Thermostat/Flaps, R they necessary? Options

[martinef1963]

I have a question and would like a "wide" view point from this forum on Thermostat/Flaps on a 914

Mine are missing - and I've rcvd one comment saying that they are NOT really necessary.

Can I get some inputs on this topic - while doing some work on my car (I'm a newbie) yesterday - I noticed that the thermostat, thermostat housing, and thermostat cable are missing - only have the pulley.

In addition - where the EFFIN are these flaps? Cause if they are not needed and they are in place - they could be a problem, right?

thanks (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[Reiche]

In Miami, you may be able to get away with not using the thermostat, but I would run one. As Type 4 noted, you still need the flap over the oil cooler (#7 in picture.) Whoever told you they aren't necessary honestly doesn't know how they function. If they are in there and the thermostat isn't hooked up, it is not likely they are a problem. They were designed to be fail-safe. IOW, they retract to full-cooling position (read below.)

The flaps and thermostat regulate how much cooling air reaches the cylinders and heads. A spring on the rod between the two sides pulls them open (full cooling) by default. When the engine is cold, the thermostat pulls against the spring, and moves the flaps to a position where they block the cooling air from going over the cylinders and heads. As the engine warms up, the thermostat lengthens, opens the flaps and allows air by. Make sure you hook up the thermostat so it pulls against the spring when cold or it won't do anything.

The flap on the 1 & 2 (driver's) side only functions as above. The flap on the 3 & 4 (pass.) side has another function in addition: It guides the air over the oil cooler. That's why it's necessary. Without it, the air has to make an unassisted U-turn to go over the cooler. Since air follows the path of least resistance, it is unlikely much will go that way. Make sure it is hooked up correctly also. The 1 & 2 side flap is solidly attached to the rod that connects the two sides. However, as the diagram shows, the 3 & 4 flap is connected by a linkage. It is possible to hook it up so it works opposite to the other flap. If you do that, you will block the air from one side when the other is getting full cooling. When the thermostat opens, they will switch. Keep driving like that and the blocked-off side will burn up.