Hoping someone can help me I came across a steal of a deal on a 76 stingray...Looks amazing sounds even better! Problem is it overheats while idling.Mechanic cleaned all lines and hoses checked that the water pump is working and the radiator. Any other suggestions? The mechanic has cost more than what I paid for the car!

 

Find a new mechanic. He took your money without fixing problem?

 

Bummer, I would suggest getting your hands dirty. Personally half the fun is learning new things about your vette. Helps to build a personal bond. Plus the forum is a great place to ask questions and gain insight.
Cheers and congrats on your purchase

 

Could be the timing. If it is too far retarded that will cause overheating.

Is the fan spinning fast enough? Could be a bad fan clutch.

Is the shroud on and is the radiator sealed around the edges so that the air isn't bypassing the radiator?

 

Most likely a 'stuck' thermostat. It would normally take quite a while for an idling engine to overheat. But, old thermostats fail...and sometimes they fail in the 'closed' position (or stick in the middle of opening). Buy a good quality thermostat and gasket. I suggest you buy a 180* stat instead of the stock 195* unit. Also buy a small tube of Permatex #2 gasket sealer. Remove water inlet housing (you will get a small amount of antifreeze loss, but nothing to worry about); clean the intake manifold gasket surface and the inlet housing surface well making sure to remove ALL old gasket material; put a light wipe of Permatex on one side of the gasket; install thermostat (pointy end up/spring down), then gasket with sealant side down; now put a light wipe of Permatex on the other side of the gasket and install the water inlet housing.

DO NOT TORQUE THE BOLTS YET...just pull them down with light pressure and let them sit overnight. That will allow the Permatex to harden up a bit. Gooey Permatex can make the gasket squish out from the joint and damage the gasket. Next morning tighten the inlet housing bolts to 30 ft-lbs. Now open the coolant fill cap and put back the approx amount of distilled water or antifreeze that you lost earlier. With cap still 'off', start the car and allow it to warm up to normal temps. You want the new stat to open and pump out any air in the system. Shut the engine down and fill overflow tank up to required level and replace pressure cap. When engine cools down, recheck fill level and top off if necessary.

Now, take it for a drive and see how the engine temp behaves. If OK, let the car idle and see if it still stays in the 'normal' range. If it still overheats, you probably have a limed-up radiator and need to go through a cleaning process with radiator CLEANER (not radiator flush). You can also check to make certain that the lower radiator hose is not collapsing. That is the suction side of the water pump line, and if the support spring (inside that hose) has rotted away, the hose will collapse and shut off water flow to the pump.

So, new T-stat, check lower hose behavior, and clean radiator if necessary. Those are my suggestions. Good luck.

 

Purchase the chassis service manual and assembly instruction manual (AIM) for your "steal." Ensure all the factory radiator and shroud seals are in place.

Check the fan clutch.

Consider having the radiator tanked and cleaned. Looks like your mechanic didn't mention that.

Consider finding another mechanic.

 

....Some great advice, especially the new mechanic!!!

 

The purchase price was low enough that you qualify for Grand Theft Auto?

Your mechanic has larceny in his heart?

Whole lota stealin' goin on here.

 

I like to look for the easy fixes first...check that the radiator cap is holding 15 psi......2nd replace the thermostat with a 180 degree Robert Shaw (if it fails it fails in the open position), 3rd check that the seals around the radiator/shroud are there and 4th check the timing

If these fail to cure the problem there are more areas to check but as I said I like to make sure the easy fixes are tried first.

Good luck.