My valves are getting pretty loud but its only when the hood is open...i know you have to change a bunch of things when you adjust them like the spacers and s***... i was just wondering who has had this done and if it was dificult for the regular macanic to do ?? ...maybe a dealership kind of job if its not to pricy??

 

Adjusting valve clearance not as simple as turning an adjustment screw. Each cam lobe bears directly against a disk-shaped steel shim of precisely machined dimensions. Changing valve clearance is done by removing the shim and substituting another with a different thickness. This service procedure requires special tools. The shims are made in thicknesses ranging from 2.32mm to 2.95mm. They can be purchased from the dealer. I'm not aware of any other source for these shims.

See Chilton (page 1-30) or Haynes (page 2B-5).

If you hear the valves only when the hood is open it is not yet time for a valve adjustment. Just close the hood.

 

Might want to turn up the stereo if you ever hear it inside the car also hehe. It,s not an easy job to do.

 

and there's alot of those valves too... 24 of them on two cylinder banks with two sets of valve covers to pull.

if it gets particularly loud though, you may want to have it checked out. i'm not sure how the valve train is arranged on the maxima, but in some instances, a reduction in clearance in a valve can keep the valve partiaully open when it's supposed to be closed and cause other damage over the long term. particularly a burnt valve or something as the valves don't get a chance to contact the valve seat and transfer the heat from the combustion process to the valve seat. other designs are less damaging, and won't allow the valve to open fully, causing gradual deterioation in engine performance... judging from Dan's description it is a shim over or under bucket design, which in most cases will cause the first instance above with the valves not closing completely over time.

try changing the oil viscosity you use too... might be a cheap way to lessen the noise.

 

My macanic said to change oil filters first and see if it goes away...i had this older filter on before and there was no sound at all...then changed to puraltor and loud as hell...he said some foriegn cars do this ?? ill try it

 

What you need is a filter with an "anti-drain back valve" which will keep oil in the passages as opposed to one that will allow oil back in the pan.

 

When the engine is running the oil pump draws oil from the sump sends it
upward through passages called oil galleries to cool lubricate all the
internal moving parts of the engine. When the engine is turned off,
gravity will cause the oil in the galleries to flow "backward" through the
oil filter return to the sump unless something prevents that. The
anti-drainback valve is a one-way valve (a "check valve") which prevents
this from happening.

If the filter has a leaky anti-drainback valve the galleries become empty
when the engine is not running. When the engine is started it takes a few
seconds for the oil pump to refill the galleries. During that refill time
the engine parts, especially the valves, make an unpleasant knocking,
clicking, or clattering sound. This symptom is more noticeable after a
long period of rest, 24 hours or more.

Oil filters made for use in an inverted or horizontal position have an
anti-drainback valve. This is true for ALL brands of oil filters. The
difference (if any) from one brand to another is the material used the
quality of manufacturer. Any individual filter might have a bad
anti-drainback valve.

The filter media, bypass valve, anti-drainback valve are all internal
parts of the oil filter. Therefore an oil filter is a "blind item"
because the user cannot judge the condition or quality by sight, sound,
smell, taste, or touch. When buying a blind item we make purchase
decisions based on "image" factors such as the influence of advertising
brand loyalties. Choosing a good filter is further complicated by the fact
that the same product may be sold under several brand names. filter brands
A, B, C may be identical except for the brand name exterior color.
The supplier for filter brand D might be the same as brand A for this year,
but be changed to brand B next year. Industry insiders will know about
this but most consumers will not.

If your engine exhibits the symptoms of a bad anti-drainback valve you
should replace the filter. You might try a different brand of filter but
(as explained above) it might turn out to be an identical product. I
personally do not believe in the inherent superiority of the factory part
but respect the opinion of those who do.