How to : Replace your Heater Control Valve (HCV)

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How to : Replace your Heater Control Valve (HCV)

Post by Dal » Fri Aug 15, 2014 7:46 pm

As you can never have too many photos, I thought I'd add a few as I've just replaced one.

Symptoms:

If your heating is stick on either hot or cold or even a bit sticky and intermittent, then you'll probably need a new Heater Control Valve (HCV) as it's quite a common failure on many Ford cars as it's a common part.

Some info:

The original part number was: 98FU 18495 AB
The new (and improved?) one is: 7N21 18495 AC
The FINIS* number is: 1714716

*Ford International Numeric Identification System

I'd recommend getting them from your local Ford parts desk for 2 reasons:
1. The ebay copies tend to be of poor quality and fail quite quickly
2. The Ford ones tend to last longer but if it does fail within a year, you'll get a replacement from Ford free of charge as new parts come with 12 months warranty.

They can be seen here side by side. You can also see the week / year dates on them. The one on the left being 8th week in 2006 and the new one being 27th week of 2013.

Image

Box:
Image

First make sure your car is cool as you don't really want hot coolant all over your hands when you do the replacement.

Fitting photos:

The HCV can be found in the middle of the bulkhead at the back of the engine bay. You'll see two pipes going into it from the engine side and 2 pipes coming out the back and going into the car to supply the heater matrix:
Image

It's easier to remove the rubber seal that goes from left wing to right wing on the bulkhead and remove the plastic "leaf" shield if you have one on a later car:
Image

Remove the rubber "boot" over the right hand side (as you look from the front of the car) of the HCV to reveal the electrical connector. Then remove the electrical connector to the HCV (as seen above too next to the suspension strut)

In place - just push down on the metal wire bar above it to release:
(You can see the two pipes coming out the back and going down into the heater matrix too)
Image

Image

Next you need to use some pliers or similar to compress the retaining clamps and wiggle them away from the HCV towards the back and the front as shown:
Image

Closer view on the engine side:
Image

Closer view on the other side of the bulkhead:
Image

With the retaining clamps out the way, you can wiggle the pipes away from the HCV and remove it out the other side of the bulkhead (not engine side). If the HCV has failed in a way that the pipes on the HCV have cracked and/or come away from the main body, you may need to fish the plack plastic part out from inside the pipe. A screwdriver or small allen key 90 degree part can help. Make sure you get it all out or else you might be doing all this again when your new HCV fails.

Removed:
Image

Install the new HCV into position - it isn't screwed in or retained in any way; the legs simply hook over the bulkhead floor and the pipes hold it in postion. (see the front bottom of them in the first picture)

Wiggle the pipes back into position on the new HCV and replace the retaining clamps to seal as seen in photos 2 and 4 above. Reconnect the electrical connection - making sure you hear the "click" of the wire either side - and replace the rubber boot above.

Refit the leaf tray (if you have one) and the rubber bulkhead strip. Then check your coolant level in the expansion tank to the left and ensure that it's still between the Max and Min as you may have lost some when replacing the HCV.

All that's left to do then is start the car and make sure you get hot and cold as you should. If you don't, then recheck you've fitted the electrical connector correctly.

It's advisable to run the car with the expansion tank lid off so any air locks can escape until the car gets up to temperature - with the car stationary of course.
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Re: How to : Replace your Heater Control Valve (HCV)

Post by crystalpuma » Sat Oct 25, 2014 12:42 pm

How hard do you have to push the electrical connector back in? Should there be any play in it once connected? My HCV isn't working but it's brand new so I can't believe it's gone that quickly. However, I can't hear a click sound when I re-connect it yet pushing almost as hard as I can doesn't induce a 'click' not does it seem to quite go all the way in (i.e. there is some play left). Do I need to push violently to get it to click or is just broken?
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Re: How to : Replace your Heater Control Valve (HCV)

Post by lusid666 » Sat Oct 25, 2014 3:04 pm

If you press the little metal bar on the plug down as you push the connector back on it makes it a bit easier.
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Re: How to : Replace your Heater Control Valve (HCV)

Post by Dal » Sat Oct 25, 2014 9:10 pm

Make sure the connectors in the plug at not bent out of shape perhaps? That might stop you from connecting properly.
It clicked back in place after I disconnected it the other week?

In fact I think what might be causing your non working hcv might be the connector pins are pushed too far apart and not connecting to the hcv. (After I pushed the DVM probe in there... Sorry :( )
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Re: How to : Replace your Heater Control Valve (HCV)

Post by zinc2000 » Mon Oct 27, 2014 3:11 pm

Good "how to" thanks for that as I may be replacing mine before it goes back on the road next year :thumbs:
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Re: How to : Replace your Heater Control Valve (HCV)

Post by crystalpuma » Wed Oct 29, 2014 5:36 pm

I can't see without physically climbing into the engine!! Will see if Kev can reach far enough.
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Re: How to : Replace your Heater Control Valve (HCV)

Post by jmanjon » Fri Aug 21, 2015 10:25 am

Thank you that was really useful. Apart from needing the arms of Mr Tickle it was really easy, many thanks. Just replacing the coolant now and we will see how it goes. My problem was RH front pipe just broke clean off as the plastic necks on the HCV had died of old age. There was no way the other 3 pipes were going to come off cleanly - they just snapped off as well as soon as I started wiggling the pipes. The allen key idea to remove the remains of the plastic neck from out of the pipe ends did not work for me as the plastic was too brittle. Because the plastic had degenerated so much the pliers just pinched bits off and I eventually struck on the idea of crushing the end of the pipe slowly with the pliers and hey presto all the bits of plastic just crumbled out. Remember to hold the pipes pointing downwards so the plastic falls out! not cascading up the pipe and into the system. Hopefully no plastic went into the system... Thanks again. I don't really post on here, but perhaps I should as its a really helpful website. Cheers all. Jon Leicester.
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Re: How to : Replace your Heater Control Valve (HCV)

Post by Dal » Fri Aug 21, 2015 10:32 am

Glad it helped :thumbs:
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Re: How to : Replace your Heater Control Valve (HCV)

Post by Frank » Fri Aug 21, 2015 11:06 am

Anyone have an online link to genuine Ford HCVs at a decent price?
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Re: How to : Replace your Heater Control Valve (HCV)

Post by jmanjon » Fri Aug 21, 2015 1:51 pm

Having just purchased from ebay I went for one at GBP29.95 made by TRW. Seems to be fine and fitter perfectly, but I don't know how long it will last... The genuine Ford ones seem to have the logo on the item picture on ebay and are all GBP45ish as quoted in this website, so that's pretty accurate advice. They start at GBP11 to GBP14 on ebay which I steered clear of. I went mid-range.
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Re: How to : Replace your Heater Control Valve (HCV)

Post by andrewjeffs » Tue Nov 24, 2015 6:55 pm

just for reference..i bought a cheap ebay one as I was desperate when my pipe snapped clean off!
Its been in the car 12 months,and even though the heater control is far more vague than the standard ford ..its still working..I also change those awful spring clamps for jubilee clips..far easier to get on/off,when you have to lean right over the engine to get to the valve..
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How to : Replace your Heater Control Valve (HCV)

Post by moondustka » Fri Apr 01, 2016 9:07 pm

No need to, it un-hooks from the lip on the bulkhead by pulling forward :)
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How to : Replace your Heater Control Valve (HCV)

Post by ArtfulHussy » Fri Apr 01, 2016 10:27 pm

It is almost always the hcv because they go brittle over time. I had mine fall to pieces while the car was sat outside work. Literally disintegrated. My car had been blowing hot for months before the plastic casing of the hcv actually gave way. Its a pretty quick and easy job to replace and the genuine part from ford isn't too pricey (around £40 I think).

I think unless you can hear the knobs on the panel not working (like mine for the directional knob) you would probably need to take the panel off and do continuity testing on whatever wiring is back there. I haven't been behind it myself so I could be wrong, just a half-educated hypothesis! Hcv probably easier to rule out IMO.
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How to : Replace your Heater Control Valve (HCV)

Post by ArtfulHussy » Sat Apr 02, 2016 8:35 pm

Its not as bad as it looks, just take your time and have a good look at how its all connected. If the HCV plastic has gone brittle it may well snap off in the rubber hoses when you try to unclip. Be careful to make sure you don't let it fall down the hose.
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How to : Replace your Heater Control Valve (HCV)

Post by Jimkey83 » Tue Apr 05, 2016 11:15 am

Does anyone know if you need to drop the coolant as I seem to be getting contradictory info regarding this, I am looking to do this myself which will save £30+, can anyone advise.
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How to : Replace your Heater Control Valve (HCV)

Post by moondustka » Tue Apr 05, 2016 11:22 am

I would personally, but I don't like coolant going everywhere because it doesn't really evaporate.
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How to : Replace your Heater Control Valve (HCV)

Post by Jimkey83 » Tue Apr 05, 2016 11:37 am

How would i even drop the coolant, there is a video which shows you how to remove but not to drop the coolant, I have limited knowledge so this a biggy for me
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How to : Replace your Heater Control Valve (HCV)

Post by YOG » Tue Apr 05, 2016 11:45 am

Depends how old the coolant is. Coolant/Antlfreeze has a finite life, and the anti-corrosion and lubricating additives will reduce in efficiency over this time. Hence, the alloy engine parts, waterpump seals, HCV, etc., will be less protected over time.
Here's some information you may find useful, I used the Hot Water Hose method:
http://www.projectpuma.com/viewtopic.php?f=51&t=9818
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How to : Replace your Heater Control Valve (HCV)

Post by Jimkey83 » Tue Apr 05, 2016 12:21 pm

Hi, would these be viable for 1.7, I know maybe not for the engine but for heater control valve etc
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How to : Replace your Heater Control Valve (HCV)

Post by Craigyrogers » Sat Jun 25, 2016 11:28 am

This is a Good how to. Thanks op. Just bought my second moondust 1.7 as a project and the previous owner had decided that removing the faulty hcv entirely was a good idea and replacing it with some copper piping.....a quick ebay purchase of a genuine ford hcv and this how to made it very easy to get the cool air going again. A few concerned about the coolant leaking out, just keep the pipes facing up and bleed the system after if any leaked out. That worked for me anyway.
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How to : Replace your Heater Control Valve (HCV)

Post by Lostbarbel » Tue Jan 23, 2018 9:07 pm

Great! Particularly useful as the plastic outlet pipe has just sheared off. Fortunately was in a traffic jam right outside a garage. They were able to disconnect both hoses and connect them together using a piece of steel pipe Of the right diameter I just happened to have in the boot! Got me home a treat.
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How to : Replace your Heater Control Valve (HCV)

Post by gavinfdavies » Wed Aug 15, 2018 9:16 pm

This happened to me just now as I was inspecting a cheap Thunder prior to purchase! The spigot fell apart in the owners has as he tried to investigate the seeping coolant. bought a 15mm female/female 90deg copper plumbing bend from wickes (£2.38 for 5!) and joined the hoses together. Got me 150 miles home ok, but want it sorting asap!
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