COOLANT IS BROWNISH COLORED

1ST POST !

i have a 2001 jeep cherokee with the I6 4.0 @ 66k miles.

i noticed the fluid in my radiator reservoir tank looked dark. so i opened it up and its a brownish rusty color.definitely not neon green. i also noticed that there is a wet area around where the head gasket is and its towards the back. i pulled the dip stick to see if the oil looked milky but it doesnt and its not over heating or loosing coolant.i even took off the oil cap and looked to see if the oil was milky on the cap and its not.oil level is good too.

i heard that the 01 Cherokee is known to have issues with the head cracking at cylinder 3 and 4 but i also have read that its the engine with out the distributor that that happens with,tjs and wjs. again that is only what i read.

im wonder if i just may need a radiator flush or maybe something is rusting in the coolant system...

also im not noticing any type of smoke out the exhaust.

thanks in advance !

You need to purchase some radiator flushing additive to clean the cooling system. Follow the instructions on the label for the flush additive. Drain the cooling system by removing the lower radiator hose from the radiator. Do Not use the radiator drain petcock valve, it has a tendency to break off. Buy 12 quarts of 50/50 premixed coolant or enough concentrate to make 12 quarts. By the normal green coolant, not the red stuff. Also, buy a new thermostat. Get a STANT premium thermostat or buy one at the dealership. Cheap thermostats often don't work correctly right out of the box.

Search and read about the 0331 cylinder head on the 2000 and 2001 Cherokees. It can crack, but it doesn't happen very often. Cracking of the 0331 head is most often related to abuse of the engine through lack of routine preventative maintenance, such as letting the coolant get old and nasty, or failing to replace the thermostat at the same time as the coolant, every 3 years or 30,000 miles.

Keep an eye on the coolant overflow bottle and watch for a rapid and repeated loss of coolant. Keep an oil on the oil level and watch for any milk shake looking oil.

thanks for the info !

Definitely sounds like time for a flush and new 50/50 mix of coolant.

You need to pull the overflow bottle and wash it out, the flush won't clean it.

XJs 00-01 with the head with casting number 0331 are the weak units. The later heads with TUPY marked on them are improved castings.

Coolant turns brownish rust color after it oxidizes. Its basically a really fancy sugar-water and it breaks down after just a couple of years. It needs to be replaced asap, and you need to start a diary for all of your fluid changes mileage and date.

ehall said:

Coolant turns brownish rust color after it oxidizes. Its basically a really fancy sugar-water and it breaks down after just a couple of years. It needs to be replaced asap, and you need to start a diary for all of your fluid changes mileage and date.

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What is it when it looks like chocolate mousse? Ford F250, 460 engine. It was the worst cooling system I have ever seen in my life. The owner--a commercial truck driver--just shrugged and said "Hey, I just drive 'em." I charged him my special dumb-a** parts and labor rate.

ehall said:

Coolant turns brownish rust color after it oxidizes. Its basically a really fancy sugar-water and it breaks down after just a couple of years. It needs to be replaced asap, and you need to start a diary for all of your fluid changes mileage and date.

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i got the jeep about 2 years ago.ive been regulary keeping up on all the maintenance.i have not changed the radiator fluid at all though. so the radiator fluid is atleast 2 years old.

i wont be able to get it flushed till the middle of the week. is it ok to drive ?

also just for the sake of learning , how does rusty coolant cause a head to crack ? does it block the channels in the engine and cause it to over heat resulting in a crack ?

thanks again.

twistedmentality said:

i got the jeep about 2 years ago.ive been regulary keeping up on all the maintenance.i have not changed the radiator fluid at all though. so the radiator fluid is atleast 2 years old.

i wont be able to get it flushed till the middle of the week. is it ok to drive ?

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I would at least dump it out and run hose water through the system. Tap water is bad for cooling systems but it'll be less harmful than sludge.

also just for the sake of learning , how does rusty coolant cause a head to crack ? does it block the channels in the engine and cause it to over heat resulting in a crack ?

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coolant does lots of different things, for example corrosion inhibitors, which are lost when the chemicals break down

Some winter left, do NOT let it set without coolant if near freezing temperatures. Draining, flushing and refill with coolant all in same maintenance session. Do a search for plenty of info on cooling system.

You can have weak or bad coolant clogging up your entire cooling system and not necessarily loose a head. You can overheat the engine and escape unscathed, or overheat and crack a head or other damage. The 00-01 4.0 heads with casting number 0331 are prone to failing between cylinders 3 and 4 by cracking.

The 00-01 4.0 XJ heads were a redesigned new casting--Chryco screwed the pooch, the casting was bad = cracked heads.

twistedmentality said:

1ST POST !

i have a 2001 jeep cherokee with the I6 4.0 @ 66k miles.

i noticed the fluid in my radiator reservoir tank looked dark. so i opened it up and its a brownish rusty color.definitely not neon green. i also noticed that there is a wet area around where the head gasket is and its towards the back. i pulled the dip stick to see if the oil looked milky but it doesnt and its not over heating or loosing coolant.i even took off the oil cap and looked to see if the oil was milky on the cap and its not.oil level is good too.

i heard that the 01 Cherokee is known to have issues with the head cracking at cylinder 3 and 4 but i also have read that its the engine with out the distributor that that happens with,tjs and wjs. again that is only what i read.

im wonder if i just may need a radiator flush or maybe something is rusting in the coolant system...

also im not noticing any type of smoke out the exhaust.

thanks in advance !

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You the guy from RCcrawler?

FlexdXJ said:

You the guy from RCcrawler?

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yup, thanks for the link...

so its the heat that cracks a head that and the weak spot. where is the stamp so one could tell what head they have ?

ill be doing a full flush at my b laws shop sometime during the next week. rite now though the garage is full.

I battled the same thing in my jeep, i have finally almost won the battle after literally 10+ fully flush sessions. I would get a silt like sludge at the bottom of the overflow, brown or brown/green coolant, and the same silt/mud settling like a paste on the radiator filler neck. If you were to remove the rad cap and stick your finger in the neck (where it is horizontal) you could literally scrape out like a 1/8" of 'mud/silt/sludge' type stuff. I bought it at 130k when it was 10 years old.

At first I fully drained the system, removing both the lower rad hose and the drain plug in the block.(was going to use the petcock but it nearly broke off so i just retightened and left it) I flushed the entire system with hose water for a long time. I did the flush in both directions in the heater core, radiator, the other coolant hoses, drain in the block ect, anywhere i could get the hose i blasted it out. Let that drain, filled with the 5+ hour flush and water, then dumped that,fully filled with distilled drove around for 15 min, dumped that and filled with 50/50 distilled/coolant.

In less than 2 months the coolant was back to its usual self! (barely green/brown, sediment floating in it/'mud' at the bottom of the overflow) So the following times (9+ literally) i just did the hose flush like crazy on it, cleaned out the overflow, always finding 1/2"+ of this mud on the bottom, then i would blow out everything as much as i could with compressed air to get as much of the remaining hose water out of there, refill with distilled water and coolant.

So far so good, i did recently change my radiator and when i changed it the coolant had be in it for about 3 months and still looked pretty good, with very slight sediment still in it, but 99% better than it was at any other time. So after the new rad went in, i did another flush/fill, and its been good (but its only been about a month or so) i think when flushing, a lot of times the radiator holds sediment caked up in it, and is slowly released into the coolant. so it just takes time and lots of flush's an eventually you get it all out.


PS: I heard a really good flush (and cheap) is using regular white vinegar about 50/50 or so with distilled, and running that for a few hours and dumping, dont leave it in too long. apparently it eats mineral deposits if someone used regular non distilled water in it.

vinegar is just acidic enough to eat the hoses. I just use tap water anymore.

yea my radiator fluid is a light clear brownish green. i dont see any sludge but it doesnt mean its not there.

X2 avoid vinegar.

Use commercial cleaner. Rinse flush several times with tap (Fill, Run ,Drain, repeat), then 3-4 times with distilled. I avoid the 50/50 premix due to leftover water in system after last flush. Dump in 1 gallon of 100% FIRST, (check capacity of system for exact amount), then topoff with distilled. Run to mix, then test for % and adjust if needed. (Don't forget the overflow tank)

Lurkers make note: the final mix in the system has to be about 50%-60%. less OR more is a bunch LESS freeze protection. ("See label for details").

well i cant get into the garage till friday to get it flushed. i wont be driving the jeep much till then....

when i got my jeep recently, it had/has a white milky coolant in the presure bottle (closed system). i thought i was screwed. but the oil looks great, no over heating, exhaust looks clean, ect. i have a feeling the prior owner used a flush type product and never finished the process. i did clean out the bottle and added fresh water and of course it instantly went white again when mixed. but it is white, not a tan or even brown. is this a common color for that flush stuff?

2stix said:

when i got my jeep recently, it had/has a white milky coolant in the presure bottle (closed system). i thought i was screwed. but the oil looks great, no over heating, exhaust looks clean, ect. i have a feeling the prior owner used a flush type product and never finished the process. i did clean out the bottle and added fresh water and of course it instantly went white again when mixed. but it is white, not a tan or even brown. is this a common color for that flush stuff?

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did you flush/drain the entire system?

no. not as of yet. the reason i had the coolant bottle off was to remove all the antilock brake system and did a 95 booster/master swap. (worked out great by the way). at the time i didnt have any antifreeze.coolant to replace with. i do now and plan to do the complete flush. i was just wondering if my assumption may be correct in that the white color is possibly comming from a flush product that is still in the system.