Cooling issue

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andycoop62
Posts: 28
Joined: Sun May 24, 2015 4:01 pm

Cooling issue

Postby andycoop62 » Sun Jul 26, 2020 5:39 pm

Weird problem, all of a sudden my temp gauge is hardly getting off the bottom but the engine seems to be really hot, just ran it while stationary and the gauge hardly moved but started to run rough and steam rising from radiator, not losing coolant though?
‘90 GPZ500s

yanw
Posts: 446
Joined: Thu Apr 20, 2017 4:54 pm
Location: Gloucester

Re: Cooling issue

Postby yanw » Sun Jul 26, 2020 5:59 pm

When it has cooled down open the radiator cap and check if there is water up to the top. If it is full then it sounds like the impeller/water pump has failed.

You can, I think, take the water pump housing off and see if the impeller rotates when you turn the bike over. Remember it won't have any coolant in so don't run it for long.

andycoop62
Posts: 28
Joined: Sun May 24, 2015 4:01 pm

Re: Cooling issue

Postby andycoop62 » Sun Jul 26, 2020 6:19 pm

Okay cheers, I was thinking either water pump or thermostat
‘90 GPZ500s

yanw
Posts: 446
Joined: Thu Apr 20, 2017 4:54 pm
Location: Gloucester

Re: Cooling issue

Postby yanw » Sun Jul 26, 2020 7:03 pm

I'd not thought about the thermostat which I think you can get to with the tank off. A new gasket for the water pump is about £7.50 if you don't make one yourself.

andycoop62
Posts: 28
Joined: Sun May 24, 2015 4:01 pm

Re: Cooling issue

Postby andycoop62 » Sun Jul 26, 2020 7:12 pm

what normally fails in the water pump? is it the shaft or impeller or do you have to change the whole lot?
‘90 GPZ500s

yanw
Posts: 446
Joined: Thu Apr 20, 2017 4:54 pm
Location: Gloucester

Re: Cooling issue

Postby yanw » Sun Jul 26, 2020 7:33 pm

I'm not sure what would fail but looking at the parts book it's a separate shaft and head. It might have stripped where it goes into the gearbox or lost the impeller. Perhaps start with the thermostat and see if it opens in boiling water

andycoop62
Posts: 28
Joined: Sun May 24, 2015 4:01 pm

Re: Cooling issue

Postby andycoop62 » Sun Jul 26, 2020 8:56 pm

Yes think I might!
‘90 GPZ500s

yanw
Posts: 446
Joined: Thu Apr 20, 2017 4:54 pm
Location: Gloucester

Re: Cooling issue

Postby yanw » Sun Jul 26, 2020 9:28 pm

If you carefully use insulation tape on the side panels and faring you can get the tank off without taking them off. The tape is to stop the tank brackets scratching the plastic. However if it does scratch please.dont blame me ;)

andycoop62
Posts: 28
Joined: Sun May 24, 2015 4:01 pm

Re: Cooling issue

Postby andycoop62 » Mon Jul 27, 2020 7:00 pm

so water pump is fine and thermostat seems to open, not sure its opening early enough though, can't think what else could cause it. Managed to break the bloody water pump cover taking it off so looking for one of them now too grrr.
Anyone had a faulty thermostat? just wondering would it cause the engine to run hot but show a cool temp gauge
‘90 GPZ500s

yanw
Posts: 446
Joined: Thu Apr 20, 2017 4:54 pm
Location: Gloucester

Re: Cooling issue

Postby yanw » Tue Jul 28, 2020 7:51 am

Bummer about the break :(. The sensor is in the thermostat housing so if the impeller is working there must be a blockage or an air lock in the system somewhere?


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