M1083A1 Starting Issues

[TomTime]

Sorry for the delayed response but situations and family issues.
A coupIe days after you posted I checked on those parts for the HEUI pre-filter and found them on line. It states the parts are for the C7 engine only. I checked the internet and could not find anything for the 3126 HEUI.
I called the local Caterpillar dealer and they said that there was no HEUI pre-filter for the 3126 and only for the C7 which will not fit the 3126.
So I called the main Caterpillar number and spoke with a tech. He said the same thing, only pre-filter for the C7 which will not work on the 3126. He said that they never made one for the 3126.

 

[TomTime]

More likely fan solenoid Or control. Do you hear a whoosh of air from the passenger dash area when you turn off the main switch?

The fan control solenoid is under the far right end of the passenger dash. It is right above eye level when standing beside the truck in the passenger door, with the kick panel removed.

The fan control is kind of reverse logic. It applies air to release the clutch and allow it to freewheel. So the 205F thermal switch in the upper radiator pipe(A0) or the ECU(A1) provides switched 24V power to the solenoid to energize it, which provides air to allow the clutch to freewheel. When the coolant in the upper radiator pipe reaches 205F, that switch(or the ECU on the A1) opens the solenoid circuit, which de-energizes and vents air with a woosh in the cab, and the fan engages. Turning off the main switch does the same thing, removes power to that solenoid valve and lets it vent the fan clutch air.

The fording switch is in parallel with the thermal switch and overrides it, providing 24V to keep the solenoid powered and the fan freewheeling. I believe fan power is provided by CB22(or the ECU)

If that solenoid is not energizing, first thing I would try is confirm CB22 is providing power, then turn on the fording sw. It provides power independent of the ECU so that might rule it out. Next I would look for 24V at the connector of the solenoid with main and fording sw on. If it is missing, well you need to dig back into the circuit to find out why. If it is there, I came up with a lower cost alternative to the rare original fan solenoid last year. Here is a link to the Youtube vid I did on it…

Good day,

Well, I finally got back to the engine fan issue yesterday. I purchased two of the new alternative solenoids and the connector kit to connect the two solenoids together. I watched yours (@Ronmar) and @CallMeColt videos, which both were excellent.
I removed the old solenoids, assembled and installed the new coupled solenoids. The air tanks were full, turn on the power switch, heard the "pssst" release of air from the solenoid. Checked the fan and, no go, fan still won't move.

Due to it was mid afternoon at this time, sitting in a metal box with glass, 94 degrees, dewpoint was 75, heat index at 101, and I was sweating like a stuck pig at a 4th of July BBQ, I didn't get to check the voltages or anything else.

Hopefully I can get this fixed soon, so I can see if there are any other issue with the fan.

 

[Ronmar]

ok, you shouldn’t hear any air release until you turn OFF the main switch.

The wet tank needs to be over 85PSI or you won’t get any air to the solenoid. Unless you are using the brakes the pri/sec tanks can set at 120 all day long with the wet tank empty. Without a gauge, the only way to know the wet tank is over 85 is when the dryer purges at 125PSI.

With the main sw on, the solenoid should be on to apply air to release the fan clutch. So under this condition, loosen the airline fitting on the fan shroud and insure air is making it down to there…

 

[TomTime]

ok, you shouldn’t hear any air release until you turn OFF the main switch.

The wet tank needs to be over 85PSI or you won’t get any air to the solenoid. Unless you are using the brakes the pri/sec tanks can set at 120 all day long with the wet tank empty. Without a gauge, the only way to know the wet tank is over 85 is when the dryer purges at 125PSI.

With the main sw on, the solenoid should be on to apply air to release the fan clutch. So under this condition, loosen the airline fitting on the fan shroud and insure air is making it down to there…

Yep, I had it backwards, as you said air should release when switch is turned off...brain fart...

Well I know there was air in the wet tank because I had the engine running to get the air tanks filled and it purged at least twice during that time. When I get home I'll check the airline fitting on the fan shroud to see if air is getting to that point. Big thanks!

 

[CallMeColt]

Good day,

Well, I finally got back to the engine fan issue yesterday. I purchased two of the new alternative solenoids and the connector kit to connect the two solenoids together. I watched yours (@Ronmar) and @CallMeColt videos, which both were excellent.
I removed the old solenoids, assembled and installed the new coupled solenoids. The air tanks were full, turn on the power switch, heard the "pssst" release of air from the solenoid. Checked the fan and, no go, fan still won't move.

Due to it was mid afternoon at this time, sitting in a metal box with glass, 94 degrees, dewpoint was 75, heat index at 101, and I was sweating like a stuck pig at a 4th of July BBQ, I didn't get to check the voltages or anything else.

Hopefully I can get this fixed soon, so I can see if there are any other issue with the fan.

If anything, you know that you will have 0% solenoid issues now. These old solenoids are bound to have a problem. Glad the videos were helpful! It sucks doing something for "nothing" sometimes, but, at least you know this will be a good part "forever".

 

[TomTime]

If anything, you know that you will have 0% solenoid issues now. These old solenoids are bound to have a problem. Glad the videos were helpful! It sucks doing something for "nothing" sometimes, but, at least you know this will be a good part "forever".

Yeah, I've had a lot of practice with checking lots of things, that weren't the cause, when I had a crank but no start engine issue. Checked everything it said to in the TM's and from SS members and from Youtube video. It turned out the injectors were frozen due to, we believe, sitting for long periods, who knew?
But, yep now I know that both solenoids are good, but still have a fan issue. I also now know a lot more of the truck since I checked, cleaned and repaired a lot of the issues that the no start could have been.

Thanks again for the videos you produce, great stuff!

 

[TomTime]

ok, you shouldn’t hear any air release until you turn OFF the main switch.

The wet tank needs to be over 85PSI or you won’t get any air to the solenoid. Unless you are using the brakes the pri/sec tanks can set at 120 all day long with the wet tank empty. Without a gauge, the only way to know the wet tank is over 85 is when the dryer purges at 125PSI.

With the main sw on, the solenoid should be on to apply air to release the fan clutch. So under this condition, loosen the airline fitting on the fan shroud and insure air is making it down to there…

Well, got back to the fan issue again. First I took the air lines off to check and make sure that the lines were not clogged or pinched, they were not. Fired up the engine and built up the air until the air dryer purged twice. Turned off the engine then turned on the power switch on and I still hear the air pssst from the solenoid and no air at the fan shroud connection, fan will not turn.

I checked the voltage at CB22. Removed the circuit breaker and checked for voltage, 0 volts. Turned the power switch on and got 24.6 volts then in a couple seconds it dropped to 20.8 volts. Turned on the fan switch with the power switch on and the voltage went to 23.8 volts.

I checked the voltage at the solenoid electrical connection. Nothing turned on, 0 volts. Turned the power switch and fan switch on and got 24.6 volts at the connection. Turned both switches off and 0 volts again.

Still no fan movement.

 

[CallMeColt]

Well, got back to the fan issue again. First I took the air lines off to check and make sure that the lines were not clogged or pinched, they were not. Fired up the engine and built up the air until the air dryer purged twice. Turned off the engine then turned on the power switch on and I still hear the air pssst from the solenoid and no air at the fan shroud connection, fan will not turn.

I checked the voltage at CB22. Removed the circuit breaker and checked for voltage, 0 volts. Turned the power switch on and got 24.6 volts then in a couple seconds it dropped to 20.8 volts. Turned on the fan switch with the power switch on and the voltage went to 23.8 volts.

I checked the voltage at the solenoid electrical connection. Nothing turned on, 0 volts. Turned the power switch and fan switch on and got 24.6 volts at the connection. Turned both switches off and 0 volts again.

Still no fan movement.

Might need to rebuild the fan clutch itself then? There is a kit for it.

 

[Ronmar]

Ok, forgot if this is an A0 or A1, but the fording sw, solenoid and fan control work the same. With the fording sw in the on/fan disengged position, when you turn on the ignition sw you should have 24v at the fan solenoid valve connector(power on = fan off). If you plug in the solenoid to that connector, what happens? The solenoid should power up and you should hear airflow If the wet tank is above 85 PSI. When you disconnect the solenoid, it should de-energize and you should hear a whoosh as the valve vents the air from the fan side of the valve. You can hear what a power-on, and a power-off and vent should sound like at 5:20 in this video. If it doesn’t sound like this, pop off the input line at the solenoid valve and make sure air is reaching the solenoid valve. Hold on tight, it should blow like a blowgun until the tank bleeds down to 85PSI.

ignition power flows thru CB 22, thru the fan sw in the disengaged position and powers the fan solenoid. On the A0 it also flows from CB22 thru the fan thermal sw which is in parallel with the fording sw to power the fan solenoid and keep thie fan disengaged. When the A0 goes over 205F the thermal sw opens to de-energize the solenoid and engage the fan. On an A1 the ECU provides 24V until the engine temp reaches the fan control point then it removes it to de-energize the solenoid/engage the fan. The fording sw is in parallel with these sources and can override them to power the solenoid and disengage the fan Regardless of engine temp. It should also power the dash light…

 

[TomTime]

Might need to rebuild the fan clutch itself then? There is a kit for it.

Well, @CallMeColt I believe you might be correct. It appears that the fan clutch is frozen. I removed the airline from the solenoid and switched on the fan switch and it was sending air to the fan clutch however the fan still will not move. Also I can hear air leaking from the area of the fan clutch, so I believe the clutch needs to be replaced or rebuilt.

A new one is out of the question at $700.00, so I need a rebuild kit.

LMTV/FMTV/MTV Engine Fan Clutch Assembly(3116/3126 CAT)

Shop the LMTV/FMTV/MTV Engine Fan Clutch Assembly at Midwest Military Equipment. Fits Stewart & Stevenson / BAE for A0 & A1 generation trucks. Fast handling time.

midwestmilitaryequipment.com

I looked online for a rebuild kit but could not find anything that specifically says it goes to the Cat 3126 fan clutch. However, there is a kit listed on the, LMTV/FMTV Parts Spreadsheet, kit "#800SKL" (comes up as 8000SKL, online) but it also states on the spreadsheet, "* not known to be installed by anyone yet. Will update soon as known".

Kit Masters 8000SKL Engine Cooling Fan Clutch Seal and Friction Lining Kit + Cross Reference | FinditParts

Kit Masters 8000SKL FA Kysor-Style Fan Clutch Seal & Lining Kit ✓ Order now for same-day shipping on eligible purchases from FinditParts.com, America's online marketplace for heavy duty parts.

www.finditparts.com

Fan Clutch Repair Kit P/N ECK1568 Ref# 8000SKL, 1681030C92, 10330543502, 9908401 | eBay

New Genuine PAI Fan Clutch Repair Kit P/N ECK-1568.

www.ebay.com

One, does anyone know if this is the kit that fits the Cat 3126 fan clutch in an A1? Two, does anyone know if anyone has ever used it yet and if it works? Three, does anyone know of a kit if the above doesn't work?

Also on a side note, one of the newly installed injectors, #1 cylinder, has already died with only about 1.5 hours of run time. In my past search for injectors I have read that people have replaced injectors, new and reman that were either DOA or failed shortly after install, so I don't fill too bad.

On a high note, there is a 1 year warranty on the injectors and company I purchased them from has ordering me another one.

Now to get the clutch repaired.

Again, thanks to everyone who has helped!

 

[CallMeColt]

Well, @CallMeColt I believe you might be correct. It appears that the fan clutch is frozen. I removed the airline from the solenoid and switched on the fan switch and it was sending air to the fan clutch however the fan still will not move. Also I can hear air leaking from the area of the fan clutch, so I believe the clutch needs to be replaced or rebuilt.

A new one is out of the question at $700.00, so I need a rebuild kit.

LMTV/FMTV/MTV Engine Fan Clutch Assembly(3116/3126 CAT)

Shop the LMTV/FMTV/MTV Engine Fan Clutch Assembly at Midwest Military Equipment. Fits Stewart & Stevenson / BAE for A0 & A1 generation trucks. Fast handling time.

midwestmilitaryequipment.com

I looked online for a rebuild kit but could not find anything that specifically says it goes to the Cat 3126 fan clutch. However, there is a kit listed on the, LMTV/FMTV Parts Spreadsheet, kit "#800SKL" (comes up as 8000SKL, online) but it also states on the spreadsheet, "* not known to be installed by anyone yet. Will update soon as known".

Kit Masters 8000SKL Engine Cooling Fan Clutch Seal and Friction Lining Kit + Cross Reference | FinditParts

Kit Masters 8000SKL FA Kysor-Style Fan Clutch Seal & Lining Kit ✓ Order now for same-day shipping on eligible purchases from FinditParts.com, America's online marketplace for heavy duty parts.

www.finditparts.com

Fan Clutch Repair Kit P/N ECK1568 Ref# 8000SKL, 1681030C92, 10330543502, 9908401 | eBay

New Genuine PAI Fan Clutch Repair Kit P/N ECK-1568.

www.ebay.com

One, does anyone know if this is the kit that fits the Cat 3126 fan clutch in an A1? Two, does anyone know if anyone has ever used it yet and if it works? Three, does anyone know of a kit if the above doesn't work?

Also on a side note, one of the newly installed injectors, #1 cylinder, has already died with only about 1.5 hours of run time. In my past search for injectors I have read that people have replaced injectors, new and reman that were either DOA or failed shortly after install, so I don't fill too bad.

On a high note, there is a 1 year warranty on the injectors and company I purchased them from has ordering me another one.

Now to get the clutch repaired.

Again, thanks to everyone who has helped!

At least you found the problem for sure now!

I can't help you on the rebuild, I just know it can be done.

Have an extra one someone gave me here that is an unknown condition with what they said was a rebuild kit for it that I just put away for a day that I might have nothing to do..... yeah right. It's a really small box though.

I'll be curious if you have the same fan clutch and if so, how the rebuild goes. May motivate me to go through the one I have so that I will have a known, good, rebuilt one that I can put on when I install my A/C kit so I will hopefully never need to touch it again.

 

[Ronmar]

You first need to determine which clutch/fan you have. I am not sure what year they shifted fan/clutch models, but I don’t believe the old model has a rebuild kit available.
you can either use your fingers, or an inspection mirror.

Old model: The fan is attached to the clutch/hub with Allen head screws.

New Model: The fan/hub is attached to the clutch with studs on the clutch that protrude thru the fan and the fan and hub are affixed with nuts and washers in the front.

If you feel and see Allen heads in front, it is the old style, no rebuild kit that I am aware of, and you must install the new model, and a new fan, as the fans are different between the two different clutches.

if you feel/see studs and nuts, then it is a new model, and that kit may be what you need…

I would pull it apart and look for a seal or some other defect that is preventing it from building pressure/releasing the clutch. This could be a bad hose or loose fitting on the front of the fan

You should not have had to turn on/engage the fan fording switch to get the solenoid to deliver air. The ECU should have provided 24V to the solenoid as soon as the main sw is turned on. It should maintain that voltage powering the fan solenoid untill the engine is hot enough to need the fan…

 

[TomTime]

You first need to determine which clutch/fan you have. I am not sure what year they shifted fan/clutch models, but I don’t believe the old model has a rebuild kit available.
you can either use your fingers, or an inspection mirror.

Old model: The fan is attached to the clutch/hub with Allen head screws.

New Model: The fan/hub is attached to the clutch with studs on the clutch that protrude thru the fan and the fan and hub are affixed with nuts and washers in the front.

If you feel and see Allen heads in front, it is the old style, no rebuild kit that I am aware of, and you must install the new model, and a new fan, as the fans are different between the two different clutches.

if you feel/see studs and nuts, then it is a new model, and that kit may be what you need…

I would pull it apart and look for a seal or some other defect that is preventing it from building pressure/releasing the clutch. This could be a bad hose or loose fitting on the front of the fan

You should not have had to turn on/engage the fan fording switch to get the solenoid to deliver air. The ECU should have provided 24V to the solenoid as soon as the main sw is turned on. It should maintain that voltage powering the fan solenoid untill the engine is hot enough to need the fan…

I have the newer model as it has the studs with the nuts. I tried to look for a diagram of the fan clutch online but I could not find one that would help with nomenclature and describing my findings.
When I checked the fan, like I said it has studs with nuts. The part of the clutch where the air hose connects into, moves freely and will rotate. But if you try to wobble it, there is about 1/8" front to back movement/play.
When I apply air to the fan clutch, by the fan switch, there is air leaking out of the center of the part that has the hose attached to it on the clutch (I hope you followed that). The air only leaked out of that area for about 15-20 seconds and stopped.
So, that part on the fan clutch that the air hose attaches to is either loose or worn out. Tomorrow I will take the shroud off and check out the clutch to see if it is just loose or worn.
As for the solenoid receiving the air when the power switch is turn on, I'm not sure, It is getting the 24 volts when the switch is turned on. I'm going to check out the clutch first and see if tightening or repairing it solves the issue.

One thing I've been meaning to ask but keep forgetting. When I turn the power switch on the fan for the transmission cooler comes on. Is that supposed to do that? Once the engine starts it goes off...at least I think it does...I don't hear it, but then again the engine is running.

Well, going to pickup my new injector and install it today, if mother nature allows me to.

Again, and I will keep saying it, thanks for all your help...I'm getting there, slowly, but getting there.

Tom.

 

[Ronmar]

There are exploded views of both fan assemblies in the A0 24P manual available here in the TM section(uploaded by ptracy). The new model shows a complete internal breakdown of the clutch assembly parts.

The air leaking for a bit then stopping would agree with the leak draining the wet tank to the 85PSI cutoff point of the protection valve. If you connect shop air to the system, i suspect it will keep leaking at the fan under those same test conditions with an air supply feeding the leak…. You can disconnect tge line at the shroud and feed it shop air directly to help you determine the leak…


The fan solenoid receives air whenever the wet tank is over 85 PSI. It only passes air when it is energized.

The aux cooler relay works just like the fan solenoid. Power from ECU off = relay(and solenoid) off = fans ON. I would suspect that with the fording sw off, your aux fans are continuing to run after engine startup.

This would indicate a wiring or programming issue with the ECU.

 

[Keith Knight]

After finding the source of my small oil leak, it's coming out of the oil pressure switch. The original switch is the NASON 19207-12419189-002 or the short number is "12419189" mid west military's supply shows one with number 12419189-001 and it looks a different than mine, eastern surplus and equipment one with 12419189-004 that looks just like mine. Reading the earlier post here you speak of using an off the shelf oil pressure switch. I found in the LMTV/FMTV parts spreadsheet on the site they reference NAPA part number 701-1578 NAPA doesn't have a picture of it but I found an image else where and it appears to have two terminals on the switch. I like the fact the original is water tight but not knowing if either of the original NASON switches are even available from them those venders would there be any other down side to using the NAPA switch quality or any thing? Besides the obvious Price difference.

 

[Ronmar]

Well quality is pretty subjective… I don't recall ever personally seeing a bad domestic oil pressure switch on a car or truck. But have come across quite a few bad Nason oil pressure switches on this forum alone, in this relatively small LMTV comunity… I do not know that I would call the Nason switches waterproof either, as some disections have revealed badly corroded contacts inside…

I see no disadvantage to using an off the shelf 15 PSI oil pressure switch, either single or dual terminal. The oil pressure switch provides a pathway to ground, so one of our 2 wires is ground. A single terminal switch provides a path to the engine block ground, so you would need to choose the correct wire to attach to the single terminal…

 

[Keith Knight]

Thanks, Sounds like I’ll be ordering the Napa version.

 

[Keith Knight]

Well....picked up the new switch from napa this morning, removed the old switch and guess what? The thread on is 1/4 NPT not 1/8 NPT so I'll be making an adapter bushing to save me from a 30 mile round trip back to town.

 

[Keith Knight]

New one is installed and working.
pulled the old one apart and it appears that I could have just unscrewed the set screw then unscrewed the plastic cap continue taking it all apart cleaned it really well tightened everything up on reassembly add a little RTV then screw the cap back on. So in the future hopefully someone with my problem of it works but leaks oil it’s basically serviceable.

 

[Ronmar]

View attachment 896742New one is installed and working.
pulled the old one apart and it appears that I could have just unscrewed the set screw then unscrewed the plastic cap continue taking it all apart cleaned it really well tightened everything up on reassembly add a little RTV then screw the cap back on. So in the future hopefully someone with my problem of it works but leaks oil it’s basically serviceable.

If the sw itself is leaking oil, i would not call it serviceable...