NickG

My wife has a 2001 Cherokee Classic with 160,000 miles on it. It knocks quite a bit until warmed up, but it has been doing that for about three years.

Her heater core and evap core are useless due to the mud in the coolant that the casting process of these engines create.

I want to get her heat going for this winter, but I don't want to put $1100* into this thing just to have it gunk up again. She's been through three radiators in about four years becasue of the situation. other than that, this thing is in better than good condition. NO rust and a solid underbody. 4wd system still works flawlessly. Engine has plenty of get-up and go.

So I'm thinking about fabricating a coolant filter. ?? Picture a heavy duty plastic bottle with a screen seperating one side from the other. Run a hose in, then out the other side just before the heater core. Now and then, take the jug out and clean/replace the screen.

I know
i have over-simplified this, but really, why would this NOT work to keep clean coolant going into the cores while trapping the elements that creat the thick "mud"?

Thanks!

*I say $1100 because I am not doing this job and would have the evap core done at the same time. This was the price I was quoted.

UserID6095

First before we get into adding an unnecessary addition to the cooling system that would restrict flow more than anything.

Have you ever had the cooling system completely flushed? The brown 'mud' you are talking about is from poor maintenance and should be flushed out not filtered out.

Edit: Just to rule out other issues, are you losing coolant? Coolant in the oil? (And for spell check, lol)






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xjoffroad

x2 sounds like you need to completely flush it.

djb383

Wouldn't it have been easier to have just done preventative maintenance??????? Flush the system thoroughly several times 'til the water runs clear, re-fill with 1 gal straight antifreeze and the remainder 50/50 mixed antifreeze. Formation of brown mud in the cooling system is from pure and simple neglect, it's not a Jeep thing, just a neglectful owner thing. Draining/refilling with new 50/50 mix antifreeze/coolant on an annual basis would take 20 minutes and $10 and probably make a radiator/heater core last for 15-20 years.

NickG

When she had her radiator replaced about three years ago, the place that did the job told her they see this in this Jeep motor all the time. They told her that flushing the system about twice a year is the best way to keep the system clean. This was a reputable shop and friend of her family who had always done the work on that Jeep for her.

After I met her, I took it to my friend's shop to have it flushed. He told me the same thing the other guy said: "I see this all the time with these Jeeps."

Twice a year sounds like a lot, and more than a normal schedule. I have had a whole lotta vehicles and have never once encountered mud coolant, and I have never flushed more than once about every two years. In fact, I doubt I did it that often.

So are you all saying these guys are full of it? I figured if this was the case, this would be the place to find out.

NickG

By the way, the cores are beyond flushing. My guy's shop spent over 8 hours trying to back flush and clear the cores. He was barely able to get some heat in the Jeep, but it is completely disfunctional again right now.

In fact, that was what killed this last radiator. After all the work they did trying to clear it, the radiator ended up leaking within a week.

I'm just trying to get some heat in this thing. Kind of a catch 22. She loves this thing and I think it is worth dropping a new motor in, but after a new motor and cores, we're talking $3000 dumped into this old thing that's worth about $2800 right now.

I dunno. Just looking for suggestions. Thanks.

NickG

Just to say I'm not totally off my rocker, this is from this forum at:

https://www.cherokeeforum.com/f2/bro...-sludge-39293/

kojoff

I had the build up in the coolant system also, but I figured it was from using tap water in the coolant system. Went to distilled water and coolant only, no problems.

UserID6095

Not trying to be **** so don't freak out.

That quote is from the OP of that thread who had the same issues as you. Brown sludge in the coolant is not common for any car/truck/rv/boat. Only common in something that never saw a coolant flush and/or the correct coolant/water mix. Distilled water should be used in a cooling system for this very reason.

There is nothing magical about the XJ cooling system that would create this mysterious brown sludge from normal use and maintenance. It happens from a combo of neglect and using tap water (which has mineral deposits). The reason you still have brown sludge lies in your problem, the heater core is full of it.

If the shops attempt at flushing the heater core was a no-go then replacing it is the only option. It must be too far plugged for normal flushing to clear up. The OP to your thread quote replaced everything to clear this up.

As far as a mechanic who tells you I see this all the time, well guess what? They also see broken cars all the time, are paid to fix whats not working all the time. Who takes their ride to a shop and says 'Hey, can you fix whats not broken for under $500?'

Did your wife own this XJ from day one?



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djb383

I say they are full of it........twice a year, now that's blowin' some smoke up the wazu. Jeep 4.0L are old school cast iron blocks/cylinder heads just like old school Chevy's, Furd's and Chrysler's with cast iron blocks/cylinder heads. Cast iron rusts if neglected and not protected. Aluminum ain't no better, it just corrodes rather than rusts but what's the difference. Like I said, it's not a Jeep thing, pure owner neglect thing. The two main reasons I bought our '98 XJ this past December......

NickG

Eh, she bought it from a rental company with about 10,000 miles on it. She probably did very little beyond oil changes.

We'll get some new cores in it and flush the bageezus out of everything. Thanks all!

djb383

To flush the block/head, use a garden hose and squirt water in the t-stat housing where the heater hose attaches and remove the rad hose from the water pump. This way water will flow thru the head, then the block and out the water pump and not flush crud back into the new rad or heater core. One of these rubber tips/squirters attached to a garden hose works really well.