68 Cutlass S Convertible 350 with jetaway. All stock.

Newbie stupid questions. I bypassed my heater. But what is the best way??
a. Run a hose from the water pump to the manifold?? to keep the circulation.
b. Cap the fitting with rubber hose caps from auto parts store??
c. remove fittings and install metal plugs??

I have used the rubber caps before but they have split and blew out all under pressure twice. Never at a good time. 30 miles from home.
If I replace the fittings with metal plugs, are the threads pipe (NPT) using plumbing plug or standard (Unified Thread Standard (UTS)) using set screw or bolt??

Another stupid question. What pressure of radiator cap 12 lbs or 16 lbs?? Is that why the rubber caps keep blowing out??

Thank you for reading this.

 

A or C. I lean towards C.

You know that this is going to disable your windshield defroster, right? This is not a great idea.

This is the reason B is a poor choice.

Pipe thread. I use brass if possible.

12 or 16, I'd use 16 and then assure that the hoses and clamps were in good condition. The rubber plugs blow out because they're cheap crap imported from some hellhole.

 

It appears that you've already done it. Which method did you use?

 

Point of clarification: Pipe threads can come in two configurations (1) NPT (National Pipe Taper) (2) NPS (National Pipe Straight). Verfiy that you are using the NPT plugs. With NPT the beginning end is a smaller diameter thread. While NPT is more common, NPT is also sold.

 

There is one other method if you want to maintain a stock look. You can put shutoff valves in the manifold and water pump, hook the heater hoses up to them and close the valves so no water goes to the heater.

 

X2 what Mr. Glenn said. I assume you are having heater core problems and as mentioned above you will lose your defroster. I've never had a 68, is it a major to swap out the heater core? That seem like it would be the best option especially beings it winter..... Tedd

 

Back in the day, Dad wanted to minimize heat leak in the summer, so he installed a 1/2" shutoff valve in the hose between the heater core and the intake manifold. He'd shut it off in the summer and open it up when it got cool. Years later when I replaced the heater core & hoses, out came the valve. The heat leak in the summer was never enough to bother me.

 

Thank you all for the input. I think I am going to plug them off. I tried using the caps and they failed twice. So I want a permanent fix. I live in southern California so the heater and defroster are not needed. I only drive it with the top down in good weather, never at night.
It rarely gets below 50 degrees during the winter, so i can only drive it about 300 days a year.

Thanks

 

Factory heater delete cars used a cap on the water pump port and a plug in the manifold hole. There is no need whatsoever to run a bypass hose, despite what people claim on the interwebs.

 

But....but....won’t the engine overheat when there is no coolant flow?


But....but.....won’t the heads get hot?


What about blowing out the intake gasket????


Have I missed any?

 

The intake gasket is a new one on me.

 

If you don't drive your convert at night with the top down, what is the point of the rest of us putting up all those stars for you to see with your sweetie?