Bleeding AHC Fluid controversy and survey

[Samak]

I have asked a Lexus dealer and a Toyota dealer to bleed the AHC fluid in my 2004 LX470 and both dealers' service managers strongly advised against doing it. My system works but my fluid is three gradients below the min mark. The curious thing is that the service adviser booked the appointment but when I showed up, in both cases the service manager met with me and explained Lexus/Toyota discourage this work. In fact they have removed the service along with the tranny fluid exchange from the 60k service. The dealers are in northern New Jersey and separately owned and operated.

So here are my questions:
1) anyone have a similar experience?
2) for all the folks who have completed the service, what has been your experience post the procedure?

Thanks in advance for your input...

 

[deanfun]

I did it at home. My LX had just over 50k miles on it and had never had the fluid changed - it was black and gross. Ride quality improved, but not significantly. No issues.

 

[hankinid]

I did it at home. My LX had just over 50k miles on it and had never had the fluid changed - it was black and gross. Ride quality improved, but not significantly. No issues.

I do mine every 30K...fluid is relatively clean. I don't notice differences in ride nor damping.

You might go to the Lexus website and see if AHC fluid change has really been removed from regular maintenance.

 

[OregonLC]

Same as others. Was dark, now red. Easy procedure. Requires two cans. Nominal improvement in ride quality. Sound PM IMO.

 

[super90]

Its in the manual as recommended preventive maintenance. I think the interval is 5 years or 60,000 miles. Local Sewell Lexus dealer did mine the first time around (was still in warranty). No issues. That was 55k miles ago.

Find a different shop.

 

[PADDO]

I have asked a Lexus dealer and a Toyota dealer to bleed the AHC fluid in my 2004 LX470 and both dealers' service managers strongly advised against doing it. My system works but my fluid is three gradients below the min mark. The curious thing is that the service adviser booked the appointment but when I showed up, in both cases the service manager met with me and explained Lexus/Toyota discourage this work. In fact they have removed the service along with the tranny fluid exchange from the 60k service. The dealers are in northern New Jersey and separately owned and operated.

So here are my questions:
1) anyone have a similar experience?
2) for all the folks who have completed the service, what has been your experience post the procedure?

Thanks in advance for your input...

I replace my fluid every 30k or so and have done so since the vehicle had around 55k on it. I will continue this practice as I see it as and inexpensive ($45 per can x 1 can) means of prolonging the life of the system whilst maintaining designed ride quality and functionality. I strongly suspect that these two dealers have their short term interests in mind and not yours. Ride quality is subjective and every system will eventually experience failure. Your vehicle is 10 years old and may or may not have a solid maintenance history, you report your AHC is working and presumably there are no stored codes, to a dealer that equates to "the system is fine, no need to touch it". This option presents the least risk with no exposure to their bottom line or business reputation. If they were to change out the fluid and lets say next week or next month you had some sort of failure or you decided the "ride wasn't as smooth as it was" I bet you'd be back at the dealer expecting a warranty fix - not aimed at you personally, please don't take it that way, its just human nature to want accountability and closure on a perceived wrong after you've shelled out $. With all the AHC system out there, built from '97 to '07 I'm sure there are Toyota/Lexus back office types crunching numbers and looking at costs and risks and the conclusion is probably "don't touch it unless its broke". I maintain that Toyota/Lexus screwed the pooch wrt planned maintenance schedules and the general dissemination of AHC technical data. From the get go if they'd promulgated a, say, mandatory 30K or 45K miles fluid change, I'd bet we'd be seeing a lot less age/miles related failures today. Too late to go back now, best thing to do is don't mess with apparently working systems, they'll fail eventually and when a client rolls in with flashing AHC lights and DTCs we can change out parts until the DTCs go away and only have to warrant the new parts we install, with its associated labor. I've a little bit of experience and background in fluid power, control systems etc and it was always drummed into us the importance of fluid hygiene, with temperature, contamination and age degraded fluid three of the biggest killers of hydraulic systems. Check out Mobil's Hydraulic Systems Care and Maintenance reference pages or go to Advanced Materials and Processes Technology Info Analysis Center publications, one paper states "75% of hydraulic systems fail due to contamination and ageing fluid". Obviously they aren't talking specifically about a Toyota designed AHC system but hydraulics in general. Regardless, sound repair and maintenance principles including the periodic replacement of aged, depleted and contaminated fluid is very important. At $45 a can and half an hour every second year why wouldn't you change it?
Carry On.

 

[Samak]

I replace my fluid every 30k or so and have done so since the vehicle had around 55k on it. I will continue this practice as I see it as and inexpensive ($45 per can x 1 can) means of prolonging the life of the system whilst maintaining designed ride quality and functionality. I strongly suspect that these two dealers have their short term interests in mind and not yours. Ride quality is subjective and every system will eventually experience failure. Your vehicle is 10 years old and may or may not have a solid maintenance history, you report your AHC is working and presumably there are no stored codes, to a dealer that equates to "the system is fine, no need to touch it". This option presents the least risk with no exposure to their bottom line or business reputation. If they were to change out the fluid and lets say next week or next month you had some sort of failure or you decided the "ride wasn't as smooth as it was" I bet you'd be back at the dealer expecting a warranty fix - not aimed at you personally, please don't take it that way, its just human nature to want accountability and closure on a perceived wrong after you've shelled out $. With all the AHC system out there, built from '97 to '07 I'm sure there are Toyota/Lexus back office types crunching numbers and looking at costs and risks and the conclusion is probably "don't touch it unless its broke". I maintain that Toyota/Lexus screwed the pooch wrt planned maintenance schedules and the general dissemination of AHC technical data. From the get go if they'd promulgated a, say, mandatory 30K or 45K miles fluid change, I'd bet we'd be seeing a lot less age/miles related failures today. Too late to go back now, best thing to do is don't mess with apparently working systems, they'll fail eventually and when a client rolls in with flashing AHC lights and DTCs we can change out parts until the DTCs go away and only have to warrant the new parts we install, with its associated labor. I've a little bit of experience and background in fluid power, control systems etc and it was always drummed into us the importance of fluid hygiene, with temperature, contamination and age degraded fluid three of the biggest killers of hydraulic systems. Check out Mobil's Hydraulic Systems Care and Maintenance reference pages or go to Advanced Materials and Processes Technology Info Analysis Center publications, one paper states "75% of hydraulic systems fail due to contamination and ageing fluid". Obviously they aren't talking specifically about a Toyota designed AHC system but hydraulics in general. Regardless, sound repair and maintenance principles including the periodic replacement of aged, depleted and contaminated fluid is very important. At $45 a can and half an hour every second year why wouldn't you change it?
Carry On.

Paddo
Excellent points and exactly why after the Lexus dealer strongly suggested to skip the work, I went to the Toyota dealer. My issue now is the bleed nipples are rusted and I worry about tackling the job at home. I can bleed the brakes on a car with no concerns but the look of the bleed hardware on the LX470 look challenging. So now I must find a different dealer and that is why I posted this question. I agree that the dealer is looking at this as a risk-reward analysis from their perspective. I am also doing my own risk-reward calculus. cheers

 

[dfrelich]

Samak. You'll be surprised how easy it is to do AHC fluid flush. If you're used to doing brake bleed with a two-man process, then AHC is much easier. It's total DIY without needing anyone else. Only thing is that... when you make a spill, you're going to have fun cleaning up.

Paddo
Excellent points and exactly why after the Lexus dealer strongly suggested to skip the work, I went to the Toyota dealer. My issue now is the bleed nipples are rusted and I worry about tackling the job at home. I can bleed the brakes on a car with no concerns but the look of the bleed hardware on the LX470 look challenging. So now I must find a different dealer and that is why I posted this question. I agree that the dealer is looking at this as a risk-reward analysis from their perspective. I am also doing my own risk-reward calculus. cheers

 

[CanadianRockyCruiser]

I did mine at home... the only real problem is that I sheared the bleeder valve off of the Height Control Accumulator (cylinder) because it was rusty... use some penetrating fluid first if you have rust. The 4 globes bled just fine, but the performance doesn't seem to be much different. Fluid was dark grey too.

 

[rustydrummer]

Easy job to DIY for less than $60. I did mine in ~an hour and I am by no means a mechanic. It's worth the piece of mind to me to keep clean fluid in the system. Very expensive fix once parts start going bad in it, so maintain it.


...via IH8MUD app

 

[uHu]

There is one answer missing in the survey:
"No. My system is behaving well because of regular maintenance, including flushing the ahc-fluid."