Hot water valve let go today.

[DMC3165]

Driving along I started smelling anti freeze today. This afternoon I was planning on changing my oil anyway but when I crawled underneath I saw coolant dripping right by the drivers side coolant line. At first it looked like that was the leak but upon closer inspection I was able to trace the leak up to the Hot water valve. At first I thought the hose near the end had split but after looking at it closer I could see coolant coming right out of the port where the control arm goes into the valve body. This looks like a royal pain in the ass to change. Mainly because its in such a bad spot. My question is how difficult is it to change this and is this part a vendor part only or is it available at a local parts store.

Thanks,

[jawn101]

Driving along I started smelling anti freeze today. This afternoon I was planning on changing my oil anyway but when I crawled underneath I saw coolant dripping right by the drivers side coolant line. At first it looked like that was the leak but upon closer inspection I was able to trace the leak up to the Hot water valve. At first I thought the hose near the end had split but after looking at it closer I could see coolant coming right out of the port where the control arm goes into the valve body. This looks like a royal pain in the ass to change. Mainly because its in such a bad spot. My question is how difficult is it to change this and is this part a vendor part only or is it available at a local parts store.

Thanks,

Do you have the original one? They are available at parts stores, you can use the photo below as an x-ref, but be aware: it was twice as expensive as at a vendor. Personally I'd get the OEM one from a DMC franchise, and not the Hervey one - his is smaller and made of very thin material, which is why I ended up seeking out a local cross-reference. I got it at O'Reilly.

It isn't really that hard to change out but you may have to remove your mixture unit. Probably not the manifold though.

[1batt4u]

Do you have the original one? They are available at parts stores, you can use the photo below as an x-ref, but be aware: it was twice as expensive as at a vendor. Personally I'd get the OEM one from a DMC franchise, and not the Hervey one - his is smaller and made of very thin material, which is why I ended up seeking out a local cross-reference. I got it at O'Reilly.

It isn't really that hard to change out but you may have to remove your mixture unit. Probably not the manifold though.

I actually have John Hervey's Hot water valve. Putting engine back, I am about to install it any day now. You don't think it is a good idea?

[Kevin]

The location makes it a bit difficult to change out, otherwise shouldn't be too bad.

As far as crossover parts, Steve replaced his with a heater valve from a 1980 Ford Bronco, $10 from Autozone, conversation starts here: http://dmctalk.org/showthread.php?26...ll=1#post45045

And Jon (from above) found one at O'Reilly, a Murray 74798 out of a 1988 Cadillac Fleetwood for $36.99:
http://dmctalk.org/showthread.php?4704-Heater-control-valve-cross-reference-improved-part&p=66860&viewfull=1#post66860

[Bitsyncmaster]

When I had my intake off, I replaced the hose on the drivers (off the head in back) hose with a longer hose. I figured that would make service easier later. I'm still running the original heater valve with no problems so far.

[DMC3165]

How difficult is it to remove the mixture unit and do I need special gaskets or anything to put it back. The part is available locally from Auto Zone for $21.99

[jawn101]

How difficult is it to remove the mixture unit and do I need special gaskets or anything to put it back. The part is available locally from Auto Zone for $21.99

Pretty easy. Remove air cleaner and W-pipe. Remove the two hex cap screes holding the mixture unit down. Remove a third hex cap screw holding the vacuum solenoid. Unbolt the WUR and frequency valves from the valve cover. Disconnect the feed and supply fuel lines (much easier to disconnect AT the FD, rather than at the fuel filter/return pipe,) the CSV and pull the injectors. Then the idle air pipe from the idle speed motor (this is the worst part). The whole mixture assembly should just lift off. If you are confident in the length and flexibility of your fuel lines you can skip some of the disconnections and just shift the unit out of the way. Use your judgement. If you disconnect fuel lines there will be gas leaking. Disconnect your battery first. Have rags handy. Work on a cold engine. And maybe have new copper washers ready to re-seal any fittings you remove. Sounds way worse than it is. And it helps enormously to remove the lower engine cover first.

[Morpheus]

If you don't mind a little contortionism, and creating a few new swear words, this job can be done without removing the mixture unit. Honestly, removing the mixture unit alone doesn't really give you all that much more room. You'd be better served by removing the intake as well. The main PITA for this job is getting clear access to the connection on the left side head.

[DMC3165]

I did it! I went with the contorionist method. It really wasn't half as bad as it looked. I had to get the part from Grady. While all the parts stores near me offered it. No one stocked it. I was going to let Grady do it but he sugessted I look at it myself and see if its something I might want to tackle myself. Glad he did it really wasn't that bad. Would've liked to have change the hoses too but that will have to wait.

[jawn101]

Oh, excellent. Good job and congrats! I wonder why mine was so much harder to get to. I will admit that removing the K-Jet didn't make a gigantic difference in ease of access but it was just enough for me.

Hope the new valve holds up for you. I don't know about you but losing that thing was terrifying for me. All the leaked coolant went right on the crossover pipe and I thought the car was burning down. Not an experience I'd choose to repeat :)

[Bikercmbc]

Go with a metal one, ive known of the plastic ones to break in half(brand new!!) within 500-1k miles. my plastic one has the vacuum nipple already broken off it.

[1batt4u]

I did it! I went with the contorionist method. It really wasn't half as bad as it looked. I had to get the part from Grady. While all the parts stores near me offered it. No one stocked it. I was going to let Grady do it but he sugessted I look at it myself and see if its something I might want to tackle myself. Glad he did it really wasn't that bad. Would've liked to have change the hoses too but that will have to wait.

Hey Chris,

Do you have a picture of the part from Grady?? Is it metal? I recently bought one from Auto Zone, its all plastic.

[stevedmc]

Bill Robertson has been using the same Autozone sourced plastic heater core shutoff valve that Steve Rice uses for 10 years now:

http://sphotos-a.xx.fbcdn.net/hphotos-ash4/486788_454031534642102_420477367_n.jpg

Both Steve Rice and Bill Robertson drive their DeLoreans 6,000-8,000 miles per year without losing a single drop of coolant from their Autozone sourced plastic heater core shutoff valves.

Both Steve Rice and Bill Robertson have full faith and confidence in their Autozone sourced plastic heater core shutoff valves.

Both Steve Rice and Bill Robertson consider their Autozone sourced plastic heater core shutoff valves to be $10 well spent.

[1batt4u]

Nice!! Happy to hear that!!!! :cool1:

Do you know the part # for his part from Auto zone? I tried putting in the # from the sticker thats on it but no luck.

[stevedmc]

Both Steve Rice and Bill Robertson are using Autozone Part #74612.

Both Steve Rice and Bill Robertson are very happy that their heater core shutoff valves are piston operated, not gate operated.

Both Steve Rice and Bill Robertson are very happy that their heater core shutoff valves are 100% isolated from the outside world, and do not have shaft seals to leak.

Both Steve Rice and Bill Robertson are very happy that their heater core shutoff valves are not made from low carbon steel and will never rust through.

[LEVY]

I would use the Cadillac one, you can't go wrong if it is good enought for Cadillac.

LEVY

[jawn101]

I would use the Cadillac one, you can't go wrong if it is good enought for Cadillac.

LEVY

I did find the one I ended up with (the Fleetwood cross-ref) to be very robust feeling. Thick plastic and metal. Working great so far!

[LEVY]

I did find the one I ended up with (the Fleetwood cross-ref) to be very robust feeling. Thick plastic and metal. Working great so far!

Good find, I will try that one.

LEVY