About 20 minutes driving this morning, coolant low message came on first time ever. Pulled over immediately and check. Sure enough, fluid is about 1 inch below the minimum marker. Did not see any obvious leaks. I have never had to top off and it has been about a year since last flush. restarted car, no message.

Ideas?

 

Well it's going somewhere. Obvious first, (and cheap), step is the pressure cap.

 

This happened to me in the fall as well. Parked the car for the night, turned it on the next day, drove a bit and had 'low coolant' showing. Topped it up and have had no such issues in the last 4 months or so...

Very curious.

 

I think my issue may have been related to a small loss of fluid when recently replacing pulleys and belts. I don't believe I remembered to top it off afterwards...silly me...

 

I'd keep an eye on it for a while. You are at an age point that you may have a leak developing, possibly a small leak that evaporates before it has a chance to get to the ground. Ever get a whiff of something you don't remember smelling before??

 

Well the pesky message has returned. The level had dropped even more and I filled it up with half a gallon of distilled water but for the past three days the message will not go away even though the level is staying at the max fill bar. Don't see or smell any leaks either.

 

Have you pressed the "reset" button ? This should clear it. I would also not keep using plain distilled water too many times or you'll dilute the antifreeze and corrosion inhibitor strength too much.

Puzzling there is no obvious visible leak; a half-gallon is a big top up !. Try looking round the engine bay after dark with a torch; its amazing how without daylight the eye is more sensitive and sees little drops of coolant lit up by the torch that are missed during the day. This worked for me with a Rover 25 that was losing coolant. I also had a Mazda Xedos that was similar to yours with no obvious leak, which turned out to be the pump seal.

 

Just posted a reply, then suddenly remembered the X350 maintenance forum I attended last year and issues with the V8 engines (the technician also covered my V6 and the diesels too).

On the supercharged V8s, there is a little $10 coolant hose lying in the engine 'V' hidden underneath the supercharger which can start to leak. The leakage evaporates off due to the heat in there, so is difficult to detect. Cheap part but labour intensive to fix, unfortunately.

 

Why does the message keep coming and going though, even with the tank now full?

 

I loose about 1" a year in coolant and can't figure why or where. Mechanic never mentions a leak when on lift. I figure that is not so bad, so I just fill it.

 

Hasn't been an issue in 6+ years...

 

From "The Sign of Four" - Sherlock Holmes 1890

"Eliminate all other factors, and the one which remains must be the truth."

• Chap. 1, p. 92; similar expressions occur in The Sign of the Four, chap. 6; The Adventures of Sherlock Holmes, "The Adventure of the Beryl Coronet"; The Memoirs of Sherlock Holmes, "Silver Blaze"; The Return of Sherlock Holmes, "The Adventure of the Priory School"; His Last Bow, "The Adventure of the Bruce-Partington Plans"; The Case-Book of Sherlock Holmes, "The Adventure of the Blanched Soldier".

 

Well the message part of your issue may be a failure of either the magnet and float inside your expansion tank, or the small proximity switch that is the level sensor. See the pic. That little gem goes up into the bottom of your tank straight below the label telling you to use orange coolant. It's an insert and turn about 45-50 degrees to lock. That would explain the message with a full tank. The routine loss of coolant is another matter. There is a leak somewhere, it just has to be found.

Cheers,

 

Dealer says they did an overnight pressure test and found no leaks. Said fluid level was low even though it was at the max fill when I dropped it off. Also said the coolant message has not returned. We'll see....

 

Steve

You will be thrilled to know the dealer just called me again to say they were mistaken and it was the expansion tank & sensor. New one going in under warranty!

 

I shouldn't be that way..........we all overlook the obvious once in a while.

 

Or ignore it as it seems to be with this particular Jag service center. Wish you worked down here!

 

Heh, Heh! I appreciate the sentiment, but I'm a Heartland kinda guy. I've grown to like 'fly-over country'.

Cheers,

 

This morning I went to check the fluid level and noticed the fluid color from the side of the new expansion tank was kind of a funky orange, not like the orange it was before. I unscrewed the cap. The fluid level was fine, however the color of the fluid on the inside of the cap was was bright yellow green and the fluid in the tank was an orangish color. On the warranty ticket they list $56 worth of JLM209723. I spoke with the dealer and was told they used the correct PINK fluid to fill the new tank.

Why does it look green?

 

Whoa! Down boy!

Don't fret. That's the correct coolant. Be aware that it has a weird property that makes it appear seemingly several different colors. Orange, pink, green red........all of 'em. It depends what container it's in, what the lighting is, it's just weird. Sometimes our service writers have to resort to sticking the corner of a white towel into it to see what the color truly is.

You are not alone........