I have a 95 GMC k1500 with a 5.7 L and I can hear a steady clicking sound.
It is hardly noticeable when the truck is cold but after about a 30 min trip
I can definitely hear it from in the cab and is very predominate when I
listen by the intake. The truck also seems to be lacking power until I get
it really warmed up. With a 500 lb load in the box I have a hard time to
keep the truck in overdrive while driving at 110 km/hr. Once warmed (30
mins or so driving time) I have no problem keeping it in overdrive. We
thought it might be one of the hydraulic lifters broken and banging away but
after pulling the valve covers off and checking for some play on the rocker
arms I found none. Any more ideas? I am mostly wondering if this will be
harmful to my engine. There is about 150000km on the engine and I run
synthetic oil.
Thanks

Is this the same problem that some are refering to as piston slap? Seems
unusual to me that it gets louder as the engine warms up.

"Rob" <roblarss (AT) email (DOT) com> wrote

No, 95's with the 5.7 were not affected by piston slap. Only the new
engines (4.8, 5.3, 6.0) have the slap. Sounds like you have something funky
going on.................you sure you're not hearing spark knock?

Have you at least pulled all 8 plugs to see what they tell you?

If the engine sucks when cold and gets better as it warms up that would seem
to suggest a non-mechanical (i.e. fuel injection, ignition, etc.) source of
your woes.

Without more information I can't even fathom a reasonable guess.

Doc

I will check out the plugs in the morning. I replaced them along with the
dist/wires/o2 sensor about 4 months ago. If you can think of any other
information that I can find that may be useful I am all for it.
Thanks
""Doc"" <noway (AT) nope (DOT) com> wrote

by the way what does spark knock sound like? I am not familiar with that
one.
I do all my own work on my vehicles and I am not to confident with taking it
into any shops nearby (live in very rural Alberta)
thanks


""Doc"" <noway (AT) nope (DOT) com> wrote

"Rob" <roblarss (AT) email (DOT) com> wrote

Do you know how to scan the PCM for codes? If you do, run a scan and see
what you come up with.

Doc

I ran a check for codes stored in the computer and there were none. I was
going to check the plugs but the blizzard outside helped me to rethink that
idea for today. Now the I can hear the sound more pronounced even when the
engine is cold.


""Doc"" <noway (AT) nope (DOT) com> wrote