Hello, so I've been having a real hard time trying to figure out what is wrong with this Jaguar. I just traded for it the other day from a guy on CL who said it's been sitting for about a year and he drove it from TN to GA, about 3 1/2 hours and I drove it home another 1 1/2 hours after trading with no problems. The next day it started overheating... So I'm trying to figure out why.. Here's everything I've done for the most part...
So this morning I cranked it up with the amount of coolant needed, after 30 mins it started overheating from being idle.
I removed the thermostat in case it had gotten stuck to see if that was the issue, still continued to overheat after driving it down the road after a few mins.
I made it to Autozone and rented a pressure test kit and there seemed to be no leaks.
I THINK the fan is running, as I hear a fan going and I can only hardly see one fan at the front of the car. Not sure if thats it?
When driving the car with heat on full blast the heat doesnt seem to be working? No clue why that is if it's overheating?
Also there have been 2 occasions where coolant had spewed out of the overflow tank, where the cap was even though it was on fairly tight.
I'm honestly out of ideas what it could be unless it's the fan but I've never dealt with anything like this, especially on a Jag.

 

I hate to say it, but it could be the symptoms of a head gasket failure, but it could be the water pump has lost some or all of its impeller blades. If coolant is not circulated the engine will overheat like night follows day.

 

Agree with checking your water pump. I had an Audi where the impeller shaft detached from the blades. So the pump would turn, but not the impeller. Like Fraser Mitchell suggests it is not unheard of for the impeller blades to shear.



Other possibility is a clog somewhere in the system. Just helped a guy on his Range Rover on a different forum having similar issues. He had changed out the water pump, hoses, thermostat and had everything checked. I mentioned an A8 engine I purchased used where a rodent climbed into and died in one of the hoses. Following this idea he had his shop check for an obstruction and found that the radiator had a block stopping flow.


I would start with the water pump - remove it and inspect. Then look for an obstruction - you can do this by pumping water through the system and disconnecting the correct hoses. If the water pump looks new - maybe the impeller blades sheared and are blocking your flow somewhere in the system. A strategic back flush could help.


Any signs of a head gasket issue? Did you check your coolant and oil for cross contamination? Maybe inspect the plugs and piston tops for signs of head gasket issues.

 

Okay! So I think I mayyy have found the issue! Well I hope! I'm pretty sure this is what has started the overheating by jamming up the blades to the waterpump but I just hope because it has been overheating so much that it didnt effect the head gaskets. I pulled out the thermostat and saw that a large plastic piece had broken off the thermostat housing and got sucked down to the waterpump... WTF right? Haha. Here's a picture of it! I really hope this is the only issue, I'll let y'all know what happens when I get the parts in today! Thanks for all the help! Also, I did a pressure test through the radiator cap, would that check for any cracks in a head gasket?

 

A pressure test can show HGF, but more certain is finding combustion products in the coolant. There are devices that check for this and most shops of any repute should have one.

 

The broken coolant housing is a very common issue. I think it's unlikely that plastic jammed the waterpump impeller. Coolant will flow into the radiator, not down to the water pump. And if by some chance it did, that plastic is so brittle it would be destroyed by the impeller.

This system is not designed to operate without the thermostat in place. When the tstat is closed, water is recirculated within the engine only. When open, the tstat blocks the recirc path and forces water through the radiator. Without the tstat, water is free to recirculate and the engine will overheat.

 

The piece of plastic was in the water pump, on my 07 VDP, put a new one in while there. As well as tensioner , idler pulley bearing, & belt, quiet, & cool now, as far as over heating.

 

Yours looks like mine did! Suggest doing a full coolant flush when you've completed your installation. Had to do the exact same thing... in February. If you're not 100% sure on how to fully r&r the housing there are several long posts made by myself and others outlining the process. Best of luck!