Ok to block of heater core?
 

Is it ok to block off the heater core plumbing on the engine and radiator?
For the purpose of pulling all the hard lines and heater core.

Thanks in advance!

K.

I don't see why not. What will you use to block it off with?

Threaded brass plug in the engine side. Plastic cap with hose clamp on radiatoR

It is a common mod on most race cars. Just make sure your plugs will hold.

The 84/85 12A have a barb T on the engine side just below the oil cooler. I had to use a rubber cap and hose clamp when I went to a front mount oil cooler.

Is that barbed "T" only on '84 & '85 12a's, or is it also on the '82(?) and/or '83 models with the OEM "beehive" oil cooler? I've been trying to determine exactly what year the 12a that's currently in my '83 GS is; the previous owner told me that it was an '84 model, but I never just take somebody's word for it without verification and proof...

The 12a in my car has the barb under where the "beehive" oil cooler used to be, and although I plan on keeping my heater core and minimal vent plumbing with some kind of modified blower motor so the car can still be drivable in moderate winter conditions (mostly just cold weather, not snow), I'd like to eliminate quite a few water hoses in the engine bay. Does that barb accept the return water/coolant from the "beehive" oil cooler or is the coolant supply line? I can check the FSM later for verification, but I don't currently have a printed copy of the cooling system section for the S3s...

Thanks for your time, help, and cooperation...

I have been running them blocked off on my race car for 12 years now.

When I ran a Mazda radiator, I had a radiator shop solder a plug in the bottom outlet.

On the engine's pipe threaded fittings, I put in pipe plugs. If the hole is not tapped, I clean the hole up really well, and then epoxy in a steel plug. Like I said earlier, no problems after many years of this. I didn't like the pluggin methods of using a rubber or plastic cap, because plastic and rubber things tend to break down after a few years time, especially at higher temps.

coo!
i have a cosmo engine for my 83rx7, i have gotton the "T" thing out and have made a threaded brass plug for the engine side.

i think i will take speedturns advise on welding the radiator, or get a koyo...

So capping off the heater core ports at the rear iron and the radiator, will that affect the cooling of the engine or improve the cooling with more flow or not matter at all and cool the same as if it were looped or just left stock with heater core ?

The heater core only flows when the heat is on. We all know the trick that if your car is heating up, turn on the heater and it will help cool it a little bit. Of course in summer you would have to suffer with the hot air.

Is this a race car or a driver?

Why not just bypass the heater core.

Because we are thinking too hard....

But seriously thats my question too.

I went ahead and blocked it with the Haltech Coolant temperature sensor :nod: , cut the brass nipple a little more than half way and tap'd it with a M12 x 1.5 thread and will seal it with some LocTite 567 pipe sealant..
https://lh3.googleusercontent.com/-0...o/DSC03885.JPG
https://lh6.googleusercontent.com/-b...o/DSC03886.JPG
https://lh4.googleusercontent.com/-W...o/DSC03887.JPG

you can just get a metal connector from just about anywhere. Has a raised ring so you know where the center is.