Looking for some help here. I just purchased a 2013 LX 570 with 131k miles. I had a PPI before purchase and tested and looked at as much as I could on this LX based on what I have read here prior to purchase. The build quality of this car is great and love driving it. I have had it 2 weeks and was planning to have all fluids changes next week and do the AHC fluid change. Well yesterday while running an errand I walk out the the drivers side under the rear door there is a big puddle and smoke from the AHC fluid. The LX is still in the N position and no warning lights came on the dash, When I got home it was still showing in the N position. With better light I checked it out this morning and the tank is empty and I see dripping around the rear globe but am unsure if it is coming from the globe or a hose. I can also see where it look wet around the shock and behind the rear tire on the frame. Assuming it just started spraying everything but can tell where it started. Trying to determine what parts I need to get ordered and can it be driven if the AHC pump can be disabled. Is my best guess the globe or shock or could I get luck and it just be a connection. Also is there a sub for the fluid that I can get local to fill the tank and try to determine where the leak started. I will get the OEM fluid once leak is fixed and bleed the whole system. I'm looking for options as there are no dealers open until after labor day and they may not even had stock of the fluid. I would like to narrow down what is leaking this weekend if possible.
2013 LX 570 AHC fail (1 Viewer)
- Thread starter BigBoy570
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- #3
I checked the line above the rear axel as best as I could and do not see anything wet. Most of the fluid is right around the rear drivers side globe.
- Thread starter
- #4
it does look like it was leaked behind the axel also, see pic above. I'm planning to get under there after work to see if I can find it but may not be able to unless I start removing parts.
Sorry to hear of this...happier point, the chassis on your 2013 is nice and clean (no rust!)
The fluid is a fairly specific hydraulic fluid so I wouldn't use a substitute. Definitely don't use brake fluid.
Are you sure the reservoir is empty? It can be very difficult to see fluid in it. You need to use a backlight from behind the tank. Also, there is room at the bottom of the tank where there can be fluid that you can't see from the access panel. But if you are that low, then it's getting critical. From under the rear bumper, I've been able to shove my phone camera in there and snap a picture. That's the best way to get a good idea of fluid level that I have found.
I know the truck says it's in N, but does it appear one of the corners is low? If you have lost fluid, after the height control valve, you should be down a couple inches in at least one corner, and if a gate valve has opened while driving, then lost height on both sides of the axle of the leaking part of the system.
If you are out of fluid and have not lost height, then the leak has to be between the pump and the leveling valve/accumulator. That would mean your leveling valves are closed and still holding pressure between the valves and the active part of the suspension. That would point towards the line NYC570 is referencing. It runs between the pump and the Height Control valve.
If the reservoir is empty and you don't have any fluid in the system between the pump and the height control valve, you definitely don't want the pump to run as it will allow air into the system. You can use the "AHC OFF" button, but remember that button is really only for when the truck is stationary. Once the truck is in motion, all the normal rules apply and the truck will ignore the "AHC OFF" command. The only way to be sure you don't run the pump would be to pull the fuse/relay for it.
highlighted the hydraulic line in green. If you had lost fluid after the height control valve, the truck would have to be on the bump stop on at least one corner. It would be the same as opening a bleeder valve from one of the corners.
Are you sure the reservoir is empty? It can be very difficult to see fluid in it. You need to use a backlight from behind the tank. Also, there is room at the bottom of the tank where there can be fluid that you can't see from the access panel. But if you are that low, then it's getting critical. From under the rear bumper, I've been able to shove my phone camera in there and snap a picture. That's the best way to get a good idea of fluid level that I have found.
I know the truck says it's in N, but does it appear one of the corners is low? If you have lost fluid, after the height control valve, you should be down a couple inches in at least one corner, and if a gate valve has opened while driving, then lost height on both sides of the axle of the leaking part of the system.
If you are out of fluid and have not lost height, then the leak has to be between the pump and the leveling valve/accumulator. That would mean your leveling valves are closed and still holding pressure between the valves and the active part of the suspension. That would point towards the line NYC570 is referencing. It runs between the pump and the Height Control valve.
If the reservoir is empty and you don't have any fluid in the system between the pump and the height control valve, you definitely don't want the pump to run as it will allow air into the system. You can use the "AHC OFF" button, but remember that button is really only for when the truck is stationary. Once the truck is in motion, all the normal rules apply and the truck will ignore the "AHC OFF" command. The only way to be sure you don't run the pump would be to pull the fuse/relay for it.
highlighted the hydraulic line in green. If you had lost fluid after the height control valve, the truck would have to be on the bump stop on at least one corner. It would be the same as opening a bleeder valve from one of the corners.
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You can only see the line from the front of the axle looking back. It's higher than the axle running in front of the crossmember. The picture that you posted isn't showing the line. Another way to trace it is to check the top of the rear driver side shock. That line crosses the line that attaches to the shock. You only need to replace the part that's parallel to the crossmember which is the one that rusts due to the heat wrap.
- Thread starter
- #8
I was able to get under there this morning and do not think it is the heat wrapped line. is it the section of line going over the cross member. Is this is or it more above the rear axel? I posted pic below
- Thread starter
- #9
Trying to determine if I can drive it to a shop. Strange is there are no warning lights on dash. Looking this up in the manual it appears I can drive with system off up to 50mph.
Turning off the 4-Wheel AHC
●The system will remain off until the height control “OFF” switch is pushed again,
even if the “ENGINE START STOP” switch is turned off.
●Even if the system is turned off, the system automatically modulated if the vehicle
speed exceeds following.
• 18 mph (30 km/h) with high or low mode
• 50 mph (80 km/h) with normal mode
Turning off the 4-Wheel AHC
●The system will remain off until the height control “OFF” switch is pushed again,
even if the “ENGINE START STOP” switch is turned off.
●Even if the system is turned off, the system automatically modulated if the vehicle
speed exceeds following.
• 18 mph (30 km/h) with high or low mode
• 50 mph (80 km/h) with normal mode
The line in heat wrap pictures is not an AHC line. It’s an insulated wire loom.
The all to common failure point that @NYC570 has helped many locate is located in the concave C channel rear cross member. This is located forward of the rear axle and the main fully boxed cross member.
The cross member you’re looking for is directly above the muffler. The lines run on top of it. You cannot see the insulated AHC line without removing the exhaust and/or sticking your phone or borescope up there. You can feel around for it with your hands.
The all to common failure point that @NYC570 has helped many locate is located in the concave C channel rear cross member. This is located forward of the rear axle and the main fully boxed cross member.
The cross member you’re looking for is directly above the muffler. The lines run on top of it. You cannot see the insulated AHC line without removing the exhaust and/or sticking your phone or borescope up there. You can feel around for it with your hands.
You can drive it.
Pull the AHC fuse.
Did you check the shocks? That left rear shock housing looks suspiciously new.
Did you check the bleeder valves (very easy to tighten down although i forget their size).
I think someone fd up a shock install here or fluid replacement here.
The only thing i can think of that would "blow" would be a shock.
Did you check the shocks? That left rear shock housing looks suspiciously new.
Did you check the bleeder valves (very easy to tighten down although i forget their size).
I think someone fd up a shock install here or fluid replacement here.
The only thing i can think of that would "blow" would be a shock.
Bleeder bolts are 10mm.
If he was losing fluid from a shock or a bleeder he would lose height. It doesn't sound like the truck has dropped. Also, i can't envision a way for fluid to get from a bleeder to the back of the rear axle. Could probably say the same about a leaky shock.
From OPs posting of where the fluid is, it almost has to be the line above the frame rail. I would keep following that until it's ruled out completely.
Here is a thread with very good pictures. This was a slightly different issue, but gives you a good sense of where the lines are. In the specific post linked, use the top of the rear shock to get your bearings as to where these pictures are oriented.
forum.ih8mud.com
My AHC failed
I had a similar issue, leak from near the driver's side rear. Lost fluid and the vehicle was stuck in low. It happened while I was driving slowly offroad so I noticed right away when the fluid hit the exhaust and was smoking. I pulled the AHC fuse to save the pump and drove it the 100 miles back...
forum.ih8mud.com
You must be right, I was thinking the same how can the tank be empty and the truck did not lower?
If thats the case it must be between the tank and the and valve assembly somewhere and you would be spot on as the gates would hold pressure.
But then why is the leak around the globe? Any leak around that would lower the truck.
OP are you sure the truck is sitting level?
Im getting curious about mine now. Do you know what causes it to fail and can anything be done proactively?
Another post from that thread with a pic of a rusted line. The poster of that picture is a mechanic that says they've replaced that line multiple times.
forum.ih8mud.com
The Height Control Valve is very close to the rear left side globe. (See the diagram in post #6 above.) The area in question is located where the line passes over the exhaust going between the pump and the HCV.
The thread I posted above speaks to both the rusted line (caused by moisture retained by heat shielding) and also a second failure where the bracket that holds the line and the line that goes to the rear shock (they run very close to each other for a brief period) pushes the two lines too close to each other causing wear on one or both lines until one fails.
My AHC failed
Make sure they install a group 27 and not the smaller group 24 or 35. They will bolt in but not have the same reserve capacity. To answer the complication question though, you might have to cycle the ignition a couple times before it starts, and in rare instances have to re-center the steering...
forum.ih8mud.com
The Height Control Valve is very close to the rear left side globe. (See the diagram in post #6 above.) The area in question is located where the line passes over the exhaust going between the pump and the HCV.
The thread I posted above speaks to both the rusted line (caused by moisture retained by heat shielding) and also a second failure where the bracket that holds the line and the line that goes to the rear shock (they run very close to each other for a brief period) pushes the two lines too close to each other causing wear on one or both lines until one fails.
The line that commonly fails is the line in your two middle pictures but it looks to be in good shape although not very clear. You should carefully check it at the heat wrap right above the exhaust just to rule it out.
A few months back a member reported that one of the lines at the central unit somehow failed. I'd remove the shield and check the central unit as well. It's near the driver side back door, next to the muffler protected by a shield. You can see it on your first picture (post #3) on this thread.
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@lx200inAR @NYC570 thank you ill check mine soon!
I h8rust. So happy to have my LX be out of the east coast.
I h8rust. So happy to have my LX be out of the east coast.
The heat wrap retains moisture and accelerates rust. I sprayed high heat paint on mine to see if it lasts longer. I did it before I installed it but it can be done with it installed.
