Help with low VANOS oil pressure!

[cornerbalanced]

Recently purchased this E46 and have been struggling with VANOS issues since.

Issue #1: When doing an oil pressure test on the VANOS unit, at idle, pressure only builds to ~150psi. When rev’d to ~3,000rpms, pressure will continually build to ~300psi and then hit a brick wall and remain at ~300psi until the RPMs are backed down to idle, in which case pressure will fall back to ~150psi.

Issue #2: At idle, cam timing will deviate from command. The longer the car sits at idle, the more cam timing will deviate from command (up to 30 degrees of deviation if it idles for along enough…will eventually misfire and stall). When driving, cam timing aligns with command normally, with little (less than 10 degrees) deviation from command. This issue is likely linked to my VANOS oil pressure issue.

What I have attempted thus far:
- Fresh camshaft position sensors
- Fresh (rebuilt) coil pack from Beisan
- Thoroughly cleaned valve body, ensured functionality (it clicks)

My mechanic is suggesting a fault with my oil pump disc, or the helical gears associated with the pump disc. He said if I had broken exhaust hub tabs, I simply wouldn’t build ANY VANOS pressure. Makes sense.

My VANOS was overhauled by Kaiv/Kevin in 2013 at ~92k miles. Beisan oil pump disc, seal kits, solenoid pack and an OE chain guide, cam bolts, valve cover gasket, etc.

Before I replace my entire VANOS unit, does anyone have any ideas/have encountered a similar issue in the past?

[maupineda]

I can think of five potential root causes

1. Seals are done and oil pressure leaks through the shafts seals
2. Your pump disk and shaft are worn and thus, do not build pressure
3. the oil feed valve is done (the one that connects from the head to the VANOS unit, there is 1bar of oil pressure fed from the head to the vanos through this valve
4. the pressure regulator valve is broken and pressure leaks through it.
5. broken / failed solenoid valve body

I would check all of the above first before spending big bucks on a spare unit.

Of all of the above, 2 - 4 are not common failures but are items that if failed, would cause the issue you have. at 300psi, you are pretty much at zero, the pressure should be at least 1470psi (100 bar)

[cornerbalanced]

I can think of five potential root causes

1. Seals are done and oil pressure leaks through the shafts seals
2. Your pump disk and shaft are worn and thus, do not build pressure
3. the oil feed valve is done (the one that connects from the head to the VANOS unit, there is 1bar of oil pressure fed from the head to the vanos through this valve
4. the pressure regulator valve is broken and pressure leaks through it.
5. broken / failed solenoid valve body

I would check all of the above first before spending big bucks on a spare unit.

Of all of the above, 2 - 4 are not common failures but are items that if failed, would cause the issue you have. at 300psi, you are pretty much at zero, the pressure should be at least 1470psi (100 bar)

For #1, are you referring to the seals on the connecting plate that sit between the valve body and the solenoid pack? Those were also replaced today, I should have mentioned.

#2 is what my mechanic is suggesting, which is prompting me to replace the entire unit. Worried if I only replace the pump disk, my shaft will still be worn which would still warrant a new VANOS unit.

#3/#4 -- makes sense, I will look into this. These parts seem difficult/labor-intensive to test which makes me more inclined to just purchase a new unit and be done with everything (hopefully).

#5 would make sense, but while cleaning the valve body itself we were able to verify functionality. Extremely loud actuation clicks were audible while using a magnet.

Really appreciate your input by the way!

[sapote]

For #1, are you referring to the seals on the connecting plate that sit between the valve body and the solenoid pack? Those were also replaced today, I should have mentioned.

#2 is what my mechanic is suggesting, which is prompting me to replace the entire unit. Worried if I only replace the pump disk, my shaft will still be worn which would still warrant a new VANOS unit.

#3/#4 -- makes sense, I will look into this. These parts seem difficult/labor-intensive to test which makes me more inclined to just purchase a new unit and be done with everything (hopefully).

#5 would make sense, but while cleaning the valve body itself we were able to verify functionality. Extremely loud actuation clicks were audible while using a magnet.

Really appreciate your input by the way!

1. He meant the seals on the vanos pistons (intake and exhaust). It's easy to remove the pistons and look.
2. I don't think disk/center shaft worn can cause this 300 psi low. Something else.
3.
4. This is external adjust regulator, why don't you adjust it and see if pressure increases.
5. I would remove the solenoid electrical connector to see if pressure increases.

[cornerbalanced]

1. He meant the seals on the vanos pistons (intake and exhaust). It's easy to remove the pistons and look.
2. I don't think disk/center shaft worn can cause this 300 psi low. Something else.
3.
4. This is external adjust regulator, why don't you adjust it and see if pressure increases.
5. I would remove the solenoid electrical connector to see if pressure increases.

Ahh, I see.

If the disk/center shaft was worn you’d think the pressure would be higher? We attempted to adjust pressure via. the regulator for maximum psi and it made little change. Filter on the regulator itself had some stuff in it but overall wasn’t incredibly dirty. My mechanic also cleaned that out with brake cleaner.

[sapote]

The disk/shaft has no reason to cause this low P.
Pull the solenoid connector off and see if P changes.

[Cubieman]

If the disc and/or shaft was slightly out of tolerance you would have a higher pressure than 300psi i would think, if both EX. Driver tabs were broken you wouldn't have any more than normal engine oil pressure.

I would see if the pistons in the pump disc are sticking or maybe if someone was in there, is it possible the little metal "nipples" that sit inside the disc were not installed correctly? Maybe a spring left out etc.?

Taking things apart may be the only way to shed light unfortunately. Maybe throw a new vanos inlet valve at it if everything else looks good. I think you would find something obvious while vanos is off.

[sapote]

If the disc and/or shaft was slightly out of tolerance you would have a higher pressure than 300psi i would think, if both EX. Driver tabs were broken you wouldn't have any more than normal engine oil pressure.

I would see if the pistons in the pump disc are sticking or maybe if someone was in there, is it possible the little metal "nipples" that sit inside the disc were not installed correctly? Maybe a spring left out etc.?

Taking things apart may be the only way to shed light unfortunately. Maybe throw a new vanos inlet valve at it if everything else looks good. I think you would find something obvious while vanos is off.

Yes, maybe only one piston out of four is working.

[cornerbalanced]

If the disc and/or shaft was slightly out of tolerance you would have a higher pressure than 300psi i would think, if both EX. Driver tabs were broken you wouldn't have any more than normal engine oil pressure.

I would see if the pistons in the pump disc are sticking or maybe if someone was in there, is it possible the little metal "nipples" that sit inside the disc were not installed correctly? Maybe a spring left out etc.?

Taking things apart may be the only way to shed light unfortunately. Maybe throw a new vanos inlet valve at it if everything else looks good. I think you would find something obvious while vanos is off.

Therein lies my dilemma. I’m able to source a fresh VANOS unit for ~$1,000, of which the seller has agreed to cover. This “only” leaves me on the hook for the labor, plus other misc. parts (Beisan Hub, valve cover gasket, anti rattle kit, sending oil pump disc out to be machined by Beisan, etc.)

As strange as it may sound, replacing the entire unit may be my cheapest option?

As long as a new VANOS unit will solve my problems, I’ll be happy. Really hoping the issue is obvious once the unit is off, as from everything I’ve seen this is an extremely unusual issue to have.

[cornerbalanced]

The disk/shaft has no reason to cause this low P.
Pull the solenoid connector off and see if P changes.

I’ll give that a shot, thanks!

[Cubieman]

If you skip the anti-rattle deal you don't have to re-set timing which will save time/money, but if you haven't already had the cam sleeve bolts replaced/loctited most definitely do that while in there, that also requires re-timing but is a LOT more important than the anti-rattle deal.

I did the anti-rattle just because, if your mechanic has done it before it shouldn't be too bad, but I definitely spent a few hours on just that my first time.

[maupineda]

Therein lies my dilemma. I’m able to source a fresh VANOS unit for ~$1,000, of which the seller has agreed to cover. This “only” leaves me on the hook for the labor, plus other misc. parts (Beisan Hub, valve cover gasket, anti rattle kit, sending oil pump disc out to be machined by Beisan, etc.)

As strange as it may sound, replacing the entire unit may be my cheapest option.

As long as a new VANOS unit will solve my problems, I’ll be happy. Really hoping the issue is obvious once the unit is off, as from everything I’ve seen this is an extremely unusual issue to have.

If you can spare a working unit for cheap, yes, I agree. I ended up buying one not long ago as I was troubleshooting my pressure issue and chose to go with a spare unit as my problem was my disc (which was the billet item from Beisan). the spare I got was from a 40K mile car, and it fixed my problem, then Beisan send me an OE "B" disc, and then I chose to put back my original unit to confirm the pressure issue was the disc, and it was, so my car was left with it original unit and an OE "B" disc as it was before messing with it, and it too has the full pressure.

I say "B" disc, as there is "A" and "B", they are supposed to be identical, but I tend to believe they come from two production lines and they are matched. The spare unit was an "A" unit.

I was planning to sell the spare unit, but heck, our cars are old and these units are like gold so I better hang to them for spares.

[cornerbalanced]

If you skip the anti-rattle deal you don't have to re-set timing which will save time/money, but if you haven't already had the cam sleeve bolts replaced/loctited most definitely do that while in there, that also requires re-timing but is a LOT more important than the anti-rattle deal.

I did the anti-rattle just because, if your mechanic has done it before it shouldn't be too bad, but I definitely spent a few hours on just that my first time.

I believe my mechanic recommended S62 diaphragm springs for anti-rattle? I know my cam sleeve bolts were done, but close to 10 years ago with OE bolts. I’ll probably have him throw in lang racing bolts while he’s in there.

[cornerbalanced]

If you can spare a working unit for cheap, yes, I agree. I ended up buying one not long ago as I was troubleshooting my pressure issue and chose to go with a spare unit as my problem was my disc (which was the billet item from Beisan). the spare I got was from a 40K mile car, and it fixed my problem, then Beisan send me an OE "B" disc, and then I chose to put back my original unit to confirm the pressure issue was the disc, and it was, so my car was left with it original unit and an OE "B" disc as it was before messing with it, and it too has the full pressure.

I say "B" disc, as there is "A" and "B", they are supposed to be identical, but I tend to believe they come from two production lines and they are matched. The spare unit was an "A" unit.

I was planning to sell the spare unit, but heck, our cars are old and these units are like gold so I better hang to them for spares.

Somehow my mechanic ended up finding brand new old-stock VANOS units. They typically retail for $3k+ but he’s able to get them for much cheaper. I figure it can’t get much better than an entirely new unit (new helical gears, coil pack, etc).

Going to have the brand new pump disc sent out to Beisan to be machined, and go through most of the seals in the unit with Beisan ones just to be safe. Unit has likely been sitting for years.

[maupineda]

I believe my mechanic recommended S62 diaphragm springs for anti-rattle? I know my cam sleeve bolts were done, but close to 10 years ago with OE bolts. I’ll probably have him throw in lang racing bolts while he’s in there.

In my opinion that is a bad idea. Just buy new “A” items specific to the S54. The s62 items add preload and slow the response of the VANOS. If your splines do not have axial play, leave them alone.