Overheating on the highway. Help!

Janderson

New Member
I have an 09’ FZ1 which I purchased recently that had been sitting for some time. It could still run with the gas that was in the tank. I replaced the gas anyways (91 octane), changed the oil etc and on the first ride it was overheating. Got all the way to 240 F before I shut it off and coasted to a stop. I’ve done all of the following...
Replaced coolant
Flushed cooling system 3 times with radiator flush
Flushed cooling system with garden hose
Replaced thermostat
Replaced radiator OE style after market- it looked clogged with minerals inside
Pressure tested system- Ok
Performed head gasket combustion leak test-Ok
Checked operation of temp gauge by removing cap while hot (safely) and measuring radiator internal temp with a probe it was within 2 F (208 vs 210)
Replaced radiator cap
Removed pipe on side of engine to inspect water pump impeller- looks ok and spins while cranking
Inspected cooling fans both are working. One fuse was blown initially fans come on around 210 F

I work at a Lexus dealer so I’ve been using Toyota pink coolant

initial drain coolant was green and smelled a bit fishy

oil looked fine when I changed it not milky, and no milky stuff in the sight glass

right now I removed the thermostat and it a little better with out it.

So currently it seems ok around town but runs a bit hot gets to about 220 F but will go back below 210. As soon as I go on the highway it overheats even when it’s like 50 F outside. It gets to 235 within a couple miles at 75 MPH
It seems to warm up much faster than my Kawasaki z1000 or my GSXR 750 even without a thermostat. It gets to operating temp in about 3-5 mins of riding then immediately gets too hot. After I shut it off only takes like 2 mins to go from 235- to like 205 then I start it and move it will go down to 190 or so before overheating again.

also it is completely stock (stock exhaust) it runs amazing and go’s just as fast as I’d expect. No hesitations or misfires. I don’t know if it’s had it’s ecu flashed I can’t contact the original owner anymore.

Please help I’m at my wits end with this thing.
 

Klurejr

Active Member
It is really odd that it only overheats on the highway where the air flow would be best....

If it was a bad sensor I would think the temp would always read high. Does the engine feel extra hot when you get the high readings?

I don't think the fan would be part of the issue, but is the fan working?

Based on everything you have posted I am thinking it might be a water pump failure, possibly something wrong with the impeller? Once you get up to highway speed and sustained higher RPM's the coolant is just not flowing enough to exchange the heat, but maybe around town the lower average RPMs are making it to where it does not matter, especially if it is cold where you live.
 

Janderson

New Member
It is really odd that it only overheats on the highway where the air flow would be best....

If it was a bad sensor I would think the temp would always read high. Does the engine feel extra hot when you get the high readings?

I don't think the fan would be part of the issue, but is the fan working?

Based on everything you have posted I am thinking it might be a water pump failure, possibly something wrong with the impeller? Once you get up to highway speed and sustained higher RPM's the coolant is just not flowing enough to exchange the heat, but maybe around town the lower average RPMs are making it to where it does not matter, especially if it is cold where you live.
Agreed, very strange usually you would expect and overheat in traffic. So I did test the sensor by removing the cap while hot and inserting a temp probe in the radiator. The reading I got was 208 F and the dash said 210 F so I believe temp sensor is ok. Also I removed the hard coolant pipe on the left side of the engine where water is feed to the water pump. Here I was able to see the impeller and it looked to be in good condition. I also cranked he bike over while this was removed because the impeller is chain driven and I was thinking it would be moving. But it was moving. Any other ideas?
 

Klurejr

Active Member
i am sorta baffled, sounds like you checked all the things related to moving the coolant around.

Unless a wrong gasket was installed at some point that is blocking critical water movement..... I really sounds like the coolant is not moving around.
 

Janderson

New Member
i am sorta baffled, sounds like you checked all the things related to moving the coolant around.

Unless a wrong gasket was installed at some point that is blocking critical water movement..... I really sounds like the coolant is not moving around.
yes thanks for the reply. I’m going to try to keep flushing it unless someone else has seen this.
 
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