| Re: [GMCnet] Coolant Cap [message #322724] [message #322809] |
Mon, 28 August 2017 06:39  |
Thomas Pryor
Messages: 143
Registered: January 2011
Karma: 1
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Senior Member |
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John, Send my your address, I will send you mine however, based on
personal experience I would take the opportunity to REPLACE the whole
overflow bottle "system"
WHY?
Under certain conditions it is a BOMB! The trip report to Rapid
City, GMC Rally
a year or so ago is the basis for my recommendation.
http://www.gmcmhphotos.com/photos/other/p63636-just-another-pretty-face.html
THE RESULT OF A (SILENT) CATASTROPHIC FAN CLUTCH FAILURE AND A OEM COOLANT
OVERFLOW BOTTLE WITH INLET SIZE OF 3/8" AND OUTLET SIZE OF 1/4". OPENING
ENGINE HOODS ALLOWED COOL AIR TO INCREASE BOTTLE PRESSURE AND EXPELLING
THE COVER. RESULT: 2ND DEGREE BURNS OF FACE AND ARM.
IMHO ROOT CAUSES:
1) Fan Clutch decoupled WITHOUT WARNING and failed to provide fan rotation
creating violent coolant temperatures. (Just came off freeway, 5 minutes of
stop & go driving)
2) The GM Cooling Design engineers of the day did not consider ALL of the
conditions that a coolant overflow bottle must operate in, SAFELY. Under
normal operating conditions the coolant bottle which has a 3/8" diameter
vent tube to expel vapor and pressure from the Radiator is adequate. The
overflow bottle outlet is 1/4" and is also adequate for normal operating
conditions. When an extreme event occurs and the 3/8" inlet is filled
with100% coolant, under excessive pressure and the escape route is a 1/4"
outlet.....................A CONDITION OF EXTREME CONSEQUENCE IS
CREATED................DON'T OPEN ENGINE HOODS UNDER THESE CONDITIONS!
AT THE END OF THE DAY............................. CHANGE OUT YOUR COOLANT
BOTTLE WITH A CURRENT DESIGN THAT ALLOWS FOR COOLANT ESCAPEMENT UNDER ALL
CONDITIONS!
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It was then that I was motivated to do something about Fan Clutches for our
GMC Tribe and myself. My Objectives were:
- When a Fan Clutch is not engaging the Fan, alert the driver, don't
wait for the temperature rise! Dash light shows electromagnetic valve in
clutch is opened
- find a current ELECTRONIC fan clutch design that can be repurposed for
our coaches. Note:Also fan must rotate the same direction as the
crankshaft as our 455 and 403 engines.
- Use coolant temperature as trigger device to actuate the fan clutch
electronics, not the engine room temperature!
- Make it adjustable and have driver ability to engage the System for
impending hi cooling demand requirements.
- Make it bolt on installation. Did not quite accomplish because of the
need to modify fiberglass full coverage fan shroud. The early 3/4 coverage
fan shroud is not compatible with this repurposed Fan/Fan clutch.
- Don't rely on Asian Fan clutches.
I think I have achieved those objectives. The cost will be prohibitive for
some but not by today's standards for replacing a EVC (Electronic Viscous
Clutch) on a current model vehicle design. Just Say'n.
Two of the modifications have been installed and are currently operating
with great feedback. (Matt Collie and Jim K. and others) They are
available from Applied GMC http://www.appliedgmc.com/prod.itml/icOid/1874
YEAH I KNOW IT'S IS AN ADVERTISEMENT, BUT THE TRIBE NEEDS TO KNOW ABOUT
THIS.
--
Regards,
Tom Pryor
4188 Limerick Dr
Lake Wales, Fl 33859
Cell 248 470 9186
Living on a waterfront is not a matter of life or death. Its more
important than that.
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| Re: [GMCnet] Coolant Cap [message #322724] [message #322814 is a reply to message #322809] |
Mon, 28 August 2017 08:17  |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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We should have three installed within the next few weeks, mine goes in as soon as I have a day to install it.
--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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