Just literally last week, hit the milestone clocked 100k miles, with so far - nary a problem!!

Put her up on ramps for oil change, as I do RELIGIOUSLY every 2.5-3k. Unbutton the undertray, and she's clean and dry as a bone - - - - as usual. So no leaks evident at all, right up until this point. All fluid levels look good, and right up to spec. Nothing looking either low, dirty, or anything at all out of sorts in any way at all.

Complete the oil change, start car & do a few run-up's to once-over everything before re-buttoning-up undertray, and everything looks good. Leave 'er idling for just a moment to pull out the right tools to put the undertray back on, and turn around to seeing a noticeable coolant drip, drip, drip coming from front of engine, on drivers-side. - ARRRGGGHHH!!!

Shut 'er down, and drip immediately stops. So crawl under to try and trace where it's coming from. It is definitely NOT from the expansion/overflow tank or the illustrious "nipple". Seems to be also from the engine block side of things, and not radiator side, or any (visible) hoses as well - but there's not much space to get good views up between the engine & radiator at all. Making matters worse, the dripping was also hitting the lower serpentine belt "splattering" coolant about and obliterating any obvious trail for me to track. So I decide to grab a bunch of shop rags & dry everything manually (fun-fun), then do a pressure-test (flush-fill/pressure kit) to try and source this sudden leak. But when I bring it up to pressure, and begin my search - - - NO LEAK!!

She fully pressurizes manually, just fine, and not even a slow leak/release of pressure (even when left for more than an hour) in the least bit at all! Hmmmm....

Okay - remove the pressure kit, button it back up, start 'er up and run her up to full temp. Still now though ...NOTHING!! Rev it up and down for another 10-15 minutes, full temp, full pressure - Nothing. Hmmmm.... One-time anomaly? ??? -

Okay, so shut it down again, crawl under to see if any evidence of leak anywhere - nothing to be found; So re-start, back it down the ramps, pull up in driveway, put car in park - get out ...LEAK'S BACK!!! As the car is idling at the top of the driveway, again all of a sudden - drip, drip, drip, drip - leak. Shut 'er down & leak then stops. Try to find source, but not enough room to effectively get in there to see.

So "Rinse/repeat" this process 2 more times. - - - Cannot get enough clear access/view to the engine front to see where it is coming from. So manually dry everything by hand again, and this time do several re-starts running it up to temp, revving... shutting down, then re-starting again - and after 3 more cycles of this - now (again) NO LEAK!

How can a leak be so blatantly intermittent like this??

Throughout all this, lost probably less than a cup total, of coolant. So topped it off this morning, and left it as is. Everything is still perfectly dry and in "good order" now, over 12 hours later.

So, what's next/what am I in for? Anyone here know?
Any thoughts/ideas (short of taking it to a dealer & being fleeced ) - and possibly what to look for/expect before I even do take it anywhere (is it safe to drive?) if anyone has similar experience, would be most greatly appreciated!!

TIA,
-Grant

 

Sounds very familiar to the leak I had several months ago on my 04STR. My leak drove me crazy trying to find it. It stopped and started numerous times. Yours probably isn't in the same place as mine, but what I had to do was purchase and put in flourescent dye and gradually trace the leak from the bottom front of the engine back up to the leak.

Pressurizing the system with a hot engineis the best way to go. I had to go up to 20+psi before mine leaked enough to find the leak.

In my case, the O-ring on my water pump had split and coolant was leaking out between the water pump housing and the block. It was in a place I couldn't see.

You are going to have to take a methodical approach and eliminate one hose at a time and all housings, one spot at a time.

 

Well there are a few hoses on that side to the after coolers, but you might be able to see those from the top. The thermostat housing is right there, so maybe the seal around the thermostat is leaking some times? Try taking off the intake tubing so you can look/feel around that area.

 

Found it!...

Appears to be the upper portion of this hose, has made contact with the serpentine and rubbed through. Now though, begets more questions... There is an upper clamp, that can be clearly removed, then it goes down to what appears to be a plastic tube section, but no clear way visible to remove the band connecting the hose to this tube (@ 3" length - as seen in picture), then, there is another lower hose that attaches this to the radiator.

Is this all one SINGLE assembly, and I also need to find exact Jaguar part (including the tube?) or... Can I just remove this affected upper hose somehow from the assembly, and replace that? At this point, I would love to be able to just now get this done as a rather "simple" DIY if at all possible. All other hoses appear in very good condition, including the bottom section of this assembly which goes to the radiator as well.

Thoughts/advice?

THANKS AGAIN in advance!
Cheers,
-Grant

 

I can tell you that I have spliced rad hose connections (including one currently on the Jag) with fine results. Some of the hoses are expensive and a PITA to get to, but cutting out a bad section might be the most cost effective way to handle it. Make sure you use a sharp razor to cut the hose and good worm gear clamps.

 

The hose is one part from Jaguar. I have replaced it.

How are your motor mounts? The engine should not be able to move enough to make the belt contact the hose but it is close.
.
.
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Okay now, so after doing a little more research, and with the input, guidance and help of fellow forum members (you guys ) - and also checking with a local shop owner/mechanic friend of mine... I am deciding to go with the aluminum insert/splice route solution.


Anyone happen to know right off the top of their heads, what this hose diameter is? I can't seem to find its actual spec anywhere!


Thanks again guys, for all the kind, considerate guidance and info!!

 

looks to be 2-2.5 get a cheap digital caliper to measure od. or get a c clamp set to it then measure that opening .....how much is the hose? new

 

Interesting thread, as some leaks can be maddeningly tough to find. Glad to hear you were able to locate it.

In addition to checking the motor mounts as previously suggested, it may also be worth it to check the belt tensioner. It could be getting weak and letting the belt flop around too much.

To prevent a reoccurrence, you may also want to rig up a little guard on the hose. Some light plastic, such as from a gallon milk jug, might do the trick. Cut a strip about 2 or 3 inches wide and secure it to the hose with a couple of Tyraps. Don't use a metal shield as that could damage the belt.

If the hose is curved in that area, a semi-rigid plastic shield won't work. In that case, you could brush on some of that flexible plastic coating used to repair the tops of the toes on leather work boots. I'm not talking about Goop or similar products that are thick, rubbery glues. The stuff I have in mind brushes on in a thin layer and even self-levels before it dries. Sorry the product name escapes me at the moment.

Edit: Found it! Here's one brand:

http://www.tufftoeworkboots.com/index.php?main_page=product_info&cPath=7&products_ id=9

 

Just a caution but when you're banging around in there with that hose be very careful about getting too rough with ANY of those plastic cooling parts. They crack or break very easily.

Just leaning on the coolant tank in the wrong spot destroys it.

+ 1 on the motor mounts issue.

 

I think this thread is haunted.

After reading this thread and posting I now have a very similar symptom!

It's so GD cold here now and then we got over a foot of snow to boot that I can't do anything about this myself for a bit. No garage.

So the first symptom I got for all of this was smelling it.
Checked the reservoir and I was slightly below the low point so I topped it up.
Next short drive maybe 5-7 miles and it was down the same amount again.

Then topped it up and the next drive was more like 90 miles and it had not dropped at all.