement. Rock has been excellent in the past on the few purchases I've ever had a problem with from them. Will call about the valve in a bit. Anyway, fitted the old DCCV, buttoned it up and replenished the coolant, and noted the outer edges of both Pilot A/S Sports on the front were worn out. Off to Trevor's for an alignment, whilst searching the web for tires (Precious needs to return to school on Sunday) I found a reasonable price on 215-60R X 16 Michelin Primacy MXV4's (H rated) down in FTW. I have 35k on a set of Primacy's on the XJ and waaaayyyy more tread left than is resident on the two Pilots that haven't been shredded by the front end...and they only have 26k on 'em. Precious will learn to appreciate the smooth, quiet ride of Touring tires vs. the previous performance-oriented models, even if she is still under 50!

It made the trip to FTW and back sans low coolant notificiation, but I did manage to put a few more ounces in this morning to top it up. Girls have it out now on another trip to FTW. Thinking it'll be good to go......though she's only got 2 more weeks.....very tempted to tell her to share with her brother for 2 more weeks so I'm certain I won't have to drag my trailer to Monroe, LA and back again before Christmas.......

 

If you are loosing coolant, and none can be seen leaking, then its internal. Check your oil to see if it is mayonaise-like. If so, you have a leaking head gasket or similar part where oil and coolant are separated by a gasket. Looking at the plugs, a compression test, or a leak-down test can give you an idea of where it is located.

Techs, please correct me if I am wrong.

 

Sorry if I was unclear. Leakage wasn't evident to a 20 yr old girl-child in a university parking lot where it rains frequently, and she is mostly looking at it in the dark. On the other hand, quite a different picture emerges with it up on ramps and the air deflectors removed, inspecting it with shop-mirrors and a borescope/inspection camera. Definitely external leakage, but even with those tools, it was not definitive whether the valve body was leaking or if it was the interface at one of the hoses. Valve-change confirmed it was the valve.