Persistant overheating on GPX600R '89

[gkep]

Hi all,

This forum has been great to me before so I'll try again:

I recently bought an '89 GPX600R and have ironed out all the bugs other than that it seems to be constantly running too warm.

Firstly I replaced a dodgy thermostat which helped to a degree.

Next I replaced a non-functioning radiator fan switch which was heavily corroded/fouled.

The temperature seems good and stable on long, open rides but the stop/start stuff round the city is when it really warms up and starts leaking coolant out of the overflow pipe.

My next guess is the radiator needs a good flushing out (I hear there is some chemical product that does this).

Any ideas sure would be appreciated!

Cheers,
Guy

[tape]

yep flush radiator... make it a 50-50 coolant water mix when re-filling the beast.

Best of all advice is to fit a manual fan switch... As a GPz900R owner overheating is normal... but Smitty will also chime in I reckon ....

Manual fan switch cost about $10

cheers

[Smitty]

yeah..as tape said
but a cupla other things to check 1st
the flush for the radiator and the engine....
as you said, is necessary
check with ya bike shop what to use
and after that 50/50 as tape said and ALL hose connections tight!
then after that, do a cooling system pressure check
and
you may find....
the radiator cap is stuffed (common)
or
you have a headgasket leak (also common on the 600 motor)
comes with old age..the gasket corrodes
and you end up pressurising the system and the overflow bottle...
which overflows when hot
or the waterpump oring gets old and perishes
and the same happens...

hth

cheers

[gkep]

Ah cool- much good info here.

Best of all advice is to fit a manual fan switch

Been wondering about this- I guess i'd wire up some sort of weather proof switch to close the circuit and then mount it somewhere... any idea where to get that sort of thing from? Boating supplies? Mount it near the kill switch?

you may find....
the radiator cap is stuffed (common)

Not sure if this is related but the first couple of times it got really hot I had overflow out from around the radiator cap. Reckon this indicates the cap is stuffed?

Failing all this it may be time to bite the bullet and check the headgasket/waterpump o-ring.

Really appreciate the help- if you guys want the latest Ghostrider DVD than email me your address (guy001_AT_gmail_DOT_com) and I'll shoot one off to you. Cheers again!

[Ment]

If the pressure cap is leaking it isnt sealing.
id still check for the head gasket, just incase but definately fix the cap.

[tape]

Ah cool- much good info here.

Best of all advice is to fit a manual fan switch

Been wondering about this- I guess i'd wire up some sort of weather proof switch to close the circuit and then mount it somewhere... any idea where to get that sort of thing from? Boating supplies? Mount it near the kill switch?

you may find....
the radiator cap is stuffed (common)

Not sure if this is related but the first couple of times it got really hot I had overflow out from around the radiator cap. Reckon this indicates the cap is stuffed?

Failing all this it may be time to bite the bullet and check the headgasket/waterpump o-ring.

Really appreciate the help- if you guys want the latest Ghostrider DVD than email me your address (guy001_AT_gmail_DOT_com) and I'll shoot one off to you. Cheers again!

Definately do the new radiator cap, I try and get photo tomorrow of the GPz switch location.. PM me If I forget.. try the cheap stuff first then if all else fails bite the bullet and look at H' Gasket.

Cheers

[Rusty]

I would have thought that if the head gasket was leaking enough to pressurize the system it would leak on long runs, not just in town.

My money's on the radiator cap and possibly clogged radiator.

[Smitty]

you may find....
the radiator cap is stuffed (common)

Not sure if this is related but the first couple of times it got really hot I had overflow out from around the radiator cap. Reckon this indicates the cap is stuffed?

cap is stuffed... from your description
and cheapo to replace...from memory around $16-$18
do that and also a rad clean out
and go for a run...

cheers

[mike-s]

Heres what i did on my old bike when it came time to flush it out.

I did a forward and then reverse radiator flush with a hose until you cant see any crap coming out. I then filled the radiator with a diluted formula of radiator cleaner, just make *SURE* that it says on the bottle it is ok for use in alloy engines as some of them can eat through alloy like its playdough. (when putting the concentrate in, put it in in dribs and drabs while filling the radiator so it doesnt get any pure cleaner on any components).

Take the bike out for about 20-50km of running and then let it cool down fill & then flush the radiator again with pure water again at least 2-3 times to make sure all the cleaner is gone.

Drain and put in a propper premixed glycol sollution. Takes about half a day from beginning to end including letting things cool down, but my engine immediately dropped a noticeable ammount on the thermo guage.

[Smitty]

mike..
nice post..spot on