Date: Sun, 30 Jun 2002 01:58:26 EDT
Reply-To: FrankGRUN@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Frank Grunthaner <FrankGRUN@AOL.COM>
Subject: Re: Aux Oil Cooler install...results Aircooled vanagon
Content-Type: text/plain; charset="US-ASCII"
Sean,
See comments below interspersed with your text. Each starts with $$!
In a message dated 6/28/02 8:51:09 AM, vgonman@earthlink.net writes:
<< Hey Frank, a couple questions...
What are the dimensions of that 5kt oil cooler?
$$ 9 x 3.5 x 2.5 inches. The inlet area is the 2.5 x 9 inch surface. In my
configuration I mount this surface horizontally with the face contacting the
underside of the air compartment. Looking at the coolers, they sure look just
like the classic air (oil) cooled oil cooler to me. I'll check a part number
eventually. I mount them with the Audi mounting plate (same system used for
the Euro GTi). I mount the two with one rotated 180 degrees in the horizontal
plane.
And, Would installing an
external oil cooler help lower coolant temps any?
$$ Yep, and for sure. I'm assuming the TIICO system has the VW water-to-oil
cooler in place. If not, get one. If you have one, keep it and add the
external. I have seen a hard operating coolant temperature drop of about 10
to 15 degrees with an oil temperature drop of 35 to 50. But the important
thing is the peak or runaway temperature point. As the oil gets hotter (250
to 275 F is not uncommon when cruising at 75-80 in Texas (AEOTW-AFAIK) with
ambient temperatures of 105 to 110 F(!)), the frictional losses get very
significant. With elevated temperatures, local hot spots develop and
cavitation in the coolant/block or head interface can develop. This is
moderated by Water Wetter, highly recommended. Anyway when local cavitation
begins, it is possible to exceed the required thermal dissipation rate and
the temperature will run up. All too quickly, the Aluminum head can warp
giving a blown head gasket. Not infrequent problem with overheated overreved
diesels in the Vanagon application. Of course, head gasket loss on a
percentage basis is still several orders of magnitude below the WBX problem,
but thermal expansion of dissimilar materials is still the root cause.
The issue that we're (We being fellows with TiiCo motors) having is that
IIRC the normal operating temp of most of the I4 motors is between 180deg
F and 190 deg F. The TiiCo motors are somewhat consistantly running 20- 25
deg hotter at 212 deg F or so.
$$ 212 is not necessarily bad. Suggests a 195 F thermostat.
This temp reading is taken via VAG-COM
reading the coolant sensor in the motor. In my case, the entire cooling
system is less than 2 years old, with the radiator being less than 6
months old. I've connected a switch to the radiator fan so that I can
control it from the passenger compartment as well as the automatic
functions via the fan temp switch.
$$ The switch is OK, but unnecessary with the proper functioning technology.
The low temperature trigger switch on the radiator is available for several
different temperatures. In my case, as soon as the internal gauge gets to the
top of the LED, the low speed fan kicks on. Of course, I run a coolant
pressure gauge so I am prewarned about air pockets and the effectiveness of
the fan. Fan triggers on, and I see a several psi drop in coolant pressure.
Wouldn't leave home without it!
I have been in the habbit of simply
turning on the fan when it gets near operating temp and leaving it on
until I shut down the van. This seems to do nothing to bring down the
coolant temps. This leads me to think that either more air (a faster fan)
has to move through the radiator to cool things down, or that I need to
come up with some other way to bring down the engine temp. Do you think an
external oil cooler might help with this?
$$ Remember, reducing the oil peak temperatures is far more important than
reducing the water or coolant temperature. Also, the Vanagon cooling system
has more than twice the thermal reserves to support a 350 HP American V8
(probably 5 to 12% less thermally efficient than the VW I4). So I would say
go for it. The Vanagon is a high stress application for any 2.0L engine. Oil
temperature is critical. Shouldn't be much below 200 F and not above 235 F.
The heavy duty VW applications use a very effective thermostatic valving
system to keep oil temperature above 180 F at all times. The oil must be
hotter than 180 to get rid of sulfuric acid residues and other combustion
byproducts., not to mention dissolved gasoline.
$$ BTW, the many wounds and scar tissue I sport on my butt induce me to offer
this point of inexpensive advice: Never trust any vendor. Especially one who
has shipped you an engine. Always go over the engine (externally) with a
torque wrench. At least make sure that those head bolts are at spec. One
under or over wrenched bolt could be all it takes.
Thanks for any info you can provide.
Sean B. >>
$$ Good luck,
Frank Grunthaner