mko

I was wondering if anyone could help w/ a strange sound I hear. I
have a 1997 Toyota Tacoma and when I start it up I hear a
'clickety-clickety-clickety' coming from the center under the hood. It
only makes this sound when it's very cold outside. Once the engine
has warmed up the sound goes away. Any ideas?

Thanks,
MKO

doug kanter

Just a hunch, but what weight oil are you using?

mko

Sorry, but I'm automotively challenged... but I believe the oil weight
is 5w/30?

Is that important?

doug kanter

It was probably not a great question to ask, but I asked anyway. :-)
Reason: I've had cars which made the sound you describe for just a second or
two until the oil got moving, especially when cold. 5w/30 is the right oil
to use, but you never know what effect advertising might have on someone, so
I asked.

If you open the hood and get close (without letting your tie dangle into the
belts), can you get a more focused idea of where the sound's coming from?
How long does it last? Does it vary with the RPMs? Change when you activate
the compressor (turn on defroster)?

mko

constant rate ticking.


- Consistently from the left-rear side of the engine compartment.
(closest point to the driver)

- Mostly in cold weather. I drive a few blocks ticking goes
away.


- If I increase engine revolution, the ticking rate remains constant,
but usually goes away.


- Ticking rate is about 3-4 ticks per second.

-No change if defroster is on.

mko

constant rate ticking.


- Consistently from the left-rear side of the engine compartment.
(closest point to the driver)

- Mostly in cold weather. I drive a few blocks ticking goes
away.


- If I increase engine revolution, the ticking rate remains constant,
but usually goes away.


- Ticking rate is about 3-4 ticks per second.

-No change if defroster is on.

mrfixit469

Sounds like a valve adjustment is in order, just did one on mine. I had
similar problems and this fixed it. To tell exactly where the sound is
coming from; get a 3' piece of vacuum or fuel line, stick one end in
your ear and move the other end around the engine while it's
running(kind of like a stethoscope). Watch out for moving objects! If
the sound is coming from under the valve cover, most likely the problem
is just an overdue valve adjustment.

mko

Thank you so much. I'm actually going on a 500 mile trip
tomorrow...is this something that can wait or should I rent a car? I
don't want to be stuck in Detroit in freezing weather on the side of
the road. What do you think?

mko

Thank you so much. I'm actually going on a 500 mile trip
tomorrow...is this something that can wait or should I rent a car? I
don't want to be stuck in Detroit in freezing weather on the side of
the road. What do you think?

mrfixit469

The noise means there is too much of a gap between the valves and
rocker arms, what you hear is the slack being taken up before the
rocker arm contacts the valve. The main problems with this condition is
that it hurts your engine performance and gas mileage. Since there's
too much of a gap, that means the valves are not opening as much as
they should and the heads are not taking in as much air/fuel or venting
as much exhaust gasses as they should. Over an extended period of time,
several months, this could lead to other problems.
If this is a fairly new condition, the trip should be fine. When you're
accelerating and you start hearing the noise, back off the accelerator
a little, don't push it too hard for too long.