Mechanics

RADIATOR FAN WONT COME ON, DOESN'T COMPLETEL

1996 Geo Prizm

Engine Cooling problem
1996 Geo Prizm 4 cyl Front Wheel Drive Manual 150000 miles

Im working on my girlfriends car, as its been having problems recently. Cooling systems always boggle me. I put in a new tstat a few weeks ago and all was fine but I had her take it to pep boys to get the cooling system flushed and they said the radiator was toast so they couldn't do it. They wanted to charge 800 bucks to put on in so I got her one for $150 and installed it. I burped it out pretty good from what I could tell and took it for a drive. The temp guage started bouncing around a little bit but never really got to the red (close though) and would go back down to the middle where it should be I pulled it over and popped the hood and the radiator fan wasn't coming on. Could this be the temp sensor or the Fan? I don't have a volt meter and have no clue how to check and see if its getting power anyway, Im thinking the temp sensor works though if the guage is reading or am I wrong? Please help, I'd like to have this on the road today because I have to work all week and she needs it for work. Thanks in advance for any ideas.
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Luvmeye22re
January 11, 2009.



Ok, I disconnected the fan switch on the thermostat housing and the fan started running so is there something more I should check than the fan switch such as a fuse or relay? I took it for a drive and it never got above normal operating temperature so I think the fan is just fine. Any thoughts would be helpful because if I can help it I don't want to just be throwing parts at it.

Tiny
Luvmeye22re
Jan 11, 2009.
Test the fan no. 1 relay see below diagram then comback when it continues-unable to read it give me your email addy.


http://www.2carpros.com/forum/automotive_pictures/12900_relay_21.jpg


Rasmataz
Jan 11, 2009.
Dntspmebshezz23@aol. Com Thanks for the response. Apparently that wasnt it. I got the fan running and I drove it pretty far and it didnt overheat. I dropped it off at her work and went home and when she left it started overheating within a few minutes. I didnt have a chance to look at it but I think I might have other problems. When I replaced the thermostat I noticed the antifreeze was really rusty and brown but it didn't seem to be a headgasket problem. Could a good flush possibly cure this along with getting the fan running? Maybe I need to burp it out more too not sure. Cooling systems always confuse me.
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Tiny
Luvmeye22re
Jan 12, 2009.
Test the water pump

One way to test for a bad water pump is to squeeze the upper radiator hose when the engine is hot and idling. Careful, because the hose will be HOT! If you do not feel much coolant circulating through the hose when you rev the engine, the pump may be bad. The other cause might be a bad thermostat that is not opening properly (remove and inspect the thermostat), or a clogged radiator.

Do the flush-make sure the radiator is not clogged-up and bleed the system. If it continues have it block and pressure tested.

Rasmataz
Jan 12, 2009.
Thank you that's what I plan to do. The thermostat is new but I think I'll pull it anyway to do the flush. The radiator is also brand new. I did not know that trick about squeezing the hose to check the water pump, thank you very much I will check that tonight. I'll report back and let you guys know how it turns out.

Tiny
Luvmeye22re
Jan 12, 2009.

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