bypass the heater control valve?

[ehall]

As luck would have it, my valve split open a few hours ago, and I ended up doing the bypass in Autozone's parking lot. On my 91, the hose from the thermostat to the top port is 3/4" on both ends, while the return hose is 5/8" on both ends. Engine runs smoother and quieter, coolant temperature is more stable, and the heat works better. I'll try to rig up a bypass from plumbing parts sometime before summer.

 

[ehall]

Looked at an '00 in the junkyard today, hoses should be usable on earlier models. The big hose is 11/16 (instead of 3/4) and the smaller hose is 5/8. They are molded for maximum clearance too, probably worth using.

 

[deltaqueen]

My valve cracked about a month ago and I just bought a new one and put it back in where the original was. No problems since. The part was less than $20 at Advance.

 

[deltaqueen]

It's an 88 xj inline 6cyl

 

[xjtrailrider]

My valve cracked about a month ago and I just bought a new one and put it back in where the original was. No problems since. The part was less than $20 at Advance.

The problem is they will not last. I crack mine every time I change the #5 and #6 spark plugs. Making a bypass is a good way to eliminate 4 connections and a potential leak. Plumbing in with copper as 5-90 suggested and adding some valves and a flush is the best way to fix the issue for good. Thats what I plan on doing.