MilwaukeeJeep

What would cause the heat to be warm at best? It never gets hot! In my friends jeep, the heat can hurt your hand its so hot. What needs to be done?

ragged1

Have you changed your water pump lately? The heater core is furthest from the pump with smaller diameter lines. A pump with a worn impeller won't move much flow.

ZINGGG

A lot can cause this. One reason is stated above. A clogged heater core can cause it (do a search on how to flush it). A stuck open thermostat can cause it - do you not get heat even when you reach operating temperature?

MilwaukeeJeep

Yes but its warm at best

Gee oh Dee

I could help you. I'm on the north side...

DubsJeepSport

I know this thread is old but did you ever get this figured out and what was the cause?
Thank you.

Gee oh Dee

Its poor flow through the heater core if the t stat is good. Its really simple.

DubsJeepSport

Any tips or tricks or how to's. I really appreciate you speedy response. thank you so much.

Gee oh Dee

If the Jeep runs at normal temp try back flushing the heater core.

The upper hose should be the inlet, lower should be outlet.

Undo the intake hose and aim it in a bucket. Undo the outlet hose, attach a garden hose to that, and back flush away. Watch what comes out the inlet, see if its clean or full of gunk.

purplegrocerygogetter

Hmmm Imma give this a try! My heater on yj has lost its umpf!

Gee oh Dee

You can try using cleaning chemicals as well, like CLR, but its pretty harsh and can eat through the heater core completely.

If you must use it, dont let it soak long, and consider diluting it with water.

purplegrocerygogetter

Ohh I dont wanna do that! Just got the leak plugged! Lol all I need is another one!

DubsJeepSport

I get that purple. I just got done ripping apart my other car to fix a leak. I still don't have the time/money to get that back together. I am in need of a break and a quick fix on this one.

fishtaconc

50/50 mix of vinegar/water will help with crud in the cooling system

MilwaukeeJeep

I replaced the heater control valve and that must have been it. I don't think it was opening all the way, something must have been obstructing the movement of the valve in the old one.