Hot water valve for heater

[Bertsl]

My heater keeps getting hot water and heating up the cabin and I don't know where the valve is to rehabilitate. I would rather rehabilitate the valve if possible and not chop the hose and put in a jury rig valve to stop hot water from getting to the core. I would like to have a heater that actually works as advertised. Is possible??

[EricH]

Originally Posted by Bertsl

My heater keeps getting hot water and heating up the cabin and I don't know where the valve is to rehabilitate. I would rather rehabilitate the valve if possible and not chop the hose and put in a jury rig valve to stop hot water from getting to the core. I would like to have a heater that actually works as advertised. Is possible??

Heater valve is tucked down in the inside front of the passenger-side footwell. Follow the cable from the heater lever if you can't find it.

The valve does tend to corrode and stick open, and often it can be removed and cleaned. Or you can still get new ones from some of the obvious vendors. Considering what an incredible PITA it is working down in that footwell... I'd go with new to minimize the chance of having to go back in there any time soon.

[JimD]

I replaced the valve once, it wasn't fun. More tedious than hard really.

If you won't have time to take on the heater valve in the near future, you can put a "band-aid" solution in place temporarily. Install a ball valve in the heater line back in the engine bay. This will allow you to block the flow of hot water thru the core and viola, not more hot air in the cabin.

Then order the proper valve and start working on your flexibility exercises.

[Dan Sarandrea (Phila)]

Later model cars have two different valves in two different locations.

Non A/C cars have their heater control valve as posted in the area above the passenger footwell. '84 and later cars, this will be just to the left of the fuse and relay box. Most of our vendors have these in stock.

A/C cars have their heater control valve located on the driver's side of the HVAC plenum. I haven't seen the installation in person, but a look in the online shop manual might help, or ask someone with A/C to post some pics. It's my understanding that these valves are hard to find new.

Can't help you on the early cars 74-78, but for all I know they could be the same as the later cars.

[EricH]

Originally Posted by EricH

Heater valve is tucked down in the inside front of the passenger-side footwell. Follow the cable from the heater lever if you can't find it.

I should add... I know that this applies to the '74, and I'm pretty sure it applies to all the 1300 cars... But I don't know about '79 on.

[ianlawson]

Originally Posted by EricH

.....and I'm pretty sure it applies to all the 1300 cars... But I don't know about '79 on......

.......and you US X-heads are soooooooooooooo lucky you don't have RHD X's to do this job on!!

cheers, Ian - NZ

[lookforjoe]

Pretty sure AC version is integrated into housing - last I looked, there was no obvious way to remove/replace the valve alone. I installed a vacuum controlled heater valve from a Volvo 740 for that reason

[tim5055]

Well, after having the valve fail and fill my passenger side floorboard with coolant as I was driving I almost want to install a ball valve like Jim suggested just for emergency use.

[JimD]

Hi Tim,

I am thinking the ball valve trick would only work on a non-leaking system.

The ball valve location I have in mind is on the output circuit. The heater return pipe comes out of the center tunnel:


A hose from this tube carries the coolant up to the tube on the head near the cam pulley. On my 78 I put a flush T in the location that I think would make the ball most accessible:



So with a ball valve in this location and closed, the system would pressurize and the faulty stock heater valve would leak in your situation. Even if you moved the ball valve to the heaters input hose (coming off the water pump) the system would still have pressure and the faulty stock valve would leak.

Maybe a ball valve in both location would allow you to cut off the system pressure to the heater. That may prevent or minimize the leak???

Update- I think I may have reversed those hoses, but I think the may point stands. If the system has pressure it will leak at the valve.

[Pete Whitstone]

Originally Posted by lookforjoe

Pretty sure AC version is integrated into housing - last I looked, there was no obvious way to remove/replace the valve alone. I installed a vacuum controlled heater valve from a Volvo 740 for that reason

I just spent some fairly large money on what is surely one of the last AC heater valves in existance. It looks pretty replaceable/self-contained to me. But that's just looking at the part. I haven't dug into the car and seen it in situ yet.

Pete

[lookforjoe]

Got pics?

I presumed it has a hard flange connection to the heater core/box - but... I just looked at the online AC schematic (pg 501.03), and the valve looks like its up against the firewall either in the middle or of slightly to the D/S. What I was looking at was obviously pos.20...

[Pete Whitstone]

Originally Posted by lookforjoe

Got pics?

I presumed it has a hard flange connection to the heater core/box - but... I just looked at the online AC schematic (pg 501.03), and the valve looks like its up against the firewall either in the middle or of slightly to the D/S. What I was looking at was obviously pos.20...

It's illustrated in the manual you reference above as part # 33 on page
50-11/12, in the exploded diagram of the heater core. It has hard inlet and outlets, situated 90 degrees from each other.

Pete

[LarryC]

could you post up a picture of the AC heater valve? Given their rarity, many of us might need to get creative, and it helps to know what we are trying to find/fab.

[Greg (in Conn)]

Originally Posted by Pete Whitstone

I just spent some fairly large money on what is surely one of the last AC heater valves in existance.

I scored the last 2 that the Di Fatta bros. had for 48 bucks each

[Pete Whitstone]

Originally Posted by Greg (in Conn)

I scored the last 2 that the Di Fatta bros. had for 48 bucks each

that a whole lot of inflation has occurred since then.

Pete

[dcioccarelli]

I can assure you that it is an even bigger pain on a RHD car as it basically butts up against the bolt securing the pedals. It is easiest to drop the entire pedal box in this case...

Originally Posted by JimD

I replaced the valve once, it wasn't fun. More tedious than hard really.

If you won't have time to take on the heater valve in the near future, you can put a "band-aid" solution in place temporarily. Install a ball valve in the heater line back in the engine bay. This will allow you to block the flow of hot water thru the core and viola, not more hot air in the cabin.

Then order the proper valve and start working on your flexibility exercises.

[bmck]

Originally Posted by dcioccarelli

It is easiest to drop the entire pedal box in this case...

Dom, the most recent time I have done it (third time), I removed the centre console and dropped the heater radiator. Most difficult bit was inserting eight feeler guages to hold back the clips on the center air vents to allow the vents to be extracted.

I now believe this is the easiest (!) method for a RHD job.

Regards,

Brian

[Bertsl]

I looked at the "exploded" view of the heater a/c unit and found the valve. While I was looking I wondered if the fresh air door and its control might be a contributing factor for venting hot air into the cabin. Letting in air outside as the car drives, across the core and then into the cabin?

[ianlawson]

Originally Posted by bmck

......Most difficult bit was inserting eight feeler guages to hold back the clips.......

.......holding the feeler gauges in place WITH YOUR TEETH, while using your 3(?) hands to arm-wrestle with all the heater core crap slipping around all over the place!
But, silly me, I'm forgetting - having done this job 3 times now, you can probably now remove/fit a new X heater valve in your lunch break??

cheers, Ian - NZ

[bmck]

Lawso,

I'm thinking about doing it professionally.

Ship your RHD X1/9 to me and I'll have the job done within 24 hrs.

$2,000 a pop - and, get this, I'll fork out for the new heater tap.

You'd be a mug not to.

Regards,

Brian