My 96 VDP has 150k+ miles, and about 3 months ago blew the impossible-to-replace hose that runs under the intake manifold.
It blew on a street where I had a 1/4 mile run to get it parked.

Being lazy (and stupid!) I decided to swap out that hose w/out pulling the intake.

I just about cried trying to get that one hose clamp on. Well, especially since I had just broken my left arm and had it in a cast.
:-)

I think I got it on right...
:-)

Anyway, the coolant is quietly and mysteriously disappearing.
A N D . . .
The temp goes up as usual, but the heater runs cold. It gets a bit 'better' if I turn on the defroster, but that thing is soooo loud!
And that only helps some - the old 'almost blister your fingers on the dash heater vents' is not there AT ALL.

Of course, it's winter in Oregon, which means a wet driveway ALL the time, so finding a leak by a drip on the pavement is a no go.
And, Mr. Sissy-Butt here hates working in the drizzle anyway . . .

Oh, the exhaust doesn't seem to be overly steamy, and the tailpipe insides are dry after a bit of a run, not even slightly gooey.

One more thing . . . the windshield does fog up a tiny bit, but the defrost fixes it quick, and there is no smell of coolant in the cabin.
Of course, Oregon lends itself to cars getting body leaks that moisturize the interior.

Ideas?

BTW: I'm an 'OK' mechanic when the map is well-drawn and the tools are in hand, but my diagnostic skills are less-than-stellar.
So: Thanks!

Charles in Boring, OR (yes, it really is called Boring!)

 

Hi Charles,

So sorry to hear of your broken arm. I'm truly impressed that you would even attempt to replace the water rail hose with one hand in a cast!

I can definitely agree that the job is far easier with the intake manifold disconnected and tied away from the engine. The additional effort to disconnect the manifold repays in a much easier and stress-free hose replacement, and you can also do those water rail gaskets, the oil filter housing gaskets & oil cooler bypass pipe O-rings, etc.

Regarding your lack of heat, two common possibilities are a stuck-open coolant thermostat, or a clogged heater core.

Regarding the loss of coolant, one suspect would be the water pump. When the seal begins to fail, coolant weeps from the hole primarily while the engine is running, so the leaking coolant tends to be dispersed by the radiator fan and evaporated by engine heat. With a bright light and an inspection mirror, you may be able to find evidence of dried coolant below the pump.

Cheers,

Don

 

Don,
Thanks for being impressed at my working with a broken arm - it was just one more stupid thing to do after stupidly breaking my arm.
:-)

And thanks for the let's-not-pull-the-head-off-yet suggestion of looking for dried-blood evidence of a minor seal leak. I'll get right on that after breakfast, a short nap, a cup or two of coffee, and "oh! look, it's time for a walk!".

I did forget to mention that there is no goo on the dipstick.

I'm fearing it is that one hose clamp though. : - (

Charles

 

hello Boring OR. My brother lives in Boring. Anyway it does not explain the loss of coolant, but as Don said could be the water pump leaking ( you hope ) or probably more likely the water rail gaskets. I just had to do them on one of my X300 a 95 XJR so the added hassle of besides pulling the manifold, as pulling the supercharger. What a pain.
But as far as the lack of heat. In my experience ( and I have probably owned 12 X300 in the last 20 years. Lack of heat is almost always the heater water boost pump fails. At right around 150k miles, it runs all the time the the system is on. And around 130-150k the brushes are gone. You would think the engine water.pump would still push some hot water to the heater core, but no.
So on this issue, in all my years with these fantastic cars, I.have had to replace exactly one thermostat, but have replaced probably 6 coolant boost pumps. But on the plus side it is very easy to do and you do not even hardly loose any coolant doing it. So it is one of the easier things to do.
Now the bad side the Jaguar specific ones are expensive$$. But the good news the same pump is used in a lot of cars, VW, BMW, etc and the only difference is the mounting bracket. So instead of $300 for the Jag specific one, I think I paid $40 for one with a different bracket out of a VW Jetta? Just loot at the pic's online and as long as the hose fittings are the right size you can make it work. You can just zip tie it in place.
So the will likely solve your heat. Good luck on the leak.
Darryl

 

hello Boring OR. My brother lives in Boring. Anyway it does not explain the loss of coolant, but as Don said could be the water pump leaking ( you hope ) or probably more likely the water rail gaskets. I just had to do them on one of my X300 a 95 XJR so the added hassle of besides pulling the manifold, as pulling the supercharger. What a pain.
But as far as the lack of heat. In my experience ( and I have probably owned 12 X300 in the last 20 years. Lack of heat is almost always the heater water boost pump fails. At right around 150k miles, it runs all the time the the system is on. And around 130-150k the brushes are gone. You would think the engine water.pump would still push some hot water to the heater core, but no.
So on this issue, in all my years with these fantastic cars, I.have had to replace exactly one thermostat, but have replaced probably 6 coolant boost pumps. But on the plus side it is very easy to do and you do not even hardly loose any coolant doing it. So it is one of the easier things to do.
Now the bad side the Jaguar specific ones are expensive$$. But the good news the same pump is used in a lot of cars, VW, BMW, etc and the only difference is the mounting bracket. So instead of $300 for the Jag specific one, I think I paid $40 for one with a different bracket out of a VW Jetta? Just loot at the pic's online and as long as the hose fittings are the right size you can make it work. You can just zip tie it in place.
So the will likely solve your heat. Good luck on the leak.
Darryl

 

Several causes of your "mysterious" coolant loss come to mind. This time of year "cold water leaks" are a problem. Here is my suggestion, make sure the cooling system is full and has bled the air pockets out. Then allow the engine to cool down completely over night while using a cooling system pressure test pump attached.. If you have any hoses leaking, you'll see them. Next, after the pressure/leak test slowly release the pressure and observe the water pump area for a sudden drip or 2. It actually takes only a very slight leak over time to cause a significant loss of coolant. As for the booster pump, you can listen to it with a screwdriver up to your ear and you'll be able to hear if 1 - if it is running, 2 - it is surging/splashing inside (air locked) or 3 - it is spinning very fast like it has no load (air locked or failed impeller)

That said, my 95 VDP some times will roast me out if not on auto and other times it will toast my feet while cool/cold air from the dash on bi level. Whilst on AUTO, my heat is less than desirable. Occasionally my booster pump quits if I let it sit for months and just a little tap brings it back to life. But it has been like this for years and I don't worry about it that much since I rarely drive it in cold weather.

 

You could try putting a piece of dry cardboard under the engine bay to help locate a leak on a wet driveway.

 

Eons ago, when I had an X300/XJR as a daily driver, I was troubled with disappearing coolant. Repeated visual checks and pressure tests reveled nothing. Never any drips to be seen.....just a occasional whiff of collant and the need to top-off regularly

I can't remember how I (eventually) discovered the leak but, long story short, it was gasket #8 in this illustration.

https://parts.jaguarlandroverclassic.../brand/jaguar/



Cheers
DD

 

Darryl,
You got one up on me - my brother is just plain old boring.

Way cool! thanks.
Or, should I say: way heat!
Thanks.
I'll track down a heater pump.

And, s i g h . . . on the coolant leak.

I gotta get some time to look at it TODAY.
It's supposed to get down to 15 on Tuesday and I've been using LOTS of water only to replace the coolant.
Yikes!

UPDATE, now the Weather Folks are saying only 28. Much better.
: - )

 

Make sure you let it run for a while to ensure you get antifreeze well mixed with the water since it may have some circulation problems delaying a good mix.Every time the first winter cold snap hit's I get to see lots of freeze damage.

 

Thanks to all for the helps.
Turns out the leak was the Octopus-to-Thermostat housing hose clamp.
Some idiot may have loosened it while doing other repairs in the same are and not tightened it all the way down.
: - )

On the heater booster pump - the local auto parts guys want $581 for it!
That's a non-starter.

There's one for an '02 Ranger for $181
Also a non-starter.

I guess it's off to used-parts land.

Or, I could put an inverter to get 120VAC and use an old aquarium pump I have...

 

As far as the coolant pump, just go on Amazon and punch in coolant pumps, and it will pull lots of them with pics. I am pretty sure the last one I bought was like $40 same hose fitting size and orientation. It just had no bracket welded to it. But who cares. Like I said just zip tie it to something in the area. And there are lots of things in the area to tie it to. $40 bucks, not kidding. I might still have the box to get a part number off of.
I think the hose fittings are for 5/8 if I remember correctly. And that is really all that matters, hose size and orientation. You will have to make up a short wirering pigtail using the pigtail off the old pump. Very easy peasy.

 

So I found the cheap replacement coolant pump that I last bought.
it is for a Sprinter van, bought it from Amazon, it was around $40 if memory serves.
This is a very common issue with all these cars at a certain milage, and it would be a shame if people dumped these cars because of something so basic as lack of heat. And then get quoted $4-600 to fix it. That is crazy.

I even tried replacing the brushes on one of mine years ago. But the brushes are a very unique size. So I had to buy the closest I could get, and file them down to fit the brush holders. A pain in the butt, and time consuming, and it really don't not work well at all.
So replacement with new is the way to go.

So hopefully Don or some other moderator can put this info somewhere where everyone can easily find it.

I have pics of the part number and the pump if I can figure out how to post them here.

 

Barchy,
Amazon likes the Bosch part # for the pump you show:

Bosch 0392020026 Electric Water Pump

Thanks!
Though, you're a day late.
:-)

I just bought a Bosch pump from Amazon yesterday, due in today.
It took me quite a while to figure out that they like to be called 'auxiliary water pumps'.
Once I figured that out, I found a pump.

BUT . . .

I think I ordered the one with 3/4" hose barbs.
:-(

I'll find out today.
If it IS 3/4" hose barbs, I'll send it back and get the part # you provided.

THANKS!!

 

Darren,
Thanks for the tip on letting it run to mix in the added coolant.
I'll drain some of the watery mix out, add coolant, pop the dead heater pump in for a bit today and run the engine a while.
You see, I may have ordered the wrong pump! So, that'll put me back a day two days on getting things fixed, which might put me in the freeze zone here ('they are threatening 8" of snow! - insert whine and whimper here).

Cheers!

Charles

 

Here is the cheap pump for the Sprinter vans

I believe the hoses are 5/8


No brackets at all to get in the way.

 

Barch,
You're right - the hoses are 5/8"

 

bummer for you. But on the plus side, I actually remember something correctly. So that goes in the win column for me😀

 

Well, after all the weather stuff all over the US, my pump got here about a week late. Which was no big deal b/c the Jag does not like trying to get traction in Oregon snow-with-an-ice-storm-on-top.
And I got it installed quite happily. Thanks, Barch!
And I'm not losing coolant anymore.
Oh, and when I changed the pump, I had to lengthen the leads, so I double-triple-checked the rotation after wiring it up.

BUT . . .

There still ain't no heat!

Huh!

I get 'a little' heat if I run it all the way up to 90 degrees. But if I turn it down to 89, it drops like a rock.

Now I'm wondering:
Is my lack of heat caused by:

• The valve next to the pump having died?
  • Prob'ly not: it's a solenoid!
• A plugged heater core?
  • What would have gotten it so goobed up that it has no heat?
• The heater electronic control unit losing its mind?
  • I'm guessing there IS such a thing, ya' know?

At this point, I am truly stumped.


Side note:
A few years back, the dash vents started working intermittently. Sometimes they'd blow air, sometimes, not. And yes, I know what those little buttons do that are labeled with arrows : - )

Sometimes if I turned the car of and back on, they'd start working.

I assume it's a vacuum paddle valve and the upstream control valve is sticking - but that is truly a guess. Or, the vacuum hose is leaking (old and brittle and prone to break - like me)

 

OK, still heat. So if you get the car up to temp, and the feel the hoses before and after the coolant pump, and then after the heater valve. So that will tell you if the pump and valve are passing hot water to the heater core.
​​​​​​There is a heater system self diagnosis you can run that cycles the heater system through all of its paces. Works all the flapper valves etc. And then gives you a readout on the display of what is not working.
found it on the Jag lovers forum, to see how to run it. I believe when you start the car you hold down the climate control on button and ? I cannot remember. Anyway you hold down the 2 buttons when starting the car and it will run the diagnostic procedure and give the codes. Which are also on jag lovers forum.
As an absolute freak of chances. On my 95 XJR I had, I had the same issue no heat even after changing out the pump. It turned out to be a swapped out relay in the trunk for the secondary fuel pump on the R sealed for the other relay when I was having starting problems. Anyway it for some reason impacted the climate control , and the Tach, weird. Anyway with the climate control in diagnostic mode it would give heat as it cycled through the heat part of the process. So that told me all the mechanical bits were working fine.
For whatever that is worth.