2001 jaguar s-type 3.0 v6 engine overheats after short drive. Replaced thermostat, coolant and notice recently hearing the radiator fan runs for awhile when ignition is turned off.

 

Bugga, didn't see this post.

Are you "asking" or "informing". just interested??.

 

Roland, first off, make sure the coolant system is full and the overflow bottle has sufficient level in it (above the MIN line). From there, I would be looking at the water pump and making sure that it is working properly. I am not sure on the S-Type, but on the X-Type (uses the same motor as I recall), the water pump is pretty easy to access and replace and is only about $50 to do if you do it yourself.

Start there and lets see what we end up with.

 

it started with the safety valve on thermostat block blowing replaced thermostat unit still getting back pressure and coolant dropping no visible leaks. have had water pump replaced dye tested for head gasket water tank pressure lid replaced still coolant light comes on after around 20 miles and back pressure build up. checked exhaust tails and water sitting in pipe

 

tried that no leaks on system. brand new water pump fitted at garage. car is running great apart from this, but this has been going on for weeks, booked to go back in Monday driving me crazy

 

asking

 

Car info? See below

 

Dave, if you just recently had the water pump replaced and then this started happening, you may have gotten a bad/wrong water pump and now for some reason it is not pumping the amount of water that it should. I know there are pumps out there with metal impellers and there are ones with plastic impellers. I also know that there are some with very deep fins and others with very shallow fins. All of these things can affect how much water gets pumped around the engine, therefore how easy it will be for the motor to overheat. You get a plastic pump that has the center of the impeller crack, the impeller will still spin somewhat, but it will not move the water like it needs to and therefore you will get an overheat condition in a short period of time. The only other possibility that I can think of is the tech that installed the water pump used too much sealant and ended up squeezing the sealant into the coolant channels and now you have blocked coolant channels which is starving the motor of water and restricting the water flow that the motor can get.

 

I think dave c has hijacked roland cotton's post about overheating.

dave c- if you're losing coolant out the tailpipes and the cooling system is over pressurized, this is not really overheating. Best revisit the bad head gasket concept.