The cheap and poorly made MTC heater control valve that I got from FCPGroton and installed only about 18 months ago broke apart, which I think could be called a catastrophic failure. The car blew out all its coolant very quickly and overheated.

In the photo below, the bent shaft on the distributor seems to be pointing at the body of the heater control valve. There should be a big nipple on the black plastic part of the valve pointing back at the bent dist shaft, but you'll notice there is not. The big nipple broke completely off of the valve and allowed the coolant to blow out very quickly. Never, never again am I going to use MTC parts. Period.


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1955 Human, Scott; 1991 745 Turbo, Brunhilde; 1990 745GL, Snuggle Bunny

MTC = Made To Crap standards. Avoid them and Scantech if you require anything the least bit durable.

I went with the four seasons model for my last two heater valves. Seems to be a good choice:


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Paul NW Indiana '89 744 Turbo 145K/ '90 745 turbo 127K

Paul, do you have a model number for that FourSeasons unit appropriate for 740/940 cars?
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See the 700/900 FAQ at the drop-down menu above right.

Steve,

The four seasons part number is 74612. It is widely available since it is used on many older domestic cars as well. I got my last ones from rock auto for about $11 each.
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Paul NW Indiana '89 744 Turbo 145K/ '90 745 turbo 127K

...the MOTORCRAFT pictured below looks more like the OE part.

FWIW, I think the one I put in my 940 preemptively when I got it in 2003 was an MTC (I didn't know any better). It's still working, but I saved the old OE one as backup. Now I'm tempted to swap it back in.

Heater Control Valve
Motorcraft $17.75 at RockAuto
Looks more like OE ($64.57 at Tasca) PN 1259327


Lot's of google hits on Ford YG136 too.

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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Thanks for this!

I'm just a couple days away from putting the MTC valve on the shelf in the 740. Looks like I'll hold off and get the 4-seasons valve.

-Ryan

I experienced an identical failure on my 940 last week. Same location broke.
Its amazing how thin the plastic is at that point. How bad/long did yours overheat? Mine is showing no signs of a bad Head Gasket as yet....knock on head.

My wife was driving home when the problem occurred. But, from what she says it didn't take long - the temp gauge went to full HOT, and the check engine light came on, that is when she noticed it. By the time it got home on the tow truck (could have been spillage putting it on the truck and getting it off) there were only about 20 oz. of coolant that came out via the lower radiator hose.

I just assumed that the head had warped and pulled it off and took it to Clearwater Cylinder Head to have the "T" cam and sodium-filled exhaust valves transferred to one of their cores and have that properly overhauled and set up. The reason that I jumped to the conclusion that the head was warped was that this all happened about two years ago, but the leak was not nearly as bad then, just a little split in the heater control valve that let out a needle-thin jet of hot water and steam. It happened within a mile of home, and the coolant was nearly full when the car got home. After letting it cool, I capped off the heater pipes, filled it up, and returned it to service. But, slowly, over the course of two weeks, it started both drinking coolant and occasional spikes of overheating. In the end the temp gauge went into the red and stayed there. It needed to have the cylinder head repaired or replaced anyway.

Moral of this story: Keep a good eye on yours. Maybe you got lucky, but just in case you didn't, keep a close watch on the coolant level, and on the temp gauge when driving. Check the coolant level every morning when the car is cold, and after EVERY use of the car. If it starts dropping you might have a more serious problem. And it is better to head it off (pun not intended) before it strands you somewhere and makes the damage worse. But, if you go a month with no coolant consumption and without any overheating, you may be out of trouble. I wish you luck.
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1955 Human, Scott; 1991 745 Turbo, Brunhilde; 1990 745GL, Snuggle Bunny