Hi all,

I was tinkering with the XJ the other night and noticed this in the coolant:


This doesn't look normal.
I have the closed Renix system and I've been searching the forum all day, not seen a single picture if all cases looks like mine.
She runs fine, no overheating, no leaks. She did boil over the other day, noticed a big puddle when I came from the store. But I also found that it was leaking under the reservoir with a bad clamp.

Worth mentioning, the water is pretty much brown. Look at the reservoir and you'll understand.
But why the bubbles? Bad HG?
Had some white puffs of smoke, but it didn't smell sweet, and they also went away after a few minutes so was probably water in the exhaust. It's been raining a lot the last few days.

Suggestions?

 

I'd start with a coolant flush. Who knows what kind of additives/contaminants are in there.

 

Good idea.
I just gotta figure out how to do that

Got no flush kits available over here, just so everybody knows.

 

do you have a garden house?

 

That I do have, sir.
I know I can shuve it somewhere, I just don't know where... And which hose to unplug so that crap will come out and so forth.

 

Update: I did the flush according to Hayne's but I couldn't access the block drain plug. However, I got the nasty old coolant out, waaay brown!
Prob rustvfrom somewhere...

Then I followed the book's bleeding process, "add coolant, then let it run til the t-stat comes on then turn off"
Uhm mine boiled over like crazy, spraying water everywhere! It was just above working temp so I believe the t-stat is bad. Right?

 

Anyone has any ideas?

 

Boiling point of water is 212*, if your thermostat didn't open until then it should be replaced.

 

Your bottle/cap is probably bad. More then likely it isnt holding pressure thus causing the coolant to not circulate properly.

that system sucks so bad, after my 2nd bottle/cap replacement i just switched it to the open system, it is so much better!!

 

I dont think it's the cap cause it boiled over without the cap on! So no pressure really...

Unfortunately I dont have the knowledge to change system or time or interest..

 

Right? Cause the cap was off and it still boiled over. Cant be anything else...

 

Well, think about it, with the cap OFF the system cannot pressurize, therefore the system cannot circulate correctly and will start to boil, there is no where for the air to escape so it boils over and out the bottle.

I am not saying your thermostat isnt toast, becuase it very well could be, but seeing it boil over and come out the cap you are pretty much garunteed to have a bad cap/bottle now also.

The cap needs to be on for the sytem to work right, if it has a crack or doesnt seal right, the system will never be right and you will overheat over and over.

Pull the tstat out and check it in some hot water, see if it opens, or if it is stuck open when you take it out, then obviously its bad. Wouldnt hurt to change it if you havent in a while anyways, its only around 8$.

 

I should also tell you that with this system, after you fill it you need to burp it to get all the air out, i do this by jacking up the back end of the jeep about a foot and start it, unscrew the temp sending sensor on the rear of the block a little to release all the air out. (Caution, make sure the jeep is cool when you do this, it will sputter some fluid out and you dont want to burn yourself.)

when you fill the engine with coolant i always do it from the bigger hose off the thermostat housing, hold it up high and pour until you get some out of the tstat housing and then put the hose back on! wahlah!

I fought that stupid closed system for 2 years, finally converted to open where it burps itself and havent had another issue!

 

Head gasket very possible .....

 

You sure make a good point with the pressure. But for history purposes, she hasn't been boiling over at all at the cap/bottle. There was some coolant by the fans yesterday, but all dry by the cap/bottle. So I feel confident that those two are fine. Can't see any cracks either, even had the bottle off the other day to clean it so.

But the t-stat should work without pressure, and that's why Im thinking it boiled over cause it never opened when temperature were right.
Is this a wrong way of thinking or does it work like this? I'm pretty newb at cars/engines so, trying to learn.

T-stat wasn't too expensive, gonna get a new one today if I can find one and then replace it, flush the radiator again and try it once more.

Thanks OleBlue!