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No heat at idle

4K views 8 replies 7 participants last post by  PtownBubba 
#1 ·
1995 Safari has no heat while warming up or idling. OK, let me tell you my diagnosis,,,, not heater core,,,, not thermostat. Here is why,,,,, in cold weather at idle,,,, the temp gauge does not move up at all,,,, heater blows cold air,,, when driving at road speed, temp gauge moves up, and heater blows super hot. Not a faulty gauge, as it follows the heater air temp,, not a clogged core,, as it blows hot air if temp gauge is up,,so hot fluid is passing through the core, until temp gauge falls back, then blows cool,but will blow hot again at driving speeds, not thermostat, as it is on the 3rd one, none changed anything. heater hoses are not hot at idle,, hot after driving, but will cool if left idling. My thought is,,,,,,,,,,, since it has the rear heater,,, which means more plumbing attached to freezing cold chassis,,,, the idling engine cannot get warm or stay warm with that added cooling of the frame,,,,at idle,,, the motor just can not get or stay warmed up. Can this be true ? Even put a cover on grill, did nothing to change what happens,,,,,,,
 
#2 ·
If the temp gauge isn't moving at idle. It is the T-Stat no matter how many you put in. Is not working right. There have been past threads on just how crappy T-Stats are and don't work new.

Mine warms up and has heat idling. Gauge moves heat comes out. Took me 4 thermostats to find one that worked right. Yep I got 3 downstairs now that are brand new in the box that do not work worth a nickle.

As per the old threads. Put it in a pan and heat it with water. Use a thermometer and see if it is opening when it should. Not early which is what yours sounds like it is doing. Or late which is overheating in the summer.

At the temp marked it should partially open. Then within 10-15 degrees above that open completely.
 
#3 ·
I went through this very problem for about two years, one of the things I found besides like what Chevymaher mentioned is air in the coolant system, with rear air I think its like 16.5 quarts, if you are not putting back anything close to that from a full flush, you will have heating issues. At least with my 99 LT RWD it was a huge problem getting all the air out of the system, at one point I had to raise the nose off the ground to get all the air out. Plenty of heat now.
 
#4 ·
Thanks guys,,,,,,,,,,,,, it almost is not a problem,,,,,,,,,,,,,, just a pain in the arss,,,,,,,,,,, jeepers,,,, 3 bad thermostats,,,,, i-carmubah, if the first 3 were bad ,, gulp,,, will it take 3 more,,,,,,, ??? The only other thing that happened, just one time,,,,,,,,,,,,,,,,,,, it got Hot, [according to dash gauge ] one time last summer while idling,,,,,,,,,,, which to me would be a thermostat,, as I got up to road speed it got back to normal operating temp,,,,,,,,,,,,,,,,,,,,, This Safari [ I call it the Escalade ] is a fantastic vehicle,,,,,,, I got it 4 or 5 years ago for little of nothing from my mechanic friend,, 230K miles but runs good,, coughs and gags a little, but just when cold,,,,,,,,,,drives sweet,, the AWD works in the background , never know when it kicks in it is that smooth,,,,great snow bunny,,,,,,,,,,,,,,,,, thanks guys for the info,,,,,
 
#5 ·
five10freak said:
I went through this very problem for about two years, one of the things I found besides like what Chevymaher mentioned is air in the coolant system, with rear air I think its like 16.5 quarts, if you are not putting back anything close to that from a full flush, you will have heating issues. At least with my 99 LT RWD it was a huge problem getting all the air out of the system, at one point I had to raise the nose off the ground to get all the air out. Plenty of heat now.
This ^....
 
#6 ·
I'd try burping it as noted above. Lift the nose off the ground and keep topping coolant into the radiator as it burps air and the level goes down . It will keep burping for a while until all of the coolant has cirulated through and pushed the air out. I had to do this with mine twice after all of the hoses were replaced. There was a stubborn air bubble in there that just didn't want to leave.

Between the T-Stat and air in the lines, I think you will find your fix in one of those.
 
#9 ·
Continuing with the language from the country of: Shade Tree Mechanic; :)

Gosh,,, I would think after 5+ years, of driving up hill down hill fast-n- slow, an air bubble would have been pushed out,,,, moved around, or the air ending up in the radiator. I recall parking it on a hill to try the burp thing, guess it did not burp, or it is not a burp issue,,,,,,but if it had an air bubble,,,,there should be no heat or poor heat at road speeds ,, just like at idle,, but at road speeds, heat is great at both front and back blowers. I will stop and pick up yet another thermostat,,,, or 2,,, and try that again. Thanks guys for your time and input,,,,,,,,,,,,,,,,,,,
 
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