Home » Public Forums » GMCnet » Radiator maintenance
Radiator maintenance [message #289851] |
Mon, 02 November 2015 12:08 |
tgeiger
Messages: 518 Registered: February 2006 Location: kansas city
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Checking to see if there is anything special to do on my radiator beside using a flushing product from a autoparts store and do a general service on it?
Tom Geiger
76 Eleganza II
KCMO
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Re: Radiator maintenance [message #289869 is a reply to message #289851] |
Tue, 03 November 2015 04:53 |
tgeiger
Messages: 518 Registered: February 2006 Location: kansas city
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Hey Jim, hows things? I did drain a couple gallons of antifreeze from the drain. It looks clean. So I put a couple gallons of coolant back in and got a new radiator cap. The issue I have is the lady that lioked it up looked up the engine and it came up with a cap that was rated 14lbs instead of the 9lbs that is mentioned in the manual. The previose cap was rated even lower, 7lbs. So should I go back and see if they can find me a 9lb cap?
I do have a plastic resevior that might need some refurbishing, can ask tto see if they have anything that matches. I'll check your sute for it as well.
Tom Geiger
76 Eleganza II
KCMO
[Updated on: Tue, 03 November 2015 04:57] Report message to a moderator
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Re: [GMCnet] Radiator maintenance [message #289871 is a reply to message #289869] |
Tue, 03 November 2015 06:33 |
Ken Henderson
Messages: 8726 Registered: March 2004 Location: Americus, GA
Karma: 9
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Tom,
I'll answer while Jim's still sleeping: YES -- Do get the correct 9
lb. radiator cap unless you have one of the new aluminum radiators.
The GMC's big, wide span radiator was not designed for more pressure.
And the years have compounded that "weakness".
The correct part number should be in your GMCMI Parts Interchange manual.
Ken H.
On Tue, Nov 3, 2015 at 5:53 AM, tom geiger wrote:
> Hey Jim, hows things? I did drain a couple gallons of antifreeze from the drain. It looks clean. So I put a couple gallons of coolant back in and got
> a new radiator cap. The issue I have is the lady that lioked it up looked up the engine and it came up with a cap that was rated 14lbs instead of the
> 9lbs that is mentioned in the manual. The previose cap was rated even lower, 7lbs. So should I go back and see if they can find me a 9lb cap?
>
> _______________________________________________
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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Re: [GMCnet] Radiator maintenance [message #289876 is a reply to message #289871] |
Tue, 03 November 2015 07:26 |
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USAussie
Messages: 15912 Registered: July 2007 Location: Sydney, Australia
Karma: 6
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Ken,
Neither was the heater core.
But it might handle the added 5 psi.
Then again it might not. :-)
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: Ken Henderson
Tom,
I'll answer while Jim's still sleeping: YES -- Do get the correct 9 lb. radiator cap unless you have one of the new aluminum
radiators. The GMC's big, wide span radiator was not designed for more pressure. And the years have compounded that "weakness".
The correct part number should be in your GMCMI Parts Interchange manual.
Ken H.
On Tue, Nov 3, 2015 at 5:53 AM, tom geiger wrote:
Hey Jim, hows things? I did drain a couple gallons of antifreeze from the drain. It looks clean. So I put a couple gallons of
coolant back in and got a new radiator cap. The issue I have is the lady that lioked it up looked up the engine and it came up with
a cap that was rated 14lbs instead of the 9lbs that is mentioned in the manual. The previose cap was rated even lower, 7lbs. So
should I go back and see if they can find me a 9lb cap?
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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Re: [GMCnet] Radiator maintenance [message #289879 is a reply to message #289877] |
Tue, 03 November 2015 07:46 |
Ken Henderson
Messages: 8726 Registered: March 2004 Location: Americus, GA
Karma: 9
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Rob,
You opened the door, so I've gotta ask: Why, if your water
temperature reaches 200*F, would you even consider using a 160*F
thermostat? YOU certainly know that the thermostat has no effect on
the maximum temperature of an engine, only on the minimum -- which
should never be that low. 180*F I can tolerate, even though 195*F is
correct, but never 160*!
The Cad does indeed tend to run hotter than an Olds, but with the
installed 195*F thermostat, the digital readout on the EBL What's Up
Display stays pegged on 196*F almost all the time, only touching 198*F
under heavy load. That's disregarding my one no-fan/slow speed
problem last year, when it pegged out near 265*F (with no damage
apparent since then).
Ken H.
On Tue, Nov 3, 2015 at 8:31 AM, Robert Mueller wrote:
> Al,
>
> I have two aluminum radiators and both of them have 9 psi caps. The reason for the pressure is to increase the boiling point of the
> cooling water, the aluminum radiator is EXTREMELY efficient and the 455 Olds in Double Trouble with a 160°F thermostat the Digi
> Panel and remote water temp gage have never gone over 200°F even in heavy traffic. \
>
> Cadillac 500's have been reported to run hotter and that's what Ken has.
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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Re: Radiator maintenance [message #289883 is a reply to message #289851] |
Tue, 03 November 2015 10:18 |
tgeiger
Messages: 518 Registered: February 2006 Location: kansas city
Karma: -1
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Thanks Ken...I'll go back to them and get the 9lb cap. Yes it is the original radiator that had been re-cored. It also has the water heater recirculation system from the engine also.
Tom Geiger
76 Eleganza II
KCMO
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Re: [GMCnet] Radiator maintenance [message #289885 is a reply to message #289877] |
Tue, 03 November 2015 11:45 |
Al Hamilton
Messages: 61 Registered: March 2008 Location: Heart of the 1000 Islands...
Karma: 12
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Ken & Rob,
Oops !! When in doubt read the instructions !! I see the suggestion for a 15 PSI cap and still have 9 pounder on. In the nine years the rad has been on the temperature has sat at about 190 all the time - never over 200 until this summer when we were in stop and go traffic for about an hour and a half. It went to 215 and I discovered the fan clutch had failed when we got home.
Thanks to you both. I see I need to change the coolant now too.
Al
Al Hamilton,
76 Eleganza II,
Heart of the 1000 Islands, Ontario
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Re: [GMCnet] Radiator maintenance [message #289889 is a reply to message #289885] |
Tue, 03 November 2015 12:45 |
jimk
Messages: 6734 Registered: July 2006 Location: Belmont, CA
Karma: 9
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With people having heater cores that are deteriorating, I would tend to
stay around 9 psi cap.
We have run accross lot of heater cores leaking and have supplied over 20
cores in the last year.
On Tue, Nov 3, 2015 at 9:45 AM, Al Hamilton wrote:
> Ken & Rob,
>
> Oops !! When in doubt read the instructions !! I see the suggestion for
> a 15 PSI cap and still have 9 pounder on. In the nine years the rad has been
> on the temperature has sat at about 190 all the time - never over 200
> until this summer when we were in stop and go traffic for about an hour and
> a
> half. It went to 215 and I discovered the fan clutch had failed when we
> got home.
>
> Thanks to you both. I see I need to change the coolant now too.
>
> Al
> --
> Al Hamilton,
> 76 Eleganza II,
> Heart of the 1000 Islands, Ontario
>
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--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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Re: [GMCnet] Radiator maintenance [message #289893 is a reply to message #289879] |
Tue, 03 November 2015 15:46 |
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USAussie
Messages: 15912 Registered: July 2007 Location: Sydney, Australia
Karma: 6
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Ken,
The 160°F was what was in there when I bought the Avion. When I R&R'd the OEM intake with the aluminum one it didn't dawn on me to
replace it. DOUH!
There is a 195° sitting on my "parts to install" shelf at the storage unit in Humble.
Regards,
Rob M.
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Ken Henderson
Sent: Wednesday, November 04, 2015 12:47 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Radiator maintenance
Rob,
You opened the door, so I've gotta ask: Why, if your water
temperature reaches 200*F, would you even consider using a 160*F
thermostat? YOU certainly know that the thermostat has no effect on
the maximum temperature of an engine, only on the minimum -- which
should never be that low. 180*F I can tolerate, even though 195*F is
correct, but never 160*!
The Cad does indeed tend to run hotter than an Olds, but with the
installed 195*F thermostat, the digital readout on the EBL What's Up
Display stays pegged on 196*F almost all the time, only touching 198*F
under heavy load. That's disregarding my one no-fan/slow speed
problem last year, when it pegged out near 265*F (with no damage
apparent since then).
Ken H.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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Re: Radiator maintenance [message #289929 is a reply to message #289851] |
Wed, 04 November 2015 09:08 |
jhbridges
Messages: 8412 Registered: May 2011 Location: Braselton ga
Karma: -74
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The parts house listing for the Olds 455 is for a 160, so that's what I put. Digipanel says 175 bar pretty much whatever we're doing.
\
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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Re: [GMCnet] Radiator maintenance [message #289950 is a reply to message #289935] |
Wed, 04 November 2015 18:11 |
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USAussie
Messages: 15912 Registered: July 2007 Location: Sydney, Australia
Karma: 6
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G'day,
I've noticed that under certain conditions Double Trouble's water temp will run BELOW 165° F on cold days. I believe that is because
the aluminum radiator is so efficient that water flowing through the thermostat bypass is enough to cool the engine below the
setting of the thermostat.
Below is a drawing out of the maintenance manual that shows a cross section of the thermostat.
http://www.gmcmhphotos.com/photos/engine-cooling-photos/p47659-thermostat-housing.html
Has anyone else with an aluminum radiator noticed this phenomenon?
The readings on Double Trouble's Digi Panel and remote temp gage are virtually the same when this occurs.
BTW Parts Manual 78Z lists two thermostat part numbers: 3027868 and 3030055. I Googled "GM 3027868" and "GM 3030055" and they were
both 195° F.
Regards,
Rob M.
The Pedantic Mechanic
-----Original Message-----
From: A.
When it comes to engine temps, higher is better, up to a point. Higher gets you better MPG and less engine wear. But it needs to be
lower than the boiling point of the coolant by enough margin to give you some wiggle room on a hard pull out of Death Valley in the
Summer. The difference between 180 and 195 is not worth arguing about. But 160 is certainly too low. 205 would probably be too high.
No GMC in the lower 48 should be running anything less than 180 or more than 195. If you have something outside that range, change
it out when "convenient".
Johnny Bridges
The parts house listing for the Olds 455 is for a 160, so that's what I put. Digipanel says 175 bar pretty much whatever we're
doing.
--johnny
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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Re: Radiator maintenance [message #289952 is a reply to message #289851] |
Wed, 04 November 2015 18:49 |
tgeiger
Messages: 518 Registered: February 2006 Location: kansas city
Karma: -1
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Senior Member |
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Wow, am I getting some puzzled looks at the Auto parts store when I ask for a 9lb radiator cap. 16lbs is what I get...even though I got a 14lb a couple nights ago. If it isn't in the computer...complete blank looks. So onto the part exchange manual.
Tom Geiger
76 Eleganza II
KCMO
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