Grandman

Hi there new to the forum and seeking some help!

I have a 2001 Jeep 4.0L
I fill the coolant reservoir and in less than 30 min run time the reservoir is down at the add mark and the alarm dings. No visible leaks anywhere.

New radiator and cap. new upper/lower hoses. New thermostat and housing.

The jeep runs and sounds good other than under acceleration there is a strange gurgling/bubbling sound behind the passenger side dash panel.

No exhaust smoke except a little when cold.

where could my coolant be going? and whats that sound?!?!

any help/ideas would be great, thank you!

kjc

The 4.0 is notorious for holding air in the cooling system. I put one of those cheap prestone flush 'n fill "t-fittings" it the highest heater hose to 'burp' out the air bubbles. Just add coolant slowly with the T as high above the engine as possible. Those plastic fittings degrade over time and will eventually crack 'n leak, so after you get all the air out, replace it with a piece of straight brass pipe. Or you could buck up and get a nice brass T with a cap.
Hopefully the gurgling you're hearing is just air bubbles, and not coolant leaking into your cylinders Good Luck!

Grandman

I hope not!

I'll try that and see what happens, thanks!

dave1123

Welcome to CF!

This is what I do to get air out of my 4.0. Make sure the heater hose that comes from the thermostat housing goes to the LOWER pipe on the heater core. That way air bleeds out thru the water pump naturally. Take out the temperature sensor on the thermostat housing area of the head and fill the radiator until coolant flows out thru the hole, re-install the sensor, top off the radiator, and fill the reservoir. Taking out the sensor gets all the air out of the head and block. Some of the REALLY old jeep 4 cylinders had a bleeder valve in the thermostat housing just for this purpose.

If it's not air in the system, it may be a ruptured heater core. Then you'll find coolant on the passenger's side carpet or running out of the A/C drain. Here's hoping that's not the problem. Just about the entire dash has to come out to fix it.

Grandman

Thank you for the reply.

I flushed it according to the way you describe and it worked! no more weird bubble/gurgle sound.

Still losing coolant and have no idea where its going though!

I dropped it off at a shop and had them look at it, they cleaned the coolant tank (it was clogged) and ran multiple compression and leak tests.
They say it doesn't lose pressure and compression tests check out.

Any ideas what this could be? it will hold above the low level line for 2 days before alarming low and under visual inspection is low. still no signs of any leaks anywhere.

Could this be a head issues? if so why would it pass a compression check? is that possible?

As always, thank you!

dave1123

Okay, your 2001 still has the 0331 head on it. The 2002 has the 0331 "TUPY" head which was supposed to cure the cracking problem. My 2000 head cracked, but just into the valve passages which created lots of steam from the exhaust and dripping from the tailpipe. They usually crack between cylinders 3 and 4 inside the valve cover and dilute the oil with coolant. BAD for bearings!

One other place it could be going is the water pump shaft bearing seal. The water pump has a "weep chamber" on it that holds about a tablespoon-full of coolant that is allowed to evaporate. When the leak gets to be more than this, it drains into the belt pulley and gets thrown off when the engine starts. I discovered this when we fired up my jeep on the lift to bleed the brakes. When it fired, there was a bunch of coolant that sprayed down the front of the engine, then stopped. WTF??? I went on-line and in the description of the AC Delco pump, they mentioned this weep chamber. AH HAH! Got it!

Check it out.

Grandman

Thank you for the information, I'll be further inspecting later tonight!