Low Heat Issue

[1Salty Dawg]

When I have the heat on it blows out the vents somewhat warm (think that is another issue) but when I switch to defrost its cool, no signs of any heat. I also can't get the vehicle temp above the middle mark that in between 100 and 210 degrees on the gauge. I recently replaced the radiator and thermostat. Yes it was one of the fail safe ones. New one is on its way. Thanks

 

[Jerry Bransford]

Yep, don't use fail-safe thermostats. Hopefully the new thermostat you ordered has the specified 195 degree rating. Don't use a 165 or 180 degree thermostat in our TJs.

 

[1Salty Dawg]

Update: Let it run in driveway for about 30 mins with heat on. Upper heater hose very hot, lower hose just warm and now have a burning plastic smell in the cab.

 

[1Salty Dawg]

Yep, don't use fail-safe thermostats. Hopefully the new thermostat you ordered has the specified 195 degree rating. Don't use a 165 or 180 degree thermostat in our TJs.

I ordered the thermostat off this write up.
https://wranglertjforum.com/threads/jeep-wrangler-tj-water-pump-replacement.279/

 

[TX99517]

Hey, so we have a 99 that had lukewarm heat. last year, I put in new thermostat, radiator and cap.

Still had issues. It's been hovering around the negatives here lately and I was stressing about since the teenager drives it. Had a friend who is a mechanic flush the heater core. He said he flushed back/forth and used air about 50 gallons of water. Said a very thick brown sludge came out of the core. Once it was all clear and no more sludge, he hooked it all up and tested.

The thing is blowing hotter air now than my 2010 Ram does.

 

[1Salty Dawg]

Hey, so we have a 99 that had lukewarm heat. last year, I put in new thermostat, radiator and cap.

Still had issues. It's been hovering around the negatives here lately and I was stressing about since the teenager drives it. Had a friend who is a mechanic flush the heater core. He said he flushed back/forth and used air about 50 gallons of water. Said a very thick brown sludge came out of the core. Once it was all clear and no more sludge, he hooked it all up and tested.

The thing is blowing hotter air now than my 2010 Ram does.

I did flush the heater core but I don't think it was long enough and I didn't have a solid stream of water coming out. Will be doing the correct thermostat and core flush again this weekend and see what happens.

 

[JESTER801]

What would be a cost to have a shop flush the heater core? I am not that confident to do it? I am having the same issue on not getting heat very hot. My wife is going crazy over it

 

[1Salty Dawg]

What would be a cost to have a shop flush the heater core? I am not that confident to do it? I am having the same issue on not getting heat very hot. My wife is going crazy over it

I have no clue what it would cost but there are write ups on this forum of how to do it. It's not hard at all.

 

[1Salty Dawg]

Update: new (correct thermostat) installed, another heater core flush with vinegar and a new water pump and temp gauge shows just under 210 now I have to keep the heat on low so I don't melt my face.

 

[Jeepr89]

To flush the heater core unhook both heater hoses and hook up the garden hose one at a time and run water back and forth until it is clean both ways. These TJ’s are one of the easiest vehicles to flush and you should be able to be done in well under an hour even with a couple drinks involved!

 

[TX99517]

Update: new (correct thermostat) installed, another heater core flush with vinegar and a new water pump and temp gauge shows just under 210 now I have to keep the heat on low so I don't melt my face.

I drove the Jeep the other day, it has hotter heat now than my truck. I had to turn it down quite a bit. The teenager is happy since we have been in the teens to negative temps the last few weeks.