1995 Chevy Cavalier Overheating and fan isn't running

I see a lot of naysayers online who have never actually tried it, and a number of people who have tried it and claim that it has worked for them, so I think it's worth a shot. :)

I'm wondering if this leak is caused by the mechanic in 2006 not replacing the torque-to-yield head bolts.

I guess if you want something done right.

This page says it's actually unlikely that a pressure test will be conclusive for a head gasket leak (as opposed to some external leak) because of the much higher pressures involved in pushing exhaust into the coolant, and because gases are molecularly smaller than coolant.

In fact, now that I look at it, this pressure tester doesn't have any kind of threaded attachment for going onto my recovery tank. :(

I should have confronted the guy about it as soon as I noticed, but I figured he knew more than me.

Would it be stupid to try to tighten the bolts more now? Would probably break them or something, right?

Oh, ok. So when the metal expands it opens the gap bigger? Seems like it would have the opposite effect.

And I'm not going to cause damage to the aluminum head by unscrewing the plugs while it's hot and expanded, am I?

Indeed, the pressure tester doesn't fit, so I gave up on that. My symptoms sound exactly like a combustion leak, though, so I'm just going to assume that's what it is.

Also I was reading that a block tester would be better for combustion leaks, and is also available at Auto Zone

but I figure it would be better to do that *after* pouring this stuff in, to see if it actually works? So I just dumped it in. I took off the upper radiator hose with a bucket pushed underneath to catch the coolant, but NOTHING CAME OUT. :( Just some drips from the engine.

There was coolant visible in the hose, though, so it wasn't completely empty. You're supposed to put the stuff directly into the radiator or upper hose, so I let some coolant out the stopcock to make room for it in the hose. The coolant that came out did look a little orangeish/brownish, but also had black dust in it. The black dust sticks to a magnet, so it must be rusting from having air in the system? :( I don't remember seeing much rust dust when I drained it and flushed it over Christmas, so I guess it's been getting worse.

So I poured in the Bar's Leaks Head Gasket Fix, which doesn't require you to drain the coolant first. It has copper-colored sparkly particles in it, which I suppose is pixie dust? :) It's a little viscous. I put the hose back on and filled up the recovery tank, opened the bleeder valve, filled up the tank, etc.

Then it said to idle the engine for 15 minutes, so I did. The thermostat didn't open fully in 15 minutes, though. I'm not sure if it's supposed to. If it is, the instructions should have said "until the thermostat opens" instead of "for 15 minutes". But I'll follow the directions and see what happens. I'm waiting for it to cool off, then I am supposed to top it off and drive around like normal. I emailed back and forth with the company and they swear that people have had success with this stuff and combustion leaks.

"If you are losing coolant, but there are no signs of leaks, you could have a blown head gasket. The best way to test for this problem is with a combustion leak test on the radiator. This is accomplished using a block tester. This is a kit that performs a chemical test on the vapors in the radiator. Blue tester fluid is added to the plastic container on the tester. If the fluid turns yellow during the test, then exhaust gasses are present in the radiator."

"A block tester, often called a combustion leak tester, is placed in the radiator filler neck. The engine is started and the test bulb is squeezed and then released. This will pull air from the radiator through the test fluid. The fluid in the block tester is normally blue. The chemicals in the exhaust gases cause a reaction in the test fluid, changing its color. A combustion leak will turn the fluid yellow. If the fluid remains blue, there is no combustion leak."

The accounts I saw said the stuff worked within a few minutes, and it hasn't worked for me after a day, so I guess it's not working? I'll give it a few days, maybe this stuff works differently because it is allowed to mix with coolant? But I'm not optimistic.

After driving it today, I opened the bleeder valve while the engine was still running. A little air came out, but then coolant. Then I shut down the engine and did it again right away. This time lots of air came out. So it's really only pushing air into the coolant when the engine shuts down. What would cause that?

It seems to increase a lot in pressure, though. When I tested it with the cap off the recovery tank, the level became steady and stayed there for a long time, and then when I turned off the engine, it suddenly increased and surged up over the top of the tank. Like it's only leaking into the coolant right when I shut it down.

Also, even after I bleed the air out at the bleeder valve, there's still gurgling in the heater core. Does that valve not get all the air out?

Alright. Now I have the block tester, which is a little clear tube and you put pale blue liquid in it and then suck air into the tube from the cooling system. If the air has exhaust in it, the liquid changes to yellow. I'll have to do it tomorrow during the day.

In the instructions, it says to identify the cylinder by running the engine with one spark plug wire removed (and purging all the coolant between tests). I didn't know you could even do that.

The fluid did not turn yellow. It's very pale blue, though, so if the yellow is pale too it's hard to tell. But it sure looked blue after I tested it. Then I put the tube right near the tailpipe and it still stayed blue, so I don't know what's up. I might try again.

It's pushing coolant out even more now than it was before, I think, and it looks kind of brownish. :(

The pressure tester I borrowed didn't work. The block tester I borrowed didn't work. The Head Gasket Fix apparently didn't work (though they say it can take up to three weeks), and now it's having trouble starting.

I took it to a mechanic. They'll look at it tomorrow morning and then ask if they can charge me incredible amounts of money to fix it.

They say it's definitely the head gasket ("the corner under the thermostat housing - that's the corner that always goes on the cavaliers").

$950 to fix it for real. :'(

He agreed with me that it failed because the previous mechanic didn't replace the head bolts. He even said they were "loose"!

Now I wonder if I could have "fixed" it just by retorquing the bolts.

I guess it's good that I got it fixed for real, but ohhhhhhhhhh $1000 hurts.

The car's been misfiring and idling poorly ever since I got it fixed. This isn't just the computer relearning, is it? I've driven it 40 minutes a day for a week and a half.