Owner's manual says nothing about where the level should be in the filler and header when the engine is cold/off. Please help as she will be driven by a friend tomorrow! Thanx in advance!

 

It's one of those Jaguar mysteries :-)

When I had an XJS I kept the level almost to the top of the filler pipe and the header tank at about half-full when cold.

Hard to tell with the header tank...I used a skinny stick as a gauge

Cheers
DD

 

Thanx, Doug. Too many "mysteries" are beginning to wreak havoc on my patience...

So I'll just top it off at the filler pipe....Please tell me there's no more bleeding to do or anything like that...

I changed out the coolant and did the whole bleed procedure a month or so back.

 

You gotta re-bleed every time you add coolant.






Just kidding, just kidding :-). Cruel joke, I know :-)

With time the XJS mysteries won't seem so mysterious. In fact, you'll become sorta fond of the weirdness of it all.

Cheers
DD

 

You really had me going for a few moments, expletives and all...

Don't think I've ever experienced the emotion of relief like I did when I scrolled down. Ha Ha very funny !

 

just wondering wot will happen if bothe pipes are filled to the top when coled, as thats wot iv been doing

 

I'd like to know about this too as this is what i have been doing and i seem to have a coolant leak I can't locate somewhere, i thought it was my caps ( found both of them to be 12Psi but put a 16 or 18 on the main.anyways it still leaks when its sitting and off so I figured its gotta be a hose somewhere....its just that it leaks RIGHT where the filler is so i figured maybe im overfilling it?

 

Hi, You should have a small pipe from the side of the header tank that disappears into the firewall corner....it goes into the LHside cavity behind the front wheel splash panel V12 (or on my UK 3.6 the RHside) Here is located the expansion tank at atmosphere which should be 1/2 full. This will be the source of that strange thump you here at times...thought you had bad suspension bushes ??? Anyway you will see the overflow just inboard, and probable no bottle fixing and a rust hole. Swear...one thing at a time.

The idea is that when the header is full and hot it pushes the extra into this tank...and the important thing is that now you have suction to draw it back when the coolant is cool if you don't open header cap and get air in the pipe.

The theory goes that you fill the header to the top, the car pushes out what it does not want via the expansion tank pipe. It cools down and you top it up cos their is some missing. So the expansion tank gets filled up and starts overflowing after a while.

Sound about right for your symptoms....now time to fix the expansion tank area.
Steve
xj-s 3.6 1988

 

wait huh? did you basically just say fill the expansion tank halfway and if its overfilled the system will push out any extra so don't worry about it?


i've actually been wondering about this because while my car has been leaking it has never once gotten "low" it just leaks down some..now i always refill it because obviously i don't want it overheating or something but i have never checked it and had it take very much fluid.

 

Hi, I have called the coolant recovery tank the expansion tank. This is the one in the rear of the front wheel arch. This is the one which should be about half full.

With the wheel arch cover in place...the only thing that you see is a 5mm steel pipe about 20cm tall and ending at the end of the inner side of the sill.
This is the overflow pipe from the recovery tank.

Nothing comes out of this pipe unless the recovery tank repeatedly/gradually gets topped-up from the header tank, but the header tank never sucks it back. Usually because you keep taking the cap off the header tank and topping off the system again.

The header tank under the hood is the one you normally fill to near the top.

OK OK...no offense intended you have to check, same here can't resist. But the best approach is after a couple of full heat and cold cycles, check the level in the header tank only. Do the same cycles again and I bet the level has not moved. If the level dropped too far the water level sensor would light the dash warning....does yours work??

Because of a C#*P design for the recovery tank, the coolant bypasses its overflow pipe and runs down the side of the tank.
Rust Rust Rust .... for the end of the sill and the lower wing.
You can usually tell which side of the car the recovery tank is on by the wing.

Hope that's not more confusing.
Have a read from Ed's site, he added a recovery tank plus it has all the nice pictures...thanks ED.

http://ecs.fullerton.edu/~sowell/jag...yReservoir.htm

Steve
XJ-S 3.6 1988