Pusher Fan

[Chazzer]

Just curious if anyone has installed a pusher fan and had positive results?

It’s been a very hot summer here and I have noticed that my temps have crept up on a few runs on extremely hot days. Mostly on big hills/mountains
such as in the Quebec Laurentian’s.

I have noticed that in extreme conditions my 2 year old Sanden will start to squeal intermittently. I really don’t want to blow that baby apart. It
is doing a fantastic job of keeping the 78 nice and cool. Thanks to Jim K, Applied and this forum I DIYed the AC a couple years back and so far so
good.

My H20 temps usually hold steady at 190 but it has moved over 200 in extreme weather. I have gauges on trans fluid, motor oil temp and diff temps.
It’s a bit unnerving to watch those three creep up, that’s usually when you may hear the odd squeal.

I believe my rad is in tip top shape as the PO had it record when he installed a DP 455.

I also have a new old stock Griffin Rad that is slightly damaged. I haven’t taken it anywhere to have it tested as of yet.
On the Griffin note: is there a brass fitting kit that is required for the Griffin rad?

Thanks in advance...
--
Jim Owens,

78 Royale,

Out skirts of Kitchener, Ontario

 

[6cuda61]

Are you thinking pusher fan with stock fan? If so the answer is "no" it wont help....it actually hinders.

I think the solution with a stock setup would be a lower air scoop for the rad (with bug/rock screen), there are a couple diy examples on the gmc
photo site. Make sure also all the air deflectors around the the grill to rad are still there and intact.

Sadly a good working A/C system on a very hot day adds heat to the rad at the cost of use staying cool.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Chazzer]

Yes, I was thinking of a pusher fan in conjunction with the existing.

I had an old school AC guy suggest it to me.
--
Jim Owens,

78 Royale,

Out skirts of Kitchener, Ontario

 

[6cuda61]

If you had something sitting on a shelf in the garage you could give it a go and fool with it....no harm in trying ....but i wouldnt buy something
personally. As i said, i would be more inclined to get more ram air into the rad when driving by making sure it all goes there and no were else.

> Yes, I was thinking of a pusher fan in conjunction with the existing.
>
> I had an old school AC guy suggest it to me.

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[Jim Hupy]

I would start by installing the 2 piece molded fibreglass shroud that
extends all the way to the bottom of the radiator, and the air dam "possum
scoop" along with the 78 style sheet metal deflectors behind the grill that
deflect all possible air through the existing radiator core. That should
reduce your cruising temperature by 10 - 15° Farenheit. Todd Sullivan
cobbled up some cardboard and duct tape pieces on a trip to So Cal in the
summer time that lowered his internal temperature by at least that much.
Crude to be sure, but effective.
Jim Hupy
Salem, Oregon

On Sun, Jul 26, 2020, 1:47 PM 6cuda6--- via Gmclist
wrote:

> If you had something sitting on a shelf in the garage you could give it a
> go and fool with it....no harm in trying ....but i wouldnt buy something
> personally. As i said, i would be more inclined to get more ram air into
> the rad when driving by making sure it all goes there and no were else.
>

> > Yes, I was thinking of a pusher fan in conjunction with the existing.
> >
> > I had an old school AC guy suggest it to me.
>
>
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[jim kanomata1]

pushing air from a propeller is not very effective.
Spend time making the existing stock parts work.
You need to realize that the radiator acts like a wall.
If your having heating problems it can help but review other options first.

On Sun, Jul 26, 2020 at 2:38 PM James Hupy via Gmclist <

> I would start by installing the 2 piece molded fibreglass shroud that
> extends all the way to the bottom of the radiator, and the air dam "possum
> scoop" along with the 78 style sheet metal deflectors behind the grill that
> deflect all possible air through the existing radiator core. That should
> reduce your cruising temperature by 10 - 15° Farenheit. Todd Sullivan
> cobbled up some cardboard and duct tape pieces on a trip to So Cal in the
> summer time that lowered his internal temperature by at least that much.
> Crude to be sure, but effective.
> Jim Hupy
> Salem, Oregon
>
> On Sun, Jul 26, 2020, 1:47 PM 6cuda6--- via Gmclist <
> gmclist>

>
> > If you had something sitting on a shelf in the garage you could give it a
> > go and fool with it....no harm in trying ....but i wouldnt buy something
> > personally. As i said, i would be more inclined to get more ram air into
> > the rad when driving by making sure it all goes there and no were else.
> >

> > > Yes, I was thinking of a pusher fan in conjunction with the existing.
> > >
> > > I had an old school AC guy suggest it to me.
> >
> >
> > --
> > Rich Mondor,
> >
> > Brockville, ON
> >
> > 77 Hughes 2600
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[john r. lebetski]

200 degrees is not hot. It’s below pure water boiling point in free air by 12F. Sounds like you are worried about that for nothing. Sounds like
you are worried about high pressures on the high side of the AC. Only way to tell is with gauges during the actual conditions. Assuming you have
134a pressures can be higher than with R12. Especially if not correctly undercharged from R12 weights. A pusher fan is tough as the front profile is
not flat with the condenser sitting out front. And when the factory fan is working properly it moves gobs of air when needed and an electric fan will
just restrict that flow. I suggest you get pressure readings in a variety of situations and confirm the base fan clutch operation not for overheating
but for AC performance.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Jim Hupy]

Boiling point of 50/50 Ethylene Glycol anti freeze and water under 9 pounds
pressure in a radiator should be 241° Farenheit. So, 200° is not
excessive. Many modern engines use a 205° degree thermostat. Head
pressures in your A/C system is where you should be looking. R-134a systems
typically run at higher pressures than either R-12 or Duracool. There are
charts in the A/C section of the GMC manual showing "normal" pressures for
your system. Myself, I prefer Duracool in my GMC. I shoot for temperature
drops in the 40° range over ambient air temperature. It will freeze up if
you lower the temperature more than this. Pressures vary with each unit,
but on a GMC that is totally empty, not quite 3 cans of Duracool will do
the trick. Duracool is legal in the USA for Agricultural Equipment, but due
to powerful lobbying interests from the R-134a camp, is not approved YET
for autos. But, it flat out works better.
Jim Hupy
Salem, Oregon

On Mon, Jul 27, 2020, 7:57 AM John R. Lebetski via Gmclist <

> 200 degrees is not hot. It’s below pure water boiling point in free air
> by 12F. Sounds like you are worried about that for nothing. Sounds like
> you are worried about high pressures on the high side of the AC. Only
> way to tell is with gauges during the actual conditions. Assuming you have
> 134a pressures can be higher than with R12. Especially if not correctly
> undercharged from R12 weights. A pusher fan is tough as the front profile
> is
> not flat with the condenser sitting out front. And when the factory fan
> is working properly it moves gobs of air when needed and an electric fan
> will
> just restrict that flow. I suggest you get pressure readings in a variety
> of situations and confirm the base fan clutch operation not for overheating
> but for AC performance.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[Chazzer]

Thanks for all the response.

I am not running R134A but went with 12A as It’s approved for consumer use and readily available here in Canada.

R134A is regulated requiring the appropriate license to access.

--
Jim Owens,

78 Royale,

Out skirts of Kitchener, Ontario

 

[Ken H.]

Jim,

If the A/C belt is slipping at high temps, maybe the water pump is slipping
too, adding to the cooling problem -- check the belt tightness & glazing.
'Tho' I agree with others that 200*-210* is nothing to worry about if
the system is good. Get that aluminum radiator in there and you'll be
happier -- it dropped my Cad500 from 240*+ to 198*steady!

Ken H.

On Mon, Jul 27, 2020 at 11:51 AM Jim via Gmclist
wrote:

> Thanks for all the response.
>
> I am not running R134A but went with 12A as It’s approved for consumer use
> and readily available here in Canada.
>
> R134A is regulated requiring the appropriate license to access.
>
>
>
> --
> Jim Owens,
>
> 78 Royale,
>
> Out skirts of Kitchener, Ontario
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>