Never mind the B_d hose, here's the B_d heater control valve, 94 edition

( Larry ) #1

After much dicking around and worrying about removing the entire intake etc., I made up a compact 15/16" crowfoot socket - basically a wrench cut at the jaws with a 3/8 drive welded on and shrunk on the grinder.

After confirming said modified socket would actually be able to grip the brass fitting and be able to move it at least 1 flat at a time, I armed myself with a couple of 3/8" extensions, ratchet and a long pipe, got the socket thing in place on the nut and managed to remove the stuck-and-leaky heater control valve.

Only minor lacerations to the back of my hand BTW, but blood thinners and coolant did make it seem worse than it really was.

Feeling pretty chipper that I got it off, I grabbed my spare from the parts car and in no time flat the new valve was on and working beautifully. Took it out for a test drive and the A/C came on when I asked it to and so did the heat - perfect!

Stopped by the shed to drop off the tools and opened the hood to have a last proud look at my work but … …drippy drip drip drip … the replacement valve leaks! :frowning_face:

Is it possible to get a new one anywhere in this world?

(Jag.Man) #2

Sure it is, how much money do you have. . . . here’s some sites

( Larry ) #3

Well appreciate the googling, however, is showing availability as “out of stock” (actually NLA/discontinued) and the other two links are for the nut and olive, which, without the valve, well …

Thanks anyway, search continues.

I might modify the system using the early model valve if I can find out how the hot water takeoff gets to the valve - Is it off the head on the earlier rigs too? What’s the fitting to the head/block/pipework?

Anybody got a pic?

(Mike Stone) #4

This isn’t a picture, but maybe it will still be helpful:

( Larry ) #5

Thanks Mike, looks like thatEAC7189 could be used and spliced up with an old style valve, unfortunately that too is NLA/Discontinued …but maybe I can get a used one? …we’ll see.

(Joseph) #6

Larry, can you tell me if there should be a vacuum for the heater valve only when I select heat? And no vacuum when the a/c is on? I installed a Four Seasons valve that (I think) opens on vacuum but every time I touch both heater lines that run into the heater core under the driver’s knee bolster, they’re very hot.

( Larry ) #7

Joe it’s the other way round - the Jag valve is normally open (no vacuum) - It closes when the A/C is selected … I looked at a couple of plastic fantastic ones offered on rockauto for 92’s and earlier, may be an option but have to check their operation too …

So how did you rig the aftermarket one from the head? I was thinking if some 1/2" i.d. tubing coupled with a new olive and the nut from the old valve then to some hose then the new valve.

It is possible to change the operation of the Jag valve to be “normally closed” too! It just depends what position the ball is in (open or closed) when the lever screw is tightened …maybe the Four seasons unit can be recalibrated if it does the opposite?

( Larry ) #8

Thanks Mike, I think I see how the old units were rigged now.

Would be nice to get a pic of the fitting or at least get an idea of the length etc

(Joseph) #9

I removed the valve housing and reused the original metal pipe. I found a round metal disc at the local hardware store to fill in the hole. I used JB Weld after I thoroughly cleaned the surfaces.

(Joseph) #10

So what we need is a Vacuum Non-Bypass Closes Heater Valve. I’m keeping my eyes on the Four Seasons 74859 valve. It has an arrow indicating the water flow and the vacuum connection faces towards the left fender and not the engine.


Price is around $22-$24 on ebay.
The I.D. of the heater hose is 5/8" (0.625" or 15.875 mm) if I’m correct.

( Larry ) #11

Wow! Very cool way to rig it, I’ll have a look at that in a sec!

here’s the rockauto valve specs, looks like it’s normally open just like the jag valve …it’s only about 10 bucks too!

Opening C IN 0.625
Number of Connectors 2 Connectors
Opening D IN 0.625
Opening B IN 0.625
Type Heater Valves
Opening D MM 15.875
Opening C MM 15.875
Material Plastic
O.E. Replacement? Yes
Opening B MM 15.875
Opening MM 15.875
Style Non-Bypass
Operation Type VACUUM
Description **Vacuum Closes Non-Bypass Heater Valve
Opening IN 0.625

and a pic:

Vacuum line on top, inside that shield.

(Joseph) #12

Larry, you gotta check for clearance. Any indication for water flow? I don’t know why mine is not working. I remember the seller told me it can be installed both ways.

( Larry ) #13

Well as I see it Joe, it doesn’t matter the direction of flow, at least not in the Jag versions of these things.

It’s just a ball with a hole through it that turns to either allow flow or block it. When you ask for A/C, the vacuum pulls up the lever and shuts off the hot water.

Judging by the rockauto pic, I’m guessing that unit doesn’t use a ball, but a piston with a couple of holes that slides up and down in the chamber or maybe it does turn, hard to say.
Not sure about clearance but it can’t be much bigger than the OEM early valve can it?

The only reason I can think of why yours isn’t working is that it’s either stuck in one position or it’s a normally closed valve instead of a normally open?

Anyway, haven’t decided what to do yet, I’m off to ‘Coast Industrial’ tomorrow, a local specialist hydraulic/tubing/pressure hose supplier. I’ll see if they can match me up with a simple rig to replace the early model head take-off system and if so, I’ll see where we go from there.

Try a ‘normally open’ valve Joe - 5-minute job and 2 hose clamps!

( Larry ) #14

Joe, I just ordered one of the valves you liked, FOUR SEASONS 74858 -

I got it on Rockauto cheaper than ebay BTW

Should have it sometime next week, plenty of time to sort out the head connection hopefully.

(Geekay) #15

Sorry to tell you but you just missed out. I ordered one from Jaguar on Thursday morning and they were showing 2 in Atlanta. Mine is sitting at my local Jag dealer ($72) with some other parts as part of my head rebuild. I just checked with them and they said the inventory was now showing zero. You might want to call Terry’s and have them double check. I was speaking with them on Thursday and they saw the 2 in Atlanta. I understand Jag has 3 warehouses. Not certain. Perhaps someone can confirm. Evidently some things like this re-surface at Jaguar - probably as a result of dealers returning excess or old inventory.


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( Larry ) #16

Oh well - win some lose some I guess …no matter- I’m going aftermarket.

My car isn’t in line for a win in the concours d’etcetera anyway!

Just wanna keep it going and be cold in summer and hot in winter

(Casso) #17

Hi Larry, when my heater valve started dripping about five years ago I was unable to source a replacement. I added one 100ml bottle of Barrs Leaks during a coolant change and it has been perfect since. I check that valve every time I check my oil level ! I’m not a fan of 'pour in radiator repairs ’ but Jaguar used to recommend using Barrs leaks at every coolant change regardless of whether you had a leak or not, so it can’t do any harm trying it just the once.

( Larry ) #18

I remember that Jaguar advice Casso, and I have thought about it, maybe it would be worth a shot …still waffling a bit …haven’t pulled the replacement drippy valve yet …my old-school hot rod mates said I should add pepper to the rad, does the same thing apparently …just not sure about the grind (or if they meant whole peppercorns :wink: )

(Casso) #19

I’ve heard of a few ’ get you home’ bodges for coolant leaks such as raw eggs in the rad etc but never Pepper ! I’d never risk anything that might block a narrow coolant passage somewhere in the system under any circumstances, but I was desperate at the time and figured if Jaguar were initially using Bar’s at EVERY coolant change there can’t be that much of an accumulative effect so one dose would be unlikely to cause any harm. The dripping ceased immediately and it has been drip free ever since, I’m still looking for a new replacement !!

(Jag.Man) #20

Don’t worry about the grind, just make sure it’s Organic . . :joy:

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