red93z34 Posted April 8, 2003 Report Posted April 8, 2003 Ok I have a 93 Z34 with auto tranny. For the past 6 months my cooling fans have not worked at all, so I put in a new thermostat yesterday and the car gets up to temp and the fans pop on, what a suprise! The car was running fine all afternoon, the fans were working and the temp stayed in the norm, now today it overheats, the fans still come on when it gets hot but when I feel the hose that goes to the thermostat its not hot, I opened the bleed valve and nothing came out, even when it was almost in the red on the temp guage, so I decided to bleed the coolant system based on a friends advice. The hose that goes to the heater next to the master cylinder, when I open the bleed valve when the engine first comes on coolant flows out but when the car gets really hot all that comes out is steam, any ideas on whats wrong? Any help would be greatly appreciated. Thanks red93z34@msn.com Quote
GnatGoSplat Posted April 8, 2003 Report Posted April 8, 2003 Yes, the bleed procedure on these cars is long and laborious. On my Turbo 3.1L, I was able to open the bleeders before refilling the coolant and most of the air actually bled itself out while I filled the radiator. With the 3.4 DOHC, it didn't work like that. I had all bleeders open, but none of the air came out when I filled the radiator. I had to run the car a LONG time before most of the air came out. Anyway, if steam comes out, you've got air in there. Just keep it running and watch that the temp gauge doesn't get too high. Leave the bleeder open as long as steam comes out. Eventually coolant will come out, and don't close the bleeder until a steady stream of coolant starts spewing (keep the reservoir topped off). If the stream is spurting, uneven, or contains bubbles, leave the bleeder open. Eventually most of the air should work itself out. I probably spent 30-minutes bleeding the cooling system on my car before I was satisfied that I got enough air out. Quote
red93z34 Posted April 8, 2003 Author Report Posted April 8, 2003 You did it for 30 minutes? I've been at it 2 days now and its still doing the same thing, once the engine gets real hot all that comes out it steam, if I turn it off and let it sit for 10 minutes and restart then coolant comes out but then as the engine gets hotter it goes back to all steam. And there is still nothing coming out of the thermostat hose. Should I keep bleeding or is it something else? Quote
GnatGoSplat Posted April 8, 2003 Report Posted April 8, 2003 Wow, 2-days? Have you left the bleeder open continuously until the steam quits coming out? It may take awhile, but it shouldn't take 2-days! When I get impatient, I'd help it along by squeezing the radiator hose while the bleeder is open, hold, close the bleeder, and release the hose. That should start sucking more coolant into the hose. This can potentially weaken an old radiator hose though, so do it at your own risk! Also, it's possible that your thermostat is stuck shut. Usually these t-stats stick open, but I would have thought the stat would have opened with 2-days of bleeding. Quote
red93z34 Posted April 8, 2003 Author Report Posted April 8, 2003 Well when the steam starts coming out the temp guage gets in the red zone so I have to shut off the car and start over, I'm thinking about just putting a new t-stat in and see what happens. The one I just put in is the cheap Autozone brand, I have a Delco thermostat coming in today that I ordered yesterday. Quote
GnatGoSplat Posted April 8, 2003 Report Posted April 8, 2003 Yeah, it's starting to sound more and more like the t-stat. I never had any overheating while bleeding the system, so your situation definitely sounds a little different. Quote
hambone Posted April 8, 2003 Report Posted April 8, 2003 i have been told that when i am trying to beeld the cooling sytem to make sure that the heater is on and the blower motor is turned to full... don't know if this will help, but if you aren't doing it, it might be worth a try... Quote
JS91Z34 Posted April 8, 2003 Report Posted April 8, 2003 I do this at work and it seems to work well. What I did on mine was keep the bleeders closed. Chock the gas pedal so the motor is turning 2k to 2500 rpms and wait for the thermo to open. Just be ready with some more coolant to dump in when the motor burps the air out. because it will drop fast!! When the motor does burp it might spit some coolant out with it but it is an effective way of removing air from the system. Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 Got a new t-stat a Hypertech Powerstat 180 degreee and it works fine, ran the car in park for over 2 hours today and it didn't overheat, now i'm just trying to get all the air out of the system. But one more ques, is it normal for the cooling fan to not come on untill the temp guage is near the red? Just wondering because my fans haven't worked since I had the car. But now with the new t-stat they come on when it gets near the red zone. Thanks Quote
gimp19 Posted April 9, 2003 Report Posted April 9, 2003 I dont have a temp gauge but the only time I ever noticed my cooling fans on (w/out ac on) is when my car was on the side of the road overheating. My temerature light came on though. Since I replaced the thermostat I have not had any problems with overheating but I also haven't noticed my cooling fan come on. I know it works though because when I check it for codes with a paper clip the fan comes on. I dont think your car should reach the red zone before the fans come on unless your "coolant temp sensor" is broken. Quote
supreme_style21 Posted April 9, 2003 Report Posted April 9, 2003 But one more ques, is it normal for the cooling fan to not come on untill the temp guage is near the red? Just wondering because my fans haven't worked since I had the car. But now with the new t-stat they come on when it gets near the red zone. Thanks My mechanic said that if the cooling fans were not engaging by 230 degrees, there is something wrong. My car had done this before.. it was eventually traced down to the coolant temp. sensor. I've had to replace that twice on my car within a year. :cuss: Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 Well my temp guage only goes to 220 and they come on way before that, usually right after the needle goes past the last white line it comes on. Quote
supreme_style21 Posted April 9, 2003 Report Posted April 9, 2003 Oh... well mine goes to 260.. I think.. Anyway.. we didn't go by the gauge in the car to determine how hot it was getting. He used some external thermometor to see how hot it was running. Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 sorry I was thinking of a diff car mine does go to 260. Im having trouble with bleeding, I open the bleed vlave when I first start the car and coolant comes out and some spurts of air with it, but when the car gets heated up all that comes out is steady steam, I just had the thing on it and it steamed for about 10 minutes straight, is this normal? And also I hear some sounds like air coming from the radiator cap, could this be causing all the steam? Its the original cap that came with the car. Quote
GnatGoSplat Posted April 9, 2003 Report Posted April 9, 2003 10-minutes straight is not unusual. I've never tried this, but I just all of a sudden had an idea to use some kind of vacuum pump to suck the air out. I don't know if it would work, but the thought just popped into my head. Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 10 minutes is not unusual of straight steam? I'll keep at it then. Thanks Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 also does anyone know about how long it will take to get the air out? and does all the air have to be completly out of can some stay in because now I notices when I have the bleed closed after the cooling fan comes on the hose that goes to the t-stat sucks it self shut, it collapses and I have to open the bleed valve in order for it to go back to normal. Quote
GnatGoSplat Posted April 9, 2003 Report Posted April 9, 2003 Well, like I said before it took me probably over 30-minutes before I was satisfied that I got enough air out. I think a little bit of air in the system would eventually work its way out. Pretty much as long as the gauge stays in the Normal range, you probably have enough air bled out. Mmmm, a collapsing hose is very unusual, I've never heard of that happening. If you haven't already, I'd take another look at that thermostat.. Quote
red93z34 Posted April 9, 2003 Author Report Posted April 9, 2003 well when it collapses I can feel the water flowing through it, the thermostar is new, just put on yesterday. Quote
red93z34 Posted April 10, 2003 Author Report Posted April 10, 2003 hey guys one more ques, do I have to get all the air out of the system or can some stay in? The car has been running for 2 hours today and not overheating, the t-stat is opening and the cooling fans are coming on. Should I leave the system alone now or keep pulling more air out? Quote
GnatGoSplat Posted April 10, 2003 Report Posted April 10, 2003 If it doesn't overheat in heavy traffic on a warm day, you're probably okay. It doesn't hurt to get more air out if you can, but if it's too much hassle I wouldn't worry about it. Quote
Tim Posted April 11, 2003 Report Posted April 11, 2003 Anybody know if you can purchase new bleeder valves? On my GP the one on the thermostat housing is broken off. Quote
red93z34 Posted April 11, 2003 Author Report Posted April 11, 2003 Just buy a new thermostat housing, they sell for $22 at AutoZone or Advance Auto parts. Go to autozone.com or partsamerica.com and you can look up the price. Quote
JS91Z34 Posted April 14, 2003 Report Posted April 14, 2003 10-minutes straight is not unusual.I've never tried this, but I just all of a sudden had an idea to use some kind of vacuum pump to suck the air out. I don't know if it would work, but the thought just popped into my head. Dont put vacuum on a coolant system!!!!!! If anyone is good with science, you will know what happens to water under vacuum..............IT BOILS Quote
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