ENGINE OIL/ WINTER/ WARMING CAR (tirade, yet edumacational.. D'oh!)

[AudiBiTurbo at aol.com]

First, I'm tired, worked and SHOPPED all weekend, so please be gentle when 
you kick me off of my soap box.  That said, here we go....

OK, here's the scoop.  You shouldn't let your car sit there and idle beyond 
what is necessary to build full oil pressure (well, the pressure is infinite if 
the oil is solid, but I'm talking real world, under flow).  For example, some 
older VWs will need 10 or 30 seconds for the oil pressure to "pump up" the 
hydraulic lifters (and get rid of the tapping noises).

As to colder thermostats.  Brett is *partially* correct, but *possibly* for 
the incorrect reasons.  Here's why:
A thermostat is designed to keep maximum heat in the engine, warming up the 
oil for proper flow at high RPM.  It also gets the oil at the contact surfaces 
free of condensation.  That is the KEY reason.  Water doesn't lubricate well, 
and it offers no corrosion protection versus oil.  What you are striving for 
is the oil to be just above 212 degrees F at the points of metal contact 
(bearings, valve stems, piston rings, etc.).  This ensures the water becomes gas and 
vents out (only to condense again later assuming the same atmospheric 
conditions, but I digress).  You want this to happen ASAP.  The heat will eventually 
permeate through the engine, further stabilizing clearances.  You ALSO want 
your exhaust gas temperatures to rise quickly to help the engine breath because 
the hotter the exhaust, the faster it "pulls" air out of the exhaust ports, 
and therefore the faster the air can rush into the cylinder via the intake 
ports.  This make more HP!  (more air in, more fuel can be burned, more HP). Note, 
this is only up to a point.  Meaning, due to exhaust (or intake) restrictions, 
air can only flow *so* fast, so excess heat only preheats the incoming air.  
Also, by heating things up more quickly, the sooner catalytic converter(s) and 
lambda (oxygen) sensors start working.  In general, up to the point that 
things start melting, the hotter the exhaust, the less the emissions.  THIS IS KEY 
for manufacturers to meet international (C.A.R.B. and CAFE standards in this 
country.. (Phil from the UK will have to insert Green Party Nazi regulations 
here) pollution standards.  If they don't meet these fleet averages, they start 
getting fines on EVERY vehicle they sell, if the individual vehicle meets 
them or not.
To recap why we want the engine to warm up quickly:
1. Better lubrication, meaning longer engine life
2. Better HP
3. Better environment (tree hugging hippies like air-cooled, pollution ridden 
VWs... I never did figure that one out!)
4. I probably missed something- I'm tired
4.5 The car costs less because the manufacturer isn't fined.
5. You get maximum heat to your heating system sooner... clear windows and 
warm fingers make safer driving (damn ACCNA instructor just HAS to bring safety 
into this tirade...)

OK, if the engine gets TOO hot:
1. Oil breaks down, metal to metal contact.
2. Intake air preheated, or due to exhaust restrictions, the maximum flow 
gains are diminished. Less HP (this is bad, unless your mother or 16-year-old 
sister's boyfriend is driving).
3. More engine compartment heat, the belts, hoses, and electrical wear out at 
an accelerated rate.
4. Engine can overheat, warping the head, blowing a seal, shifting a liner, 
etc.

Back to the good stuff:
To get the engine up to temperature in the shortest amount of time:
Let idle for a few (no more than 30 seconds, give or take) to stabilize oil 
pressure.
Accelerate very gingerly (slowly).  Use only minimal revolutions without 
bogging the engine.
Short shift (see above... remember- the oil is not at maximum lubricity, 
you're already running rich/colder because of cold-start protocols, and the 
thermal stability at this point is weak.

OK, how do I know when it's OK to "give 'er a go?" (That quote was for Phil 
from the UK for me suggesting car regs in Europe are controlled by Green Party 
Nazis)  Well, for most vehicles (especially VAG products), it's when the 
indicated oil temperature is 180 degrees F.  This will ensure the oil is above 212 
F where it counts.

Why go colder thermostat?  Well, let's say you drive harder than grandma, or 
live in death valley, USA.  All you want is the engine oil to reach 180 
degrees F indicated and NO MORE.  You've already maximized the engine lubricity and 
thermal stability... more heat just means less HP, once you're up to 
temperature.  Also, if you run the car normally with a lower temperature thermostat, 
you have more "headroom" to run the car harder and longer, say at a track event 
(ACCNA or Tracquest are both good....).

Yes, some people have a "summer" thermostat and a "winter" thermostat in the 
middle climates (like here in upstate NY).  It really depends on your setup 
and how you operate your car.  Run hard at Watkins Glen.... lots of straights 
and high speed, so lots of cooling airflow.  Run hard at Lime Rock Park (or NYC 
or Boston or I-95), much lower speed, much less airflow.  Yes, the slower you 
go, sometimes the "hotter" you run!  (I'll regret that quote someday, I just 
know it....).  LOL

I hope I've helped, and we really need archives, since good, sleepy tirades 
that are barely offensive are difficult to come by.

Cheers!
Mark Rosenkrantz
AudiBiTurbo at aol.com


In a message dated 12/21/2003 5:34:06 PM Eastern Standard Time, 
brett at cloud9.net writes:
At 3:14 PM -0600 12/21/03, Todd Young wrote:

>You don't want to get in, start it up and through it in gear and go

The owner's manual is quite clear on this.  Get in car, drive.  Do 
not 'warm up'.  I think the 200q20v manual might say something about 
driving it gently until the engine has warmed up slightly; I don't 
recall.

You will do more damage letting it idle, because engine 
components(piston+sleeve for example) don't reach design temperature 
nearly as fast as they do under load.

This is the same reason why colder thermostats cause cylinder wear- 
the tolerances are carefully designed to be perfect at the 
temperature the thermostat is set for.

Brett