m20 coolant block off plate

[turbski]

Im installing a coolant block off plate on my M20. The heater core was bypassed last year. It split and the car only gets driven when its warm out so no loss there.
the question is, From the bottom of my expansion tank is a hose that runs to my thermostat housing, Its Td in the middle, left side goes to the thermostat housing, right goes to the back of the cylinder head, What hose gets plugged? Gotta be the one im deleting< I get that, but why is it Td?

OBV I cant just plug the line off the bottom of the tank, could I just run a new direct line from tank to thermostat and not install the round plug?

[turbski]

I guess a better question to ask is, what is the function of the coolant hose from the bottom of expansion tank to the thermostat housing? Heating system only?

[turbski]

ok, found this is the coolant return hose, originally routed to the heater core, the line from the back of the head was also to the other nipple of heater core. that being said, do i have to keep the bottom of the expansion tank tied into the thermostat housing?

[turbski]

Got sick of searching. Went back to re read the build thread of "das beast" and stumbled upon all the info I needed. Haha the diagrams and posts from dvallis and forcedfirebird made it super clear. Not to mention got to drool over that build again!

[turbski]

update

finished up the bitch tube repair and heater delete yesterday. Ran the line from the bottom of the expansion tank back to the t-stat housing. the system was bled and tested and works very well.

It was very easy with the intake manifold off to get to the back of the head and was the only way to get the tube out.

[Beamerboi]

Just got my 325is running but I think I have a leak on the outlet. The hoses are dry but there is water leaking off my trans bell housing. I hope this is the problem. I have a whole other engine so maybe I’ll try that gasket.

[turbski]

If I had kept the HVAC system in this car I would have gone OEM gaskets on everything. I so far have had no luck with much aftermarket/ "used" gaskets. I used the condor speed shop coolant plate and gasket supplied. not sure who makes it but from what I can tell OEM BMW is the go to.

[dvallis]

Here you go

[turbski]

Thank you. I blocked the back of the head, ran the line from bottom of expansion tank to return on t stat housing and the line from side of block goes to stock location on t stat housing.

[ForcedFirebird]

I typically weld the TB cooling hole shut and put an oil drain plug in the back of the block. If you don't have access to a welder, you can thread the inside of the small hose on the t-stat housing and run a bolt in it - but bypassing it like you did also works.

I prefer to force the coolant aft in the block and forward through the head, any of those other hoses will allow coolant to bypass this operation.

[turbski]

so, if I gather the routing correctly, its ok to block the port on the back of the head and I could also block the port on the driver side of the block (and corresponding t-stat connection) if I felt inclined. The engine bay has been shaved and painted. getting rid of the hoses that I did made it wayyyy cleaner. basically if it does not serve a purpose (for my application) then it gets the kibosh

[ForcedFirebird]

Correct. This also eliminates the expensive tee hose, as you can just use a regular hose to go to the expansion. For a really clean look, you could also block off the tee hose at the thermostat housing and use an early model water pump that has the spigot on the passenger side for the early model expansion tank - then use a trick aluminum expansion tank that sits on the battery tray. ;)

Edit: I did this recently on an s54 swap, would work just as well for an m20....

[turbski]

Now that is a clean engine bay