Coolant loss, bubbling coolant

If you pull the plugs and look at them, a plug that has seen coolant will be super clean.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Thanks Mike,

I pulled all the plugs and they all looked clean. I replaced them around a month ago. One of the plugs had more carbon on the outer rim then the others but not a noticeable difference on the electrodes.

Mike Roma> If you pull the plugs and look at them, a plug that has seen coolant

I mean a leak into a cylinder will make the plug look clean like new.

You can have leaks into the exhaust. Usually you can actually see smoke coming out the rad or smell it when that happens. You also might be able to feel puffs of compression if you put your hand over the rad opening when it is first going.

I had a head gasket go like that an the coolant foamed up like a wash mach>

snipped-for-privacy@gmail.com did pass the time by typing:

Gonna give you another thing to look at. Especially if you don't have water in the oil or a grey cloud following you, I'd suspect a leak in the overflow system.

The coolant system in your jeep is a closed/airless system. i.e. the coolant should be even with the radiator cap when you take the cap off a cold radiator. The overflow bottle should have a low and high mark. With the engine cold the coolant should be about in the middle or just a bit below the high mark.

What can happen is a crack in the overflow bottle or in the hose that runs to it. As you drive the expansion drives some coolant out and it dribbles down on the road. When the engine cools down air (rather than coolant) gets sucked back into the system.

As air gets into the system this problem gets progressively worse.

You check the overflow bottle by filling it up. and looking for leaks Generally what ever is remaining indicates where the crack is. The hose is just a matter of looking.

Thanks for the great ideas. The coolant is not bubbling like the picture. It is more like a burp.

I will double check the over flow bottle and hose. I can go through a liter of coolant in around 1.5 weeks.

There definately are no visible leaks on the over flow...what I mean is nothing is leaking on the ground.

DougW wrote:

Just checked the coolant bottle and hose. There are no visible leaks. I took them off, filled with water, pluged the hose and upper outlet and blew in the top. Nothing came out.

Any other ideas? I'm looking for all options before I take the head off.

bbb wrote:

bbb did pass the time by typing:

Possibly a teeny leak in one of the hoses that's only spraying when the system is under pressure?

I had one like that too. I was losing coolant but could never figure out where until I noticed my battery was 'wet' one day. It was a pinhole in a core that finally got big enough to make it to the battery on the firewall. Before that it was just spraying on the ground under acceleration when the pressure was highest.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

I had one too on a Chevy truck. Got so frustrating that I took it to my buddies shop where he specializes in cooling systems and AC. The thing would hold pressure with a pressure tester, and he even put the UV dye in the coolant, but still nothing. Only after letting it run for about 2 hours did it start to leak. It sprayed a stream about the same size as a piece of thread from the upper hose.

Chris

I had a similar situation on my 02 tj. 4L. I never noticed the bubbling in the coolant, but I also never checked because mine occurred at 20k miles and I brought it back to the dealer.

Like you, I did not see any leaks, no bubbles in the oil, no smoke; nothing typical of a bad headgasket or cracked head. I think I was losing coolant at a similar rate that you are.(that was 2 years ago, I cant quite recall the exact loss rate.)

I don't want to ruin your day, but mine was a cracked head.

I hope yours turns out to be a gasket or something ridiculous.

Ditto on my '01 XJ. Coolant loss was cracked head. The engine only had 29K miles. So warranty covered it.

Brian

you can guess all you want but a cooling system pressure test is what u need to put on the vehicle and look for leaks this way u can verify any external leaks

there is a kit available now that u can add the engine coolant to and mix if the head gasket is leaking and combustion chamber chemicals into the coolant it will show up and to what degree. most well stocked parts stores can get it how long ago was the water pump replaced?? could be the wrong one if it was recent there is 2 versions that spin in opposite directions

Mike Roma> I mean a leak into a cylinder will make the plug look clean like new. >