Rusty coolant

[03Sport]

Hi-

Jeep was running a bit hotter than normal today, so once it cooled down I checked the coolant levels. Level was OK, but the fluid was full of rusty sludge. I flushed everything out about a year ago when I did the water pump- no rust back then. Should I just flush it really well again, then add some rust inhibitor, or what is the best way to get this resolved?

Thanks-
Brady

 

[LibertyTC]

The best way to get this resolved it through the dealer using their flush machine, not expensive and the proper way to do a flush.
Here is a recent post with good info on flush machine..
Link: http://www.jeepkj.com/forum/f196/so-i-want-flush-my-coolant-system-56395/
Hoat coolant is a reddish brown, is this the coolant u used last time?
I would install a new OEM Dealer thermostat as well.
Hoat needs to be flushed every 5 years.
Hope this helps.

 

[tjkj2002]

if you didn't use HOAT coolant that could be your whole issue.The MOPAR HOAT coolant,Zerex GO5,and Ford's Premium Gold coolant are the only HOAT coolants,all others regardless of label are OAT coolants and do not play well mixed with HOAT or in your cooling system.


Also if you home flushed your system using anything but distilled water you will cause sludge issues since tap water is loaded with minerals that sludge up in your cooling system.Never ever use tap water or bottled water unless it's labeled distilled water.

 

[03Sport]

Thanks for the response- I think it may be too late for that... started it up again later, drove it around the block- now moving up to the 3/4 mark on the temp guage. decided to go ahead and just drain it and do a quick water flush thru the radiator- added just some plain water to fill it up again (temporarily) and to see how it would do. Started it up, still went to the 3/4 mark, and now hearing "thumping" noises in the overflow tank,... sorta sounds like head gasket to me.
The weird thing is, it was totally fine a week ago. no overheating at all. I go on vacation for a week, come back, drive it 5 min to the shop to have them check out a few things- pick it up, and the same afternoon it goes crazy.

 

[tjkj2002]

Thanks for the response- I think it may be too late for that... started it up again later, drove it around the block- now moving up to the 3/4 mark on the temp guage. decided to go ahead and just drain it and do a quick water flush thru the radiator- added just some plain water to fill it up again (temporarily) and to see how it would do. Started it up, still went to the 3/4 mark, and now hearing "thumping" noises in the overflow tank,... sorta sounds like head gasket to me.
The weird thing is, it was totally fine a week ago. no overheating at all. I go on vacation for a week, come back, drive it 5 min to the shop to have them check out a few things- pick it up, and the same afternoon it goes crazy.

That thumping noise is the water/coolant boiling in the engine block due to a air pocket.


On some vehicles the cooling systems are rather a pain in the rear to correctly bleed.1 way that has always worked for me is to use a "no-spill" funnel(google it,there cheap and very handy) and run the engine till it starts "thumbing" (like you described) or over flowing the "no-spill" funnel and I immediately shut the engine off and put the stopper in the funnel.Wait a few mins for the system to start cooling off and remove the stopper(have extra coolant handy) and the system will be under a vacuum and suck coolant in very fast filling all the air pockets.


Granted the KJ with a 3.7 is not such a system,fill via the bleeder on the upper hose(metal part,engine side,8mm plug) so it fills the engine before the radiator.

 

[03Sport]

Thanks for the responses. Pretty sure it hasn't had HOAT coolant in it, and I understand about the tap water- but at this point im just trying to figure out if I have a bad head gasket. If I can keep it from overheating, I will definitely go back in with distilled water and the correct coolant. Think it is too late at this point. Had my daughter rev it a bit and quite a bit of moisture droplets were coming out of the tailpipe. No white smoke, since it's just water in there now. no milky oil either, so it sounds more like a compression breach- still bad news. Guess I'll take it in and have them confirm it.

 

[tjkj2002]

Thanks for the responses. Pretty sure it hasn't had HOAT coolant in it, and I understand about the tap water- but at this point im just trying to figure out if I have a bad head gasket. If I can keep it from overheating, I will definitely go back in with distilled water and the correct coolant. Think it is too late at this point. Had my daughter rev it a bit and quite a bit of moisture droplets were coming out of the tailpipe. No white smoke, since it's just water in there now. no milky oil either, so it sounds more like a compression breach- still bad news. Guess I'll take it in and have them confirm it.

Water coming out the tail pipe is 100% normal,if you don't have water coming out(when engine is cold) you got issues since the combustion process produces water.When the engine is hot and the exhaust system is at full operating temp the water boils off faster then a cold engine/system.


Using a block test kit(Napa has them,cheap and easy to use) will confirm a head gasket(or cracked head) issue.


White smoke is coolant burning in the combustion chamber,blue smoke is oil.