I'm having a little trouble here my 99 vanden plas the temperature gauge is going up into the red when I drive it For a few minutes, and once it does go in the red I pull over and no joke sit for a full minute turn the key to the second position and the gauge goes back to half every single time. I've had the coolant drained and refilled yesterday and when we let the car run for 10 minutes it was right back at the top so we shut the car off for 5 minutes, and when he took the cap off for the coolant he had to use pliers to take it off because of the pressure which seems to me like there's nothing wrong with the hoses or the radiator but the guage still goes up and I'm not sure if 99 model year indicates that the engine is at a high temp on the information screen or if its just a red light above the fuel and temp gauge. I drive it to the shop pulling over on the highway several times to wait for the guage to go down but I never saw smoke or anything come from the engine and it hit red line several times on the way there. Even when I drive fast with the heat full blast to get the guage down it still climbs. I'm not to sure what could be causing this issue my roommate says it could be the thermostat causing the problem I just wanted a second option on it to see if anyone knew more about it.

 

Are both radiator cooling fans running? There is a low fan speed and a high fan speed. After the engine has cooled off overnight, take the expansion tank cap off and make sure that the coolant level is 1” below the top of the inside of tank. If you’re repeatedly fighting that cap, you need to get some dielectric grease and apply it on the threads and o rings of the cap. Dielectric grease is silicone based and will not expand the rubber o rings like petroleum jelly.

 

Yes both fans are working they run when I turn the car off to cool it down i seen on Google that cars will run the fan even when the car is off to cool it down if its just been turned off and the computer reads a high engine temp ive tried running the ac cold to see if it would make the guage go up faster but it seems to move at the same intervals regardless of the ac or heat being on or off.

 

I'd suspect the thermostat is not working correctly. Might change that and the temperature sensor mounted on the water pipe near the thermostat housing just to be sure. Inexpensive parts and at least might bring peace of mind. Don't overheat the engine!

 

If changing the thermostat then change the housing for aluminium one too.
https://www.sngbarratt.com/English/U...20Id%202902077)

 

The AJV8 engine thermostats will stick CLOSED when they fail.
The earlier AJ6 and AJ16 engine tmostats would fail OPEN and the engine would not get to operating temp.

Jaguar issued a TSB decades ago.

 

yes it has the aluminum housing

 

Haven't gotten around to looking at it yet possible update next week ran the car and let it sit with the ac running and the following day did it with the ac off and the needle took the same amount of time to reach the top still no check engine light so that's a good sign.

 

New update:
I got it changed out drove around for an hour the needle isnt moving anymore but i am getting a low engine coolant light pop up randomly but the needle doesn't move i do smell a hint of coolant when the light does come on but when ever it turns off the smell goes away.

 

From first start and the engine coolant temperature gets to normal operating temperature (95*C/203*F), the coolant level rises. It’s possible that the level sensor inside the expansion tank is going bad. However, if you smell coolant, find out where it’s coming from.

 

The coolant sensor level device is inside the expansion tank and over time they can get sticky and clogged. It can sometimes be worth reaching in with your finger and manually sliding it up and down a few times to clean the runners and remove any residue that could cause it to stick. Obviously when the engine is cold!

 

Follow #10 to conclusion: you have a leak if you smell coolant. Sometimes they dry up quick, making discovery tough.

But once in a while (actually more often), the hoses from the tank are misrouted.

They must be as shown, otherwise coolant blows out.

 

I checked the tank after letting it sit while at work last night the coolant was extremely low to where I could see the level indicator almost completely i filled it up to the neck and when I drove on the highway home I didn't get the low coolant message but I'm going to drive it for a few days to see if i am losing a significant amount or if it was just not filled up all the way.

 

Speaking of low coolant, this might help: My car would slowly lose coolant, and sometimes I'd get a whiff of coolant smell, but I never saw a drip anyplace for the longest time - couldn't find a leak of any kind. Then one day I was under the car, maybe changing oil or something, and I noticed a little drip near the splash panel ahead of the front left tire. The drip wasn't even on the ground yet, just dangling there ready to drop. The investigation led me to the overflow tank ahead of the front wheel. The hose in the tank that draws coolant back up to the expansion tank was partly disconnected, so the expansion tank was able to shoot coolant into the overflow tank when needed, but couldn't really draw it back out correctly, so eventually the level rose in the tank to the point where it would run out the little vent hole sometimes. Meanwhile, the coolant would seem low in the expansion tank. I think it must have been happening while driving (and only a tiny bit at a time), because I never saw a drip on the floor of the garage. Just had to add coolant once in a while. I fixed the tube and haven't had trouble since.

 

So far I haven't seen any changes, the tank has been pretty much at the same level so far, when I went for a drive in the morning and let it sit for 3 1/2 hours some pressure was still in the system so it was up to the neck of tank and come out a little out of the top when I took the cap off. but after rechecking it at night it was a little before the neck of the bottle where it was i did squeeze the hoses in the front of the engine to make sure the level didn't drop but it looks ok as of now. dont mind the spill that's from when I initially opened the cap when there was pressure but this is the level its been at the past few days.

 

When I had a slight coolant leak I could smell occasionally but never see it turned out to be a joint for one of the little hard hoses that run from the expansion bottle, it dripped onto the engine & evaporated.