2002 XK8. On cold engine I can squeeze upper radiator hose and coolant in reservoir sloshes around. Also on cold engine I can squeeze lower radiator hose and coolant in reservoir sloshes around just the same. The lower hose goes through the thermostat. Am I right in thinking my thermostat is stuck open? I'm pretty sure the thermostat has a small hole open at all times. Doesn't seem that hole could cause the same sloshing.

 

Rethough my post. Thermostats fail in the closed position. Guessing I don't have one.

 

It's difficult to tell from the sloshing. As to whether you have a thermostat, does the engine reach operating temperature within 5 minutes or so even using the rubbish Jaguar temperature gauge? If it does, I'm sure that you will have a thermostat fitted.

Richard

 

This seems to be a case of a solution searching for a problem.

if you are concerned that your thermostat is missing just open up the housing and look.

 

I just now walked outside and checked. When I squeeze my lower hose the fluid in the reservoir sloshes. My thermostat is an OEM Motorcraft unit, about a year old and it works fine.

You're OK. You do not have a problem.

 

Sorry if you expended some electrons reading and responding to my post.

 

Thanks for the effort. Guess that much pressure gets through the small opening. Didn't want to go through trouble of opening without a new thermostat. Was just about to click on a RockAuto order. You saved me $30.

 

sorry for what ? Reading & Responding to this forum is very informative / relaxing / and interesting.

I started learning a lot when I left my thin skin at the door.

Z

PS a spare parts shelf, including a thermostat , comes in very handy. That said, my 22 year old original thermostat is more accurate than new ones I’ve purchased..

 

First there is a hole in the thermostat so water will move through it when the hose is squeezed....Thermostats are supposed to fail open but depends on the design/
Get a new 82 deg C thermostat and fit it then you will have made an improvement and if you have the technical knowledge get the fans to run half speed 24/7 or fit a switch to bring them on in traffic.

 

Figured out easy way to check if thermostat opening. Had thermostat tower cap off becase going to run combustion gas check. Started cold. Water coming in small amount until thermostat opened and flow increased.