Eastsider61

I have a 1998 Jeep Grand Cherokee w/4.0 I changed the thermostat and upper and lower radiator hoses. Now I have no heat, did have the heat before changing items. What could be going on? Whats the fix?

Thanks,
Mark

tiwvr1

check coolant lvl. Low coolant lvl will cause this. It might of had a air pocket in it that came out after u ran it.

ol"blue

X2. Make sure you get the air out of the system. Also, did you use the correct temp. t-stat?
And Welcome to CF.

Eastsider61

Thanks for the welcome to the site.
The jeep does have warm air just not hot air as it did before. As far as the jeep we replaced the thermostat with a fail/safe 195 degree it stated it was OE recommended. The jeep temp runs around 140 to 150 now after the change. Should I have went with a lower temp thermostat? I checked both hoses from the heater core and both are about the same temp to the touch. That says I don't have a clog in the core. The anti freeze levels are full. Now with trapped air, there is no bleeder valve how do I release the air? Any other suggestions.

jack1981

the thermostat should be a 195 degree one. to burp the system simply make sure engine is cool. remove radiator cap and allow engine to reach normal running temp. this will allow all air pockets to surface to the top. then allow engine to cool, top off radiator if low and replace cap.

Gee oh Dee

You can buy special funnels with plugs that help, they come with adaptors so they can attach to most radiator caps.

There is a small chance the tstat that you put in was bad. If your truck is running ar 140-150 degrees its not getting hot enough, but that could be the gauge reading inaccurate because of air pockets slowing coolant flow.

1ABrian

This may sould silly but did you put the thermostat in backwards?

Gee oh Dee

Would it even fit?

1ABrian

I did mine like 2 years ago, I dont even remember but figured I'd throw that out there. Ive seen it done on other vehicles......even if the thermostat was stuck open, you'd get SOME type of heat eventually. Air pocket is valid too but once again, I think you'd get minimal heat and a collapsed upper rad hose

Gee oh Dee

He said it runs at about 140-150, nowhere near running temp. Waaay too cold.

1ABrian

so were looking at an air pocket only. I would tend to agree. Figured I'd toss out the other options. I guess scratch the collapsed rad hose cause that would be a bad rad cap.
The upper rad hose would still get hot as the bottom even if there was air in there correct??

retreaded jeeper

when 'burping' the system as described occasional check, look in radiator to see if water/antidreeze is circulating.

Eastsider61

We have more heat now since I bleed out the air by removing the cap and letting the engine get to temperature. The heat won’t run you out but it will warm the truck up. Should I attempt to redo the bleeding process every couple of days to ensure all air is out or one time is good enough? We do have circulation within the radiator. Any other things to look at to increase the temp.? Thanks to all that replied.

retreaded jeeper

bleeding once should be enough.at this point you are kinda on your own .if you block the radiator eirh cardboard listen and watch all your gauges that over heating doesn't occur.a coolder thermostat will allow water to pass thru engine to heat up,but also radiator to cool off.