Problems with cooling fan (start)

[Parusina]

Pls Help...

For SHO 1994 I have the problem dealing with engine fan.

- engine starts and heats (OK)
- thermostat opens (OK), ECT switch is OK, Computer OK
- coolant temperature riches high value but fan doesnt start (overheating)
- after 10-15 mins fan starts and all OK. After: all OK (fan works properly).

Next time (after engine cooling) any engine start is the same (has the same problems) excluding the situation with good traffic (fan working is not required, after 30-40 min mooving the fan works properly).

 

[projectSHO89]

Use an accurate external thermometer to obtain actual operating temperatures before assuming there is a fault. thein-dash guage is seldom accurate.

Normal operation is for the fan(s) to come on at around 210-212F and for the high speed fans to engage abouf 5-8 degrees higher.

Based on the limited information you provided, it is not possible to determine if the fans are working correctly or not.

Steve

 

[Parusina]

I replaced ECT sensor 3 years ago for the same reason. Is it possible that lifecycle for ECT sensor just 3 year?

 

[GT86]

This is a very similar problem I'm having I have a 94 atx which has two fans the one on the pass. side comes on but I seem to never seem to be able to see the other one on the driver side ever one. The thermostat opens without any problem but one the car is driven for anywhere from 15-30 mins especially in traffic and stop and go traffic with red lights the temp guage will rise up to the N and O on the guage when the A/C is running. If I turn the A/C off and drive for 10-20 mins with it off the guage will drop back down to about halfway but once i turn the A/C back on the temp guage will start rising again.

 

[Parusina]

Please advise...

As I understand there are 2 coolant temp sensors in the car (SHO 94).

First in engine (ECT sender which measures the coolant temperature inside the engine / connected with gauge and managing relay).

And second sensor should be somewhere close to radiator (which resistance becames null if the coolant temperature in radiator rises up 215F and cooling fan starts to work...)

Is it right? Are there 2 sensors or just 1 (ECT sender)?

 

[Parusina]

ECT sender unit

Please advise...

As I understand there are 2 coolant temp sensors in the car (SHO 94).

First in engine (ECT sender which measures the coolant temperature inside the engine / connected with gauge and managing relay).

And second sensor should be somewhere close to radiator (which resistance becames null if the coolant temperature in radiator rises up 215F and cooling fan starts to work...)

Is it right? Are there 2 sensors or just 1 (ECT sender)?

 

[SHOZ123]

This is a very similar problem I'm having I have a 94 atx which has two fans the one on the pass. side comes on but I seem to never seem to be able to see the other one on the driver side ever one. .........

Both fans should come on at the same speed. Check for voltage at the connector of the dead fan when the other is on. If there is voltage there then the fan motor is bad.

 

[SHOZ123]

There are two coolant temp sensors. One is for the gauge and the other is for the PCM. The PCM will turn the fans on based on the ECT signal.

When the fans are on check the voltage. If it is 12V or more then this is from the high speed fan relay. The low speed fan relay goes through a dropping resistor and the voltage will be lower. Sounds like the low speed relay is toast if they are only coming on at the high speed setting. Could be the dropping resistor is bad too. This is located in front of the radiator next to the center crash sensor.

 

[Parusina]

Sounds good...

But all fans work ok after 30-40 min driving. The engine has overheating problems just after starting and driving Stop & Go (any fans (low & high) dont work). After 10-15 min overheating fans turned on. After that: all ok...