Coolant burping or Head Gasket?

[allanbegg]

Have a 2003 Baja (wife's daily driver) with 177K miles on it.

I recently took it on a 300 miles road trip and ever since, it's been having problems.

 

I had checked coolant level before going on the trip and had to add some coolant.

Two days after my trip, the wife called in a panic because the car had overheated.

I took a look and thought that the coolant was coming out of the overflow bottle cap.

Or, I hadn't seated the radiator cap properly, when I filled it a few days before.

We checked for leaks (burst hose, radiator, etc.)and couldn't find anything wrong.

I added coolant and sent her on her way. She checked a few times on the way home (about 10 miles) and it looked ok.

She drove it about 40 miles the next day and there were no problems.

The next day, she drove it about 20 miles from home and then called to tell me it had overheated again.

 

I had it towed home and looked for a leak again. Couldn't find anything, but the coolant flow again indicated that it had come out of the overflow cap.

I decided that perhaps the thermostat was sticking periodically and that's why it had worked properly a few times, but then overheated a couple of times.

I replaced the thermostat (with a Stant brand) and filled the radiator with 50/50 anti-freeze and water.

 

The next day, I decided that I was going to drive it and watch the gauge.

(Up to this point, I have no idea what the temperature gauge was doing, as my wife never looked at it)

Drove for about 6-8 miles, and everything appeared normal. The temp gauge slowly came up to normal position and sat there.

Watching very closely, I could see it going up above normal, ever so slightly and then drop down to normal.

Suddenly, the gauge jumped up into the red (within a couple of seconds) but then came back down to normal (in about 5 seconds).

It then went back up towards the red over the course of 10 seconds, at which point, I pulled over and popped the hood.

Nothing leaking and the engine didn't seem to be real hot. Drove another mile to our destination and then let it cool down for a couple of hours.

Drove home and the gauge started to creep up, after 8-10 miles. Got it home and let it cool down.

 

A little reading on the internet and I have convinced myself that it needs "burped".

 

Drove up onto a set of ramps, pulled the radiator cap and let it run.

Was getting air bubbles out of it immediately. Let it run until warm.

Air bubbles are continuously coming out of the radiator. Doesn't matter if the coolant is cold or warm.

It just keeps bubbling. I get a bubble every second or two. Coolant level seems to heave a little and then drop down a little.

Put the cap back on and shut it off. Made sure that the overflow bottle had plenty of coolant in it.

 

Let it cool down for an hour and repeated the process.

I noticed that the radiator hadn't sucked any coolant in from the overflow bottle.

Pulled the radiator cap and let it run.

Was getting air bubbles out of it as soon as the engine was running.

Let it run until warm, bubbling the whole time. Put the cap back on and shut it off.

Made sure that the overflow bottle had plenty of coolant in it.

 

Decided to try to drive it to work this morning. Got about 6 miles, when the temp gauge starts rising.

Shut it down and let it cool down for about five minutes. Drove another mile and it starts heating up again.

 

At the moment, I do not know if I am not burping it properly, or if I have a blown head gasket.

Any advise or pearls of wisdom would be appreciated.

 

Sorry for the long post.

 

Allan

Edited November 25, 2013 by allanbegg

[ivans imports]

blown headgasket welcome to the blow headgasket club have had this senario 20 tims this year it pushes the coolant out becuse cly preshure is 175-200 psi pushing agansit 12 psi rad preshure the combustion leaks into coolant sestem and over preshures the rad cap this is what you are seeing

[ivans imports]

I do most between 135000kms and 240000kms so 177000miles is done perty good.

[idosubaru]

they are not very forgiving with bleeding air but this sounds like it's going to be headgaskets.  an exhaust gas in the coolant test will confirm it if you have any suspicions.

 

those usually leak externally and at the initial onset you can add the required Subaru Coolant Conditioner and that will stop initial leaks.

but if she overheated it really bad (you said  - not paying attention to the guage - engines can not be overheated, bad things happen) then that exacerbates things quickly and could have caused a worse than normal failure.

[allanbegg]

Does anyone know if the Block Tester (available through AutoZone's loaner program) is reliable?

What other method can I use to validate the head gasket as being the cause?

 

Thanks for the quick replies.

 

Allan

[idosubaru]

i would use the stuff that tests for gases in the coolant.

 

if ivansimport says the compressed air works then that's a good option, he does this all the time.

[ivans imports]

It simulates cly preshure and can be left on for long periods of time to see if any leaks. I have done so many I just smell the coolant and can instantly tell combustion in rad has a very distint smell and any oily film / gasy smell in coolant. anyway the compresed air in cly test works very well is a bitt hard to setup but will confirm yes or no if that is problem. I a'm lucky to get 1 out of 200 that is something other than headgasket. Sometimes leaking water pump or rad but rare.