[Biturbos4] burnt oil smell /oil leak
keman at interwolf.net
Fri Jul 29 12:30:38 EDT 2005
Valve cover gaskets and timing chain tensioner gaskets. The 2.7's have
timing belts, but the two cams at the top of the head are connected via a
small chain. There's an oil pressure driven tensioner on that chain that
also serves as means to adjust the exhaust camshaft timing since it
doesn't just push down on the chain- it sits in the middle of the loop and
pushes up or down, effectiving advancing or retarding the driven camshaft
by increasing the length of the chain between the cams on one side or the
other. Ingenious, simple design. Unfortunately .. it LEAKS. :P This device
fits both under and outside the valve cover, with the valve cover gasket
bisecting it down the middle.
Chain tensioners are in front on the drivers side, and in back near the
firewall on the passenger side. You can guess which is easier to do. When
these leak, it starts out by just getting wet. Then it gets a little more
wet. And it'll stay at this point for about 30k miles, just producing a
little oil smell, and maybe a few drops of oil under the car. It can let
go though, and create quite a mess eventually. It takes a while though,
it's rarely sudden. They usually go for a few years in the leaking-stage.
I've seen them leak as early as 20k miles.
It would be worth, initially, loosening each 10mm nut that holds the valve
cover down, then tightening them all down in sequence starting with the
ones in the center and working your way outwards back and forth. Tighten
them to 115 inch/lbs (roughly 10ft/lbs). I did that and my valve covers
stopped leaking entirely at like 70k. They were dry at 95k when I sold the
Anyone can do the valve cover gaskets if they're careful and don't drop
anything into the head. It's best to use compressed air and blow all the
dirt off the edges and pits and valleys before removing the cover. The
timing chain tensioner gaskets .. are a whopping $10 part, that the dealer
will charge you 4-5 hours per side to replace. If you've never done one,
you don't wanna try, there's a few metal dowels in the chain tensioner
which easily drop into the engines depths if you're not ready right there
with a magnet to catch them should they fall when removing the tensioner.
I glued an LED penlight to a small mirror which I'd hold at 90 degrees
looking at crack between the tensioner and the head as I removed it, to
watch these dowels and see if one was being naughty.
If you have the special tool for compressing the tensioner (collapsing
it), its gasket can be done in 30 minutes a side, without taking the
camshaft or tesnioner out (what the 4-5 hours pays for). This isn't
actually a tool, it's a device that ships with new timing chain tensioners
that keeps them collapsed during shipment. They're basically a piece of
nylon and a small 6mm allen key bolt.
One bargaining tactic you can try to use to force a dealer to charge you
say, an hour a side, is offering them a choice. You'll pay 4-5 hours a
side IF they replace the camshaft seals at no additional charge (besides
the price of the seal, like $8) since... the camshafts will be out, RIGHT?
Or.. you'll give them an hour a side if they use their special tool and
skip the camshaft seals (they rarely leak at less than 180k miles anyways)
on this install.
Some dealers in-the-know will smile and do it for an hour a side at this
point, because EVERY audi tech knows this trick. Some will play dumb. Some
will still charge ya 4-5 hours and use the special tool and tell you they
replaced the camshaft seal-- and the tech lied to the service advisor so
he has no idea. You can try to ask for the old seals back as proof that
they changed it. But I wouldn't put it past them to cough up a few used
seals they had laying around. I know you guys wanna trust the dealer, but
they hire kids fresh outa UTI and in a job where you make more money by
getting the job done faster.......
In the end, camshaft chain adjuster gaskets are a drama-filled topic,
that's even more colorful when it's in-warranty. That special tool isn't
actually a tool, warranty doesn't want to pay a tech 3 hours per side when
the tech can do it in 30 minutes, but can't make the tech do it for just
30 minutes of pay because the book SAYS you have to remove the camshafts,
and if you don't, if you really, really, really botch this job up.. you
spin the intake valves against the pistons and make them all look like
wilted daisys, now the dealer has to buy a new cylinder head and we alllll
know that it's price is only exceeded by the massive amount of labor
necessary to swap one. Ie: step one- remove engine. So. A lot of techs
make a lot of money doing these chain tensioner gaskets, and AoA hates it.
It's rather interesting that it even leaks. You can see the effort that
they put into making it not leak. The two gasket mating surfaces are
miled to a specific roughness, the gasket is a multi-density composite
steel/synthetic rubber with surface-adhered silicone barrier traces. This
is the kind of gasket you'd use on a billion dollar sattelite up in orbit.
Yet... they leak. Baffling.
On Fri, 29 Jul 2005 tstifler at att.net wrote:
> Keman once wrote about the most likely area the 2.7 will have an oil leak - I can't find that thread. I now smell a burnt oil odor when I get out of the car when engine is hot. Was that the valve cover gkt ?? Easy fix ?
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