I was putting the engine tin back on the engine and though I should reattach wire/cable from the bellows to the flapper arm and check it for full operation.

I used a heat gun and it took about 30 seconds - video shortened a bit.

It starts out in cold engine mode (flaps diverting air away from cylinders and away from oil cooler). As it warms up it moves to full cooling mode (flaps diverting air across cylinders and oil cooler).


https://www.youtube.com/watch?v=fpTWUNm1Qn8

Thanks for posting that....needs more sound!

really REALLY COOL! settles the how do they work ? 1 nomination for classic thread status.

Thanks! I was hoping it settles it and not open "that" can of worms with this video.

It really is pretty simple when you see it in action - hard to argue with physics...

Waiting for the "why don't you just wire them in full cool mode" all the time replies.

I've had my car for about 3 years now, and I had been assuming that the temperature gauge didn't work, or was disconnected. I finally got to take the car for a real drive this fall, and the gauge actually moved! Now I'm assuming my flaps don't work, and are stuck on full cool. Thanks for the video!

If the wire from the bellows to the flap arm is broken/missing the flaps "default" to full cool. Some builders permanently position the flaps at full cool.

They should be used - there is a reason they are there (warm up).

Well, if you lived in So Cal, you wouldn't need no stinking thermostat






... and you can pin the flaps in the full cool position ...

I like show and tell !

What do you want to hear? A louder heat gun?

You know I LOVE stuff like this, don't you?

I spent a fair bit of money and time building my engine.
While I may be in southern California, i want my engine to get up to temp as quickly as possible and stay within the temp range as close as possible.
That said, i have working T stat and flaps.
And I am in the camp so should everyone else.

I think the general consensus is just that. Get the car up to operating temp as designed by the engineers. SLITS once told me the /6 was designed to operating at 190 degrees at which point the car "sealed" up. Probably similar theory for a /4.

There are a lot of reasons you want the engine to heat up to operating temperature quickly. A cold motor needs a richer mixture, causing increased emissions, additional cylinder wear, and lower fuel economy. You also want to get the oil up to temperature quickly to drive off any absorbed moisture, reducing internal corrosion and deposits, and preventing the oil from emulsifying with the water and "sludging". That's why keeping the flaps and thermostat working properly is the right thing to do for your engine.