M1165a1 power steering and overheating

[Lepruchaun13]

Hey all I am working on a m1165a1 and am having a dewsey of a time figuring out this issue. I have bled the power steering system numerous times to eliminate any air pockets in it. After doing so power steering works great, take it for a test drive and it is no longer working. The truck additionally will overheat on this test drive about 20 minutes into it. After stopping and unplugging the time delay module the engine started to cool down but power steering still does not work. We have replaced, power steering pump, power steering reservoir, hydro boost, time delay module, power steering solenoid, pcb, both temperature sensors, and manifold. This truck has just recently had an engine replaced as well as the alternator. If you all have any ideas please let me know. This truck has been in the shop for two months now so please help!

 

[Retiredwarhorses]

sounds like your fan clutch never engaged on the over heat, on the PS issue? You probably have the wrong serpentine belt.

 

[Milcommoguy]

The HumV breakfast challenge...
There's a lot going on here with a lots of parts changing. Try to narrow it down to one worm at a time. I think of the machine as systems all working together. Changing part the way I am reading this... is like chasing worms, LOL. Seriously, go back to the beginning at engine replaced and work thru each SYSTEM. Keep in mind the engine replacement and all the system interactions.

When I see a scramble to change lot of parts, upon further investigation (asking questions) there becomes an "AHA moment" The Great Gang here will start with lots of questions to drill down to the problems. Be sure to be very clear as to the when, what, observation, testing, results questions.

One worm at a time, CAMO

 

[Lepruchaun13]

Thanks for your response. I do understand how it looks like we have been throwing parts at it. We replaced the engine back in end of April beginning of may. Verified that all plugs and wires were re connected and placed all parts back in truck. Started experiencing surging issues and found the alternator/voltage regulator had been fried as well as the pcb. Trace that issue back to the bus bar behind the batteries and replaced the alternator and pcb, no more surging.

Took it on a test drive and found the truck to be overheating, tested time delay module and found it to be bad, replaced time delay module. Took truck for another test drive still experienced overheating(the issue is always resolved by unplugging time delay module) determined the solenoid was bad and replaced it. Still overheating. Since the pcb came with the glow plug temp sensor replaced that and the other temp sensor as well. Still overheating

At some point during this noticed the power steering reservoir was leaking and replaced it. Also noticed the power steering was no longer working properly, (again works after bleeding cuts out halfway through road test). Took all the lines off to verify no plugs were left in them and replaced the manifold on the line as well. We then decided the power steering pump must be faulty and replaced it. Still overheating and no power steering.

Having bled the power steering each time we disconnected lines and components we determined the only other item that could have caused an issue would be the hydro boost so we replaced that but to no avail, still no power steering and it is overheating. The only other component left is the rear dif and the steering gear.

This was our process as we have worked on this truck. Again thanks for responding and any assistance you can give!

 

[Milcommoguy]

Now your talking. This break down some of the things going on in the systems... electrical, cooling, steering / hydro with a better idea where to jump into and squish some worms.

The inter web thing is great HumV help here. You are the boots and eyes on the problem, accurate data GOOD. Guy's here will be live firing questions aiming to get a fix.

WELCOME to the group. Hang in there..... a little radio silence right now, hehe. Calling W5DTW.... LOL Someone check out front of the Chinezzze restaurant.

I am still fighting gremlins. A higher form of worms, CAMO GOOD LUCK

 

[Mogman]

Thanks for your response. I do understand how it looks like we have been throwing parts at it. We replaced the engine back in end of April beginning of may. Verified that all plugs and wires were re connected and placed all parts back in truck. Started experiencing surging issues and found the alternator/voltage regulator had been fried as well as the pcb. Trace that issue back to the bus bar behind the batteries and replaced the alternator and pcb, no more surging.

Took it on a test drive and found the truck to be overheating, tested time delay module and found it to be bad, replaced time delay module. Took truck for another test drive still experienced overheating(the issue is always resolved by unplugging time delay module) determined the solenoid was bad and replaced it. Still overheating. Since the pcb came with the glow plug temp sensor replaced that and the other temp sensor as well. Still overheating

At some point during this noticed the power steering reservoir was leaking and replaced it. Also noticed the power steering was no longer working properly, (again works after bleeding cuts out halfway through road test). Took all the lines off to verify no plugs were left in them and replaced the manifold on the line as well. We then decided the power steering pump must be faulty and replaced it. Still overheating and no power steering.

Having bled the power steering each time we disconnected lines and components we determined the only other item that could have caused an issue would be the hydro boost so we replaced that but to no avail, still no power steering and it is overheating. The only other component left is the rear dif and the steering gear.

This was our process as we have worked on this truck. Again thanks for responding and any assistance you can give!

If the solenoid valve was bad unplugging the TDM would not have changed anything, time to look at the fan thermal switch, if you unplug it and the fan runs all the time the switch is bad.

 

[Mogman]

View attachment 901370 Now your talking. This break down some of the thing going on in the systems... electrical, cooling, steering / hydro with a better idea where to jump into and squish some worms.

The inter web thing is great HumV help here. You are the boots and eyes on the problem, accurate data GOOD. Guy's here will be live firing questions aiming to get a fix.

WELCOME to the group. Hang in there..... a little radio silence right now, hehe. Calling W5DTW.... LOL Someone check out front of the Chinezzze restaurant.

I am still fighting gremlins. A higher form of worms, CAMO GOOD LUCK

Just got back a few minuets ago

 

[Lepruchaun13]

If the solenoid valve was bad unplugging the TDM would not have changed anything, time to look at the fan thermal switch, if you unplug it and the fan runs all the time the switch is bad.

Where is the fan thermal switch located? I can’t find that in the TM?

The real issue seems to be that it does not seem to have the appropriate hydraulic power. The power steering continues to struggle regardless of the fan overheating. Went over the TM yesterday and the ps pump we pulled off was for the 199000-240000. We replaced it with the 240000 and above ps pump due to the truck being above 240000. Is there a big difference between the two? Swapped the fan solenoid again with a known working one but have not noticed a difference.

 

[Mogman]

Where is the fan thermal switch located? I can’t find that in the TM?

The real issue seems to be that it does not seem to have the appropriate hydraulic power. The power steering continues to struggle regardless of the fan overheating. Went over the TM yesterday and the ps pump we pulled off was for the 199000-240000. We replaced it with the 240000 and above ps pump due to the truck being above 240000. Is there a big difference between the two? Swapped the fan solenoid again with a known working one but have not noticed a difference.

It is in the water cross over on the drivers side, (where the top hose connects to the engine) that later pump has a little higher pressure, will not make any difference in practical terms.

 

[Retiredwarhorses]

Where is the fan thermal switch located? I can’t find that in the TM?

The real issue seems to be that it does not seem to have the appropriate hydraulic power. The power steering continues to struggle regardless of the fan overheating. Went over the TM yesterday and the ps pump we pulled off was for the 199000-240000. We replaced it with the 240000 and above ps pump due to the truck being above 240000. Is there a big difference between the two? Swapped the fan solenoid again with a known working one but have not noticed a difference.

you still haven’t answered the question about your serp belt…

 

[Lepruchaun13]

you still haven’t answered the question about your serp belt…

Are you saying the wrong belt completely or routed wrong? As far as I can tell there is no reference to the belt having been replaced in the lifetime of this truck, and I have verified that it is routed correctly.

 

[Lepruchaun13]

It is in the water cross over on the drivers side, (where the top hose connects to the engine) that later pump has a little higher pressure, will not make any difference in practical terms.

we had replaced that with the initial diagnoses of overheating, unfortunately it made no difference.

 

[Mogman]

If unplugging the TDM which causes the fan to run all the time "fixes" the overheating then you have an issue with the fan control system.

Most of the new parts out there are Chicom crap including thermal switches, this is one of the big issues with just throwing parts at a truck instead of actually troubleshooting to the fault, many end up with multiple crap parts installed that make the situation even worse and much harder to troubleshoot.

Again, unplug the thermal switch, if the fan runs all the time then the TDM and valve are likely OK, if not you have a TDM/Valve problem.
Then with the thermal switch connected the fan does not come on when getting to the point of overheating the switch is bad.
Also have you confirmed it is actually overheating by using a laser temp gauge? the factory gauges vary widely on their accuracy and the HMMWV runs hot anyway, seeing 230 deg or more on a factory gauge is not uncommon.

What RWH is saying is it is possible the wrong belt may have been installed and it may not be tight enough, this could cause the water pump and PS pump to slip.

 

[Lepruchaun13]

If unplugging the TDM which causes the fan to run all the time "fixes" the overheating then you have an issue with the fan control system.

Most of the new parts out there are Chicom crap including thermal switches, this is one of the big issues with just throwing parts at a truck instead of actually troubleshooting to the fault, many end up with multiple crap parts installed that make the situation even worse and much harder to troubleshoot.

Again, unplug the thermal switch, if the fan runs all the time then the TDM and valve are likely OK, if not you have a TDM/Valve problem.
Then with the thermal switch connected the fan does not come on when getting to the point of overheating the switch is bad.
Also have you confirmed it is actually overheating by using a laser temp gauge? the factory gauges vary widely on their accuracy and the HMMWV runs hot anyway, seeing 230 deg or more on a factory gauge is not uncommon.

What RWH is saying is it is possible the wrong belt may have been installed and it may not be tight enough, this could cause the water pump and PS pump to slip.

I have verified the belt is correct and is tight but have not been able to test the thermal switch yet.

 

[TOBASH]

I seem to recall another member years ago had an issue where the power steering cooling radiator was plugged, or some such sort issue. Have you made sure that you have free flowing fluid through the cooler and that your stack is clean?

 

[Retiredwarhorses]

I have verified the belt is correct and is tight but have not been able to test the thermal switch yet.

im curious how you determined it’s the correct belt…and tight enough.
The wrong belt is only 1in longer, but has some serious side effects.

 

[Lepruchaun13]

I seem to recall another member years ago had an issue where the power steering cooling radiator was plugged, or some such sort issue. Have you made sure that you have free flowing fluid through the cooler and that your stack is clean?

We had that thought and bypassed the cooler altogether, no improvement.

 

[Lepruchaun13]

im curious how you determined it’s the correct belt…and tight enough.
The wrong belt is only 1in longer, but has some serious side effects.

Compared it to another trucks belt

 

[TOBASH]

We had that thought and bypassed the cooler altogether, no improvement.

Did you bleed the system of air after bypass by lifting the front 15 degrees and turning wheel lock to wheel lock 20 times with the engine running?

 

[Lepruchaun13]

Did you bleed the system of air after bypass by lifting the front 15 degrees and turning wheel lock to wheel lock 20 times with the engine running?

Did you bleed the system of air after bypass by lifting the front 15 degrees and turning wheel lock to wheel lock 20 times with the engine running?

I didn’t specifically measure the angle but yes it was up off the wheels and was turned from full stop left to full stop right 20 times