running hot

radiator and resivour is circulating fluid, engine is in upper level of operating temp. Gas tank is getting hot and spitting fuel out the overflow and fill cap. Seems to be running to hot, cooling fan is working, any ideas?

Inside of the system may be corroded or crudded up restricting circulation. First thing is to flush cooling system.

Sorry to here, hope it's going to live.
Have you had any past trouble or is this a sudden change? You may have a defective T-stat. Hopefully it's not a leaking head gasket, this will cause Air-lock in system and over heat quickly. You can do a cheap-o leak down test for the head gasket by removing the spark plugs and putting compressed air in to the spark plug hole when that cylinder is at TDC firing position with the radiator full and cap off. You will see bubbles coming up in the fluid from the offending cylinder/ gasket. My book doesn't show me this model, I'm sure some else will know if the water pump is gear/ or belt driven? If belt it could be toast, or slipping.
Hope it's simple.

Just flushed the coolant, so I'll try the T-stat. That seems the logical choice. It's a 79 1300 with only 9500 miles, hope it still has some more life.
Thanks for the ideas.

If it's not the thermostat:

You may want to take the radiator off and have it hot tanked. Old radiators collect crud that partially or completely blocks the tubes, reducing coolant flow capacity. Having them boiled out usually improves this.

Sometimes the water passages in the block and head get narrow over time due to rusting which restricts water flow. happened on an old Dodge I had, and it would run hot on the freeway no matter what I did.

The other question is the water pump, which may be OK.

Thanks, I will let you know what the out come is.

Hi kz1300ak,

I've got two 1300's.

1300's often run hot. Some owners have resorted to adding a layer of that bubble type heat insulation to the bottom of the gas tank. I agree that you should probably pull the radiator and have it cleaned. Other things you can try include: upgrading the cooling fan blade to the six blade type that was manufactured at one time by Muzzy's. Using one of those wetter water additives with your coolant. Also there's a shear pin behind the water pump impeller that can fail allowing the impeller to not spin up properly. I went one step further and relocated two of my coils to the tool tray which vastly improves air circulation behind the radiator and over the top of the motor. I also ditched the deceleration air system. I can actually remove my valve cover without removing anything more than the tank and plug wires.

KZCSI

The other things that can make an engine run hot is igniton timing advancer running too advanced and if the engine is running too lean.