i was working that exact avenue today. I found a lot of air when i pressured the system and loosened that hose. I will try it , I have still no heat unless I reve the motor. I also got the fans to kick on today. The hose by the heater valve/oil filter is where I have been "milking" I was thinking of getting a brake fitting and reverse fluid injecting it thru the head(blocking the upper hose) . Dang s2's are a pia...

 

I just had this problem a couple weeks ago. It was overheating, and it seemed that the fans weren't coming on even though I didn't mess with the fan switch and they were fine before I drained the coolant. I was all ready to start tearing the system apart, replace the thermo, replace the fan switch, etc.

The whole problem was because I was trying to bleed the car with it jacked up in the front. I tried it like this for an hour. Finally, we thought to lower the car and try bleeding the cooling system with the car flat on the ground. That was all it took. It seems that air was becoming trapped in passages when the front end was lifted.

 

Well, another update. I took it for a short road trip tonight (about an hour at highway speeds). When I first started out on the highway, I watched the temp gauge slowly rise to just below the third mark and just stay there. There was no heat and I was running at about 70 mph. It stayed like that for about 20 minutes and then when I was turning onto another highway, I nailed it pretty hard on the interchange and within 10 seconds the heat came on and the temp dropped to just above below the second mark. The second mark is normal for me this time of year on the highway. So, about 10 minutes later I felt the heat slowly go away but the temp is staying steady at the second mark. This was how it was for the whole trip back even at idle unless I nailed it up to 4-5K rpms and the heat would come back for a little while.
I give up...I don't know what else I can do to get the air out.

Maybe I can make a fitting for the filler neck and throttle body hose and hook them up to a high speed pump with about 60psi?







Actually..... I wonder if that would work...hmmmm

~Clint

 

1) Were you bleeding it with the car on level ground?

2) Are you sure it's air and not a heater core problem?

 

Have you done a leakdown test or had the coolant 'air' sniffed for exhaust gases?

 

If you are having this much of a problem with bleeding the system then you have problem somewhere else.

 

mine is definetly not a head gasket, the car has great compression, leakdown of less than 6%, perfect plugs and no leaks...hold 10psi all night. when you pressure up the system, the level goes down. I know that the system is tight. I am not getting water from the pump..I am suspecting the new pump installed by the last owner is a bad one, the impeller is spinning on the shaft. My car doesn't use any coolant. The s2 is much different than any 8 valve car because it has so many different possible coolant paths, and there is no real way to pour directly into the top spout.

 

I should be happy now with my S, I've never spent more than 15 minutes bleeding mine.

 

I have great compression, all cyl. 200+, I haven't done a leakdown. When I pressurize the system it holds pressure. Like Nick, when presurized, the coolant level goes down. I've bled the system probably 20 times using different methods, the air is still there.
Right now, the car does one of two things, either it will drive fine and everything works or it will want to overheat. For example, all day yesterday I drove it around town, no problems. Tonight, I am driving up to the store....overheat. I can hear the air in the heater core boiling when this happens so I know there is air in there, I just can't get it out!
One thing I noticed, my heat is scorching when it is wanting to overheat, you can't hold your hand to the vents...it is that HOT!

I'll keep trying to bleed and test other areas...that's all I can do. I've been thiunking maybe the heater core is clogged, but I have no idea how to check it. Advice anyone?

~Clint

 

Just remove the heater core and bypass it with a hose...then see if it overheats. If all is OK with the heater core bypassed, you need a new one...or see if you can repair yours.

 

mine doesn' overheat, I actuall drove the car home from ohio in september and it ran perfect, parked it on a hill (facing down) and when i got to it a month later...no heat

 

How can I test the waterpump to see if it is bad? No leakage..but maybe the bearings or the impeller?

What about blockages, what are the signs?

Can I measure the pressure from the waterpump?

Is there anyway I can INCREASE the pressure to force the air out?

I think I am going to try and replace the waterpump unless I can rule it out. So far, my radiator cracked, rad. cap was bad. I still have air in the system and intermittent overheats so......what the hell happened in the cooling system?

 

Pull the plugs and check for wetness or one(s) that is really clean.

Then pull the DME relay (cut fuel) and crank the engine. Whether or not coolant flies out will be an important datapoint.

 

I'd put as much coolant as you can in -- fill the reservoir -- and then pressurize it and check for leaks -- check around the heater core and for leaks under the car. If the level goes down, fill it again and pressurize it again. The coolant has to go somewhere. When coolant gets out, air gets in. If you find no leaks, then I'd pull the spark plugs and see if one or two are shiny -- like they've been steam cleaned -- that would suggest a bad head gasket. A compression test will not always reveal a leaking head gasket. After trying 20 times to bleed, you are either the world's worst bleeder (unlikely) or you have something else wrong.

 

well, my car will and does hold 10psi on the tester for as long as it's on there, I am leaning to a bad impeller on the pump(spinning on the shaft) but it doesn't even come close to over heating. oddly if i squeeze the hose by the valve, it feels empty. i wonder if a loose fitting t stat would make it hard to bleed. I run the car, and i see no fluid loss, it is the darndest thing.whe I pressure the system, the level goes down signicicantly, but when i release the pressure, it goes back to the same level as before it was pressured. I have filled the core from the top rear of the head...I am baffled honestly, I have worked on cars a long time and never saw this happen, I am next gonna vacum it down to pull the coolant thru.