If the coolant/antifreeze is not green and clear, then poor maintenance/neglect are most likely the cause, regardless of miles/age. Simply popping the rad cap and pulling dipsticks can give a good indication of how a vehicle was (or wasn't) maintained. Once a year, it only takes 15 minutes to pop the bottom hose, let the coolant drain and refill with fresh 50/50 premix coolant. Done it that way for many years on many vehicles and have never had cooling system or head gasket issues. Seems to me that owner neglect is the main issue with regard to 4.0L cooling system issues.

We bought our '98 XJ at auction 12/09 and felt reasonably comfortable about bidding on it after popping the rad cap, pulling dipsticks and peeking under the oil fill cap.

 

I have 2 questions:

1. Just replaced my water pump, now I have a significant coolant leak. Having problems tracing it though. Common causes are what, thermostat (pump blew when i was out of town and a garage replaced the water pump, not t-stat)? Hoses are fine.

2. I know "chocolate milk" oil is an indicator of a blown head gasket, but does it ever go the other way where oil gets into the coolant? My coolant was nice and green, but now it looks brown. My oil is perfect. Could it be the new pump is just moving the coolant better than the old pump and releasing some sludge from the radiator and heater core?

 

I got everything with the cooling system all fixed and their are no leaks now. I am having a different problem now though after I have that done. I was driving the truck around and it started to stumble and run very rich. I went home and ran the code reader on my ScanGuage II and it came up with P0171 which means it is lean and I guess the system is dumping more fuel to compensate. I did snag the O2 sensor line pretty hard when I was doing the lower radiator hose but I went and unplugged it and plugged it back in and everything appears to be fine with it. Could this condition be happening because the temperate sensor in the thermostat housing is not reading well enough? I did get some gasket remover on it while I was cleaning it but so far it is reading just fine on my dash. I unplugged both of them and then undid the + battery cable to reset the system with everything plugged back in and the truck ran fine and like normal for about 10 minutes and then it started to do the surging rough idle again but it isn't giving me a check engine light anymore. Anyone have any ideas?

 

My 2001 Cherokee had brown muddy coolant when i bought it is March I had it flushed in July and now (in November) my heat isnt working so I checked the coolant and its brown again. Judging my what everyone is saying im hoping the dealership didnt flush it well enough. I think im going to replace the thermostat and do a thorough flush until there is no sludge or brown color. Any other ideas???

 

And it makes a squeeking noise when i first start it and hit the gas... maybe related??

 

Good plan.

 

Maybe, but most likely a loose belt.

 

since the dead sea scrolls have re-opined thought to comment on that brown coolant. stop leak! any one heard of it? most shops put it in after a flush, take a look at Bars leak silver bottle an you'll see what getting at.

 

I really doubt a few ounces of stop leak (1 bottle) in a clean 3 gal. cooling system will turn the coolant into brown coolant sludge, likes in the pic.

 

there is this flush **** you buy at autozone. let me see if i can find a link.

http://www.autozone.com/autozone/acc...uestid=1453875

looks like this except it says something flush.

anyways i had the same problem. poured the **** in there. drove with it in there two days. flushed. did it again another two days. flushed and put new **** in there. cleannn and greeeeeen

 

ehh not sure. shop i used to work at had this **** you pour into the coolant and it would turn a certain color if the gasket was blown. cant think of the name. id keep flushing and keeping an eye on the oil.

 

The sludge looks like someone went heavy on the stop leak. We had an F150 come into my shop that we had recommended a radiator for on a previous visit. Owner said he'd take care of it himself. Truck came back in on a wrecker a month or 2 later and the owner complaining of overheating after he "fixed" the leaking radiator. Come to find out he "fixed" it by throwing in a bottle of Bars Leak whenever the coolant was low. The ENTIRE bottom half of the radiator was a solid block of Bars Leak, and the rest was the brown sludge like is in your picture. Ended up costing the guy almost $1300 for a new radiator, heater core, all hoses, water pump, multiple flushes, and all the labor... I hate Bars Leak...

 

Sounds more like SFB syndrome was the real problem.

 

what does that stand for lol?

 

Sh_t For Brains.