help, cooling problem - Toyota Nation Forum : Toyota Car and Truck Forums

squeaks · 06-25-2010, 09:46 PM

I just bought a 89 gts and it runs great but for some reason after about 20 minutes of driving the temp guage will start to go up, it never gets to the H but it will move up then back down then back up then back down and it is not when I am at a stop. I have looked and I do not see coolent in the oil or vise versa, I am not quite sure what it is

***heartdisease*** · 06-25-2010, 10:45 PM

I would start by changing the thermostat. Or take it out and run like that too see if it gets hot then.

90 GP · 06-26-2010, 03:53 AM

Usually the temp gauage should register at midpoint. When it raises above that the electric fan kicks on and runs till it gets back to midpoint.

squeaks · 06-26-2010, 11:55 AM

yeah so it started to heat past midpoint so I pulled over and checked and the fan wont come on. Any ideas?

90 GP · 06-26-2010, 12:18 PM

Could be the temp sensor, relay (in relay box under hood) burned out fan motor or as simple as a bad connection at wiring plug for fan.

squeaks · 06-26-2010, 12:57 PM

Where is the temp sensor?

90 GP · 06-26-2010, 01:29 PM

Sensor should be on the thermostat housing. Try to direct wire the fan and see if it comes on to rule it out first. If it works you will have to troubleshoot the wiring to find problem. There are three fusible links on positive battery terminal connector. Might want to check those out to see if one is blown. It could possibly be a source of power to the circuit.

squeaks · 06-26-2010, 05:39 PM

Quote:

Originally Posted by 90 GP

Sensor should be on the thermostat housing. TRY TO DIRECT WIRE THE FAN and see if it comes on to rule it out first. If it works you will have to troubleshoot the wiring to find problem. There are three fusible links on positive battery terminal connector. Might want to check those out to see if one is blown. It could possibly be a source of power to the circuit.

Silly question but how do you direct wire the fan

90 GP · 06-26-2010, 06:24 PM

Disconnect the wire harness leading to the fan . Take two lenghts of wire and attach one to the terminal of the disconnected plug( that's still attached to fan ) and connect it to a good ground (engine block). Take the other wire and attach to the other terminal and momentarily touch it to the positive terminal of battery. The fan should operate when you make contact with the positive terminal.

90 GP · 06-26-2010, 07:10 PM

I was looking at a wiring diagram for the corolla. There is a 7.5 fuse in the black fuse/relay box under the hood that feeds the power circuit for the fan. Check to see if it's blown.

squeaks · 06-26-2010, 08:14 PM

ok so the 30 and the 7.5 fuses are fine and I was going to check continuity in the relays and realize I lost mt ohmmeter. so now I have to wait till tomorrow to get another one great.

90 GP · 06-27-2010, 03:27 AM

This is the wiring diagram if you want to check it out. Figure 4 is for fan relay.

http://opc.mr2oc.com/online_parts_ca...CorollaFWD.pdf

90 GP · 06-27-2010, 03:32 AM

Does the car have a/c that works? The fan should come on when a/c is running.

squeaks · 06-27-2010, 07:24 AM

No, not ac or power steering