Lr4 5.0 HSE only normal height available

[gsxr]

I'm going through this right now, after a year or two of intermittent "only normal height available" messages. Similar symptoms with the compressor "working hard" after a minute or two running. IID tool shows fault code C1A20-64(6C), "Pressure too slow filling". Compressor and motor temps climb to 100-120°C and pressure struggles to hit 250psi.

I removed the original Hitachi and tried replacing the desiccant beads in the drier (old ones were not really bad, which surprised me) but there was no change. Exhaust valve rubber looked fine too. Couldn't find any significant leaks either. Gave up and ordered a new Genuine Hitachi from RM European, $575 delivered... arriving today. Anything you find in the $200-$500 USD range is going to be fake "Hitachi-type" junk, don't get suckered by the low prices.

I'll post after I get the new one in hand, bench test compared to the old one, and get it installed. Hopefully by tomorrow.

As you'll find in other threads, if you have an original Hitachi and change to an AMK compressor, you must also replace the control relay, cut pipes and use splice joints to connect different pipes, and possibly reprogram the ECU as well. You also have to try and find a complete AMK kit that includes the plastic enclosure which I believe is also different. I didn't want to go through all that hassle as I haven't heard anything about the AMK being any more reliable/bulletproof. (?)

If the new compressor doesn't fix the problem, I'm gonna be grumpy.

 

[avslash]

I'm going through this right now, after a year or two of intermittent "only normal height available" messages. Similar symptoms with the compressor "working hard" after a minute or two running. IID tool shows fault code C1A20-64(6C), "Pressure too slow filling". Compressor and motor temps climb to 100-120°C and pressure struggles to hit 250psi.

I removed the original Hitachi and tried replacing the desiccant beads in the drier (old ones were not really bad, which surprised me) but there was no change. Exhaust valve rubber looked fine too. Couldn't find any significant leaks either. Gave up and ordered a new Genuine Hitachi from RM European, $575 delivered... arriving today. Anything you find in the $200-$500 USD range is going to be fake "Hitachi-type" junk, don't get suckered by the low prices.

I'll post after I get the new one in hand, bench test compared to the old one, and get it installed. Hopefully by tomorrow.

As you'll find in other threads, if you have an original Hitachi and change to an AMK compressor, you must also replace the control relay, cut pipes and use splice joints to connect different pipes, and possibly reprogram the ECU as well. You also have to try and find a complete AMK kit that includes the plastic enclosure which I believe is also different. I didn't want to go through all that hassle as I haven't heard anything about the AMK being any more reliable/bulletproof. (?)

If the new compressor doesn't fix the problem, I'm gonna be grumpy.

Are you in an LR3 or 4? Asking because I thought the older LR3's ran at the 248psi, but that the LR4's max pressure was reduced to 148. Just curious.

 

[gsxr]

It's a 2010 LR4. And the pressure is definitely 245-250psi max.

Are you sure about the LR4 max pressure being reduced? I've not read that before. The FSM has conflicting info (see below), first it says compressor max pressure is 16.8 bar (244psi) but the reservoir has working pressure above that, and max pressure is 335psi...?

 

[avslash]

You have the documents, so I'm going with your answer.

I have not really had any issues with mine other than a faulty valve block, so I have never dug into it or tried to measure it. I do remember reading two posts years ago either here or on EP that the maximum pressure had been reduced to 148psi to deal with a high volume of compressor failures on the LR3.

As with anything on the internet, got to take it all with a grain of salt.

 

[avslash]

Just broke out my service manual, and it does agree with what you posted.

I'm guessing what I have circled in red is what I saw referenced. No idea if that actually changed from the LR3 or not. Don't have an LR3 manual.

 

[avslash]

On a side note, how does a compressor with a maximum pressure of 243.6psi supply a reservoir with a working prssure of 253.75psi.

Thermal expansion from the air heating as it is compressed? Not a physicist so just curious.

 

[Stuart Barnes]

On a side note, how does a compressor with a maximum pressure of 243.6psi supply a reservoir with a working prssure of 253.75psi.

Thermal expansion from the air heating as it is compressed? Not a physicist so just curious.

The working pressure is the pressure that the reservoir or “receiver” is designed to operate at for its expected lifespan. In our case 253.75 psi or 17.5 bars if we’re fond of si units.

The highest temperature that the air from the compressor will reach is that at the immediate discharge pressure when it exits the compressor. (Assuming it’s not affected by engine exhaust etc)

Effectively the pressure and temperature will both dip when the air enters the receiver. The pressure slightly and the temperature more so.

If you have a garage compressor you’ll feel that the compressor is toasty warm when it’s running, especially the discharge pipe compared to the relative cool temperature of the receiver.

 

[gsxr]

Update on my compressor replacement... while the fault went away, I think the new compressor is just masking the root cause of the problem. But I need data from other vehicles for comparison.

More details in a separate thread here:
https://www.landroverworld.org/threads/air-compressor-temperature-what-is-normal.42049/

 

[avslash]

Won't be back with mine for a week or more, but if no info for you by then, I will take some readings.

Aren't the compressor and the three valve blocks the only "active" part of the actual mechanical system? if you rule out malfunction with those items everything else in the system is passive and I would think you would basically be searching for a leak at that point. If the problem is in the control system, you would probably be looking for a sensor that was out of spec and causing the system to see a lower pressure than what is actually in the system or a heat sensor not tripping an "overheat" warning.

Are you getting a "compressor overheat" error message? I know I have seen that message on mine in a few limited circumstances. If not, and you are not experiencing any other symptoms like a drooping, I would tend to just keep an eye on it.

Compressors get HOT. I carry a little Viair unit with me and it will singe you skin after it has been running for two or three minutes.

Anecdotal, I know, but if your compressor temperature sensor is functional, you are not getting the "overheat" warning, and there are no other symptoms, I tend think it is probably within spec.

 

[gsxr]

Correct - it could be a leak somewhere, that I'm not finding. This is what I'm trying to figure out. AFAIK there is only one pressure sensor, at the main valve block. I don't think there's any way to test it other than just replacing it and seeing if there is any change.

There is no fault code stored for "compressor overheat", either with old or new compressor. Not sure if there is a fault for that but I should check the FSM. With the old compressor, a couple times I did see a notification in the cluster something like "height will adjust when system cools", implying the compressor or motor exceeded the temp limits shown in the FSM.

The compressor and motor temp sensors are part of the compressor assembly, so both those items are brand new on the new compressor.

While I am not getting any 1 corner dropping, if parked for a week or longer, all four corners slowly start to drop evenly... maybe a couple inches. Not sure what that may indicate?