Thermostat install direction

The answer is quite simple though — the front of the engine is the end where the drive belts are located. If you were to install your gaskets on the left and right side based on looking at the engine from the front of the vehicle, the gaskets would be incorrectly installed. The UP stamp is found on Fel-Pro head gaskets for Subaru engines, which have horizontally opposed cylinders. The edge of the gasket with the Up stamp must be kept up toward the top of the engine block.

In these cases, it does not matter which direction the gasket is installed. If it were crucial, it would be marked. There are no directional markings on the gaskets. Water outlet and thermostat gaskets can be installed with the striping facing either direction, as long as there no directional indicators.

If there are bypass holes, the gasket must be installed in the correct orientation to allow coolant flow. When installing Fel-Pro exhaust manifold gaskets, if there is a smooth, metallic side and a composite side, the metallic side should be installed facing out, meaning toward the exhaust manifold.

This smooth surface of the shiny side will allow the flange of the exhaust manifold to slide as it expands and contracts during heat cycling from engine operation. Learn more about Fel-Pro quality gaskets that are specifically designed for the repair environment, find your car part , or find where to buy your auto part today. The reason it is called a jiggle valve is that it typically has a little piece of metal that jiggles around inside the hole.

Through my research, though I realize it serves an important function. The jiggle valve helps keep rust or other junk in the coolant from clogging the small opening. By jiggling around as the coolant flows it breaks up gunk and keeps it from clogging the hole. Pretty cool! However, I would always recommend using the OEM thermostat, gasket, and then making sure you install the jiggle valve location according to the FSM. They should help. There is no one way that fits all, however, if you properly bleed the cooling system the jiggle valve should not come into play.

Those are a huge pain in the butt, and avoiding coolant bleeding problems is worth the five minutes to research which way the jiggle valve goes. I have read this one online time and time again and have yet to give a try. It goes like this. When installing a thermostat place an Advil, Aspirin, Tylenol, or another pill that will dissolve inside the thermostat lip making it sit partially open.

This will allow easier bleeding, as you can fill the car with coolant and it will be able to burp through the thermostat cold. Reassemble the system. Replace the coolant and check for leaks. Typically you fill the coolant, run the car, wait for the thermostat to open up and keep topping up the coolant. With this trick, you can bleed the cooling system easier, and my vote is any way to make bleeding the coolant is easier gets my vote.

On some cars, it is impossible to install the thermostat upside down simply because it will not fit back in the housing. However, on other cars or trucks, it is entirely possible to install the thermostat backward and has been done by countless people. Before removing the thermostat, pay attention to the way the thermostat aligns inside the housing.

To check the alignment, note which direction the bleed pin—near the edge on the round base of the thermostat—points to.