Ready to explode another myth about the GMC motorhome that really worries people

thomas g. warner

New member
Mar 24, 1998
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Thanks for the info that your water pump is running the wrong direction.
Could be a start of destroying another major myth and that is we need the
cast iron water pump impeller or the engine will overheat. I PERSONALLY
THINK THAT IS BUNK!

If the pump runs backwards the radiator will run at greatly reduced
efficiency ie;reversed flow thru the thermostat, reverse water flow thru the
radiator etc. Mondello says the the best way to correct an overheating
condition if everything is in good shape is to cut off some of the stamped
impeller blades thus SLOWING down the flow of water thru the radiator core.
maybe he is right. Aren't you doing very close to the same thing by running
your water pump backwards?

Do you have a temp gauge showing actual temp, and if so has it changed? Time
to start getting info on another myth. Time to come out of lurk Arch and
take charge.

>
>
>>Aren't you having cooling problems from your water pump and fan running
>>backwards. The fan now pushes air thru the radiator and the coolant flow
>has
>>been changed?
>>
>
>New fan (reversed) is installed as part of the kit so air is still sucked
>through the radiator.
>
>Waterpump apparently can run either way but perhaps not as efficient in
>reverse. However, temps are good.
>
>Heinz
>
>>
>>

>>>No such thing as a stupid question... at least not on this list :-)
>>>
>>>The only item running in reverse is waterpump and fan.
>>>Just to be sure I had it on ok I called Leigh and doublechecked.
>>>
>>>The suggestion to make a tool using a socket and weld a bar onto it didn't
>>>wash. Apparently tool steel doesn't weld well.
>>>I'm going to look at Sears for one of them new fangled ratchet handles
>that
>>>have a whole in them where a bolt or allan wrench will hopefully fit
>>>through.
>>>
>>>In the meantime I'm hoping the locktite will hold until I get home to
>>>investigate/fix further. Of course that might be a while.
>>>
>>>Heinz
>>>
>>>
>>>-----Original Message-----
>>>From: GMC77PB
>>>To: gmcmotorhome
>>>Date: Wednesday, March 31, 1999 9:18 AM
>>>Subject: Re: GMC: Anyone running the Serpentime belt kit besides me?
>>>
>>>
>>>>May I ask a stupid question? Does the Serpentine belt change the
>rotation
>>>of
>>>>the alternator? If so that could be the reason the nut comes loose. May
>>>need
>>>>left hand threads
>>>>Justin
>>>>
>>>>
>>>
>>>
>>>
>>Tom & Marg Warner
>>Vernon Center NY
>>1976 palmbeach
>>
>>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
And another thing about running the water pump "backwards" --- the fan clutch
will also turn backwards and they are designed for specific direction of
rotation. Don't know what happens if you run the clutch backwards but it must
not work as intended.
Gary
'77 Kingsley
North Bend, Oregon Coast

> Thanks for the info that your water pump is running the wrong direction.
> Could be a start of destroying another major myth and that is we need the
> cast iron water pump impeller or the engine will overheat. I PERSONALLY
> THINK THAT IS BUNK!
>
> If the pump runs backwards the radiator will run at greatly reduced
> efficiency ie;reversed flow thru the thermostat, reverse water flow thru the
> radiator etc. Mondello says the the best way to correct an overheating
> condition if everything is in good shape is to cut off some of the stamped
> impeller blades thus SLOWING down the flow of water thru the radiator core.
> maybe he is right. Aren't you doing very close to the same thing by running
> your water pump backwards?
>
> Do you have a temp gauge showing actual temp, and if so has it changed? Time
> to start getting info on another myth. Time to come out of lurk Arch and
> take charge.
>

> >
> >
> >>Aren't you having cooling problems from your water pump and fan running
> >>backwards. The fan now pushes air thru the radiator and the coolant flow
> >has
> >>been changed?
> >>
> >
> >New fan (reversed) is installed as part of the kit so air is still sucked
> >through the radiator.
> >
> >Waterpump apparently can run either way but perhaps not as efficient in
> >reverse. However, temps are good.
> >
> >Heinz
> >
> >>
> >>

> >>>No such thing as a stupid question... at least not on this list :-)
> >>>
> >>>The only item running in reverse is waterpump and fan.
> >>>Just to be sure I had it on ok I called Leigh and doublechecked.
> >>>
> >>>The suggestion to make a tool using a socket and weld a bar onto it didn't
> >>>wash. Apparently tool steel doesn't weld well.
> >>>I'm going to look at Sears for one of them new fangled ratchet handles
> >that
> >>>have a whole in them where a bolt or allan wrench will hopefully fit
> >>>through.
> >>>
> >>>In the meantime I'm hoping the locktite will hold until I get home to
> >>>investigate/fix further. Of course that might be a while.
> >>>
> >>>Heinz
> >>>
> >>>
> >>>-----Original Message-----
> >>>From: GMC77PB
> >>>To: gmcmotorhome
> >>>Date: Wednesday, March 31, 1999 9:18 AM
> >>>Subject: Re: GMC: Anyone running the Serpentime belt kit besides me?
> >>>
> >>>
> >>>>May I ask a stupid question? Does the Serpentine belt change the
> >rotation
> >>>of
> >>>>the alternator? If so that could be the reason the nut comes loose. May
> >>>need
> >>>>left hand threads
> >>>>Justin
> >>>>
> >>>>
> >>>
> >>>
> >>>
> >>Tom & Marg Warner
> >>Vernon Center NY
> >>1976 palmbeach
> >>
> >>
> >
> >
> >
> Tom & Marg Warner
> Vernon Center NY
> 1976 palmbeach
 
Along this line, small impeller, smaller pulley, higher or same volume as
original. Right?

Just an inquisitive mind.

Roger