Whining noise after replacing time delay module.

[Gatorfabny]

First time posting so if this is in the wrong section, please excuse me lol.

So I replaced my time delay module in my '89 M998 6.5 3 spd. It now has a whining noise as before with the old module it didn't have it. I've checked fluid levels, all are good. So I'm not sure what it's causing the whining noise. Any input/help/advice is greatly appreciated!!

 

[NDT]

Sounds kinda like before your fan was on all the time, now it’s cycling, when the fan is off, the “Cadillac valve” makes that sound.

 

[kzeyus]

Wrap a bicycle inner tube around the Cadillac valve and mount back into place and see if that helps.

 

[Gatorfabny]

Sounds kinda like before your fan was on all the time, now it’s cycling, when the fan is off, the “Cadillac valve” makes that sound.

Actually now that I've replaced the time delay module the fan runs constantly. Even on a cold start, the other day it was 56° out truck said all night started up fan ran right away

 

[Gatorfabny]

Wrap a bicycle inner tube around the Cadillac valve and mount back into place and see if that helps.

Would it be all right to put like boiler pipe insulation around it or would that cause it to get too hot?

 

[Milcommoguy]

Might want to isolate the problem before isolating the valve. The "hissing" sound is fluid bypassing / regulator orifice when energized and amplified being mounted to the foot well box. Doesn't take much to dampen the sound. Old bicycle inter-tube works well.

Place a 0-200 PSI gauge in place of the line feeding the fan. Normal 90 to 165 PSI valve ON. If not valve or PS pump ???

While this part of the cooling system is simple... It can send new owners into a tail spin. SEE THIS first chapter to get a heads up>>>

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

OUT on a limb here... If the rig is new to you ??? Stuck, rusted, busted Fan Clutch are an issue.

Sounds like fan clutch could be the bigger problem is my free guess with the free manual to boot, CAMO

 

[Action]

Just because the fan is spinning does not mean it is "locked" on. It will free spin on its own.

 

[Coug]

I agree with Action.
When I was looking at my own fan issues, it was easy to tell when the fan was engaged vs just spinning.
When engaged, if you rev the engine and there is any loose debris on the ground nearby under the truck, it will get blown away/moved by the air from the fan. The fan moves LOTS of air when engaged.

 

[Milcommoguy]

Not an expert, here or on TV. Pretty good at rolling around on the creeper with 16 inches of ground clearance LOL.

Yes this is all true. The fan spins when the engine is running. The difference characteristics sounds and power required of a free wheeling verses an engaged fan can be demonstrated on a cold engine.

In a correctly working system... cool engine running, pulling the connections to solenoid valve, TDM or a temp sw lead should engage fan.

It's a bit subtle... so a couple of plug in's and wait wait wait and pull's and watch and listen... for it. Having one work the throttle a little helps to get the effect you looking for.

Note: Key to proper temp / fan cycling is the "electrical temperature switch" in the water crossover manifold. Think of it as the heart beat to the rest of the system.

The TDM and control valve follow along if all are working correctly. Correctly is the BUZZ word, as a malfunction requires a little more probing. These tests can quickly determine which parts need replacement. The free little Hummwv manual will get one pointed in the right direction. Wish I had a dollar for the times I linked to it here. > https://gear-report.com/wp-content/uploads/2017/03/HMMWV A1 Troubleshooting.pdf

Failure is not the option were looking for on the HumV fan circuit.

Here a little observation. Every Spring / Summer, overheating FAN issues. Come around to late Fall /Winter, white smoke and glow plugs.
New first timers... anything goes. The cycle of HumV I guess. Just saying, CAMO

 

[springer1981]

Starting with the first picture page 8 of my build thread is my fan clutch problems.. https://www.steelsoldiers.com/threads/my-new-1992-m998-avenger.184818/page-8

To see the fan clutch working you can watch the clutch while you plug and unplug the time delay module. In the picture below, watch the piece with the red arrow point to it. Compare it to the end of the fan mount and you will see it move about 1/4" in and out. That will tell you if it is engaging and disengaging with the time delay. Once you see what in vs out looks like, you can tell if it is engaged just by looking at it.

The whine might be coming from a bearing in the clutch so try to isolate the noise before you fix anything. My cadillac valve doesn't make any noise.

 

[Gatorfabny]

Not an expert, here or on TV. Pretty good at rolling around on the creeper with 16 inches of ground clearance LOL.

Yes this is all true. The fan spins when the engine is running. The difference characteristics sounds and power required of a free wheeling verses an engaged fan can be demonstrated on a cold engine.

In a correctly working system... cool engine running, pulling the connections to solenoid valve, TDM or a temp sw lead should engage fan.

It's a bit subtle... so a couple of plug in's and wait wait wait and pull's and watch and listen... for it. Having one work the throttle a little helps to get the effect you looking for.

Note: Key to proper temp / fan cycling is the "electrical temperature switch" in the water crossover manifold. Think of it as the heart beat to the rest of the system.

The TDM and control valve follow along if all are working correctly. Correctly is the BUZZ word, as a malfunction requires a little more probing. These tests can quickly determine which parts need replacement. The free little Hummwv manual will get one pointed in the right direction. Wish I had a dollar for the times I linked to it here. > https://gear-report.com/wp-content/uploads/2017/03/HMMWV A1 Troubleshooting.pdf

Failure is not the option were looking for on the HumV fan circuit.

Here a little observation. Every Spring / Summer, overheating FAN issues. Come around to late Fall /Winter, white smoke and glow plugs.
New first timers... anything goes. The cycle of HumV I guess. Just saying, CAMO

Thank you for the input and advice!!

 

[Iambiig]

Thinking it was a slipping transmission issue, the tech said it was a bad fan clutch. Before buying the $600 fan clutch, the cadillac valve tested bad. Would assume the valve would mirror a fan clutch issue? The problem was that the truck sounded normal, than at higher RPMS made like a jet engine sound (similar to slipping trans)

 

[Action]

Thinking it was a slipping transmission issue, the tech said it was a bad fan clutch. Before buying the $600 fan clutch, the cadillac valve tested bad. Would assume the valve would mirror a fan clutch issue? The problem was that the truck sounded normal, than at higher RPMS made like a jet engine sound (similar to slipping trans)

The jet engine sound is normal. That is what you hear when the fan kicks on.
Even if the fan isn't "on". you will still see it spinning.

 

[Iambiig]

The system seems way over engineered. Would it be possible to replace the system with a normal centrifugal fan clutch? Why all the bells and whistles with hydraulics?

 

[Milcommoguy]

Sure... one could do that. IMO, Easier to read up and understand the in's and out's of how it works in the case of the fan system. It will make sense as to the design.

But hey... do your thing, CAMO

 

[Coug]

There are some people that have replaced the hydraulic clutch system with a thermal fan clutch, and I haven't heard any issues related to doing so.

The military system of "fail to full operation" of the system makes sense in a military setting; and I like knowing that if something goes wrong it will engage, or if somehow it does fail disengaged, , I can unplug a wire under the dash and have it work at full power (which I did have happen once, bad TDM)

 

[Iambiig]

Just one more thing, would a failed cadillac valve prevent the hydraulic system to engage the clutch..?

 

[Coug]

Just one more thing, would a failed cadillac valve prevent the hydraulic system to engage the clutch..?

If it somehow failed in the open/energized position, which would be extremely rare.

The fan clutch requires pressure to disengage. When power is applied to the cadillac valve, it sends fluid pressure to the fan clutch. When no power to the cadillac valve, the fan hub is bypassed and the fan clutch is fully engaged.

 

[papakb]

The fan in the HMMWV operates backwards from everything you expect and you need to keep this in mind when working on it. When the engine is cool there should be 24v power to the cadillac valve sending fluid pressure to the clutch disengaging it. It's when the engine reaches ~220 degrees the 24v power to the cadillac valve turns off removing fluid pressure to the clutch causing it to engage. This is a fail safe mode that makes the fan run if power is lost to the TDR or cadillac valve so the engine doesn't overheat. If you listen you can hear fluid running thru the valve on a cool engine that shuts off when the fan actuates.

This is the hissing sound some new owners complain about that can be solved with a simple band of rubber between the hose clamp that holds the cadillac valve on it's mounting and the body of the valve itself.

On a cool engine you can also unplug and plug the TDR, watch the fan clutch move forward and backward and listed for the hissing sound to come and go to test operation.

A word to the wise, replace the hose clamps on the fluid lines with aeroquip aircraft fittings and that'll stop all those hydraulic leaks around the valve.

 

[Iambiig]

The fan in the HMMWV operates backwards from everything you expect and you need to keep this in mind when working on it. When the engine is cool there should be 24v power to the cadillac valve sending fluid pressure to the clutch disengaging it. It's when the engine reaches ~220 degrees the 24v power to the cadillac valve turns off removing fluid pressure to the clutch causing it to engage. This is a fail safe mode that makes the fan run if power is lost to the TDR or cadillac valve so the engine doesn't overheat. If you listen you can hear fluid running thru the valve on a cool engine that shuts off when the fan actuates.

This is the hissing sound some new owners complain about that can be solved with a simple band of rubber between the hose clamp that holds the cadillac valve on it's mounting and the body of the valve itself.

On a cool engine you can also unplug and plug the TDR, watch the fan clutch move forward and backward and listed for the hissing sound to come and go to test operation.

A word to the wise, replace the hose clamps on the fluid lines with aeroquip aircraft fittings and that'll stop all those hydraulic leaks around the valve.

The cadillac valve tested at 20 ohms. I do not notice any movement on the fan clutch plugged or unplugged. The truck was not overheating. Funny thing, I did notice the hissing sound at times while steering, didn't really think anything of it. There was a distinct sound change when on the highway, that sounded like a slipping trans or a spooled up turbo.