Hi,
2008 XJ Vanden Plas
On trip to the mountains at about 7000-8000 ft (if that is important), engine coolant low, light came on. Made it to destination (~2 hr). Engine temperature held steady at midpoint without going above normal spot. Car is definitely low on coolant. Took it to mechanic (his mom has same car) and he said there was some leakage around thermostat housing. He tightened things up, but said he could not get a replacement part in time.

Did a quick test: With full coolant drove maybe 20 miles before warning came on. Drove an additional 40 minutes. Warning stayed on and engine temperature is steady.
Home is 6 hr drive. Can a nurse it home and what would best practice be? Alternative is to leave car with mechanic and figure out how to go back home and then back up here to retrieve.
Help!
Andy

 

DO NOT rely on the instrument cluster to indicate the coolant temperature! The instrument cluster gauge does not indicate a temperature change between 96 C and 128 C. Overheating the AJ-V8 can cause the block and cylinder heads to warp causing the head gaskets to fail.

Use a smart phone with the Torque app and connect to the vehicle via the OBD port using a Bluetooth interface.

It would be a wise decision to have the vehicle repaired with a replacement water outlet than attempt a long drive.

 

I would definitely leave the car with the mechanic. In the meantime, I would just rent a car until the Jaguar is ready for pick up.

 

Thank you for the advice. That is now the plan of record.

Andy

 

Here's what I would do:
1. Confirm there is no coolant leakage;
2: When the engine is cool ensure the coolant level is in the min/max range, adjust as needed;
3. Pressure test the expansion tank cap. Should hold to about 16 psi. Mechanic should have a tester
4. Verify the coolant temperature with a laser thermometer. About 200*F. Mechanic should have the thermometer ;

If these all check out, I wouldn't hesitate to drive the car home.

 

Given we know there is still a leak of some size, I am going to play it safe and have the repair done. We found a place for a one way rental and we will do the additional round trip when the car is fixed.
Thank you all for the advice.
Andy

 

Be afraid...very afraid I’m in the middle of changing out my cylinder block (4.2 s/c) and three pistons, water pump, and many other parts. It was approaching 150,000km when I encountered events very much like you have described. I can’t advise you on a plan of action but can only suggest you seek very good council.
Best of luck to you.
-Bob (‘06 Super V8)