Fan Solenoid replacement

[Dpas1973]

OK... last call to the fan guys. Then I am blowing this thread off. LOL

Don't know what one has. All rusted up, bent busted, went swimming in the ocean... whatever. This "tap and a wack" may work to free up the clutch AND you maybe just be that unlucky dude.

To put it all together, look over my last posts to this COMMON STUCK fan fail points. Here are some pictures for those that like pictures. YRMV

Years ago with nothing to do... painted my fan hub red. YEP red. Not only does it look cool and run cooler, but easier to tell and see when working correctly.

This photo engine is off... fan is engaged as a reference. Logic is not conventional... Hydro pressure off, fan lock-up. This is where the air hose comes in.
I point to the hub ring to take the hits. See arrow. Use a long 3/8 extension if you don't mind banging on your tools that way. I don't !

Go at it at right angles to hub. Not so much as pointer angle shown. Air applied. Gota have air 150 PSI, rotate around. get at it from another direction.
View attachment 813736




This may help. Squirt your favorite "Mr. Mechanic" in a can in the air, on your helper... trying for the opening where the bent welding rod is pointed. Take a break and let it do the work. Maybe do this first. Yea first. Don't worry it will dry out. Safety first.
View attachment 813737



This photo is engine running. Fan is engaged. Air is a moving thru radiator stack. In my Red Line set up, I and Bear know that it is working.

To test system, any component disconnected will produce FAN LOCK UP. The valve solenoid, the valve mechanical action, the TDM, crossover temp switch (or an internal wiring break ) or real low PS pump pressure (along with everything else failing)

BUT a failed / stuck clutch, there's no choice but to start there with air hose at the ready. MY logic IMO. Again YRMV.

The last word in the design is FAN clutch FAIL. If system can't cycle... Likely cooler than normal operating temps all around. Stuck means stuck. Rimes with F and F problem. Doesn't hurt anything, (overall performance) just not working as design and more money at the pump and freeze you buns off in coming months.
View attachment 813739


OK... beat that horse to death. NOW see the thin red line. Using hub ring as a gun sight. Clutch/ fan assembly under hydro pressure move towards engine, hiding red line. Fan is free wheeling (more or less) engine HP picks up a bit, temperature stabilizes towards the lower temps. Give it a minute or two, (lots of hysteresis) engine temp on the rise, thermostatic switch in crossover OPENS and BANG on comes the fan, hot air is blow thru the cab.
View attachment 813740

This is not a sure thing in all cases. With no history, maintenance records, abuse and any and all thing that can go wrong Humv, is just another chapter for the hobby. Worked for me and others. Saved a buck and smell like WD-40.

Not a fan any more, CAMO

Free advice is free. Storytime, send likes. No bears or unicorns were hurt in my fan fix.

Thx brother that was a better explanation than the tm manual. I have a serpentine belt and the rear of the clutch does not look like yours.


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[Ajax MD]

The photos are great. This maybe ought to be a sticky.

 

[Dpas1973]

OK... last call to the fan guys. Then I am blowing this thread off. LOL

Don't know what one has. All rusted up, bent busted, went swimming in the ocean... whatever. This "tap and a wack" may work to free up the clutch AND you maybe just be that unlucky dude.

To put it all together, look over my last posts to this COMMON STUCK fan fail points. Here are some pictures for those that like pictures. YRMV

Years ago with nothing to do... painted my fan hub red. YEP red. Not only does it look cool and run cooler, but easier to tell and see when working correctly.

This photo engine is off... fan is engaged as a reference. Logic is not conventional... Hydro pressure off, fan lock-up. This is where the air hose comes in.
I point to the hub ring to take the hits. See arrow. Use a long 3/8 extension if you don't mind banging on your tools that way. I don't !

Go at it at right angles to hub. Not so much as pointer angle shown. Air applied. Gota have air 150 PSI, rotate around. get at it from another direction.
View attachment 813736




This may help. Squirt your favorite "Mr. Mechanic" in a can in the air, on your helper... trying for the opening where the bent welding rod is pointed. Take a break and let it do the work. Maybe do this first. Yea first. Don't worry it will dry out. Safety first.
View attachment 813737



This photo is engine running. Fan is engaged. Air is a moving thru radiator stack. In my Red Line set up, I and Bear know that it is working.

To test system, any component disconnected will produce FAN LOCK UP. The valve solenoid, the valve mechanical action, the TDM, crossover temp switch (or an internal wiring break ) or real low PS pump pressure (along with everything else failing)

BUT a failed / stuck clutch, there's no choice but to start there with air hose at the ready. MY logic IMO. Again YRMV.

The last word in the design is FAN clutch FAIL. If system can't cycle... Likely cooler than normal operating temps all around. Stuck means stuck. Rimes with F and F problem. Doesn't hurt anything, (overall performance) just not working as design and more money at the pump and freeze you buns off in coming months.
View attachment 813739


OK... beat that horse to death. NOW see the thin red line. Using hub ring as a gun sight. Clutch/ fan assembly under hydro pressure move towards engine, hiding red line. Fan is free wheeling (more or less) engine HP picks up a bit, temperature stabilizes towards the lower temps. Give it a minute or two, (lots of hysteresis) engine temp on the rise, thermostatic switch in crossover OPENS and BANG on comes the fan, hot air is blow thru the cab.
View attachment 813740

This is not a sure thing in all cases. With no history, maintenance records, abuse and any and all thing that can go wrong Humv, is just another chapter for the hobby. Worked for me and others. Saved a buck and smell like WD-40.

Not a fan any more, CAMO

Free advice is free. Storytime, send likes. No bears or unicorns were hurt in my fan fix.

Ok I hooked the air hose up to the fan Schrowd beat it and it started to free spin. Hooked everything back up and now it still won’t go over 190 degrees lol.


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[Coug]

Ok I hooked the air hose up to the fan Schrowd beat it and it started to free spin. Hooked everything back up and now it still won’t go over 190 degrees lol.


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How are you verifying this temp? The inside gauges are notoriously inaccurate, so if that's all you're looking at you need to get a laser temp to verify.

Plus you said you just installed a new thermostat.

I'd go back, verify with a laser thermometer on the coolant hose what the temp is after it's been driven for a bit, and if it's still that low you should test the thermostat in a pot of water with a thermometer, it should only just barely be starting to open at that temp, and the fan running full time shouldn't be affecting the engine temp that much unless the thermostat is open.

Did your engine temps read that low before you replaced the thermostat?

Have you taken it on a drive on the freeway or uphill or anything else that would put a decent load on the engine in order to get the temps up? If your fan clutch is freed up now, doing a decent drive should cause the fan to kick in if it's just a gauge/sender problem. If fan kicks in, then it's the gauge, if it doesn't I'd definitely remove the thermostat to test.

 

[Dpas1973]

How are you verifying this temp? The inside gauges are notoriously inaccurate, so if that's all you're looking at you need to get a laser temp to verify.

Plus you said you just installed a new thermostat.

I'd go back, verify with a laser thermometer on the coolant hose what the temp is after it's been driven for a bit, and if it's still that low you should test the thermostat in a pot of water with a thermometer, it should only just barely be starting to open at that temp, and the fan running full time shouldn't be affecting the engine temp that much unless the thermostat is open.

Did your engine temps read that low before you replaced the thermostat?

Have you taken it on a drive on the freeway or uphill or anything else that would put a decent load on the engine in order to get the temps up? If your fan clutch is freed up now, doing a decent drive should cause the fan to kick in if it's just a gauge/sender problem. If fan kicks in, then it's the gauge, if it doesn't I'd definitely remove the thermostat to test.

Yes brand new TSTAT and I did take a laser temp it’s around 180-185 the only part I didn’t replace that I’m waiting for is the Cadillac valve. I changed the time delay and fan drive switch on the cross over. The gauge is on the $$ per laser thermometer. Like I said I can free spin the fan with the air house hooked up to the fan shroud once I reconnect the hose to valve nothing


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[Coug]

Yes brand new TSTAT and I did take a laser temp it’s around 180-185 the only part I didn’t replace that I’m waiting for is the Cadillac valve. I changed the time delay and fan drive switch on the cross over. The gauge is on the $$ per laser thermometer. Like I said I can free spin the fan with the air house hooked up to the fan shroud once I reconnect the hose to valve nothing


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It will only disconnect the fan when pressure is built up in the system, the only way to really check with the engine running is use something like a 2x4 to GENTLY rub against the fan to see if it slows it down. Even with pressure in the system and the clutch disengaged the fan is going to spin, it just won't have much force behind it.
what thermostat did you put in?

 

[Dpas1973]

It will only disconnect the fan when pressure is built up in the system, the only way to really check with the engine running is use something like a 2x4 to GENTLY rub against the fan to see if it slows it down. Even with pressure in the system and the clutch disengaged the fan is going to spin, it just won't have much force behind it.
what thermostat did you put in?

The one from Mac motors


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[Coug]

The one from Mac motors


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There is still always the chance it is defective or something causing it to stick open, so removing it to verify it's opening temps is still advisable.

 

[Dpas1973]

There is still always the chance it is defective or something causing it to stick open, so removing it to verify it's opening temps is still advisable.

The one I took out was the same story. I just drove 26 miles on the highway at 65mph and it didn’t go over 190


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[Milcommoguy]

I got to say "The 2X4 in the fan test is just plain crazy" said that and another word that can't be written LOL. That's why I painted a stripe to clearly see crutch action.

Once one gets a feel for the goings on (proper operation) with the system it will make more sense between lock up and free wheeling.

Now that the clutch is working ???? Time to work back thru the other components.

There's many ways to proceed. In this post not knowing current conditions other that the crutch works ?? with air pressure is most important. IMO

With a cold start engine, running... pulling the solenoid plug should engage fan. You will notice or should (pay attention) an increase in air flow and wind turbulence like noise from fan. This is the lucky / easy test WITH all components in play, working correctly. But not fool proof.

To save time (ME) follow the trouble shooting guide I provided earlier. Once one get a complete understanding... it's becomes easy to be the cooling system diagnostician.

Wood splinters and fan parts don't mix well, CAMO

Here it is again chapter one. A working clutch assembly will make more sense now >

https://gear-report.com/wp-content/uploads/2017/03/HMMWV%20A1%20Troubleshooting.pdf

 

[Dpas1973]

I got to say "The 2X4 in the fan test is just plain crazy" said that and another word that can't be written LOL. That's why I painted a stripe to clearly see crutch action.

Once one gets a feel for the goings on (proper operation) with the system it will make more sense between lock up and free wheeling.

Now that the clutch is working ???? Time to work back thru the other components.

There's many ways to proceed. In this post not knowing current conditions other that the crutch works ?? with air pressure is most important. IMO

With a cold start engine, running... pulling the solenoid plug should engage fan. You will notice or should (pay attention) an increase in air flow and wind turbulence like noise from fan. This is the lucky / easy test WITH all components in play, working correctly. But not fool proof.

To save time (ME) follow the trouble shooting guide I provided earlier. Once one get a complete understanding... it's becomes easy to be the cooling system diagnostician.

Wood splinters and fan parts don't mix well, CAMO

Here it is again chapter one. A working clutch assembly will make more sense now >

https://gear-report.com/wp-content/uploads/2017/03/HMMWV%20A1%20Troubleshooting.pdf

Thank you again. Do you use Teflon tape on the Cadillac valve connections I’m going to change it tomm? I see nothing happen on a cold start disconnecting the solenoid plug


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[Milcommoguy]

Teflon tape, YES. Did one read the trouble shooting steps? Not seeing any hands going up. LOL

My steps are the way I would go at it. Measure the Cadillac vavle solenoid coil resistance. Should be around 65 Ohms. +/- at the plug. Also check for any resistance each lead to ground. Should be infinite. This test pointing to a good solenoid coil.

Note: proper valve runs a bit warm due to PS fluid flowing thur valve and heat generated in the coil windings. Most of the time the fan is not in lock-up. It is waiting on the thermo switch to reach tempture (ato OPEN brealing the voltage to the coil. This is when the coil is energized with 24 Volts allowing it to run warm. Watch out for OPEN and SHORTED coil resistance, the killer of electrical fan system.

Next, with my all time carry test leads with small alligator clips, using 24 volts from batteries, connect leads to the Cadillac valve connector. Positive to exposed pin and negative to the one down in the hole. With engine running (try not to rap up the wires in the fan were looking to fix)

If you remove one of the wires (engine running) the fan / clutch should engage. Not sure ??? reconnect and watch and listen. Try again. don't stick any thing in there to test lock-up. At idle it is pretty obvious that there is an action - reaction of fan to follow wire connection. All connected up and working CORRECTLY fan moves towards engine in a freewheeling mode, turning BUT not working.

Now disconnect one of the wires and fan should lock up moving away from engine... air speed picks up. Slight but obvious fan noise as in is slicing through the air and not a 2X4. Just look and listen. If all is working at this point you will know. Connect and reconnect allowing fan to follow along and you to learn its operational "finger print". Keep this in one's noggin.

If that works more steps to follow. If not... mechanical action of valve is wack. NOTE : Make SURE hose connection are going in the right direction on the valve ports.

That should keep you busy. Next you got the TDM and thermo switch to check.

Next time on "AS THE FAN TURNS", CAMO

 

[Dpas1973]

Teflon tape, YES. Did one read the trouble shooting steps? Not seeing any hands going up. LOL

My steps are the way I would go at it. Measure the Cadillac vavle solenoid coil resistance. Should be around 65 Ohms. +/- at the plug. Also check for any resistance each lead to ground. Should be infinite. This test pointing to a good solenoid coil.

Note: proper valve runs a bit warm due to PS fluid flowing thur valve and heat generated in the coil windings. Most of the time the fan is not in lock-up. It is waiting on the thermo switch to reach tempture (ato OPEN brealing the voltage to the coil. This is when the coil is energized with 24 Volts allowing it to run warm. Watch out for OPEN and SHORTED coil resistance, the killer of electrical fan system.

Next, with my all time carry test leads with small alligator clips, using 24 volts from batteries, connect leads to the Cadillac valve connector. Positive to exposed pin and negative to the one down in the hole. With engine running (try not to rap up the wires in the fan were looking to fix)

If you remove one of the wires (engine running) the fan / clutch should engage. Not sure ??? reconnect and watch and listen. Try again. don't stick any thing in there to test lock-up. At idle it is pretty obvious that there is an action - reaction of fan to follow wire connection. All connected up and working CORRECTLY fan moves towards engine in a freewheeling mode, turning BUT not working.

Now disconnect one of the wires and fan should lock up moving away from engine... air speed picks up. Slight but obvious fan noise as in is slicing through the air and not a 2X4. Just look and listen. If all is working at this point you will know. Connect and reconnect allowing fan to follow along and you to learn its operational "finger print". Keep this in one's noggin.

If that works more steps to follow. If not... mechanical action of valve is wack. NOTE : Make SURE hose connection are going in the right direction on the valve ports.

That should keep you busy. Next you got the TDM and thermo switch to check.

Next time on "AS THE FAN TURNS", CAMO

Already replaced the Thermo switch lol


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[Thumper580]

I'm in the same boat... Replaced all the ancillary parts. Fan still stuck. Sprayed it and been hitting the metal ring. If it doesn't brake loose I guess it cant be removed because I doubt the holes are lined up to remove the bolts......

 

[Milcommoguy]

Not the easiest to get at and remove. It could be really gummed up... but I would bet a donut it can be saved in truck. Have to get air on it to assist the process. Have you applied air @ 150 PSI and then work on it?

The guys with the fan that runs a lot or all the time IMO is not working right. Here in the Mojave desert 110 degrees my rig cycles on for less a minute, off for six and back on when moving 50 MPH. Temp gauge follows fan between 190 - 220. In winter at 35 - 40 out hardly ever comes on.

Out of breath on this problem, CAMO

 

[Thumper580]

Not the easiest to get at and remove. It could be really gummed up... but I would bet a donut it can be saved in truck. Have to get air on it to assist the process. Have you applied air @ 150 PSI and then work on it?

The guys with the fan that runs a lot or all the time IMO is not working right. Here in the Mojave desert 110 degrees my rig cycles on for less a minute, off for six and back on when moving 50 MPH. Temp gauge follows fan between 190 - 220. In winter at 35 - 40 out hardly ever comes on.

Out of breath on this problem, CAMO

125 psi and repeated "tapping" with a hammer.... Nothing...

 

[Milcommoguy]

Well, I tried from here. It has and can work. Here's some encouragement.



Good luck. Oil and beer, CAMO

 

[Thumper580]

OK another question....
Is there suppose to be power steering fluid in the hose that goes from the Cadillac valve to the fan clutch??? Just checking.

 

[AAVP7]

OK another question....
Is there suppose to be power steering fluid in the hose that goes from the Cadillac valve to the fan clutch??? Just checking.

Yes. The clutch is hydraulically actuated, with PS fluid as the hydraulic medium.

 

[Ajax MD]

...except that we don't use power steering fluid, we use Dexron/Mercon ATF.