After driving in a rain storm for about 15 minutes fairly aggressively, I pulled into my garage and smelled a burning odor. I raised the hood and saw a white plume coming from somewhere below the cam cover on the passenger side (L-H Drive) about halfway between the front and rear of the engine. I didn't have time to look more closely. The coolant was about 3/4" down when I checked it the next morning. I hadn't checked it in months.
So, I just ran her twice as long as I did when I discovered the leak the other morning. Can't get the plume. I don't recall that there are any hoses that low on the engine. I inspected as well as I could and didn't see any hoses.
Has anyone ever experienced such a thing?
I will pull the bottom cover and see if there are any drips. I just put it back on 2 weeks ago because I wanted to be sure there were no leaks since I replaced all the hoses a while back.
While I have no way of knowing for sure, I suspect whatever is wrong happened when I drove her & discovered the problem. I say this because I surely would have noticed the odor before..

 

I presume you topped up the coolant reservoir with the correct coolant ? Has the level dropped again since top-up ?

 

Mystery?

 

Thanks, Fraser. Ok, I drove her the same distance last night as I did when I discovered the leak. The coolant level had dropped about the same amount when I checked the level this morning. So far:

1. I think that the leak occurred during the drive the day I noticed it. I say this because, at the rate it leaks, I would have gotten a light in short order.
2. It does not seem to leak when not running, but I will check more closely.
3. Since the plume disappeared, I can only assume that the source of the leak may have changed its opening size or shape.

This weekend, I will remove the bottom cover to see if any fluid accumulates on the floor. I suspect it will have puddled on the cover unless it is a head gasket. From all appearances she runs perfectly.

If there are no signs of a leak, it must be the head gasket. I will do some research to see how to test for that. Has anyone had any experience along these lines? If so, any & all help will be greatly appreciated! Are there any other sources of a coolant leak below the cam cover?

Thanks, best and Happy U.S. Election Day!

Steve S.

 

Has your radiator been replaced?
My coolant level was slowly dropping.
But was unable to find the source at first.
Finally i saw a slight, small stain, on the passengers side, radiator seam.
Mine is not an XJR, but both have twenty year old radiators, if still the original.

 

Thanks, Wingrider.

I will check, but this seems like a leak that would be more noticeable. I hope that when I remove the bottom cover, a leak will show. The idea of something like replacing the head gasket is daunting.

 

Steve, I'm sure you know to check the oil cap and dipstick for chocolate milkshake indicating a possible blown head gasket. White smoke out the exhaust and the smell of fuel in the coolant expansion tank. I think they even make a sniffer for that.
Hope that's not the case after all your hard work. Hopefully, just some rainwater trapped in the exhaust manifold that went up in steam.

 

Thanks, Luv2fly. Yes, I had just reviewed symptoms of blown head gasket and will check for them. There is definitely a leak, but it could be independent of the plume of white smoak. I am hopeful, when examined, it proves to be something "simple". Will let you know.

 

Pleased to report that the oil is as shimmering as liquid gold & there are no signs of use, abuse, or H2O on the dipstick or the filler cap.

No coolant under the car; however, I haven't yet removed the bottom cover. I am hopeful that there will be coolant on the cover when it is removed and I will see a leaking hose.

Carpe diem,

Steve S.

 

Hi, Steve!
Didn't you do valley hose couple of months ago and coolant pump?
I would start from doing serious memory jog! Also, Get yourself a , if don't have one. This will let you see if there are any traces of coolant in hidden places, like valley or rear bell housing.
My best!

 

Thanks, Big Guy! Yes, I replaced all hoses. & I have had a sinking feeling that what you are suggesting may be the case: The Valley hose may have disconnected. I thought the clamp seemed rather light.

I had already decided, before I had received your post, to use the borescope. I also thought that I could probe under the supercharger for coolant with a paper towel wrapped probe.

If the Valley Hose is disconnected, at least I've done this before. However, I will not have to bore and tap the water pump hole, repair a plug, etc.

The challenge will be how to do it most efficiently.

But, first, I need to diagnose, but I fear, it is likely the Valley Hose has disconnected, Damn!

Best,

Steve S.

 

Took her for a spin this morning for 30 minutes & she ran like a top. No sign of anything out of order.

Ran her for another 30 minutes in the garage & if I didn't know better, I would say that I had just driven her in from the showroom floor.

I turned her off & was going to let her cool & remove the bottom cover & then, & then a drip was seen under the front bumper cover in the vicinity of where the hose(s) is(are). If I were more adept with the borescope, I suspect I could have found the source. I will remove the bumper cover & report back.

I still have questions: Why did I not see this before? A possible answer is that I never drove her enough to have the puddle in the bumper cover overflow. Also, why haven't I smelled the burnt odor or seen the white plume that attracted me to the problem at first?

Will be back after I remove the bumper cover...

Quite a relief to know it isn't a head gasket or something in the valley!!

 

Removed bumper cover & air intake stuff. No sign of leaks around the hoses or water pump.

Beginning to think that it might be the radiator as suggested by Wingrider. Will search the site for detecting radiator leaks. Will be back.

Best,

Steve S.

 

@04Xjrsteve
Steve,

What about supercharger coolant pump? Mine started leaking. Hard to see. Showed up on undertray. Or HVAC cooling pump, Easy fixes if either of those.

Dale

 

Thanks, Dale. The driver's side lower edge of the supercharger radiator seems to be the culprit. The supercharger coolant pump is on the right side & shows no sign of leaking. I will look for the HVAC pump, but a quick search produced no results.

 

Great that you found it;
Is replacing it a big job, just how much needs to be removed?

 

A funny thing happened on my way to deciphering the mystical ways of the five cooling gizmos on the front of my R. before I could ascertain the minutiae of the engine radiator, The SC radiator, one unknown intercooler, transmission oil cooler, and another one:

I pooped the bumper cover off, removed the air intake contraption, wiped all surfaces like I was prepping for surgery and placed paper towels into every conceivable nook & cranny that could possibly leak. After putting the intake stuff back in place (amazing how easy this has become!) I fired her up for a 20-minute symphony of vroom when suddenly - oh, the horror! I remembered I was late for drinks with our notoriously gregarious, cardigan-wearing communist neighbor. My long suffering wife made it abundantly clear that my presence was non-negotiable, lest my underwear be starched to here-to-for unknown stiffness. So, I shut her down and headed straight to the shower.

After coffee this morning, I found no coolant anywhere. I started to extract each piece of paper towel and then, lo and behold! (See picture of the offending fitting!)

You can’t imagine my disappointment in not having to enlighten myself of all of the nuances of the delightfully twisted minds who designed this highly effective and convoluted…

A massive thank you to all you wonderful folks on the Jag Forum—your wisdom and humor have been invaluable. I'm deeply grateful for all your help, and trust me, I'll be back with more tales of automotive misadventures soon!

Carpe diem,

Steve S.

 

Since the leak was at the nipple where I attached a new hose during my Valley Expedition, the fault is not with any part or anything by Jaguar, but with yours truly.
If we weren't headed out of town and the holidays not so close, I would have removed the clamp, which, I believe, was the original one and I reused it. Instead, I just sistered one next to it as per the photo.
I wonder if I could have done something to preclude this from happening? New clamps all around? About half of the hoses came with new clamps, others did not. Perhaps, had I run the car before reinstalling lamps & bumper cover, etc., that may have found it. But I doubt that because the leak just started a few weeks ago..C'est la vie, mon fifi.
Unless something unforeseen happens in the interim, I will change the transmission oil mid-winter or early spring. At the same time, I'm going to tackle the ACC again; pity, because I never use it!
Best,
Steve S.

 

Hoping this works for you.
Genuine Jaguar hoses have came with the clamps included.
But if not badly rusted, reused spring clamps have worked out fine for me.
The radiator's plastic connector may be at fault.
Hoping not, radiator replacement, is rather time consuming.

 

What's up with ACC, Steve? You know it can be bypassed, reverting to standard cruise. Threads are on here. Going to see if the Jag tech I know can do it for me.