98 Wrangler Heat Issue

[Bomberbeer]

Hello, I'm new, i apologize if this has been asked before.

I am banging my head against the spare tire in frustration.

My 98 Wrangler (4.0L, 6 cylinder, stick) has 290,000 miles (yes, 290,000) and last year (winter wasn't so bad then) my thermometer gauge slowly, over time, crept leftward from the 210º mark, and is now past the "\" mark and heaed towards 100º. The engine does not heat up to the "expected" level.

Two years ago the Water Pump failed, and Firestone replaced the water pump, belt, and radiator fluid (but not the thermostat).

Two weeks ago i replaced the thermostat with an OEM grade 195º replacement. truth be told i had never done it before, so it took a while, and i had to use two gaskets to get it to seal right.

I was told afterwards i probably had an air bubble in it - so i parked it on the incline of the driveway, and added more fluid when the thermostat opened and the fluid level went down. I capped it off.

The temp gauge remained the same - at about 150º. not very exciting, and not very warm in the passenger area, either.

I checked the hoses, and when the jeep is running at "max" or "operating" temperature, the main hoses are warm, and the hoses leading to the heater core are both hot (the one going in and the one coming out.

Last night i tried replacing the radiator cap with a new one - it fit much better, but it did not solve the problem either.

I believe i am doing something wrong, but i dont know what. When i took it to a local mechanic last year (when the gauge was below 210, at about 190) he said "you have heat, it is fine.

I know it wasn't fine. My Jeep always felt like it had a pipeline to Hell, because it blew some seriously hot air all through the 1998-2006 time frame.

The heat had been loosing it's OOMPH before the water pump failed. Ever since, it hasn't gotten better.

To recap:
98 Wrangler 6-cylinder Stick (no Air Conditioning)
New Thermostat
New Radiator Cap
Fluid is moving in radiator
Thermostat opens and closes.
Hoses to Heat Exchanger seem to be working.
The Gauge never shows it going up to 210º
There is very crappy heat coming out.

Please tell me it is something as odd as "you have a blown fuse" or something.

Dan

 

[xt master]

You may have a problem with your instrument panel itself.I believe it is vacuum controlled.You may have a leak or broken hose all together.

 

[SteelHeadz]

You Might have a Vacuum leak that's affecting both the HVAC door operation and engine performance. Engine vacuum is routed thru the firewall with the evaporator lines. there should also be a Vacuum Reservoir mounted under the battery tray. Check these lines for leaks.

 

[Bomberbeer]

Thank you gentlemen!

I decided last night to re-flush the heat exchanger with warm water (hooked a hose up to the basement faucet. Though i did not see sludge or other crap come flying out (i was focused on keeping the hose connected to the exchanger) i did keep it going until i could loo over and see clear water flowing out.

I reconnected the two hoses, and viola! Insto-hot air.

Well, not really insto.

Anyhow, the gauge is still low, but the heat is back on. Which leads me to believe the gauge or sensing unit is dying, but everything else is working fine.

Thanks again for your thoughts!

Dan

 

[House Norris]

Hey group ( 98, 2.5, Automatic Wrangler) I 'm having a problem with over heating immediately when engine is started I replaced radiator, top hose, Thermostat and all new fluids. I have fluid flow and I've tripled checked my connections and appear to have no leaks. What else can I check or replace to fix problem? Thanks

 

[josue estrada]

maybe coolant temperature sensor?

 

[superj]

you keep filling it and hte fluid is disappearing? or you have a good fluid level but it immediately goes hot?

is your water pump good? when you open the radiator (prior to it over heating) can you see the fluid moving through the radiator? you might have a bad water pump