Hi guys,

The temp guage hasn't gone above about the 210 mark. I know from reading the other current overheating thread that the guage isn't the most accurate thing in the world, but - is it possible for it to overheat and still read 210 if it appears to be working otherwise? It's cold when it's cold, gradually heats up to 210 as you would expect it to, and stays there.

However, my overflow tank bubbled over after a trail yesterday, and once before, I could hear it circulating through as if it was going to overflow, but it didn't. Would it overflow without being overheated?

Thanks!

if there's too much coolant in there it can still happen without overheating ...

Maybe more going on here, too. Head gasket leaks can sometimes force the coolant out. Is the stuff fizzy? Like a soft drink?

What happens when it cools off? Does it suck the fluid back down in the overflow? If there's a bad hose between the radiator and the overflow tank, it will be able to push the heated/expanded coolant over to the overflow, but then even a small vaccum leak in that same hose will prevent it from pulling it back to the radiator. So what happens is that you're low on coolant, but the overflow tank is full to the brim.

When the engine is cool, try taking the radiator cap off and looking inside to see your coolant level. If its low, you've discovered the problem.

OK - I just checked it cold and I think I know what happened.

Yesterday, I thought I could smell hot coolant, but the temp guage was at 210. So I pulled over to a station and nothing was bubbling, radiator cap wasn't too hot too touch (though a glove) and the coolant overflow level was at the 'full' mark. Just now, after sitting for several hours, the overflow level is well below the full mark. Took the radiator cap off and fluid is sitting right at the top where it's supposed to be. So it's getting back and forth and it's not fizzy or anything - dirty, but I know I need a flush and fill and that'll happen pretty soon.

Here's what I think happened - I feel a little dumb for not figuring it out immediately, but the bubbling threw me off... I had just gotten through running these camel-backs or whoop-tee-doos or whatever you want to call them. Basically short hills where I let the Jeep take a momentary break from gravity I think I just splashed enough coolant out of the overflow tank to make it onto the fender.

I guess I'm just not used to the gurgling & bubbling that it must be doing in the process of circulating fluid back and forth between the radiator and overflow.

quote:

Originally posted by Iceman:
if there's too much coolant in there it can still happen without overheating ...

I agree, I pay attention to my coolant resevoir and fill it when it falls below the add mark, when it's hot so that should be accurate, but when I fill it, it leaks out within a day or so and the resevoir again, shows low, I guess it doesn't matter as the rad still has plenty of fluid.
It must be ok as it was 115 here today and with the ac running in city driving the engine temp was about 215.