Kawasaki over heating

[Gregor 4,847]

My brother has a Toro Grounds Keeper, with a 22HP Kawasaki, water cooled engine. The engine over heats. If he leaves the radiator cap loose, it won't overheat. He has checked the thermostat, and says it's OK.  What would you do?  Thanks   Greg

[Maxwell-8 4,367]

clogged radiator? or maybe broken pump if the thermostat is bad. A cooling-system pressures the system so it can cool better. strange yours doesn't overheat without pressure, but does with pressure.

[Gregor 4,847]

1 hour ago, Maxwell-8 said:

clogged radiator?

That was my first thought also, although I'm not sure whether a loose radiator cap would make any difference or not. Then again, I am 200 miles away from the tractor. You don't always get the whole picture when you are 200 miles away.

[Skipper 1,789]

Leaking headgasket? Can put bobbles into cooling system, and can on some engines cause bad flow and overheating. Just a shot. Have seen these symptoms in some car engines, and headgasket was nearly always the cause.

 

check if there is bobbles in the coolant reservoir, when you rew it.

 

Edited May 14, 2021 by Skipper

[ranger 1,798]

Coolant leak somewhere? Head gasket/cracked head? Perhaps only leaking when hot and under pressure? Any coolant loss or bubbles visible in rad/header tank, or evidence of excess pressure whilst running with rad cap removed? Is it actually overheating, or just gauge/warning light indicating that it is?

[Gregor 4,847]

6 minutes ago, ranger said:

 Is it actually overheating, or just gauge/warning light indicating that it is?

That's the part I don't know. He says gauge operates normally with cap loose, but I am not there to actually see it, and know whats going on.

 

When it does overheat, it is not forcing coolant into the reservoir.

Edited May 14, 2021 by Gregor

[ranger 1,798]

49 minutes ago, Gregor said:

That's the part I don't know. He says gauge operates normally with cap loose, but I am not there to actually see it, and know whats going on.

 

When it does overheat, it is not forcing coolant into the reservoir.

Maybe a faulty sender, pressure forcing coolant into sender causing resistance values to change?

Thats where these “Puppies” come in useful, don’t need to be super accurate with measurements, comparison at different stages will tell you more. Blue-point one I’ve had for 30+ years, expensive! Cheap eBay one shows almost identical measurements.

 

Doug.

p.s. Another tool you didn’t know you needed, but can’t do without once you’ve got one. (Also works for checking for Covid high temperature, but do turn the laser off first!).

 

Doug.

 

[Gregor 4,847]

18 minutes ago, ranger said:

Another tool you didn’t know you needed

You're right. I think I do need one of those. Just ordered one.

[gwest_ca-(File Mod) 11,451]

A rad cap raises the boiling point of the coolant approximately 3F degrees for every pound of pressure.

Will be interesting to hear what makes him think it is too hot if it is not pushing coolant into reservoir.

 

Garry

[Gregor 4,847]

He is just reading the temp gauge. With the cap on, it pegs out. With it off, it reads normal. Keep in mind this is all second hand info.

[Rob R 973]

I believe some of those engines did not use a water pump and used physics to circulate the water..... in these machines the mix is critical you need to investigate using the correct manual for that engine - tractor....... just my two cents.....

[ranger 1,798]

21 minutes ago, gwest_ca said:

A rad cap raises the boiling point of the coolant approximately 3F degrees for every pound of pressure.

Will be interesting to hear what makes him think it is too hot if it is not pushing coolant into reservoir.

 

Garry

Exactly. That’s where the non contact thermometer comes in, a quick and, (relatively), easy way to check the engine / radiator temps in various areas with cap on, and cap off should help identify where / if there is a problem. Perhaps thermostat failing under pressure and closing? Radiator hose delaminating under pressure? You would expect to see coolant loss though.

Edited May 14, 2021 by ranger

[ranger 1,798]

11 minutes ago, Gregor said:

He is just reading the temp gauge. With the cap on, it pegs out. With it off, it reads normal. Keep in mind this is all second hand info.

Cable from the sender running across the rad cap and shorting, 😢remove cap, short cured. 😃

[gwest_ca-(File Mod) 11,451]

We do not know how his gauge is wired.

Some will peg if the wire to the temp sender on the engine is disconnected.

or

Some will peg if the wire to the temp sender on the engine is shorted to ground.

 

Try both to see why it is pegging.

 

Garry

[Gregor 4,847]

I am actually trying to get him to haul it here. He just hauled it from his home in Az. I don't think he feels like hauling anymore. Anymore than I want to drive over there with a screwdriver, and a pair of pliers trying to fix it.