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Radiator Flush

MountainGoat

NAXJA Forum User
Location
PNW
Ive done many old school fixes in the past... but this is the first time I have ever tried this. Like many people Ive been fighting with my 1988 XJ's issues on over heating. I wouldnt even have the AC going and the dammed thing would overheat. I thought about getting a better radiator, Aux. Fan, fan clutch, etc...
Scanned thru tons of threads talking about this very problem and what some have done trying to fix it. The other day I was talking with a customer of ours that used to own a radiator shop. I told him the issues I was having about the overheating. He told me to drain the coolant out and put in two gallons of white vinegar and run that for two days. I did a search and found some people have tried this... so I went ahead and tried it....

When I drained the coolant it was the usual green color... I allowed the engine to cool off and then flushed it out with regular water....... then ran some air thru the radiator to get out more water...... Then I put on all the hoses and fill it with white vinegar... started it up and let it run with the cap off the bottle..... allowed it to cool down and filled the bottle up again.... did this till it wasnt sucking in all the fluids....

Then I drove around and ran some errands.... she was running hot as normal.... Drove around most the day this way... then let it sit over night.... drove around half the following day and she didnt run hot at all.... hmmmm?

Went home and allowed the XJ to cool down... then poped the cap and pulled the lower hose off.... the white vinegar went in clear.... after two days it came out black with all kinds of crap... staining the cement... I flushed the system several times... ran air thru it to get out as much water... then added coolant........ also changed out the thermostat and gasket..... replaced some hoses.... Drove around and it was always at 200 now... with AC on in stop and go traffic didnt get above 220 (before it would go into the red)... went back home... now for step two... the PO painted the grill red and also painted the trans and a/c coolers as well as part of the radiator..... I pulled the grill and sprayed some aircraft paint stripper all over the coolers and radiator... let it sit... then applied another coat....... blasted it out with water for about 30 minutes trying to get our as much crap as I could.......

So far the XJ as been running great..... cooling is acceptable and I am happy with the results..... Next weekend I will drain the system again and replace the upper and lower radiator hoses and fill with 50/50 mix so to get out as much of the tap water as I can.... then replace the clutch fan and go to a better aux fan.... maybe off a later model, or just replace it with a 12" after market fan.

I also intend to run hood vents and fender vents to help aid cooling.


Ready for some feedback and suggestions......


Here is a write up I found interesting too... that John Deer Coolant Eye looks pretty cool.

http://www.andersonimprovements.com/hobbies/truck/coolingsysservice.htm
 
I'm thinking you should also check the aux. fan fuse in the PDC box under the hood. Mine comes on religiously at 210 + .

you shouldn't need another fan, if yours is working. If the fuse is good try direct power to the fan to verify its operational condition.
 
That's a fantastic low cost solution. I'm one of those who spent countless hours and $ replacing everything, when root of problem was probably clogged modine radiator that was installed by rad shop. I would have tried a new clutch fan and the white vinegar method in a heartbeat. Make sure you use distilled water with the new fluid mix to prevent any contaminants that could come from your tap water. Test out the new clutch fan before diving into a new aux fan. The new clutch may be the final ticket to consistently cool temps.
 
The aux fan is coming on when it should. I just wanted something more efficient. Which is the best stock fan to use from a later model jeep? I called around today and no one had one that would fit a mid 90's ZJ. Im thinking of using the 12" electric fan to take the place of my old stock aux fan... then replacing the fan clutch and calling it a day. Will run me about 52 bucks for the aftermarket aux fan.
 
’97 and up Cherokees have an s curved fan that is supposed to be the bomb. I’ve tried for almost a year and haven’t found one in a junkyard yet. They do have a different connector than the earlier models so you will have to change that out. As for the after market electric fan, I’d save your money. I went through 2 different after market electric fans and neither one could pull as much air as the factory one. I finally ended up replacing the factory clutch fan with a flex fan. At highway speeds it pulls the same amount of air as the factory fan, but at slow speeds and stop and go traffic it excels. I don’t have problems over heating on the trails any more.
 
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