Jeep Wrangler Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter #1
i have seen people on youtube back flush the heater core! any opinions on this..would try this myself but dont have access to a hose right now...good ole northest winter. and when you ask a shop to do the 5 minute job they want to flush the entire system and charge me 90-100 bucks!
 

·
Registered
Joined
·
44 Posts
have you changed thermostat yet? If not, i would try that first...If that dont fix it then sounds like you are gonna have to find access to a hose or pay a shop to do it..it really isnt hard to do...i did on a few autos...the way i did it was take both hoses off heater core and put the hose to one of them and flush it out...takes a couple minutes and done...
 

·
Registered
Joined
·
92 Posts
Make sure to put a195° thermostat in it. Mine had a 180° and never seemed to get Jeep toasty enough. I have to turn it down now because it gets too hot with the 195°.
 

·
Registered
Joined
·
8,968 Posts
I would make sure you have the correct thermostat first. If you do, you're probably looking at a bad heater core. You can try flushing it first which might buy you a little time but if you develop any leak at all in the passenger side compartment that means the heater core is shot.
 

·
Registered
Joined
·
717 Posts
to check the thermostat & core

You can do the old "farmer hand check". If you have the 2.5L engine and it is cold outside (below +10) the heater is all the engine needs to keep cool below the thermostat setting, no matter what it is. If you are running an engine fan that is contributing to the problem.

To check the temps by hand, start the engine and let it warm up with the heater off. It will warm up faster that way. It will warm up to the thermostat setting (guage may not be correct) and then the stat will open. That will let a rush of cold water in from the radiator and that will drop the engine temp and the stat will close, at least partially.

When it is getting up to temp before the initial opening of the stat, put your hand around the upper radiator hose, close to the engine but away from the fan. You will feel the water temp go up, then go down.

Keeping your hand on the upper radiator hose, let the engine come up to full temp. Maybe have to have someone ride the gas a little. Once it is up to temperature you should be able to barely hold the upper radiator hose. If you can hold it tight, then the stat isn't coming up to temp enough. Actually, once you get used to it you can tell almost exactly what the temp is by how tight you can hold the hose.

If the stat is working right, take ahold of the heater hose that is going TO the heater core. That should be as hot, or hotter, than the upper radiator hose. If so, then you are getting flow to the heater.

Now the part that tests the heater core. With the fan off, take ahold of the outlet hose FROM the heater core. That should be almost the same, if not THE same as the inlet. No air flow through the heater core means little heating and little heat loss from the coolant flow.

Now turn the heater fan on full blast. Again, hold the outlet hose. You should feel a difference, but not much. If there is full flow then there will be little actual heat loss from the coolant going through the heater. If the flow is restricted, then the flow will be slower and less, more heat will be extracted, and the hose will be cooler. A cooler outlet does NOT mean a more efficient heater core, it means restricted flow.

If the stat is open, then you will likely have to have someone run the RPM's up to about 1200-1500 to get the water pump up to full flow of the system.

If you aren't sure about "feeling" the temperature, check someone else's rig that is heating properly. Get a feel for what it SHOULD be like. All these modern gauges are great, but God gave us the most useful ones anyway.

If you notice, when you pull up to a stop sign and idle the heater temp will go down. This is mostly due to the decreased flow from the water pump. If you let it idle only, in really cold weather, the heater won't put out as much because the heater is enough to cool the engine and the thermostat is actually taken out of the system, as is the radiator.

Hope this helps.
 

·
Registered
Joined
·
23 Posts
Discussion Starter #6
the previous owner did the thermostat. not sure which one he put in it but i did feel the hoses today and they both were hot and warm but i had a small puddle of green anti freeze on my passenger side floor mat!!!!! what exactly does that mean? bad heater core? if so, what does this job entail so i can go to the shop with a little knowledge. you know how somw shops like to exaggerate things to collect more dough! thanks for all the info guys!!!!!!
 

·
Premium Member
Joined
·
546 Posts
"fivestar9968",

Removing the heater core is simple. You can do it easily, even if you are new to the "mechanical field." I did it today to my 1992 YJ and it was out in less than 30 minutes. If you want to do it, let me know and I will be happy to help you. The hardest thing is removing you battery tray and draining your radiator. After that is done, it is simply removing nuts from the engine compartment that hold the heater core assembly to the firewall (on the other side of the firewall, inside the cab).

I don't know what the mechanic labor list is for this job, but it probably is a lot. You can do it and learn about your jeep in the process. I would suggest you take a lot of digital photos so you can see how it goes back together when you are ready.

Many people want to either flush out the heater core or replace it. If you are leaking on the inside of the passenger compartment (cab), you need to replace your heater core. There are no hoses that run inside the passenger compartment on a YJ. Your heater core has a leak in it and it has to be replaced.

Take care,
 
1 - 7 of 7 Posts
Top