Hi have a 2002 Jaguar S type V6 2.5 car drives great it has done 104567 miles I only do the school run every day and run the missus to work twice a week I suppose I do about 60 miles a week today I drove from Manchester to shefeild about 42 miles and my car overheated halfway there so I stopped and topped it up with water carried on with my journey stayed in shefeild for a few hours then drove home car drove fine it has done this twice know as anyone any idea why this is happening also it takes about 2 miles of driving in traffic before the temp gets up to normal could it be the thermostat I have had jags all my life and normally the heat up quickly regards Graham

 

Could be lots of things (eg. thermostat, silt, pump, air pocket) but sounds like the usual issues of a hole in the radiator/radiator tank or hole in one of the hoses. Have a look if you can see any obvious water leaks with the engine running or just turned off. Needs immediate attention and all the usual cooling system checks. Keep an eye on the temperature gauge. You need to turn the engine off immediately if anywhere near the red. If you must drive, drive with the radiator cap 'cracked' so there is no pressure build up. I never like filling up a hot engine with cool/cold water; things can easily crack, maybe just trickle pour the water in the radiator. A few dollars/pounds to change the thermostat and any soft hoses.

 

Graham-

If you are adding coolant, It has to be going somewhere. It would almost have to be a leak unless the temperature creates enough pressure that it exceeds the pressure rating of the cap on the reservoir. Basically what I'm saying is you need to get the coolant system pressure tested soon. Running low on coolant is a scenario that is never good.

As jya pointed out above..lot's of potential issues here. Some are easy..some are tougher to fix if you are not handy with the spanners. I've seen vehicles newer than yours have acidic coolant that ate the impeller off of the water pump. In no way am I suggesting that the water pump is the issue here. I am saying that running your engine too hot will destroy the engine so get it checked out as soon as possible.

BTW..Looking through your posts..kinda all over the place as far as questions. ABS sensors, spark plugs, centre consoles. It would help these experts here if you would go ahead and add your model and location to your signature. I see GGG did that on one of your posts.

Thanks.

 

Have the system checked for leaks after a cold-soak, preferably overnight. Pressurise the system to 1 bar and see if it drops after 10 minutes. If so, inspect for leaks around the coolant reservoir, upper radiator hose and water pump. A sticking thermostat can also cause the vehicle to overheat.

DO NOT rely on the temperature gauge in the instrument cluster to tell you if there's an overheating situation as it doesn't change from 96 C to 129 C. Use a bluetooth adapter connected to the OBD port and a smart phone with the Torque app to check coolant temperature. Normal operating temperature should fall between 85 C and 95 C, unless you're stuck in traffic on the motorway.

 

I'm not sure this suggestion is applicable to the S-Type. From my limited experience, when the pressure can't build up to normal, the coolant doesn't flow properly through the many passages in the system. I had a small hose spring a leak near the top of the engine. It mostly leaked air, not much in the way of liquid escaping. However, it prevent normal pressure from building up while driving. I only found it with a coolant system pressure tester. But while it was leaking, the temperature ran above normal and the heater output was poor, both at the same time.

 

I ran the car for many months with a loose cap Karl after a hole in the short elbow thermostat hose. It was not ideal of course but that elbow hose on the blown V8's is not easy to get to, you need to remove lots of bits first to access and change.. I had to top it up occasionally in that state but otherwise I had no issues.

 

How about it Graham?

Did you find your coolant leak?