94 grand am spewing coolant from overflow tank

[sirofsirs]

First:
94 Grand Am
2.3 OHC

As I was parallel parking in a parking spot today next to by building I noticed the scent of coolant. By this time I was in the spot and I looked down at the dash and noticed the the temp gauge was close to overheating and the coolant light was on. I quick shut off the car go out and noticed there was a river flowing away from my car. Opened the hood and there was coolant spewing out from my overflow tank. I have class now until 9:00 tonight. So i figured I'd let it cool and then come back to it later. I'm going to try to get more coolant and fill it back up and see what ti does later tonight after driving it for a bit.

What could have caused this? A bubble in the line somewhere? If this is the case could one suddenly occur after months of carefree driving? Give me any suggestions.

Mind you I'm living in Philly and my home home is an hour away and I don't have real tools with me. (Have a socket set and some screwdrivers and allen wrenches).

so please help!!

Matt

edit: I also shut the engine off before I opened the hood so I hadn't noticed if the fan was running or not. So I'll check this when i get home.

[GTP Dad]

This sounds like it may be a stuck thermostat. The engine overheated because the water is not circulating. I doubt that air is the culprit. If I were you I would fill the car with water only and take a good supply with me. Possibly the thermostat will open correctly and the car will run ok on the way home. Be careful and watch the guage so you don't damage the engine. If it overheats, stop let it cool and then refill the radiator again. I would change the thermostat asap and even remove it if you can before your trip unfortunately on th2 2.3 it is very hard to get to so you may have to suffer through until you can get home. That should cure the problem and that is why the coolant was boiling out of the reservoir.

[sirofsirs]

Originally Posted by GTP Dad

This sounds like it may be a stuck thermostat. The engine overheated because the water is not circulating. I doubt that air is the culprit. If I were you I would fill the car with water only and take a good supply with me. Possibly the thermostat will open correctly and the car will run ok on the way home. Be careful and watch the guage so you don't damage the engine. If it overheats, stop let it cool and then refill the radiator again. I would change the thermostat asap and even remove it if you can before your trip unfortunately on th2 2.3 it is very hard to get to so you may have to suffer through until you can get home. That should cure the problem and that is why the coolant was boiling out of the reservoir.

could you please tell me how to remove the thermostat. I've only had this particular car for 6 months and haven't needed to do any significant work on it, so wouldn't even know where to begin looking. Plus all recent cars I've had have had the thermostat right under the refill cap. So could you forward me to someplace or try to explain where it is?

[sirofsirs]

Well I added some water, and it was fine. Drove around for a while it was fine, at stops it would sometimes rise, but for the most part it was between the dash after 100 and 220. So I parked it again and kept the idle higher to get it hot to see if the fan would kick on... and the temp gauge got to 220 and it never went on. Sooo tomorrow I try to hook my fan directly up to the battery to see if it's the fan or not.. if its not the fan i can only assume the sending unit. Is there anyway to actually check the sending unit? How hard is it to get to the sending unit if it needs to be changed?
thanks
Matt

[GTP Dad]

It is possible that the coolant was low and caused the issue. For a 2.3 the thermostat is in the rear and I would purchase a manual for your vehicle before tackling this job. Also if you used just water you will want to make sure to drain some of it back out and add the proper coolant. The fans work on a temp sensor and are turned on by the ECM. If the fan isn't working it may be due to a bad sensor or the motor could be bad on the fan. If the motor is bad go to car-part.com and search for wrecking yards in your area. If you are in Philly, Harry's U-pull It is a low cost alternative and he has a yard within an hour of Philly. You can probably get a good fan for $10 from there. Good Luck!

[sirofsirs]

Thanks a lot for your help. Yeah I do need to get a manual, been meaning to get a haynes but this car hasn't given me any trouble and have been busy dropping a SBC 350 into my fiero, so have been kind of ignoring this one.

Could you tell me where I'd find this sensor that the fan is connected to? I followed the line and it just runs into the rest of the wiring harness which is rapped and I'm not really sure where it goes. So can you give me specific point in the engine bay that I should be looking? Although now thinking about it, if this is the case the fan would be one hell of a pain in the butt to change... so I'll back out and look at it again to make sure I'm following it correctly.

Originally Posted by GTP Dad

It is possible that the coolant was low and caused the issue. For a 2.3 the thermostat is in the rear and I would purchase a manual for your vehicle before tackling this job. Also if you used just water you will want to make sure to drain some of it back out and add the proper coolant. The fans work on a temp sensor and are turned on by the ECM. If the fan isn't working it may be due to a bad sensor or the motor could be bad on the fan. If the motor is bad go to car-part.com and search for wrecking yards in your area. If you are in Philly, Harry's U-pull It is a low cost alternative and he has a yard within an hour of Philly. You can probably get a good fan for $10 from there. Good Luck!

[sirofsirs]

I hot wired the fan and it worked fine. So I'm thinking its either a relay or sender of some sort. When I let the car run for a while last night, I also tried turning on the AC thinking that when I turn on the AC the fan should turn on. It never did. So you think it could be a relay or temp sending unit of some sort? If so.. where can I find either of these things?

Thanks for all your help
Matt