The Stovebolt Site Forums The Shop Area Engine Shop 216 over heating

Need an opinion or advise .. I am running a 1940 chevy 1/2 ton pick up with a 216 engine. The engine is out of timing i asume just a little because I got a hit and miss back fire coming out of first gear and second gear but does not happen all the time i been running it like this for just a while because i Havent had time to get it to the shop. Heres where i need some opinion or advise . A while back i noticed a pin hole leak on the radiator on the core just under the top tank. But it wasn’t over heating at all even with it back firing every now and then .Its a huge deal just to pull radiator . I have to break down entire front end and pull off the hood its not a quick pull. So now its over heating and im not sure if its from the pin hole on radiator or the timing issue. I would hate to take it to shop to get it timed and it starts over heating before they can get it timed. Would a small pin hole on top of the radiator cause it to over heat or can i asume its most likely coming from the timing issue. I do see water circulating in radiator and i am not running a thermostat. Never ran a thermostat and never had a over heating issue. What should i do pull radiator and fix pin hole before i put in shop or try and get it timed with the radiator have a pin hole on it ?

From what you have said first try a tune up and then flush the system to clean out the water jacket. If you pressure test the radiator, only put a small amount of pressure on the system, I think less than 3 pounds.

When it overheats is it out/low on coolant? If so, you need to get the radiator repaired regardless of whether or not you tune/time it. 🛠

When it over heats the coolant level is good and its circulating inside the radiator when i take off cap and check it. Can a small hole at top of radiator with coolant level good still cause engine to over heat ? One thing i did notice and im not sure if this is how it should feel or not, with truck running i squeezed upper and lower radiator hoses and it feels like theres no water going thru them i can squeeze them pretty good . With truck running should i have alot of pressure at hoses where i shouldnt be able to squeeze them like that ?

The answer to your question as to whether the pin hole can cause the engine to overheat is no.

I suspect from your description of squeezing the radiator hoses is that you are overdue for a change of hoses. You should not be able to squeeze good hoses like that.

Since you will be changing the hoses, why don't you just keep going, remove the water pump, remove the hood, undo the cowl to radiator brace at the front and one side then rotate the brace upward, undo the 6 bolts holding the radiator and remove it. Take it to a radiator shop to get it repaired and cleaned out. Flush the engine block. Do a tune up. Put everything back together with a thermostat and you will be good to go.

I drive my stock '51 pickup with a 216 in 115 plus degrees in the Phoenix area with no problem at all.

You can do it! And you will be glad you did.

Kent

The pinhole is not the cause of overheating. It would be a good idea to get the rad cleaned out and repaired. If you can flush the block, that would be good too.

Ok thanks to u all for the good advise .. jus going to pull radiator and flush out block ... maybe add a thermostat..

Definitely add t'stat.

Ed

YES Thermostat! And a trip to the radiator shop.

Shouldn't the 1940 cooling system run a zero pressure radiator with a vent tube in the top tank? If someone has put a pressure cap of any capacity on it, that's a mistake. It's also what is causing the "pinhole" leak. There should be NO pressure at all in that system, and if you run a thermostat, don't go above a 160 degree unit.

Bottom line- - - -you need to get the radiator repaired. A "small" leak is like being a little bit pregnant- - - - -the situation isn't going to improve. You should also do a "block test" where a colored liquid is used to detect exhaust gas in the coolant. If the indicator liquid turns from blue to green (small leak) or to yellow (BIG leak) it's time for a head gasket change or worse, the head is cracked.

Paragraphs and punctuation are your friends. Some of us old geezers get out of breath reading posts like yours!
Jerry

Yep a no pressure cap is necessary for sure. Another way to check exhaust gas in cooling system is to find a garage with an old emission machine. You can put the exhaust sniffer at the top of rad w/o cap on and detect hydrocarbons...᠁ If they are present, head gasget issue, if not, you're in the clear. Well in the clear as far as a tear down, but be diligent to locate the issue and service it.

Thanks for all the help . For those who mentioned might have a head gasket issue. So is it possible to have a blown head gasket and no water in the oil ?

Yes.

Yes again

If you have a blown head gasket without water in the oil, the water is being burned. If you pull the spark plugs, the cylinder with the blown gasket will be extremely clean while the rest of them will have normal discoloration. The spark plug has been literally steam cleaned.
Carl

I had a 503 that leaked water with no visible signs on outside of block, no signs in combustion chambers, all due to several loose head bolts on one side, got it home OK with sodium silicate until I had to add antifreeze, disabled sodium silicate. Firemen are not mechanics.

Ed