Pretty good actually. Sorry I didn't post the followup.

I replaced the rad cap: that stopped the boil over in the reservoir (I assume since the old cap wasn't holding pressure, it was allowing the water to boil at 212.)

As it turned out, the PO had 100% water in the coolant system...so all that crud in my system was parts of my radiator and water pump I suppose.

I had the system flushed several times, replaced with a 50/50 mix. The water pump still looked ok surprisingly, it was only about a year old, so I left it in there for now, same with the radiator. Though, I suspect the radiator will need to be replaced sooner rather than later.

Since doing this, I tried the same hill, under nearly the same conditions (the outside temp was about 5 degrees cooler than before) and the Jeep performed great! It never got above 210 and I drove it straight up a mountain.

I don't think I damaged the engine from these 2 overheats luckily, and I'm keeping a close eye on the coolant system from now on.

 

Also, forgot to mention, I did replace the tstat, with a 195 failsafe version. Also, replaced the upper and lower hoses on the radiator. The old ones where completely full of gunk.

I'm actually surprised the system was keeping the XJ cool under normal driving conditions, it was completely full of sediment and only comprised of water.

 

Just goes to show how strong these engines are. Awesome work man glad its running good for you now. I need to flush mine sometime, doesnt look bad but it couldnt hurt.

 

and a good time to mention this is why you only use bottled distilled water to mix your coolant, and or buy the more expensive 50/50 at the store. tap water is full of iron among other things that lead to deposits in the cooling system

 

FWIW, the Prestone jug does NOT say "distilled water must be used". I would think tap water would be fine, since it's clean/drinkable. Even if distilled water is used, things will rust/corrode when the antifreeze/coolant/corrosion protection levels fall/weaken.

 

you don't see the benefit of using water with reduced or no hard iron, ash, chlorine, lime or flouride?

okay.. just realize what you're doing to save that .99 cents a gallon

depending on where you live in the country and the quality of water it may be okay and it may be a very bad idea

 

All I said was, I don't see the "absolute must" use distilled water.....neither does Prestone. The OP can decide if .99 cents is a deal breaker or not. Absolutely must use distilled water is misleading info.

Absolutely must maintain adequate corrosion protection is a fact, whether distilled water is used or not.

 

radiator manufacturers will say not using distilled water will void warranty...

 

I always recommend distilled water in the cooling system. Cheap investment for the benefits received.

 

Replaced our rad last summer.....saw nothing with the new rad instructions saying anything about "must use distilled water". I'm not saying distilled water is not a good idea......all I said was the Prestone mixing instructions don't say distilled water must be used to mix. Kinda like the manual not saying synthetic oil must be used.....would they prefer u use it, hell yes, but it's not absolutely required. Let's move on, ok?

 

yeah i did mine not too long agoas well and agree with you on the distilled water, although the rad i put in had a sticker on it saying use only distilled water and another saying flush system before install or warranty void...not sure what the instructions said because i never opened them

 

you are one odd dude

 

I agree with u on that.....you're not the 1st, probably not the last to tell me that.

I disagree with u regarding it being an "absolute must" to use distilled water. Is it preferred/a good idea, yes.......doom/gloom if u don't, NO. What dooms a cooling system is owner neglect/letting corrosion protection deplete. Again, all I said was, Prestone doesn't say on it's jug must use/mix with distilled water. That's a fact.

So, posting a simple fact makes me odd?....., if so, my bad......just a factual kind of guy, I guess.