Re 164 idle, oil, coolant, tires

["C.M. Smith" <cmsmith@domain.elided>]

My personal standard for adequate tires is how often they squeal under
cornering forces, or slide unacceptably. My 164 L seems quite happy with
195/65 P6000 Performance tires (NOT the all season version, I dislike every
no-season tire I've driven on). The factory's choice of Goodyear NCT's was
less than inspired, they were too hard and basically a pretty crappy tire.
Wider, lower profile tires, involve a ride/harshness trade-off which is
only worth putting up with if you prefer the crisper cornering feel. In
street use I'd be very surprised if they provide sufficiently higher levels
of grip to make the trade-off worthwhile, but it's a pretty personal decision.

I'm suspicious of the benefits of so called long life coolants. Seems
mainly aimed at extending engine service intervals as per pressure from the
US regulators, right up there with 100,000 mile sparkplugs, who needs 'em?.
GM's perfectly silly ECU subprogram that allows you to drive x miles with
no coolant is along the same lines. Who would ever drive an Alfa with no
coolant ( oh oh, I did once but the engine didn't care, it was winter and
enough coolant remained to protect the engine!!! it was an emergency etc
etc it's a long sad story and I'm sorry. already) Glycol/water should be
adequate and if you flush your system every two years there appear to be no
advantages to newer coolant formulations promising extended life (for the
coolant not the engine, please note!).

IMHO no Alfa should be run on 30 weight oil.  A 40 weight is the minimum
and 50 should be better. If  you like conventional oil, I'd follow the old
rule of thumb and use the narrowest winter/summer spread you can find, no
more than a difference of 30 between the numbers. If synthetic is your
preference, the lower winter number should not matter much  because the oil
is performance rated , not viscosity rated. If the higher number is 40 or
50, that's what counts. When cold, thin is good in a synthetic, not so true
of conventional multi grades because of the viscosity "improvers" they have
to use to get the oil to flow at cold temperatures.

The  owner of the 164 with the high idle problem might check the throttle
position switch. Mine went ever so slightly out of adjustment and the
engine would not idle, intermittently. The switch is mounted on the
throttle spindle and senses the idle position and the full throttle
position to bypass the main ECU program at idle and full throttle
respectively. It contains two micro switches triggered at the two throttle
positions and is "calibrated" with reference to the idle switch. There is a
slotted mounting tab on each side, back off the screws and turn the switch
unit until the idle micro switch just closes when the throttle plate is at
idle position (check throttle cable adjustment and free movement before
assuming the switch is out of whack.) The correct setting is more detected
by the feel of the switch clicking closed than any real audible sound. Then
secure the switch and the idle should work fine. Of course, the air bypass
switch may be sticking. They tend to build up deposits over time, and can
get tight when hot and stick open. Fuel injector cleaner in a can sprayed
into the throttle plate and bypass loop will unstick most air valves,
engine off of course!!! 
Michael Smith
Calgary, Alberta
Canada
91 Alfa 164L, White, original owner 

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