Water pump design changed in 85 ????

[gervais]

hi all
i add to dismantle the thermostat on my 84 and in the same time i decided to check the water pump because i add a VERY serious
problem of over heating here that result in 2 head gasket blown up but so far not much more.

i orded from HOnda a new thermostat and the radiator cap.

i have looked at the "turbine design" of the water pump and there is a major difference in the 85 and 84,
one is in aluminium and the 84 in some sort of plastic/faberglass ,,i dont know.

the aluminium seems to be more aggressive in design,in pitch angle and i wonder if honda made an amelioration on that in 85??

i read al lot of comments (now) about overheating and guys installing bypass switch and pilot light to turn ON the rad fan much more early.

and experiences??

thanks
Gervais.

[WingMan71]

Well... based on the part numbers alone, SOMETHING changed in the water pump.

Starting in 1985, the water pump is part number 19200-MG9-681.

It appears, based on part numbers, that the water pump went through three versions sometime since the first 1984 version.

First 1984 water pump - part number 19200-371-020

That part was superseded by part number 19200-MG9-680.

Then, that part number was superseded by part number 19200-MG9-681 (same as the '85 and up water pump)

Your discovery that the turbine was made of a different material (plastic) in 1984 and changed to aluminum in 1985 confirms that the two years use different water pumps.

The change to an aluminum turbine to me means that the '84 plastic ones probably proved to be a problem, perhaps either breakage or longevity issues.

I had a 1984 GL1200 Interstate back in the day, and also still have a 1987 GL1200 Aspencade. I have never had an overheating problem with either of them, but then again my bikes get all of their recommended maintenance and more.

The water pump may not be the only issue on an overheating engine. If the entire cooling system was not regularly flushed and refilled according to the required maintenance schedule, there could be restrictions or blockages in the coolant passageways in the engine and hoses and the radiator itself that are causing the overheating. Heck, you cold have a radiator that is so plugged up that it is only flowing about half of what it should. Might be time to take the radiator out and take it to a radiator shop and have it professionally cleaned inside. These bikes are all over 30 years old now, and if they've been neglected or sitting unused for long periods things can get plugged up.

***

[SilverDave]

I so agree ... 30 years is a long time for a rad to block up ...
and at least around here , if you can find an older rad technician ... you Rad can be cheaply " Rodded" to clean it up ... and they love doing that !! ( an old skill they thought they'd never use again )

Modern car rads are plastic, and if they are blocked... they must just throw them away

https://www.roundforge.com/articles/rep ... -recoring/


Get it repainted matte black while its in the shop ... and replace all the hoses ..... NAPA carries a hose you can cui to get a top and bottom hose ...


SilverDave

[gervais]

well
i ordered from the Honda dealer here a new OEM thermostat and the rad cap too.

in the present time the radiator is in a solution of water and vinegar too help clean inside of any ,,,,material that could obstruct the inside .vinegar is very good and gentle on metal.

this bike was in a dealer back show room for 2 maybe 3 years that i learn AFTER i baught it,,i was screewd by this dealer,,he will never see me again and after a while i heard about his reputation!!! Honda have not a good one in this ,,one.


i am waiting for gaskets kit and a used water pump from a 85 i found in good condition so at least i will update,upgrade the water pump.

gervais

[WingAdmin]

You are correct. Honda changed the water pump impeller design for all their bikes, from the old bakelite "turbine" impeller to an aluminum one. It is stronger, more reliable, and resistant to heat.

Old design:

New (current) design:

[gervais]

well
the bakelite one is the one that i have here on my 1984 and i found a good used one in one of my Groups of GW owners.

i also tested this morning my old thermostat,it opened at 195 degree and not even full open so it was not functionning properly
thats certain.

i baught an OEM thermostat and waiting another radiator cap,the one i received is too small and i found this parts numbers on the web so conclusion: telephone at a DEALER and ask the right part number at their parts dept.

gervais