But what about sailing down the highway with all that air coming
through the radiator. If
the clutch fan does not need to run in this case, does the thermostat
then
regain the task of regulating?
I'd like to butt in here.
I do not believe that there is much of a ram-air effect in these
coaches. Like anything else, air will follow the path of least
resistance. The radiators in these coaches just sit in front of the
engine, there are no baffles directing the air that passes through the
grill to the radiator, consequently, the air mostly just goes around. I
had a terrible overheating problem with my GMC (mostly due to my own
ignorance about clutch fans) when I first purchased it. The temp gauge
would hit the half way mark (original sending unit) and stay there until
I started up the Alpine grade east of San Diego, then it would rocket
upwards until coolant puked everywhere. The entire problem was the
clutch fan. It never locked up. So here I am at the top of the grade,
refilled with water, temp gauge at the halfway mark again. (Remember, I
thought this reading was "normal") I start down the grade, 4 miles or
so.....the temp gauge never dropped lower than the halfway mark even
though I was moving over 65 mph with almost no throttle and even
touching the brakes occasionally. If any "ram air" was getting through
that radiator the temp should have dropped. It didn't. So now I read
about fan clutches in the archives & the light comes on...duhhhhh.
Hayden 2797 installed, back on the grade, half way to the top of the
grade the temp finally moves past the one quarter mark to just past the
half-way mark & the fan clutch locks up. The temp dropped so fast I
almost missed it. If any ram air is passing through the radiator, I
have to believe it is only a nominal amount and not enough to rely on
for any real cooling effect.
I met a neighboring GMC owner a couple of weeks ago who had baffled
the air flow from the grill through the radiator. Nice job, looks
simple and also looks like it belongs there. I'm going to stop by and
throw some before & after type questions at him. I did ask him why he
had cut-outs on the sides of the baffles & he said that he thought the
engine compartment was getting too hot & needed some air flow through it
that didn't come through the radiator first.
Maybe I'll talk to him today......after I replace my clutch fan, for
some reason after just a couple of hundre miles on it, it decided to
fail in the "locked" position. This thing sounds like the Wright Bros.
coming down the highway.
Steve Ferguson
San Diego
through the radiator. If
the clutch fan does not need to run in this case, does the thermostat
then
regain the task of regulating?
I'd like to butt in here.
I do not believe that there is much of a ram-air effect in these
coaches. Like anything else, air will follow the path of least
resistance. The radiators in these coaches just sit in front of the
engine, there are no baffles directing the air that passes through the
grill to the radiator, consequently, the air mostly just goes around. I
had a terrible overheating problem with my GMC (mostly due to my own
ignorance about clutch fans) when I first purchased it. The temp gauge
would hit the half way mark (original sending unit) and stay there until
I started up the Alpine grade east of San Diego, then it would rocket
upwards until coolant puked everywhere. The entire problem was the
clutch fan. It never locked up. So here I am at the top of the grade,
refilled with water, temp gauge at the halfway mark again. (Remember, I
thought this reading was "normal") I start down the grade, 4 miles or
so.....the temp gauge never dropped lower than the halfway mark even
though I was moving over 65 mph with almost no throttle and even
touching the brakes occasionally. If any "ram air" was getting through
that radiator the temp should have dropped. It didn't. So now I read
about fan clutches in the archives & the light comes on...duhhhhh.
Hayden 2797 installed, back on the grade, half way to the top of the
grade the temp finally moves past the one quarter mark to just past the
half-way mark & the fan clutch locks up. The temp dropped so fast I
almost missed it. If any ram air is passing through the radiator, I
have to believe it is only a nominal amount and not enough to rely on
for any real cooling effect.
I met a neighboring GMC owner a couple of weeks ago who had baffled
the air flow from the grill through the radiator. Nice job, looks
simple and also looks like it belongs there. I'm going to stop by and
throw some before & after type questions at him. I did ask him why he
had cut-outs on the sides of the baffles & he said that he thought the
engine compartment was getting too hot & needed some air flow through it
that didn't come through the radiator first.
Maybe I'll talk to him today......after I replace my clutch fan, for
some reason after just a couple of hundre miles on it, it decided to
fail in the "locked" position. This thing sounds like the Wright Bros.
coming down the highway.
Steve Ferguson
San Diego
wner-gmcmotorhome]On Behalf Of Steven D.
