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Brownish antifreeze after road trip?

BillR

Toy Jeep driver!
Location
Flagstaff, AZ
The coolant in my overflow bottle is now a brownish color. It was green before I left on a 1500 mile trip last weekend. The engine's got just under 50K miles on it.
The oil looks fine, as does the ATF. Is the coolant just old, or did I knock some junk loose in the radiator during the freeway miles?
Ideas??:confused:
 
UPDATE...
I changed out the antifreeze and flushed the system. There was about 1/2" of sludge on the bottom of the overflow bottle.:(
I take it that this is a bad thing...:confused:
 
sounds like rust? I might be going out on the limb here, but if your cooling system wasn't getting hot enough to open up the t-stat and take the long way around before and on the trip it got hot enough to do so.... it might have picked up all the crud that was accumulated there in one shot....

Kejtar
 
Did you use your heater on the trip? You could've had a good amount of sludge in there that got let loose into the system. I'd do a full flush of the cooling system, including the heater core.
 
First let me ask have you been doing all the preventive maintenance on your vehicle. You know checking the coolant level on a regular basis and topped off or have you just used the vehicle and figured no need to check the coolant?

Also have you been keeping the coolant in the overflow bottle at the "full cold" line when the engine is cool or have you driven with the overflow tank empty?

I have read stuff from GM with vehicles using Dexcool and now GM recommends dealers fill the overflow bottle to the "full hot" instead of the "full cool" line when service is done on a cool engine.

If you have been running the overflow tank low or empty then you have had air in your system, that would explain in part why you have rust.

The drive you took was a good thing, flushed out some bad stuff.

I had a buddy whos family moved from SF, CA to St Louis, Mo in the early 80s. They drove their cars to missouri. He told me they were perking out rust and sludge out of the engines. They had a 65 chevy which they had added a coolant recovery bottle to. They would climb these big grades and the coolant in the recovery bottle was perking and there was a 1/2 to 2 inchs of sludge in the bottom. They had it happen several times but finally the car "cleaned" itself.

I take it your XJ does a lot of trips less than 30 minutes so it gets warm but not totally. I think you just gave your XJ a good run and if you travel again to that place check your coolant again you may of had more brown in the coolant.

Coolant does lose it's anti corrosion addatives over time. I know alot of people who change coolant every 2 years when using the green coolant.

I think part of the issue may of been you changed the way you drove the XJ. The engine is use to what every you normally do and then you put it on the road for 20 to 30 hours and it was running fully warmed up for 8-12 hours vs less than a hour.

Just brain storming.

Martin
 
I think I should take my truck on a long drive now... question: I had a slight coolant leak issue a little while ago and every now and the I would have to fill the overflow bottle up a bit, sometime with water (tap) and sometime with coolant (always green but not always the same brand). So now I'm pretty sure my mixture is not 50-50 and not same water or coolant... is this damaging to do?

- Thanks...
 
My 92 FSM says to run as close to 50/50 antifreeze mix as possible, but NO MORE THAN 68% glycol, due to cavitation problems in the cooling system at higher concentrations.
 
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