Late model thermostat housing elbow

[gravy26]

During a head gasket replacement when I pulled off the thermostat housing I found the input side elbow has only a small hole - see attabelow - is this correct?

[Al Schober]

That's a restrictor. A lot of owners use that (or a valve) to reduce/control the flow in the engine bypass. It forces more water to take the path through the block. Some owners (myself included) like to run their engines on the cool side (120 or 130F), and will a) use a restrictor, and/or b) use no thermostat.

[romantic comedy]

As Al said, it is an added restriction. I think there was a bulletin about that. It gave instructions on how to make that small orifice to restrict the flow thus sending more water thru the block for more cooling.

I like the idea of a valve at that point.

I run a late model thermostat with FWC (home made). It runs all day at 180. I have a valve in case it wants to run hot.

[gravy26]

Thanks, that's what I was thinking.
The engine at idle stays around 140 but after 30 mins of motoring along it will creep up to 160.

I guess I'll leave it in place.

Mike M.

[rickandlee]

Always clean your cutting board well after poultry and thermostats.

I've been running no thermostat and a bypass valve (fully open) for this winter and my temps never got above 100° on the gauge. A few extra dollars appeared in the boat bank account a little while back so decided to try a Moyer thermostat and new housing. The temps come right up to 160° and stay there no matter the power setting. Objectively through carefully observation the fuel mileage increased 11%. I will not live long enough for this increase in mileage to pay for the thermostat but subjectively I think the engine runs smoother at that temp. Thanks Moyer for the fine work on the thermostat.

[JOHN COOKSON]

The engine at idle stays around 140 but after 30 mins of motoring along it will creep up to 160.
I guess I'll leave it in place.
Mike M.

How long has it been since you've done an acid flush?
A bit of reserve cooling capacity is good to have.

TRUE GRIT

[tenders]

My version of this is a bolt stuffed into the hose at the tee. Some water sneaks around the hex head. Temps are always low, salt water precipitate is a non-issue, any high temperature is an immediate indication that something unusual is going on, and you are welcome to your 11% mileage improvement at 160 degrees.