AHC Fluid color - What is normal/abnormal?

[RomanianAdrian]

Hi guys,

I have read a lot of threads on here regarding preventative maintenance however I haven't been able to develop a definitive understanding of what is the normal coloration for the AHC fluid as seen in the reservoir.

About 8 months prior to today: I had Lexus of Portland "Flush" the AHC fluid which was dark blue at the time. Checking the reservoir a week after the truck was returned I thought they forgot to refill the reservoir, turned out the fluid was so clear I couldn't see it.
Fast forward to today: The fluid has turned dark grey, so dark that when I shine my 5W LED flashlight through the bottom of the reservoir, no light makes it through the fluid to the top. So I took the truck back to Lexus of Portland and they say they inspected it and that "The fluid is in great shape, the discoloration is due to the remaining fluid not flushed out during the previous service." I paid $200+ for a flush and ended up with a drain and fill... whatever I'll do it myself next time.

I am worried the clear fluid filled during the 1st service was actually brake fluid, gathering from what I've read in other threads on here it could be a can of AHC fluid that is older(prior to them adding colorants to it). If it has been years since the new fluids with colorants have been around, isn't it reasonable to doubt that the dealer's mechanic actually used AHC fluid?

1. Any recommendations on how I may get a sample of the fluid tested for brake fluid? What kind of test should I be looking for?
2. What color should the fluid be after 8-months post drain & fill?


Thanks in advance,
Adrian

 

[CurbsEnthusiasm]

Saturday I flushed my AHC system. What came out of the reservoirs and the spheres was a dark greyish/black. I ended up using about 2 cans of fluid to flush everything until the point it was a consistent pink/red just like out of the can.

 

[hankinid]

Does it smell like brake fluid??

Steve

 

[Wilsil]

Adrian, the color in my reservoir is non existing as well, very clear.
Even after 20,000 kms the color hasn't changed.
I have decided to call a local Toyota dealer and order 2 cans of AHC fluid and do the flush.

 

[PADDO]

Hi guys,

I have read a lot of threads on here regarding preventative maintenance however I haven't been able to develop a definitive understanding of what is the normal coloration for the AHC fluid as seen in the reservoir.

About 8 months prior to today: I had Lexus of Portland "Flush" the AHC fluid which was dark blue at the time. Checking the reservoir a week after the truck was returned I thought they forgot to refill the reservoir, turned out the fluid was so clear I couldn't see it.
Fast forward to today: The fluid has turned dark grey, so dark that when I shine my 5W LED flashlight through the bottom of the reservoir, no light makes it through the fluid to the top. So I took the truck back to Lexus of Portland and they say they inspected it and that "The fluid is in great shape, the discoloration is due to the remaining fluid not flushed out during the previous service." I paid $200+ for a flush and ended up with a drain and fill... whatever I'll do it myself next time.

I am worried the clear fluid filled during the 1st service was actually brake fluid, gathering from what I've read in other threads on here it could be a can of AHC fluid that is older(prior to them adding colorants to it). If it has been years since the new fluids with colorants have been around, isn't it reasonable to doubt that the dealer's mechanic actually used AHC fluid?

1. Any recommendations on how I may get a sample of the fluid tested for brake fluid? What kind of test should I be looking for?
2. What color should the fluid be after 8-months post drain & fill?


Thanks in advance,
Adrian

It's difficult to accurately assess the color of the fluid whilst it's in the reservoir so I'd drain off a couple of ounces into clear jar and look at it in daylight. The fluid starts out pink/rose (it was a clear/strawish color before 2009) changes to red as it ages and with use and age can end up a deep cola/caramel color. The term "flush" is used pretty liberally here - changing the fluid in this system is basically a drain and refill, there is no recirculating it's just a reservoir at the top with four dead ends at each actuator, fluid moves back and forth but doesn't recirculate so it's impossible to remove 100% of fluid when you drain and refill. If you suspect your system has been contaminated with brake fluid you can do a water reactive test. Into a meticulously clean detergent free jar drain 3 or 4 ounces of fluid off from your main height accumulator, add half the volume of your oil with distilled water, agitate to mix and let stand for 5 minutes. After 5 minutes you should see a clear delineation between the water on the bottom and the oil. There will be a thin froth interface between the two but the water must be clear and this indicates the oil sample most likely has not been contaminated. If the water is milky and there is "scum streaks" on the glass jar this suggests the oil is contaminated. Here is what a sample of 6 month old oil looks like with water added, and the same sample with a few drops of brake fluid.

 

[RomanianAdrian]

Thanks for the replies,

I was not able to smell the suspension fluid but will post back with the(hopefully favorable) test result as pictured above. Nice little test.

Just to confirm: AHC fluid should be clear or rose is the color when new, no other colors like blue or green? As it ages it can turn dark which is fine unless it changes to grey, brown, black -which would mean it's time to drain & fill? Thanks a million guys.


Adrian

 

[PADDO]

This is what new fluid looks like, pink. The only other color I've ever seen is clear/straw pre 2009. Definitely not green or blue. It darkens with age and can look horrible if it is years old. The book says to change it every 60k miles but I prefer to change mine at half that distance. The reason the water reaction test works is that the mineral oil based AHC fluid is hydrophobic - tends to rejects water and brake fluid DOT 3, 4 is hygroscopic - tends to absorb water, hence the cloudy water if brake fluid is present in the sample.

 

[RomanianAdrian]

Thank you for the advice,

I managed to get my hands on a $50 tin of AHC fluid and a flavor injector. Pictures attached. Unfortunately my fluid is looking milky under the line of "old fluid stuck in the system mixed with new". I distinctly remember the fluid having a tint of dark blue/green before they drained and filled and charged me for a flush.

I can't just yell at the service adviser because he already has demonstrated he's not knowledgeable on the matter... Buy a bunch more fluid and flush like mad?

If this was your LX what would your next steps be?

AHC+WATER

• RomanianAdrian
• Jun 3, 2015

Sample of my AHC fluid with water, 5 minutes after agitating. Note milky water below fluid.

New AHC Fluid

• RomanianAdrian
• Jun 3, 2015

$45 @ Toyota dealer parts department. Note part number on the tin.

AHC fluid sample

• RomanianAdrian
• Jun 3, 2015

Sample taken 9 months after dealer "flushed" system. Today they say they only drained and filled...

 

[Wilsil]

Flush as described.

 

[dnp]

Yeah, if it had any blue coloration to begin with, it could be that you had been "lubed" by someone in the past (i.e., some idiot at a quick oil change had filled your AHC container with washer fluid.......however, if your reservoir was still at an "appropriately full' level, that's probably not what happened. In that case, I have no idea what would have caused a blue tint to your fluid)