Ye Ol' Cherokee

98 xj 4.0

weak heat.

tried to backflush according to directions and videos, hoses came off fine, set every thing up, and FAIL!

i put the garden hose up to the heater hose, and it would barely go through, just kept spraying all over the damn engine. some went through the other end, but not much because it was just spraying everywhere. i tried duck tape, tried wrapping it with plastic. no luck. have up on the count of not wanting to soak engine.

what am i doing wrong! please help

Roler

Did you check if both your heater hoses got hot?If not, you most likely have no (good) flow through your heater core and that could explain why you have trouble flushing it...

Ye Ol' Cherokee

they do get got. the upper one gets scorching, the lower one also gets very hot, but not hot enough that i can't put my hand on it. so there is SOME flow, which would explain my minimal heat (pretty hot til its like 50 outside)

CCKen

Don't put too much pressure in the heater core, there's a chance it will rupture. You need to use chemicals to break the crud loose.

There's tons of threads on this subject if you would just search for them. Use Google.

Ye Ol' Cherokee

i have searched. ive read every post about this that i could find. always do before i tackle a project big or small. i am still having trouble, so i post my own thread, hoping to have someone address my situation in particular.

i have only seen people use clr, but that says to not use on aluminum, so im skeptical about that.

new info though, i popped the hoses back off, looked inside. inside of both hoses are rusted.

obviously will need replacement, but can i do the flush first? question for everyone

Turbo X_J

No magic formulas involved with this, if you can't get water to pass through it the heater core is plugged up solid. The radiator might be fubar as well.

DFlintstone

Maybe try CLR or something strong, since you likely need to change it anyway. If it does, indeed do something bad you can bypass the HC until you get it changed. Just a thought. (I'm talking about just in the core, not the engine!)

Btw, I did try CLR on mine since it's never been 100%, it didn't seem to do anything at all. (since it does work, I didn't go really strong with it)

Firestorm500

Get the Prestone professional flush kit and try it.

GenMandalore

What I did was using a funnel, clr, and gallon of distilled water and an empty jug. Disconnect both hoses and on the return hose, pour the CLR into the return and let it sit for about 10 minutes or so. Then pour in distilled water and watch the trash come through. Repeat about 4 or 5 times. On the last flush pour water through until as clean as it can be, connect the hoses and try. Be warned, I did the same thing only to just bite the bullet and replace the heater core.

redmuck

what I did was take the hoses off the core and I had 2 short pieces of water hose clamped to each pipe, other ends have water hose screw on ends,which I screwed onto a couple of washing machine fill hoses that are not being used. so one hose goes into a bucket and the other has a on/off valve that gets screwed onto the water hose. rinse one way then put water hose on other hose and reverse rinse.

DFlintstone

Redmuck, like Ken mentioned, applying home pressure (50 LBs?) to something designed for less that 20 Lbs..........well, that's taking a chance. Again like I mentioned above, if it's toast you can try about anything...you can always bypass the HC and keep on going! ...

JamromXJ

I used my Nail gun compressor and dropped the pressure output to 10PSI. I filled the hose with water, taped the pressure nozzle to the top intake hose with a ton of electric tape to form a best possible seal and applied the air slowly; raising the pressure from 10, to 15, then to 20 until the clog blew out.

Then I did the same in the opposite direction. Back and forth until it totally flushed out.

Bottom line is you can use air, but be smart with it. Start low, and slowly work up the pressure, but not more than 20psi.

Hope that helps,

JR.

Firestorm500

Modern homes have to have a restrictor set at 60 PSI and an anti-backflow valve.

My shop, which is over 50 years old, has 96 PSI pressure.

I could blow a heater core right out of a Jeep.

djb383

The CLR (Jelmar) website says "do not use CLR in a radiator".....the heater core is a small radiator.

DFlintstone

Howdy DJB, been missing you...As far as CLR..lawyers maybe? (it might work, or be helpful, but not be OK to say it? )

Curious about your .02 over here> https://www.cherokeeforum.com/f2/ren...-weird-199792/