SharkSkin

Bob, that 2nd valve sounds like a great idea. I have a vacuum switch that I was planning to install, basically a winter/summer switch where in one position it is a pass-through, in the other position it connects the heater valve to the vac reservoir. Your suggestion seems like a more elegant solution. Have you identified a part that will do the trick?

dr bob

Need to stop by the local parts place and get a Four Seasons 74614 or equivalent. It's a fail-closed valve with 5/8 hose ports on it. Original fitment is to some Ford products. There are a couple different pictures floating around on various websites. One shows a valve with a pistong actuator, while others show it with a diaphragm. I started off simple at the NAPA website and just scrolled through their pictures and descriptions. They list it as a Balkamp (NAPA house brand...) 6601024 if you want to look, and then share the Four Seasons part number too. For the vacuum, a T in the line between brake booster hose and the little check valve looks like the right spot on my S4. I'll have the intake off weekend after next and plan to do the fit-up then. I'll post pictures of course if it turns out as I think it will. Good News is that the NAPA part has a real genuine one year warranty, and it's a metal part rather than plastic. I know I know, I'm adding more weight...

dr bob

Stopped by the local Advanced Auto Parts store and gave the clerk the number to cross-reference. They can't. Their system only knows applications. No descriptions either. System is built to be fool-proof I'm sure. And it is fool-proof. May need to just bite the bullet and get a couple from Rock or one of the other online vendors.

Meanwhile, for those playing along at home, the valve is originally used on the legendary Escort GT and GL models, the Mercury Lynx and Topaz, and the Ford Tempo, all in years 1984 and 1985. It's a pretty narrow window. If you go shopping locally, the key is that the valve needs to be closed when no vacuum is applied to the actuator.

borland

dr bob,

On my truck, the vacuum actuated heater valve also opens when you shut off the engine. But no hot air blast when you restart on a warm engine.

The difference is, Ford installed a cold water traps in the roomy engine bay. The heater core inlet and outlet pipes at the fire wall are 6 inches lower than the top of the cold water traps. Here's what they look like....



I found a 3-way solenoid valve on eBay for about $16 with shipping. I posted a photo of it at the other other thread here: https://rennlist.com/forums/928-foru...uration-4.html