Overheating all of a sudden

[dlrshort]

I just had a lot of work done on my '66 327/350 horse and now the car is overheating......never did it before. The only changes to the cooling system were new hose from expansion tank to the radiator and the lower fan belt had been missing and was replaced. I drove the car about 45 minutes and then about the time I pulled into my drive way it overheated and boiled over. I suspected the thermostat and changed it, but it didn't help. Am I looking at a water pump problem or could it relate to that lower belt some way?

Dave S.

 

[ricktret]

I just had a lot of work done on my '66 327/350 horse and now the car is overheating......never did it before. The only changes to the cooling system were new hose from expansion tank to the radiator and the lower fan belt had been missing and was replaced. I drove the car about 45 minutes and then about the time I pulled into my drive way it overheated and boiled over. I suspected the thermostat and changed it, but it didn't help. Am I looking at a water pump problem or could it relate to that lower belt some way?

Dave S.

What work did you have done to the car? There are modifications that will make it run hotter. Are the belts tight? Is the fan working properly? If the car's running hotter due to the modifications, I'd first try using a "water wetter" such as Red Line, and then try a 160 degree thermostat.

 

[tigernut]

You might have an air bubble in the cooling system. Have you purged the cooling system to make sure you got all the air out?

 

[dlrshort]

What work did you have done to the car? There are modifications that will make it run hotter. Are the belts tight? Is the fan working properly? If the car's running hotter due to the modifications, I'd first try using a "water wetter" such as Red Line, and then try a 160 degree thermostat.

No mods should have made it run hotter. I'll try Red Line.

 

[dlrshort]

You might have an air bubble in the cooling system. Have you purged the cooling system to make sure you got all the air out?

Could you please explain about purging the system, why would that be necessary with what was done? Also, is there an easy way to tell if your water pump is working properly. I don't hear any noise or see any leaking.

Thanks for your ideas.

 

[67HEAVEN]

Could you please explain about purging the system, why would that be necessary with what was done?

Thanks for your ideas.

My L-71 didn't come with an expansion tank, but in theory I imagine air would entire the system during the hose replacement to the expansion tank.

If I needed to purge/burp/get rid of air in my bigblock (without expansion tank), I would remove the rad cap (only when engine is cool - safety, safety, safety)....idle the engine to normal operating temperature while observing any drops in fluid level. Shut down...add fluid. (some people add fluid while it's running) Let cool. Repeat three or four times as necessary until fluid level stops dropping. Replace cap. Go for a drive. Monitor temperature and fluid levels carefully for the next while.

Perhaps there's a different way of doing it on cars with the expansion tank.

 

[dlrshort]

'67', any way to tell quickly if I have a water pump problem?

 

[67HEAVEN]

By the way, if I haven't welcomed you already, welcome ricktret and tigernut....welcome to the

 

[67HEAVEN]

'67', any way to tell quickly if I have a water pump problem?

Assuming that no fluid is evident at the weep-hole (below water pump shaft area) and that the belts are properly tightened, the pump should be turning with the belts without noise or wobble.

 

[jerrybramlett]

I just had a lot of work done on my '66... The only changes to the cooling system...

Please explain what other work was done. You can cause a car to overheat with engine work other than on the cooling system.

As for Water Wetter and other magic automotive juices, forget them. They can't possibly make an appreciable difference or the car companies would install them to allow smaller (cheaper) radiators. A different thermostat rating will only change the temperature at which it begins to open. Once the thermostat is open, it's open.

Remember that small block mid-year Corvettes were not overheaters when new. If you have a stock engine and cooling system in good condition, you won't see 210 degrees when it's 95 in the summer and you're stuck in traffic. To boil over with antifreeze in your system you must have been around 240.

Water pumps don't suddenly stop pumping water without bearing or seal failure. Either one of those problems would have been apparent.

One more question: what do you mean by "lower" belt? I can envision a front belt for the water pump and alternator, a rear belt for the water pump and idler pulley, and maybe a power steering belt off the crank only. Which one do you mean?

To make sure you don't trap any air in the block and heads, just drill a 1/8" hole in the thermostat to allow the air to escape while you're filling the system in the normal way through the fill tank.

 

[vettefinderjim]

Timing change?

Did anyone change the timing? ie., did you get a tune up, oil change? or other work?

I need to know what work was done to the car to be able to see what they may have touched that results in overheat.

Was it overheating while driving home? Or did it just puke once you turned off the motor in the driveway after you stopped? It may something as stupid as a loose rad cap......or torn gasket in the cap.

 

[ricktret]

Water Wetter works. My '64 runs 14 degrees cooler with one bottle of Red Line.

 

[dlrshort]

Thanks for all the ideas, I meant the water pump belt was replaced, not the one to the alternator. There wasn't one on before. A full ignition tune up was done as well with plugs wires and ignition. Timing was reset. Oil pan and rear main seal were done. If the car was running hot on the way home I did not notice. I had it parked in the driveway idling, as I was resetting the idle. As I walked away the car boiled over.

 

[67HEAVEN]

Thanks for all the ideas, I meant the water pump belt was replaced, not the one to the alternator. There wasn't one on before. A full ignition tune up was done as well with plugs wires and ignition. Timing was reset. Oil pan and rear main seal were done. If the car was running hot on the way home I did not notice. I had it parked in the driveway idling, as I was resetting the idle. As I walked away the car boiled over.

Hmmmmm...

 

[dlrshort]

Hmmmmm...

Hmmmmmm. I'm wondering what you mean by Hmmmmm.......!!

 

[67HEAVEN]

Hmmmmmm. I'm wondering what you mean by Hmmmmm.......!!

Timing was reset. I'd be checking that.

 

[BLACK MOON]

Sounds like timing. Recheck the timing and burp it.
Just a suggestion.

 

[studiog]

I agree with the timing. Maybe too much advance?

 

[WayneC]

Timing

 

[ricktret]

Check your timing. Advancing the timing will often make the engine run hotter.