We drove from Portland to Ashland and back to Portland. About. 5 1/2 hours one way. I had my boyfriend check the coolant levels and instead of checking it he filled it and overfilled it (I assume). He was driving and all of the sudden heard a noise so he pulled over and saw the coolant expansion tank had cracked. He then changed the coolant expansion tank but it's still over heating and we can't figure out how to burp the tank. When we tried parking on the hill and pulled of that one thing and the bolt (I forget the name of it, sorry) to burp it with the nose down coolant leaks from the front of the engine block

 

That thing on the back should be the coolant temp sensor, and parking nose down sounds right for burping the system, but if coolant is coming from the front I would check the waterpump and hoses. My waterpump leaked out the weep hole till I fixed it and it started after a long freeway trip also.

 

You don't have to do all that. Just leave the cap off, start the Jeep and run it at fast idle until the thermostat opens.

Continue running at fast idle, observing the coolant in the tank. When the spitting and bubbling stops, it's bled.

If it still overheats and overpressurizes the tank, that is one symptom of a blown head gasket.

 

I read it's different with a closed system and you can't just leave the cap off?

Were gonna check the water pump in the morning, but that seems to be where it's leaking from. You can kind of aee it drip down on top of the serpintine belt and down to the front of the block from the water pump. Will change the a belt too since it got wet

 

Would a failed water pump cause more pressure in the cooling system and lead the expansion tank crack?

Also, it only leaks when pointed nose down.

 

It could if it overheated, those crack easy when they are older, especially if overheated, if it leaks only nose down your coolant level could be low. When mine went it would leak after I shut it off once it built pressure.

 

No.

Have the cooling system pressure tested to find the leak.

Also, replace any black coolant tank cap with a 703-1396 cap from Napa, even if yours is new.

 

Two completely different answers. Awesome.

So you're saying it could be leaking simply because the coolant is low?

I'm gonna go ahead and change the water pump in the morning ( it really seems like thats the problem) along with the thermostat and serpentine belt. I'll post back tomorrow.

 

The coolant is low because it is leaking. Find the leak and pinpoint the issue.

A pressure test is the best way to do so.

Don't go too far off on the tangent of burping the system.

 

When we pulled of the thermostat housing and waterpump the gaskets were dust. So we changed those the thermostat and the waterpump. Flushed water through the system, then burped it. It's running like a champ. Temp gauge hasn't budged from 190.

 

See how easy that was.....

 

You've got it backwards.

BECAUSE it's a closed system, you leave the cap off. That's the only way the air bubbles can vent to the atmosphere.

Semi-closed systems vent themselves through the overflow bottle.

 

Leave the cap off on initial fill.

Always use the 703-1396 cap.