Questions on Valley Pan Gasket replacement and Oil Check Valves
02-10-2009, 09:11 AM
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Questions on Valley Pan Gasket replacement and Oil Check Valves
I'm tired of the mess on the garage floor from the oil leaks from my 1996 A4 QM 2.8 V6. I already replaced the valve cover gaskets, lower oil pan gasket and the oil cooler O-ring, so the Valley Pan Gasket is next on the hit list - oil is trickling down the rear of the engine from up above, this is the likely source. The car has 115,000 miles and has been taken care of - owned since new. Plus, I'm now getting the EGR "insufficient flow" CEL, so I will need to deal with the IM in any case, might as well make it a project. And yes, I plan to flatten out the cover's surface using Mance's honing technique - great idea.
I have a few questions on this upcoming job:
1. How to remove the Valley Pan cover once you get to it? The lower oil pan required serious wailing with a rubber mallet to dislodge it from the upper pan, so I expect similar adhesion on the other end of the engine. I have a feeling that prying a thin piece of aluminum is not ideal, so what have people used to get this cover off?
2. Is any gasket sealer required for the gaskets between IM and the cylinder head? If so, which one is recommended?
3. I found a good writeup for this job as part of the 12V.org procedure on replacing the Oil Check Valves. Are these check valves problematic on our engines? As long as I'm that deep into the engine, does it make sense to replace them preemptively, or just let them be? If replacement is recommended, are aftermarket valves OK or only genuine Audi ($$$) replacement parts (don't get me started on non-Audi water pumps!)?
I have a few questions on this upcoming job:
1. How to remove the Valley Pan cover once you get to it? The lower oil pan required serious wailing with a rubber mallet to dislodge it from the upper pan, so I expect similar adhesion on the other end of the engine. I have a feeling that prying a thin piece of aluminum is not ideal, so what have people used to get this cover off?
2. Is any gasket sealer required for the gaskets between IM and the cylinder head? If so, which one is recommended?
3. I found a good writeup for this job as part of the 12V.org procedure on replacing the Oil Check Valves. Are these check valves problematic on our engines? As long as I'm that deep into the engine, does it make sense to replace them preemptively, or just let them be? If replacement is recommended, are aftermarket valves OK or only genuine Audi ($$$) replacement parts (don't get me started on non-Audi water pumps!)?
02-10-2009, 09:45 AM
#2
My answers w/caveat that other's opinions will vary...
1. Just lift it up with your fingers once bolts are out. Enough oil has wept under/over the gasket it's already loose. Additionally there are "tangs", finlike structural reinforcement blades between bolt holes in the top of the cover. Worst case pinch one of those with pliars and pull up. And be double-damn sure to lap the VP Cover gasket base or you'll be back in there again almost immediately as it is warped seven-ways-to-Sunday! The first few laps around a flat surface of 160-220 grit sandpaper will show you just how much it warps and bows upwards between bolt holes all the way around it's gasket perimeter.
2. "Required?" No. Recommended? YES!! Permatex Aviation Sealant is what I've used many times and for decades but sealants are personal as beer... everyone has their favorite and it ain't always Budweiser! I think gasket surface preparation counts more these days than actual sealant compound used. Sealants will only seal as well as you've prepped the surfaces it has to bond with. A slightly rougher finish than stock that's squeaky clean, dry and free of any oily residue will provide the best "tooth."
3. Unlike water pumps etc I've never heard of or seen anything but Audi OEM check valves and available from the dealer. That's not to say they don't exist. I've never replaced them because I've had no issues/problems with them. But I have removed them, blown them out with brake cleaner then compressed air to remove any debris or varnish and tested their springs, ***** and seats with a small rod and blown against them with breathpower and 40psi compressed air to see if I could overcome their spring or cause air to leak past the *****/seats. Did install new ones in the ground-up engine I'm building simply because EVERYTHING is new in that engine including the secondary, lifter anti-drain check valves in the heads! If your oil is up to the full mark on dipstick and oil warning light in dash goes out when engine starts after sitting overnight in 1.5 to 2.5 seconds your check valves are fine. If it takes 4-5 seconds for that light to go out you might wanna consider cleaning or replacing them.
HTH
2. "Required?" No. Recommended? YES!! Permatex Aviation Sealant is what I've used many times and for decades but sealants are personal as beer... everyone has their favorite and it ain't always Budweiser! I think gasket surface preparation counts more these days than actual sealant compound used. Sealants will only seal as well as you've prepped the surfaces it has to bond with. A slightly rougher finish than stock that's squeaky clean, dry and free of any oily residue will provide the best "tooth."
3. Unlike water pumps etc I've never heard of or seen anything but Audi OEM check valves and available from the dealer. That's not to say they don't exist. I've never replaced them because I've had no issues/problems with them. But I have removed them, blown them out with brake cleaner then compressed air to remove any debris or varnish and tested their springs, ***** and seats with a small rod and blown against them with breathpower and 40psi compressed air to see if I could overcome their spring or cause air to leak past the *****/seats. Did install new ones in the ground-up engine I'm building simply because EVERYTHING is new in that engine including the secondary, lifter anti-drain check valves in the heads! If your oil is up to the full mark on dipstick and oil warning light in dash goes out when engine starts after sitting overnight in 1.5 to 2.5 seconds your check valves are fine. If it takes 4-5 seconds for that light to go out you might wanna consider cleaning or replacing them.
HTH
02-10-2009, 01:21 PM
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Thanks for the informed reply
And double thanks for the edit/expansion - I didn't quite understand what you meant by "VP Cover gasket base", but I now assume that you are talking about the mating surface of the cover itself, and just to clean up the mounting surface on the block very well.
When I replaced the oil pan gasket, I spent much more time cleaning off the baked on gasket/oil residue than the rest of the job combined!
When I replaced the oil pan gasket, I spent much more time cleaning off the baked on gasket/oil residue than the rest of the job combined!
02-10-2009, 01:48 PM
#4
Yes, that's right. And rough up the cast iron mating surface in top of block as well...
with the same 160-220 grit finish that you used on the VP cover underside gasket surface. Then tightly pack newspaper or rags down into the check valve area and rough-up the smooth factory VP "flycut" gasket mating surface on top of the block. Just a little piece of sandpaper between your thumb and index finger and be sure to blow out the bolts/bolt holes with BC & compressed air afterwards! Apply Loctite 242/torque to 7ftlbs in a criss-cross pattern and walk away FOREVER! Takes 5 minutes longer to do it really really right and provides a dramatically enhanced sealing surface over the OEM glass-smooth gasket mating surface on the "deck."
02-10-2009, 02:04 PM
#6
There is no "recommended" torque sequence/pattern per Bentley on those bolts...
but I did mention a "criss-cross" pattern. And "BC/compressed air" means brake cleaner/compressed air which I did recommend for the bolts/holes before using Loctite 242.
02-10-2009, 02:47 PM
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Re: There is no "recommended" torque sequence/pattern per Bentley on those bolts...
I saw a post on here with the info. I believe it was 7 to 15 IN POUNDS (Critical must be inch pounds - not foot pounds). Start in the center in a crisscross pattern working outward to the ends. Search the forum to validate.
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02-10-2009, 03:26 PM
#10
there's a LOT of misinformation/disinformation given on forums. A forum is not...
the be all/end all of accurate information exchange as in many cases people are simply mistaken or unintentionally passing along faulty info they have received.
If you REALLY want to see it in B&W I'm happy to take a pic and post it here but I was right the first time, ie; there is no pattern or sequence protocol and the torque spec is 7ftlbs, and NOT inlbs. By the way you can loosen between 11-13inlbs between your thumb and index finger. I can torque a 10mm hex head bolt to 11inlbs by fingers alone without any tool! Does that REALLY sound like the correct torque measurement for a valley pan cover to you? I have Oakley sunglasses that get their side frames adjusted to 6inlbs with a Phillips screwdriver that is only .0625" (1/16") diameter!
If you REALLY want to see it in B&W I'm happy to take a pic and post it here but I was right the first time, ie; there is no pattern or sequence protocol and the torque spec is 7ftlbs, and NOT inlbs. By the way you can loosen between 11-13inlbs between your thumb and index finger. I can torque a 10mm hex head bolt to 11inlbs by fingers alone without any tool! Does that REALLY sound like the correct torque measurement for a valley pan cover to you? I have Oakley sunglasses that get their side frames adjusted to 6inlbs with a Phillips screwdriver that is only .0625" (1/16") diameter!