[Etnier]

There's a diversity of info on 968.net concerning the proper manufacturer, part number and source for a metal Heater Control Valve replacement. That's next on my list of things to do: does anyone have accurate and current information as to what part I should buy, and where?



Thanks...

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[EEZATOY]

John,



Its an Audi part #74671 (autozone 846444?), but they are now part metal and plastic - In January I was able to check around at different Autozones and found one of the older ones(all metal) still in stock - so you should check around and see if you can find one of those. You should also get some hose clamps to replace the funky clips that are stock.



Sam

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[Darth Coupe]

John, there is a great thread that will give you everything you need on www.968.net This is where Bruce and I described what is needed, the procedures, and pictures. Good luck.

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[flash]

the search mechanism there is rough - you end up with a lot of stuff to go through before you get close to the right thread - i gave up after 4 wild goose chases - any way you could post a direct link to the correct thread?



by the way eric - i LOVE the "highlighted word" feature in the search engine on this site - much better - you don;t have to read the entire thread to find the post with what you are looking for - just scroll until you find the highlighted word - cool

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[SANDOVAL]

This topic is being moved to a new area of the forum. I think it is imortant to keep a seperate archive of information that new owners should be aware of. Please ask a moderator to move a topic to the "Post's that any 968 owner should read!" forum if you have a topic that you think should go in this collection of information.

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[Etnier]

Well, to date this thread isn't completely informative in that we do have the correct Audi/Autozone #'s but it stops there. I was able to get that (all-metal) part from AZone, (thanks eezatoy: both numbers are correct). My searching experience at the other site was like Flash's. There are many threads that match the criteria. I think Darth might be referring to this thread, but it's four pages long and wanders quite a bit.

Towards the end Darth says "Finally, it is complete! The Autozone heater control valve fit is in my car as we read. I have some pictures, but nowhere to host them right now. I think I will try to get a write up done and maybe give it to Jason at Paragon to host, and then maybe do a write up in here when I get some time." Darth: this would make a great pdf for the DIY section here. I could put the pdf together if you send me what you have.



Eric: once we get this all sorted out please feel free to reduce the thread to the essential elements. Otherwise we might have another 4-pager here!

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[Carl968]

The part no. #74671 is the correct part no. at Autozone but it is for the plastic version of the heater control valve. The original no. at autozone was #846441 (audi HCV metal part) and it was superceded the #74671 number. I spoke with the northeast parts distribution center and they say that only the plastic version is available.

Carl

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[Etnier]

Well, as Eezatoy said in the 2nd post in this thread, it's really a store-by-store thing at this point. I called the closest store to me, explained the situation and they told me they had the all-metal valve in stock. (Incidentally, that metal valve had a 74671 part number loud and clear on the box.)



What we now need are-

• • an alternate source for an all-metal part for latecomers
  
  • a DIY/pdf. Eeza has PM'd me with useful info on this, but has no images. If Darth or someone has hi-res images and any installation wisdom they'd care to pass on, I could distill this all to pdf.
  
  

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[Greimann]

Having never had the "pleasure" of having my HCV fail, is the failure mode due to some plastic part snapping off thus making a metal version desirable?



Is the failure a leak that is due to the decay of an internal elastomer seal that could be present in the plastic and metal version?



Just curious why a metal version is the preferred replacement.

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[EEZATOY]

Dave,



From what I've read they have a tendency to self destruct and draining your coolant all over the road. I would guess it has to do with the heat and it being plastic - mine was purely preventive - and an easy relatively cheap($27) mod.



I don't think the metal one will totally self destruct so if it fails you would either end up with constant or no heat - but at least you could still drive.



Sam

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[Jim Child]

I'm very familiar with this problem. I've personally seen three 968 HCV failures, all of which occured on the track. One was my in my own car, another was in a good friend's car which I witnessed in my rear view mirror. The third one was in another friend's car which I observed from the passenger seat when I was instructing. This is a very bad thing to have happen on the track because it sprays coolant all over the rear tires making it very difficult to keep the car pointed in the intended direction...



The stock valve is basically two plastic pieces glued together. In failure mode the glued seal fails, and the two pieces come apart spraying coolant everywhere.

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[Eric_K]

The previous owner of my car had a HCV induced introduction to the Watkins Glen armco. Luckily it was minor. The HCV has been banished from the car (along with a lot of other stuff too <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> ) I think a metal one would be a good investment.



Eric

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[Jim Child]

In all three cases we were extremely lucky and managed to keep the car on the track, but it could have easily been a disaster. Really not something you want to take a chance with even if all you do is push it hard on exit and entrance ramps.

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[flash]

i'm thinking about relocating the thing farther away from the problem (exhaust manifold) - in think all it will take is some longer hose

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[sparky]

OK guys and gals, this is the very first thread I read after registering, but so far no banana. Seeing as I'm keen to get my recently purchased 968 Club Sport on the track down under here in Adelaide I am *very* attracted to a simple mod to keep me and the armco as distant relatives.



But sadly this thread hasn't helped me... yet.



All I need to know is : - what is the HCV part I need , where do I get it, how do I install it?



thanks in anticpation...

sparky

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[Etnier]

As mentioned above, it's an Audi part: #74671. (It's said to be #846444 in US Autozone stores, but when I went to Autozone I was sold a part marked as coming from "Factory Air", with only the Audi number on the box.) I was hoping that Darth would send me or someone his photos and stuff so a DIY could be put together, but maybe what follows will help.



I haven't attempted the work yet, but Eezatoy PM'd me to mention that it's a fairly straightforward job, esp. if you remove the larger hoses at their other ends. Here's an edited version of his message to me:

I changed mine when I was doing a oil change- its easier to access the HCV with the oil filter out. After removing the oil filter I covered the oil filter bracket with plastic (make sure you cover it tightly), because when you disconnect the HCV you will empty maybe a quart of fluid from the cooling system.



The HCV is tied into the cooling system by two short hoses: I disconnected them where they connect to the system (leaving them attached to the HCV) as they are more accessible that way. Once you have the assembly out, disconnect the hoses from the old HCV and connect to the new Audi HCV. Leave the clamps (good time to change to normal hose clamps at this time) slightly loose so you can adjust the angle of the HCV (position the lower outlet toward the radiator, upper outlet toward the heater) when you get it installed.



I did take Bruce's advice and bent the vacuum stem from a 90 degree to straight up and added the J-B Weld bead to seal it.



Wish I had taken pictures when I was doing it - that would help with the DIY, but I think when you start looking at it it will make more sense. It’s really pretty straightforward - other than working in tight corridors and keeping the coolant out of the oil filter bracket.

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[sparky]

Thanks for good info on installation John, but is that Audi part: #74671 always the metal version?

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[BruceWard]

Sparky, I believe you are in Australia which would make it difficult to go to Autozone and see what is in the box. That part # was originally an all metal HCV but is being replaced a part plastic version.



The part that you want looks like the one on the right in this picture



Also NAPA sells a very similar all metal part. The NAPA part number is BK 6601410 and can be found at http://www.napaonline.com . This is the NAPA part



The part is from a 1987 Audi TQ. You should be able to call up any local store and ask for the heater valve for a 1987 Audi TQ then find out if it is all metal. If so it should work.

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[Harvey]

This same plastic part fails pretty often in the 928 also. So I bought a spare one for the 968.



Harvey

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[968 Cab]

Wow, this is a very useful thread cause I had the HCV split and fail just like the somebody said! Lucky I had a OEM spare around, but I think I will get a metal one just the same - that lump of plastic must get pretty toasty so close to the header. Thanks to everyone for the PN etc!

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