throttle body warmer coolant circuit

[e30vert]

I don't remember who it is, but at least one group makes a delete plate for the coolant fitting on the throttle body. Not necessary, just for aesthetics. No chance it can leak vacuum or anything if you leave it open, or just unbolt the plate and throw it away.

The amount of heat the TB removes from the system is absolutely negligible vs a radiator or heater core, and the flow is minimal.
The only reason not to cap both ends instead of loop the lines, is effort.

Thanks this is exactly the information I was looking for. I got one of those spiffy machined throttle body coolant block off plates . It looks great.

I busted off one of the bolts and figured no need to use and extractor and then retap.


I tapped and threaded in bolts into the throttle body (as well as applying thread locker and silicone sealant ) to cap the coolant input and output. I also capped off the coolant passage on the back of the block.

[e30vert]

Question: The little nipple shown in the lower left hand corner coming off the throttle body. Where does the hose route to?
The big one in the center goes back to the input on the heater core that sends coolant through the firewall to the heater core. Correct?

[Northern]

Question: The little nipple shown in the lower left hand corner coming off the throttle body. Where does the hose route to?
The big one in the center goes back to the input on the heater core that sends coolant through the firewall to the heater core. Correct?

Pretty sure that's the Evap line from the charcoal canister

[e30vert]

Thanks North! How about the big one in the middle of the throttle body? I dont think that is a coolant line after I reconsidered it. That would make no sense.

[Northern]

The big one in the middle of the blockoff plate? That's the vacuum source for the crankcase vent on the valve cover.

[TobyB]

Nothing's going to damage the engine.

capping off the heater circuit won't hurt anything, but might make the cooling system just a little bit harder to bleed.

Looping the heater hoses creates a bypass of the radiator, but it's relatively small, so unless you're out of extra radiator
capacity, you won't notice.

My version is to loop the 2 together with a restrictor, so that air can easily bubble out, but not much water flows.

And only because it makes it easier to dump and refill the coolant every season.

t