How to replace 1983 Volvo 240 heater control valve

The goal in documenting this installation is to facilitate sourcing the parts and tools needed and provide instruction.

First off a great resource article can be found here:

Replacing the heater control valve in a Volvo 240 wagon - Hagerty Media

However, I found the ferrule does not need to be removed and the complicated bending of the wire just right can be avoided as well.

I started off getting an actual replacement part of the original heater control valve off of eBay. It was pretty expensive, over $100 at the time, but I thought having the same part would make things easier. Unfortunately after what was a serious pain in the ass , clamping off all the coolant hoses, getting hoses off the old valve, and installing the new valve, I came to find the new valve had a leak due to a very small hole in the welding at a joint and a few days later I was left with a huge mess of coolant that leaked under the carpet of the driver’s side footwell, and had to remove the seat and carpeting to clean everything up.

After that I came across the Hagerty article that suggested using a universal heater control valve, which are much cheaper and probably better quality as you can easily buy them at a local auto parts store.  In order to make the universal valve work however, you need to get some adapters and an extra section of heater hose, which actually makes the install a little simpler. Here is a picture of the hose, it is not completely seated on the valve at this point and the coupling has not been installed yet either.

Before you remove anything, make sure you have hose clamps and/or vice grips to stop the flow of coolant.  I clamped off the supply and return hoses in the engine bay as well. I found the hose clamps from harbor freight worked pretty well.

You  also need to be prepared for quite a bit of coolant to leak when you remove the valve so get a good sized trash bag covering the floor below the workspace.

The next step was probably the most difficult, removing the hoses from the old valve.  In my case they were stuck on there pretty good, and after a lot of trial and error, I found that a wide flat-head screwdriver to initially loosen up the ends, combined with some thin wrenches to apply enough force to move the hose off the valve stem worked the best.  Initially I used a single wrench just bigger than the diameter of the valve stem to work it down, and then I used two of the wrenches together side by side and pulled them against each other, with one touching the valve side of the control valve, and the other touching the hose.  This worked well.

After removing the old valve, the installation of the universal valve went pretty much the way of the Hagerty article.

When it came to installing the control wire however, I could see that bending the braided wire would not be easy and error prone to making sure it was at the correct distance to properly control the valve. Also, any necessary adjustments would be complicated as well.  I spent quite a bit of time trying to find the right part.  I finally found a shaft collar and terminal lug that ended up working well.

The hole on the terminal lug is not the correct orientation, so I was able to drill a hole at 90 degrees to the original.  To keep the drill bit from slipping, first create a “pit” in the copper with a nail and hammer where you want to drill the hole. 

The final assembly:

Parts:

O’Reilly Auto Parts:

• Murray heater valve: part number 74827

• Radiator hose: part number MBH 20338

• Heater hose connector: part number MTM 47094

• Hose clamps: part number MHC MP5512V

Ace Hardware:

Shaft collar: inner diameter about 5/16” if I remember correctly.

Lowe’s:

Southwire Terminal lug: Item #3720801 |Model #65180040

Tools:

• Harbor freight hose clamps (Pittsburgh Automotive Fluid Line Clamp Set)

• Thin wrenches: Amazon (Super-Thin Open End Wrench Set, Metric, 8-Piece, including 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 22, 24 mm, Slim Spanner Wrench Set with Rolling Pouch)

• Vice grips

• Wide flat screwdriver

• Plastic trash bag