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I seem to have a very slow undetectable coolant leak. I can drive for 300 to 500 miles without any indication of coolant loss, no "Low Coolant" message. Sometimes just after a several hour trip within ten minutes drive electric fan goes on and coolant is leaking from radiator pressure cap. Electric fan is staying on after the engine is turned off and I am spilling coolant.
I have changed the thermostat housing and the thermostat. Also changed the waterpump and the radiator cap. We even put a pressure test on it and it seemed fine. And I have adequately learned how to bleed the system after any time I add coolant to the system.
Car will run for several hundred miles with no problem. It almost seems that after a longer higher speed drive on the next start up coolant may be lost, pressure builds and systems gets hot creating the overflow.
Has anyone had to deal with this and is so ultimate solution. Any commentary is appreciated. *When everything is running proper, This is the finest driving machine I have ever been in.
I seem to have a very slow undetectable coolant leak.
.....
Rob
XJ8 Jaguar 2004 Vanden Plas
XJ8-L, 2005 normally-aspirated.
'Invisible leak' here was in the trough where the small hose enters the header tank. Fluid was going neatly down the back, being blown-away in the fan slipstream on my usual 240+ mile trips, only leaving a few tell-tale drops on the ground after shut-down 'once in a while' until it got progressively worse.
Bought new tank with its innards.
Shudda waited. It is back in its box for 'next time'.
Found the leak to actually be in the HOSE just where it attaches.
Couldn't believe how many sharp-angle bends the OEM one had. Wot were they smoking? Mayhap 'manhattan geometry' 7-layer PC-board trace layout invaded their CAD/CAM?
Replaced it with ignorant straight hose run in a lazy loop to not introduce an air-lock, cut the silly plastic covers to clear it and not stress the tank fitting.
End of problem for me.
May have nought to do with YOUR mystery, but all it takes to check for it is a dry wad of Kleenex stuffed around the tank nipple and temporarily 'duck' taped.
If it turns orange and wet instead of STAYING dry, ye've found yer klew...
Same Kleenex trick works most places that it isn't a fire-hazard.
Have at it - its cheap. And pray the coolant is not being ingested by the engine. That isn't cheap...
Usually the culprit is the coolant expansion tank. You may purchase it at rockauto or other forum sponsors. I've been through this early this year and also repaired my radiator fan replaced the bearing it's a sealed type fan motor but I don't want to keep the car down so I dremeled the fan motor seal then replace the bearing.
Usually the culprit is the coolant expansion tank. You may purchase it at rockauto or other forum sponsors. I've been through this early this year and also repaired my radiator fan replaced the bearing it's a sealed type fan motor but I don't want to keep the car down so I dremeled the fan motor seal then replace the bearing.
Agree
Where the small venting tube enters the header tank the nipple the pipe pushes onto gradually cracks all the way round until the pipe falls off, but the owner normally notices the coolant loss before this happens. There is also the other end of this pipe, which on the V6 engines goes into a plastic water rail. I had to replace both ends on my car. Why car makers persist with these plastic parts I would really like to know !
Another tip for finding coolant leaks: wait until dark and use a flashlight/torch. It's easier to see small coolant leaks or drips glistening in the beam of the lamp.
The way the X350 components are arranged, unless its the top hose that connects to the reservoir, you really have to view things from below. I have a pair of drive-on ramps that come in handy for this. Raise the front of the car and carefully chock the rear wheels. Start the engine and crawl underneath, taking great care not to touch any moving parts or allowing your hair to be caught between a belt and pulley.... Lie on your back and carefully inspect every hose and every fitting you can see. This is how I found a tiny pinhole leak in one of the hoses in the "rats nest" below the coolant tank. In our case, the leak was spraying a tiny stream of coolant onto the bottom/side of the reservoir, where, like Bill's, it was being blown away by the radiator fan, leaving little evidence after the engine was shut down.
After assessing what it was going to take to replace the leaking hose, I decided to replace all the engine coolant hoses so I wouldn't have to dig into that mess again anytime soon. I wasn't able to find any aftermarket hoses, and the best price I could find on OE hoses was at jaguarmerriamparts.com.
I spent months looking for a very minute mystery leak. One of my mystery leaks turned out to be a small coolant hose that would have less than a pinhole leak but enough to cause the coolant low light very 3-4 months.
Also check the seams of the radiator. Small leaks can start here and evaporate without much trail.
Start the engine and crawl underneath, taking great care not to touch any moving parts or allowing your hair to be caught between a belt and pulley.... Lie on your back and carefully inspect every hose and every fitting you can see.
+1 on replacing ALL the hoses once you have to start.
Past 70 now, no fear on the hair, but not much body flexibility - nor even tolerance - for crawling under a vehicle, either. Not even powered-OFF.
Had thot to invest in a fibre-optic 'snake' to do that sort of remote viewing, but then again - there are tons and tons of 'webcam' and similar goods out there that might be as good.
Or better - given that they inherently capture to disk, and a video stream can be ****-ized later from a comfortable perch.
Anyone already done this sort of 'research', Jaguar-specific?
I have managed to find most leaks using the inspection camera
I dont try to find the issue with the car running rather let it stand overnight then look to the red residue left behind by the coolant loss.
I managed to locate the leak in the o ring seal on the aux pump and the thermostat bypass hose this way
I was not able to locate the pinpoint leak on one of the hoses this way and added some fluro die to the the system. After adding the die I just ran the engine for about 30mins in the garage. I then searched with a UV torch (same one I use for AC work). The Floro die showed right up. I could then replace the hose and flush the system
Oh yeah if you are replacing hoses do yourself a favour and get a remote hose clamp tool. It make life so easy
I want to thank everyone for their input. I just purchased a new Jag coolant auxiliary pump. My mechanic will install later this week. We are also flushing the system including the heater core and replacing the Radiator cap with a Jag oem. (Their is a differance in the pressure rating).
Im also going to do a oil analysis. Im a Yacht Broker and we commonly do this in boats and yachts, not sure why its not utilized more in autos. Also goig to do a Hydrocarbon test on the coolant, ($40.00 kit at advanced auto). Well worth it in finding out if you have a blown head gasket.
Agree
Where the small venting tube enters the header tank the nipple the pipe pushes onto gradually cracks all the way round until the pipe falls off, but the owner normally notices the coolant loss before this happens. There is also the other end of this pipe, which on the V6 engines goes into a plastic water rail. I had to replace both ends on my car. Why car makers persist with these plastic parts I would really like to know !
My nipple is completely broke off! Any suggestions on how to do videos and where to buy new reservoir? Thanks Fred
Why car makers persist with these plastic parts I would really like to know !
Thought I'd come back and try to actually answer that with something other than 'least-cost'. Especially as some may not be the least-cost at all.
The past few weeks I've been dealing with three of my 'non-Jaguar fleet - two of them very much over-age-in-grade and destined for disposal.
Now - I'm old enough to have started on 1920's vintage restorations and 1940's vintage plain-old 'used cars' onward. An era when 'rubber' often still was just that - not one of hundreds of different synthetic elastomers.
Taking note as I went on the '84 Jeep, '91 GMC, and '00 Dodge here besides the heavily plastic-infested '05 Jaguar, the surprise was...
- that steel lines had failed from corrosion, even when 'aluminized',
- several races and tribes of 'rubber' had perished.. and
- pressure-die-cast aluminium / other 'light alloy' parts often showed pitting or worse.
- the 'plastic' parts I *expected* to be aged, crazed, cracked, or at least borderline diabetic ...
were actually in the best shape of all - even 30+ years after leaving the factory.
Doesn't mean they don't fail. We know better.
But we are also reporting ONLY the failures - not the ones still good over long spans of time.
EG: failure of plastic whatizits probably remain a minority amongst the general count of vehicles, and even so, is often on parts that have rightfully EARNED refit in having served long and well BEFORE failure.
That indicates to me that the maker's have actually made at least SOME plastics choices that were more appropriate to the application than first appears.
Or that our prejudices have allowed giving them credit for.
My nipple is completely broke off! Any suggestions on how to do videos and where to buy new reservoir? Thanks Fred
Must have hurt like Hell. First-off, I'd suggest finding a less passionate partner, lest the next video be a 'snuff' or cannibalism film, not just rough sex..
As to the header tank?
Got mine (2005 XJ8-L, 4.2) from Rockauto.
Not ALWAYS the cheapest, but close enough when not, and very much my favourite as to easy navigation, confirming / comparing correct parts, and getting them in-hand quickly.
07-15-2015, 06:48 PM
XJ8 2004 Slow Coolant Loss and Overheating
