Overheating at idle

[Reverend]

I got my car running after changing ballast resistor. It starts up nicely like under palm tree. Actually when little warm, it starts better than my daily driver Anyways, i started the engine and let it run for 5 or so minutes, i checked the gauges and heat was almost at the red bar so i instantly turned it off. It roared a bit after i turned it off, almost like it was starting by itself.

There was no unusual smoke, no leaking of water. I removed thermostat and gonna change that first. Any other reason why it might have overheated?

[ozconnection]

The thermostat is a good place to start. Check the new one that it works before you put it in. Piece of mind, I had one once that was new but didn't open. It was a real pain in the arse and kept me very busy freaking out, spending time and money looking for other problems that didn't exist.

Check the tension and condition of your fan belt.

How old is your water pump? Maybe the impeller blades have corroded but the pump doesn't leak or squeak.

When was the last time you cleaned your cooling system? Scale can build up inside the block that can prevent the proper transfer of heat to the coolant.

How clean is the outside of your block? Thick crap ie mud and/or oil can make the engine overheat.

How's your radiator? Have you used any stop leak products lately? Special oily products that block leaks can also reduce the efficiency/heat transfer ability of the engine and radiator by blocking some of the coolant tubes and the oils used in these products can act as a thermal insulator.

What's in your radiator? Water, water wetter, ethelyne glycol, propylene glycol, many choices and many different results. I personally use distilled water with a bottle of water wetter. No problemo's

Do you use a fan shroud?

What is the condition of your radiator cap?

How are your heater and radiator hoses? All in good condition without any fraying or collapse? Scale can and often builds up on the inside of the hoses and can drastically reduce coolant flow.

How much ignition timing? Vacuum advance connected to ported or manifold vacuum?

Mixture strengths by itself won't cause an overheat but in conjunction could make a bad situation worse. Idle speed? Choke on all the time?

Easter is here, seems you could spend a little bit of time 'checkin' things out' under that palm tree!

[ChrisZ]

I might be wrong, but if your car is dieseling, then a good place to start will be to check if you got ignition and carburation right, what spark plug are you running ?

Chris

[Reverend]

oz: Dont know about the waterpump, fanbelts did give a little whining sound. Cooling system has been completely flushed and all the hoses except those that go to heater core inside cabin have been replaced. In radiator theres water and green anti-freeze. 60/30. Havent use any anti-leak stuff yet. I have the original fan shroud.

I dont know about timing, i dont know how to check or adjust it but the engine runs very well, it just overheats. :stupid:

ChrisZ: I run Bosch plugs.