Calgary Jeep Association
4x4 Related Groups => Tech Talk => Topic started by: S-FLY on February 12, 2009, 09:19:34 AM
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So, when I bought my xj, I didn't have much heat and it'd take forever to heat up. I changed my thermostat yesterday and notice it was stuck wide open (must be a safety setting for when it over heats?). Anyways, I noticed the old one had a little pass-through with a ball bearing type thing but the new one didn't have this... is this important?
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I just did my 95 for the exact same reasons. I don't recall either the old thermostat or the new one having a bypass so I'm going to say... not important
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Right on. I'm just curious what it does really, my old one had it and Sprockett's old and new one had it and I thought we had the same motor. Here is the thing in question (this isn't my t-stat, but the arrow points to the bypass):
(http://i395.photobucket.com/albums/pp39/stanyoung/random/1.jpg)
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Mine was a Stant and looks like this
(http://www.autopartswarehouse.com/images/product_images/images/stant/13009.jpg)
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Found the answer, it's called a jiggle valve. I guess they did away with them, it was for air to pass through.
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i installed on in a ford exploder and jeep grand on the same day. the grand was a failsafe and had the valve, couldnt get failsafe for exploder and it dint have a valve
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I don't like the fail safes, everyone of them I had failed in the stuck open position. I've rarely had a failure with a regular.
The hole as you said is a jiggle valve for helping bleed air from the system. It should be installed in the 12 o'clock position when installed in a Jeep 4.0L to help bleed air from the system.
I usually disconnect a heater hose when filling the system to help bleed air out. My old '89 4.0L would get airlocked if I didn't.