Does CHS11S.....Change Color Over Time?
Discussion
Hey Folks,
I'm diagnosing some Power Steering foibles on my '13 DB9....namely, that I feel a slight judder when turning the wheel. I know that can be a failing power steering pump, but I've literally never heard of that happening on a DB9, so I'm looking at other options first.
I noticed that my power steering fluid was a couple ounces low in the reservoir........but when going to fill it up, I saw something more odd:
My car should have CHF11S from factory (at least, the cap indicates that), which is usually GREEN. But the fluid in my reservoir is ORANGE.
The CHF11S fluid in my old E46 M3 was still green after 20 years....did someone put the wrong fluid in my car during a flush at some point in recent history?
I'm diagnosing some Power Steering foibles on my '13 DB9....namely, that I feel a slight judder when turning the wheel. I know that can be a failing power steering pump, but I've literally never heard of that happening on a DB9, so I'm looking at other options first.
I noticed that my power steering fluid was a couple ounces low in the reservoir........but when going to fill it up, I saw something more odd:
My car should have CHF11S from factory (at least, the cap indicates that), which is usually GREEN. But the fluid in my reservoir is ORANGE.
The CHF11S fluid in my old E46 M3 was still green after 20 years....did someone put the wrong fluid in my car during a flush at some point in recent history?
Edited by andratch on Tuesday 4th November 04:05
That's very strange.
My early DB9 uses CHF11S and it is green.
I carried out a full flush a couple of years ago,the old fluid tends to go black when old not orange, look at Aston 1936.
Steering wheel judder does point to a defective pump, but I would dump all that orange fluid and refill with CHF11S.
My early DB9 uses CHF11S and it is green.
I carried out a full flush a couple of years ago,the old fluid tends to go black when old not orange, look at Aston 1936.
Steering wheel judder does point to a defective pump, but I would dump all that orange fluid and refill with CHF11S.
Edited by paulrog1 on Tuesday 4th November 06:26
paulrog1 said:
That's very strange.
My early DB9 uses CHF11S and it is green.
I carried out a full flush a couple of years ago,the old fluid tends to go black when old not orange, look at Aston 1936.
Steering wheel judder does point to a defective pump, but I would dump all that orange fluid and refill with CHF11S.
I'm hoping that the fluid was filled wrong at some point - standard ATF and CHF11S are quite different, so maybe that is enough to get things back functioning properly. The fluid that's in there is 'clean,' so it's not like it turned dirty-brown with use over time, but it's definitely not green in any way. My early DB9 uses CHF11S and it is green.
I carried out a full flush a couple of years ago,the old fluid tends to go black when old not orange, look at Aston 1936.
Steering wheel judder does point to a defective pump, but I would dump all that orange fluid and refill with CHF11S.
Edited by paulrog1 on Tuesday 4th November 06:26
If not, the power steering pump doesn't seem too terribly difficult to access, assuming there aren't any hidden bolts that require half the engine to come apart. There are no noises or other indications of issue from the pump yet, so perhaps it just doesn't like the viscosity or whatever.
LTP said:
And the judder?
Without bleeding the system, the judder was actually worse at a standstill (just in park, turning the wheels back and forth while stationary). I did the "heat the fluid up to 100C and turn the wheels" procedure, which I assume just helps bleed the system, and it got *way better*, but not 100% fixed. I suspect that it starts juddering when the pump is running too slow to keep up with the speed I want to turn the wheels. Next i'll see if it still judders when i raise the idle to about 1200 rpm with my foot. I haven't had a chance to check for my shimmy at speed, but I suspect it's still there. I am starting to think that might be related to some worn suspension item, or perhaps a very slightly out-of-round wheel. I had a new set of tires put on recently and they balanced fine, so I'm hesitant to believe that it's a bent wheel because that usually comes up in balancing.
The annoying symptom is: I just get a bit too much "loose feedback" from the road when driving. At low speeds on crappy roads, it almost feels like bump steer, just a little judder and movement that feels 'loose' and takes away from the car's confident feeling. When I was putting in H&R lowering springs last month, I didn't notice any torn bushings or anything of the sort, but I wonder if I missed something. There aren't too many components to even consider, just upper/lower control arms, trailing arms, and tie rod ends. The car only has 15k miles, but it's also 12 years old...
andratch said:
Without bleeding the system, the judder was actually worse at a standstill (just in park, turning the wheels back and forth while stationary). I did the "heat the fluid up to 100C and turn the wheels" procedure, which I assume just helps bleed the system, and it got *way better*, but not 100% fixed. I suspect that it starts juddering when the pump is running too slow to keep up with the speed I want to turn the wheels. Next i'll see if it still judders when i raise the idle to about 1200 rpm with my foot.
I haven't had a chance to check for my shimmy at speed, but I suspect it's still there. I am starting to think that might be related to some worn suspension item, or perhaps a very slightly out-of-round wheel. I had a new set of tires put on recently and they balanced fine, so I'm hesitant to believe that it's a bent wheel because that usually comes up in balancing.
The annoying symptom is: I just get a bit too much "loose feedback" from the road when driving. At low speeds on crappy roads, it almost feels like bump steer, just a little judder and movement that feels 'loose' and takes away from the car's confident feeling. When I was putting in H&R lowering springs last month, I didn't notice any torn bushings or anything of the sort, but I wonder if I missed something. There aren't too many components to even consider, just upper/lower control arms, trailing arms, and tie rod ends. The car only has 15k miles, but it's also 12 years old...
So did it judder before you fitted the lowering springs?I haven't had a chance to check for my shimmy at speed, but I suspect it's still there. I am starting to think that might be related to some worn suspension item, or perhaps a very slightly out-of-round wheel. I had a new set of tires put on recently and they balanced fine, so I'm hesitant to believe that it's a bent wheel because that usually comes up in balancing.
The annoying symptom is: I just get a bit too much "loose feedback" from the road when driving. At low speeds on crappy roads, it almost feels like bump steer, just a little judder and movement that feels 'loose' and takes away from the car's confident feeling. When I was putting in H&R lowering springs last month, I didn't notice any torn bushings or anything of the sort, but I wonder if I missed something. There aren't too many components to even consider, just upper/lower control arms, trailing arms, and tie rod ends. The car only has 15k miles, but it's also 12 years old...
LTP said:
So did it judder before you fitted the lowering springs?
There are three symptoms here:1) Judder when turning the steering wheel while stopped, as seen in my video here: https://youtu.be/eR4KZAI3CS8
2) Light shimmy in the steering wheel at speed
3) "Loose" feel in the steering when going over rough spots in the road, especially when turning
- 1* was mostly fixed by changing the fluid, it's still slightly present though. I suspect that this happens when the RPM is low and there's high demand for power from the steering rack...I'm going to check this by raising the RPM and turning the wheel.
- 2* and *3* still persist, unchanged.
Vsix and Vtec said:
Is it possible the fluid you replaced was Slick50 PAS leak stopping PAS fluid? It might be the previous owner had a weeping rack and did a magic bottle fix before selling it on.
Good idea, but I'm pretty sure that's not the case here. The car has no signs of leaks, current or prior.Forums | Aston Martin | Top of Page | What's New | My Stuff