t_jer

1.) A4 2.8 12V AFC - Anyone know the part numbers for the oil check valves under the valley pan?

Found once before, but they seem to be hiding from me.


2.) Also, I'm thinking of replacing these check valves, but wanted to see if this was going to be a waste of my time first? Car has 180K miles and would love to see it make 200K +.

Few weeks ago, a lifter tick was coming from driver side and would not go away even after idling for long period of time. Replaced the upper oil check valve under driver side valve cover, no help.

Next, decided to replace all the lifters thinking blocked lifter passage and valve cover gaskets. This cleared up the lifter tick on the one side.

Problem now is the car will tick on first start up (both sides) for about 5 seconds then go away. The car will sit and idle with no ticks as it reaches operating temp. I will then rev car up to red line then back to idle, maybe 4-5 times, and tick will come back. It will sit at idle and tick for about 30 seconds or so then eventually stop. My thought is there is not enough oil pressure keeping lifters from ticking at higher RPM's.

I have since removed the oil pan and cleaned pick-up & screen and any sludge in oil pan. Also, recently started running an Auto RX treatment in car, but haven't put any miles on car yet. The tick still occurs on start up and high RPM revs.

Will replacing these check valves in valley pan help clear up my problem or should I be looking at other issues like bad pump, clogged oil passages, oil pressure relief safety valve?

Thanks for help.

Kris Hansen

I thought the check valve only worked to keep oil up in the heads, but I'll see if I can find the number.

AudiMick

Don't the check valves prevent the oil draining backwards when the engine is turned off?

That way there is always some oil present at startup.

Not sure why that would help the noise when the motor is running since presumably the valves should be open.

Presumably the valves could stick shut I suppose but that would be unusual.

What oil are you using. Do you have the correct filter with correct bypass valve?

I used Chevron Delo 15-40W on my 96 V6 for many years. Some lifter noise at initial startup but quiet when warmed up 168K miles.

I rarely revved the motor though.

t_jer

I was thinking the check valves would probably cure the lifter noise on start up, but was curious if its possible they could cause low oil pressure at higher revs to the lifters? So do the check valves only stick in closed position causing higher oil pressures then?

Currently using Castrol dino 10W 40 with a Mobil One filter.

Previously, Mobil One synthetic 5W 30 with Mann filter.

However, I haven't tried a Mann filter after the lifter replacement, oil pan clean, etc. I was hoping to put some miles on the car with the Auto RX before replacing the filter again, but maybe I should?

jimrobertson

This noise is normal. I have 455,000km on my car (275,000 miles).I use regular oil 10w40 winter, 20w50 summer;diesel oil filter.Bentley says that "oil rentention valves must be replaced if the valvetrain sounds noisy on short drives,although the noise may go away on longer drives." The ticking sound could be your EVAP valve.Ticking there is normal.

t_jer

I'm not certain the EVAP is the ticking sound I'm hearing. Do you really have to listen for the EVAP tick sound, or is it very prominent on both driver and passenger side of engine bay?

This to me really sounds like the lifters are making the noise, as if the oil pressure drops when the RPM's are high for period of time and starving the lifters slightly. You can def hear it from inside the car and don't really have to listen closely for the sound. Thankfully, it's not loud enough for me to believe it is a rod knocking, or something worse. Sounds like an upper engine problem for sure.

I do have a few Mann oil filters sitting around in my garage. Should I try and change the filter to one of those, or is the Mobil 1 filter a good choice?

Thanks.

MartinH

To be really sure of what your oil pressure is you should connect a gauge and monitor it for a while and then compare with the factory spec. You can then compare oil pressure with the noise the engine makes.

MartinH

Jim - 275k miles eh! What significant parts have you had to replace?

rickyboy

Audi factory engine manual also tells you to replace the check valves if you have tappet noise on startup. It made a big difference when I replaced mine. I snapped a camshaft a few months after noticing the ticking and I'm pretty sure it was related to a lack of oil getting to the top of the engine -so I'd advise changing them.

You'll have to take the inlet manifold off and then you will see the valley pan. They're a bit pricey for a couple of non-return valves - they'll cost you £34 from audi.

Part no 078 103 175 D - note this is for a 2.6 ABC engine although I doubt they are different, can someone confirm?

t_jer

I appreciate the advice. You are correct on the part number. It is the same for the AFC engine. I had already ordered the valves end of last week.

My plan is to first change the valves and see what that clears up. I suspect the valve noise on start up will be silenced, but not the lifter noise at higher revs.

Next, I plan on replacing the Mobil 1 oil filter on it now with a Mann filter to see if that helps with the higher RPM revs.

If still getting valve noise then will take to shop and have them do a oil pressure test. Will go from there, maybe pump?

Thanks for the comments.