Question about 1991 Nissan Pickup

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Cooling fan clutch seems to be seized up. it continues to run all the time and increases with engine rpm

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  • Nissan Master
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Can you move it fairly easy, no grinding of bearings when engine is off, by hand? If yes, your truck may be running hot. If no, time for replacement.

Posted on May 10, 2009

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My 1999 ford RAnger has heat but the fan makes alot of noise and does not blow out the heat and the trucks gauge will go hot. What would the issue? Heater core or mayb just the fuse?


Diagnose Cooling Fan Clutch On engines with belt-driven cooling fans, a fan clutch is often used to save energy and reduce noise. The fan clutch disengages slows or disengages the engine's cooling fan when extra cooling isn't needed. The fan pulls air through the radiator and air conditioning condenser when the vehicle isn't moving fast enough to provide adequate airflow for cooling. A fan can eat up anywhere from a couple of horsepower up to 12 or 15 hp on a big V8, so by reducing the parasitic horsepower loss on the engine the fan clutch makes a noticeable difference in fuel economy

TWO TYPES OF FAN CLUTCHES basic types of fan clutches: thermal and non-thermal (also called "torque limiting Thermal fan clutches have a temperature-sensitive bimetal coil spring on the front that reacts to temperature changes. When the air coming through the radiator is hot, the spring expands and opens an internal valve that reduces clutch slippage. This causes the fan to spin faster for increased cooling. As the air cools, the spring contracts and closes the valve. This increases the amount of clutch slippage, allowing the fan to slow down and decrease cooling FAN CLUTCH OPERATION

The clutch consists of a fluid coupling filled with a silicone based oil. In the cutaway view at the left, the area between the teeth on the clutch plates is filled with silicone fluid. An internal valve opens and closes a passage between the main fluid cavity and a fluid reservoir. When the passage is open, fluid enters the clutch and makes the fan to turn faster. When the valve is shut, fluid flows back to the reservoir but doesn't return, causing the clutch to slip and the fan to turn more slowly.
The non-thermal (torque limiting) fan clutch doesn't have a temperature sensing capability. It reacts only to speed, slipping to limit maximum fan speed to about 1200 to 2200 rpm depending on the application.

FAN CLUTCH PROBLEMS

A slipping fan clutch is often overlooked as the cause of an engine overheating problem.
As a fan clutch ages, fluid deterioration gradually causes an increase in slippage (about 200 rpm per year). After a number of years of service, the clutch may slip so badly that the fan can't keep up with the cooling needs of the engine and the engine overheats. At this point, replacement is often necessary.
Other signs of fan cluch failure would include any looseness in the clutch (check for fan wobble), or oil streaks radiating outward from the clutch hub.
If the clutch is binding, the fan may not release causing excessive cooling and noise, especially at highway speeds

CHECKING THE FAN CLUTCH

A good clutch should offer a certain amount of resistance when spun by hand (engine off, of course!). But if the fan spins with little resistance (more than 1 to 1-1/2 turns), the fan clutch is slipping too much and needs to be replaced.
If the fan binds, does not turn or offers a lot of resistance, it has seized and also needs to be replaced.
Fan speed can also be checked with an optical tachometer, by marking one of the fan blades with chalk and using a timing light to observe speed changes, and/or listening for changes in fan noise as engine speed changes.
You should also try to wiggle the fan blades by hand. If there is any wobble in the fan, there is a bad bearing in the fan clutch, or a worn bearing on the water pump shaft. A bad water pump bearing will usually cause the water pump to leak and/or make noise, but not always. Remove the fan clutch and see if the play is in the water pump shaft. If it feels tight (no play or wobble), replace the fan clutch.

FAN CLUTCH REPLACEMENT

Many experts say it is a good idea to replace the fan clutch at the same time as the water pump if the water pump has failed. The reason is because both age at about the same rate, so if the water pump has failed, the fan clutch may also fail soon. As as we mentioned earlier, a high mileage fan clutch may be slipping excessively increasing the risk of overheating.
When you buy a replacement fan clutch, make sure you get the same type (thermal or nonthermal) as the original. You can always upgrade from a nonthermal to a more efficient thermal fan clutch, but never the reverse. Or, you can get rid of the fan and clutch altogether and install an aftermarket electric fan kit to cool the radiator.

Sep 28, 2016 | Ford Cars & Trucks

3 Answers

Overheating and antifreeze coming from cap, but fan to cool it down, is barely turning what could cause this.


Could be a faulty fan motor, or fan relay.
You should be able to run a wire from battery power to the fan to make it run at full speed to test.

Sep 04, 2015 | 1996 Geo Tracker 2 Door

4 Answers

Does the engine cooling fan run continually


No the cooling fan should run continuously.

May 11, 2014 | Ford Fiesta Cars & Trucks

1 Answer

The van starts fine when at non operating temperature but after it runs and warms up and i turn it off THEN try to start it i have to wait for it to cool down to get it to start.(it's just warm not...


On engines with belt-driven cooling fans, a fan clutch is often used to save energy and reduce noise. The fan clutch disengages slows or disengages the engine's cooling fan when extra cooling isn't needed. The fan pulls air through the radiator and air conditioning condenser when the vehicle isn't moving fast enough to provide adequate airflow for cooling. A fan can eat up anywhere from a couple of horsepower up to 12 or 15 hp on a big V8, so by reducing the parasitic horsepower loss on the engine the fan clutch makes a noticeable difference in fuel economy.

A slipping fan clutch is often overlooked as the cause of an engine overheating problem.

As a fan clutch ages, fluid deterioration gradually causes an increase in slippage (about 200 rpm per year). After a number of years of service, the clutch may slip so badly that the fan can't keep up with the cooling needs of the engine and the engine overheats. At this point, replacement is often necessary.

Other signs of fan cluch failure would include any looseness in the clutch (check for fan wobble), or oil streaks radiating outward from the clutch hub.

If the clutch is binding, the fan may not release causing excessive cooling and noise, especially at highway speeds

CHECKING THE FAN CLUTCH

A good clutch should offer a certain amount of resistance when spun by hand (engine off, of course!). But if the fan spins with little resistance (more than 1 to 1-1/2 turns), the fan clutch is slipping too much and needs to be replaced.

If the fan binds, does not turn or offers a lot of resistance, it has seized and also needs to be replaced.

Fan speed can also be checked with an optical tachometer, by marking one of the fan blades with chalk and using a timing light to observe speed changes, and/or listening for changes in fan noise as engine speed changes.

You should also try to wiggle the fan blades by hand. If there is any wobble in the fan, there is a bad bearing in the fan clutch, or a worn bearing on the water pump shaft. A bad water pump bearing will usually cause the water pump to leak and/or make noise, but not always. Remove the fan clutch and see if the play is in the water pump shaft. If it feels tight (no play or wobble), replace the fan clutch.

I posted this to another Ford Problem and I believe it applies to you as well.

This is a shot in the dark with out running diagnostics myself but here it goes, I had a 1988 Cavalier that would just die while I was driving it. On short drives, in the morning, when the engine was cool... it would not die. It would only die after the engine heated up to a certain point.

I took it all over the place to see what the problem was and nobody could figure it out, until finally I took it to my local Firestone shop and they had a special diagnostic tool that checked all of the electrical connections and low and behold I had a misc. wire that crossed the back of my engine from one side of the engine bay to the other. This wire was melted to my engine block and when the engine heated up to a certain point the wire would short out.

After they pinpointed the wire they replaced it with an in-tact wire and it worked beautifully.

Again, I am not stating that this is for sure your problem, but take it from me that there are better diagnostics to run then your standard error code ODB II dump.

Hope that helps and let me know if there are any developments.

Brian

May 26, 2011 | 1995 Ford Econoline

1 Answer

Whenever I turned on the air condition in my Ford Explorer 2006, after few second the radiator Fan start running very frequently on high speed making noise. When the fan starts on high the rpm of the...


The cooling fan is supposed to come on when the /ac compressor clutch cycles on, and off when it cycles off.
The idle speed kicks up to compensate for the additional a/c compressor load and the additional alternator load. usually, just the low speed comes on until it hits a much higher temperature.

the system should cycle 4 to 7 times/minute at 79 degrees F.

Here are some things to consider:(The PCM (engine computer) is NEVER defective, don't replace it). I don't think it is the ECT (engine coolant temp sensor) or the Cylinder Head Temp Sensor. Or the VSS or the MAF sensors.


The electronically controlled fan clutch is controlled by the powertrain control module (PCM) based upon requests for airflow to cool the engine, transmission and A/C condenser. If no cooling is required, the electronics permit the fan to spin at a slower speed yielding improved fuel economy.
-------------------------------------------------------------------------------------------------------------------------------
Inoperative or damaged:
  • Electronically actuated fan clutch
  • Electronically actuated fan clutch controller
  • Wiring, connectors, relays or modules
  • Engine Coolant Temperature (ECT) sensor (4.0L SOHC)
  • Cylinder Head Temperature (CHT) sensor (4.6L [3V])
  • Mass Air Flow (MAF) sensor
  • Vehicle Speed Sensor (VSS)
  • ----------------------------------------------------------------------------
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
Retrieve any DTC Codes (Diagnostic Test Code). Autozone will do for free.

--------------------------------------------------------------

The cooling fan clutch actuator valve controls the fluid flow from the reservoir into the working chamber. Once viscous fluid is in the working chamber, shearing of the fluid results in fan rotation.

The cooling fan clutch actuator valve is activated with a pulse width modulated (PWM) output signal from the powertrain control module (PCM). By opening and closing the fluid port valve, the PCM can control the cooling fan clutch speed. The cooling fan clutch speed is measured by a Hall-effect sensor and is monitored by the PCM during closed loop operation.

The PCM optimizes fan speed based on engine coolant temperature (ECT), engine oil temperature (EOT), transmission fluid temperature (TFT), intake air temperature (IAT), or air conditioning requirements. When an increased demand for fan speed is requested for vehicle cooling, the PCM monitors the fan speed through the Hall-effect sensor. If a fan speed increase is required, the PCM outputs the PWM signal to the fluid port, providing the required fan speed increase.

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May 20, 2011 | 2006 Ford Explorer

3 Answers

2001 chevy s10 loses power, will not stall, restart runs better.


SOUND LIKE ENGINE GETTING TOO HOT.THAT WILL CAUSE LOST OF POWER.CHECK COOLING CLUTCH FAN IF IT HAS RESISTANCE WHEN ENGINE HOT FAN CLUTCH IS GOOD.IF FAN CLUTCH FREE WHEELS WITH NO RESISTANCE WHEN ENGINE HOT.FAN CLUTCH IS BAD.THAT WILL CAUSE ENGINE TO RUN HOT WHILE DRIVING.

Jul 23, 2010 | 2001 Chevrolet S-10

1 Answer

Eng. code P1484


P1484 - Cooling Fan System Performance

06-06-2005, 10:51 PMHere's what the GM Manual says about this code:

The cooling fan relay sends a pulse width modulation (PWM) signal of 12-14 volts to the cooling fan clutch through the cooling fan clutch supply voltage circuit. The powertrain control module (PCM) uses this PWM signal in order to control the speed of the cooling fan clutch. The signal controls the position of the oil control valve inside the cooling fan clutch. If the cooling fan RPM is different than the PCM is expecting, DTC P1484 will set. The actual cooling fan RPM vs the desired cooling fan RPM is not always exactly the same. There can be up to an 800-RPM difference.

The engine is running.
The system voltage is greater than 8.5 volts.
The intake air temperature (IAT) is greater than -7°C (19°F).
DTCs P1481 and P1482 are not set.
The engine speed is less than 3200 RPM.
The engine speed is not changing more than 250 RPM for 5 seconds.
Fan command is greater than 0%.


The maximum allowable error of 1000 RPM in the cooling fan speed occurs for 100 seconds.
The PCM detects that the cooling fan clutch is locked up.


The Reduced Engine Power indicator illuminates only if the PCM detects that the cooling fan clutch is locked up.
The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
The PCM will store the conditions as Freeze Frame/Failure Records data.
The PCM commands the cooling fan clutch to 100%.

Important
Follow this procedure in order to clear DTC P1484 after completing a repair.



Use the Clear DTC Information function on the scan tool.
Perform an ignition key cycle.
The PCM turns OFF the MIL after the third consecutive trip that the diagnostic test has run and passed.

The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

An inline connector could cause an intermittent DTC. Ensure to test for poor connections and pin retention at all inline connectors. Refer to system schematics for connector and locations.
If the condition is not present, refer to Testing for Intermittent and Poor Connections in Wiring Systems.

Disconnect the harness connector of the cooling fan clutch from the shroud. Inspect the exposed wires between the harness connector and the tubing.
If DTCs P1484 and P0113 are set, and the weather conditions are cold, the cooling fan code may be false. Clear DTC P1484, and after an IAT sensor check, allow the DTC to reset .

I'd say that 'fan clutch is faulty' is your problem, based on the information you gave. Thank you for using Fixya and good luck

Jul 10, 2010 | 2002 Chevrolet TrailBlazer

2 Answers

My trailblazer (2002) was making allot of noise as i gave it gas.


should have the coolant temp sensor replace from the sound of it. if bad it will think it is cold and dump more gas to keep it running. it also runs the fans

Aug 13, 2009 | 2003 Chevrolet TrailBlazer

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