I recently changed my oil and topped up my coolant on 99 Cherokee 4.0l. Well I grabbed the wrong bottle of coolant and a splash of mopar orange coolant went into the green in the resiovir. Probably about 2-4 oz made it in before I realized I messed up. Now I'm reading that orange and green will cause gelling... was this enough to ruin my cooling system? It is still running fine and obviously I need to do a flush now but now I'm hearing what sounds like rotor/break grinding coming from the rear of the engine compartment at idle. Maybe gel in heater core...I'm assuming its somewhere near the passenger side/glove box area?

Thanks for your thoughts in advance...

 

If it hasn't been run, you can drain the tank and flush it out and refill it. I don't think it's going to hurt anything since you didn't add much but if the coolant is starting to look nasty, this would be a good excuse to flush the system.

 

Whew! When I read "orange" coolant, I thought you might be referring to GM DexCool. That is the worst coolant on the planet IMO.

 

I did the same thing, Are you sure that is bad. I did not put to much eather and have checked it and it looks fine. I thought is would be good not bad for engine.
Please let me know what you learn.

 

There's probably much better info (as to compatibility) on the side of the antifreeze/coolant jug vs opinions one reads on the net. If a cooling system all crudded up, it's a matter of when, not if, something fails. Postponing a good flush/refill just moves the when date up.

 

If it truly was Mopar coolant, then it was G05 (HOAT). It really shouldn't cause a problem. However, if it was an OAT coolant (Dexcool or most universals), I would be a little more concerned.

 

I think I will flush it anyway, it could probably use it. I'm gathering that this terrible grinding sound is unrelated and just a coincidence? Any thoughts on it? It seems to closely match rpm"s and is sometimes almost non existent and sometimes very loud. Sounds a lot like break grinding when I'm idling.

 

did a flush today but there was red coolant in the resiovir very little !!
add a green on it

 

Take the belt off and run it a few moments to see if the noise disappears. If so, spin each pulley, water pump, etc by hand...see if one feels rough, loose or makes noise.

 

A little coolant mixing didn't cause the noise.

 

Thanks all, the coolant seems OK...still going to flush it but it seems OK. The noise is coming from the AC compressor. When it is engaged it is fine and when the clutch releases the grinding noise happens... now I need to figure out if I want to replace the whole thing or repair it.