I have a 1999 jeep cherokee sport 4.0. I have been having problems with the cooling system getting gunked up. I had the system flushed multiple times, replaced the radiator, thermostat, and the waterpump. The other day it began heating up again and making a rattling noise. I took it to the garage and they said it was a head gasket. Later they told me it was not worth fixing because the motor was junk. They said jeep motors are known for being acidic and mine is rusting from the inside out and that is where the gunk in my cooling system was coming from. But previously when they flushed it they told me it was the heater core. I'm not sure what the problem is because I never heard of anything like this. I would appreciate some advice. Thanks.

 

JMHO, find a new shop. How old is the fan clutch? Any cast iron motor rusts on the inside when the corrosion protection in the coolant gets weak. Drain it, flush it, fill it with fresh/new 50/50 antifreeze coolant. Keep close tabs on the color and drain it, flush it, fill it again with new coolant at the 1st sign of going from green/yellow to rusty/brown. The sooner u change it, the longer u can go between flushes. Read my sig.

 

X2 DJB

 

well, your motor *might* be junk now... but that doesn't mean they're all bad.

I'd say find someone who *wants* to work on your vehicle (the shop you were taking it to clearly does not) preferably someone who knows Jeeps and is willing to flush it out and then see where you're at.

 

I also have absolutely no heat, I just assume its because the cooling system is gunked up but even after being flushed there is still very little heat.

 

More often then not when the cooling system is flushed, the gunk gets in the heater core, and needs to be flushed separately. There are some videos/how to's on how to flush the heater core and/or entire cooling system. So even if its something that you dont want to tackle yourself you can arm yourself with knowledge. The XJ cooling system is just barely up to the task when in good shape, so it is of utmost importance that an eye be kept on the cooling system.

 

good point fish, I didn't think of that. I've run into the same thing, somewhere in my junk box I have a length of heater hose with a female garden hose fitting on one end for just that purpose. didn't use it on a Jeep but on other vehicles. Completely disconnect heater core from rest of vehicle, clamp "adapter hose" on one fitting, if the other one is pointing somewhere you don't want water, get another length of heater hose or garden hose and clamp on that fitting so the outlet water doesn't go on your carpet or whatever, fire that sucker up. If it's completely clogged this may not work well though, domestic water supply can be anywhere from 45-80 PSI and you heater core is probably only rated for 17 PSI or so, it'll either clean it right out or bust your heater core

Good news is that heater hoses are typically either 5/8" or 3/4" which are also standard garden hose sizes.

OP: nother question for you. When your engine was flushed did they pull the block drain as well as the lower rad hose?

 

X2 on finding another shop.

Like has been said, ANY iron block engine can rust if the coolant isn't mixed properly.

As for possibly having a bad head gasket, you can find a shop to fix that for you.

These engines run 200K-300K miles without any major problems quite often. If you fix the head gasket and get the cooling system cleaned out you should have many miles ahead of you.

Best of luck

 

The motor/head (both cast iron) have large coolant passages and many nooks and crannies where large chunks of solid/rusty crap form, when vehicle maintenance is neglected. The heater core and radiator have very small coolant passages. 3 guesses and the 1st 2 don't count as to what happens when large chunks of crap meet small coolant passages.

It's always best to flush the core, motor and rad separate of each other. Remove the heater hose and rad hose from the t-stat cover. Remove the heater hose and the rad hose from the water pump. Stick a garden hose in 1 heater hose (flush), then in the top rad hose (flush), then in the heater hose nipple on the t-stat cover (flush). This way, solid crud goes to the bucket and not to another part of the cooling system.

 

OP, where are you located? You might be able to find someone on here to take a look at it for you.

 

I'm from Rimersburg.

 

PA?

If so post up in the North Atlantic subforum and see if anyone's in your area who can take a look at it or recommend a shop to go to. I'm 4 hours west of you or I'd take a look at it.

 

Well I replaced the head gasket and had it flushed and everything seems ok except when I idle it starts to shake like it wants to stall out. Not sure what this could be.. any suggestions? I'm hoping its something easy to fix..

 

X3 on finding another shop. My 1990 has 260K on the engine and is still a strong daily driver (well, up until yesterday...).

And a backwards flush of the heater core with an air compressor... a bit of a pain to do, but man it works amazingly well. You can find a couple how-to videos on YouTube, but if you want to blow HOT air from your heater again, I totally recommend it. It's amazing how much sludge I got out of mine.

As far as the rough idle now... any other symptoms? Besides replacing the head gasket, did you do anything else?

 

I had the cooling system flushed but that's it. No other symptoms that I have noticed. It just starts to shake when it is idling.