The Stovebolt Site Forums The Shop Area Engine Shop 1943 Chevy 216 Overheating Problem?

I have a 1943 Chevy with 216. It crankes right up and purrs like a kitten. It starts to run hot in about 10 mins or so @ a idle. I thought it was a water pump problem so I just replaced it but that wasnt a fix. You can take the cap off the radiator and the water doesnt move much unless you rev the truck up bit and then is sucs down and will come back when you let off. The oil is good with no signs of water. I pulled all 6 spark plugs and they are all dry. I thinking maybe something with the head or head gasket but dont know much about that. Anything suggestions on what to try first before I pull the head? Thanks for any help

If your upper and lower radiator hoses are hot to the touch it's likely not the water pump. If only the lower is hot it likely is the water pump. If you're not getting water in the oil I doubt it's a head gasket issue. Most likely you need to flush the radiator and engine block.

Radiator clean? Thermostat opening?

What do you mean by getting hot. Is it puking out the overflow?
Do you fill the rad correctly. Should be a couple inches down from the top when cold. Does your bottom hose have a coil in it.
It could be collapsing.

It sounds like your thermostat isn't opening. Try removing it temporarily, and see if the circulation improves, but don't run completely without it, as it also controls the rate of flow through the radiator. Most stovebolts need a 160 or 180 degree thermostat. The 195 degree stats didn't come into use until the late 1960's when manufacturers started using high-pressure cooling systems and higher engine temps for emission control reasons.
Jerry

When I replaced the old waterpump, I also went to replace the thermostat and found It didnt have one installed in it. I left it that same way after I put in the new waterpump @ first but it now has one installed beacuse someone had told me that might be my problem but it didnt make a difference. Both the upper and lower hoses are about equally warm. The lower hose is coiled. When I had replaced the waterpump, I also removed the radiator and flushed it good along with the block. Both flowed water through them well. You can rev the truck up and see the water suck down and when you let off it comes back up. After about 5 -10 mins of running the gauge rises to the hot range and then it will start coming out the overflow tube after I shut the truck down? Dont know what elese it could be but a head problem but I had heard you would have water in the oil or oil on the plugs. All siz plugs were nice and dry and no water in the oil? I'm lost

I am wondering if you are getting all the air out when filling. I pull the temp sender out while filling, until water comes out, then reinstall. This makes sure there is no trapped air.

Any history on this truck? Been driven at all? Did this start following any work, or gradually, or out of the blue, or . . .

Belt tension tight?

Running with the thermostat out DOESN'T change anything?! I guess that rules out vapor lock at the 'stat. General wisdom is to drill one or two small holes in the flange of the 'stat to allow air to escape on first start-up. But don't, as a rule, run without the 'stat in.

Seems like that would say that either the water isn't circulating properly, or that even if it is, it isn't up to the task.

Blockage in the block?

Mine ran lean for a while, overheated, even with a properly functioning cooling system. Pulling the choke out a little made it cool off immediately, but it had to be just the right amount.

-Michael

You didn't mention the deg of thermostat you put in.

The truck had sat for about a year in a airplane hanger prior to me getting it without running. Thats the main reason I changed the waterpump out beacause the fan had some slight resistance when it turned by hand. Prior to trying to start it for the first time since it sat, I had changed all the fluids,removed and flushed the radiator and block since I was changing the waterpump out anyways. They both flushed and ran water through them good and clean. If I remember correctly it might have been a 180 degree thermostat that is installed but not 100% sure of it. I have heard it might be air trapped in it as Pre '68 Dave posted above so maybe I will at least give that a shot. Trying any suggestions before I tear into a head. Thanks for the help everyone!

I've used this trick to find a head gasket leak without a teardown- - - -Remove the fan belt to disable the water pump,(engine cold) and remove the thermostat housing. Fill the engine with coolant until it is at the level of the T-stat with the lower radiator hose still connected. Start the engine, and goose the throttle several times. If there's a head gasket leak, you'll see bubbles at the thermostat opening, or if the leak is really bad, water will gusher out of the head. That's the reason for disabling the water pump- - - -you'll get an immediate spurt of coolant if the pump is turning. The engine will run for 30 seconds or so before the coolant starts to boil, even with the pump disabled.
Jerry

Took the thermostat out today and checked it. It was a 180 degree. Should I get a lower temp thermostat when I put it back in? Seems a bit high since the truck gauge it reading hot @ 212.

When I took off the top hose and thermostat housing I also removed the lower hose and flushed water through the cold block directly through the opening @ where the housing bolts on. Water flowed well and come right out of the water pump. The truck was off. Just making sure it flushed good. I also ran water through the radiator and it also flushed good. I still have both hose disconnected and the thermostat housing off. Any suggestions I can try while I have them off? I really dont know what else to try? I have some people telling me it the head and some telling me its not since I have no water in the oil, no water coming out the exhaust and no oil on the plugs when I remove them.

Before I removed all that, I did try and remove the temp sending unit first until the water flowed out so I could make sure all the air was out but I could not get the unit out. The bolt unscrewed and slid up the wire but the probe is stuck pretty good in the block and didnt want to come out. I didnt want to break it?

I would check the vacuum advance and timing.

I will definitely check those and see. Maybe thats it. I'm not real sure on how to check the timing on this old thing? Any good ways that work best that you could share? Thanks so much!

I would say it is probably headgaskets. It is possible for head gaskets to leak in to exhaust ports and not make its way in to the oil. Which would cause the coolant to overheat rapidly. It is simple to test. Go the an autoparts store and buy a kit to test the coolant for carbons. Simply remove the radiator cap, start the engine, put the tool where the radiator cap goes on the radiator. The tool has fluid in it and will change color if you headgaskets are leaking. It tests for exhaust fumes in the coolant.

I dont see it in the posts. Did u flush through the block and open the lower rear block petcock and flush through there?

drill a 1/8 hole in the flange of the thermostat this will let the coolant fill the block and does not affect the running temp as far as i can tell. philip

Gonna try to check and adjust the timing in the morning. Anyone got any good techniques to use for this old 216? I'm really in the dark with this and could use some help? Thanks

Rotate the engine by hand until the ball (size of a BB) is in the timing window by the starter. Clean the ball good and put a dab of white paint on it. Makes it a LOT easier to see when you're standing on your head with a timing light.

If I can see that the timing is off with the light, how is the best way to adjust it until its correct? Thanks for the help

There will be a clamp on the distributor base that you loosen then turn the distributor. A little turn goes a long way.

There is a coarse adjustment clamp as Tiny mentioned, but there is also a fine adjustment, that is the bolt just to the rear of the distributor. You loosen the bolt and twist the distributor by moving the vacuum advance.

Is your problem overheating or rough running? I have never seen timing affect the operating temperature of an engine. Running rough/backfireing, yes timing will effect that. You need to check your headgaskets. If an engine overheats rapidly, with everything else checking out, 99% of the time it is head gaskets. Exhaust getting into the coolant causing rapid temperature increase.

No, the truck cranks, idles and runs as smooth as can be. I bought a head gasket test kit to check for carbons in the coolant and everything in good on that end. I havent yet fooled with the timing yet... I did just take the thermostat back out and all the hoses back off do do some more flushing. Water flushes right through the radiator with ease and when I had water to the top of the block (truck not running) where the thermostat was, water flows right through and comes out the water pump how ever and found that when you open the petcock drain on the drive side engine block you get no water @ all. I have taken the whole plug out and still get no water out that drain? I do see a freeze plug not far from that location but I dont know if I should remove it or not. Do you think this has anything to do with the problem?

Timing does matter in an engine that is overheating.

If it head gaskets or exhaust, you can find this easily by having the engine idling and fill the radiator to the top. Watch the coolant. Most times there will be a few bubbles from fillng, but they should stop. If you continue to get bubbles after a couple of minutes then you may have a head gasket or exhaust problem. Possibly a cracked head.

The 216's were prone to cracking heads.

I finally got the block drain petcock unclogged by using some air and cleaner back flushing it back and forth. At first it wouldnt even drip out but Once it started flowing I kept flushing until clear. Its was some pretty dirty water for some time. Now its all clear when I flush. I put it all back together after that and gave it a try. It took a lot longer before it started to get hot but it still gets hot or at least thats what it says. I think maybe now it just a bad gauge because I dont think I could hold by hand on the block or stick my finger in the radiator if it was up to 200 degress like it says? I now have to check the gauge but I cant get the temp sending unit out of the block? I have it unscrewd and up the wire but the probe is still stuck down in the block and I cant free it. I havent pulled to hard beacuse I dont want to break it. Any suggestions on how to get it out?

I also bought the head gasket and cracked block test kit just to check? The fluid in it stays nice and blue and doesnt change. Hopefully its just a bad gauge now? If I could just get it out to change it.

The bulb isn't held by a fastener besides the one you seem to have loosened already. It's most likely just some crud holding it. Some gentle persuasion with some back & forth twisting should free it. Just don't pull on the capillary tube.

Soak the temp sender with some penetrating oil like PB Blaster or Kroil, and gently shake or twist it as close to the cylinder head as possible. The capillary tube is very fragile, so proceed with extreme caution. There are no shortcuts- - - -just be patient and work carefully. Once the sensor is out of the head, you can check its operation with a pan of hot water and a candy thermometer, etc. to check its accuracy. If the radiator isn't boiling coolant out, it's probably not as hot as the gauge is indicating.
Jerry

Yea, Thanks guys. Thats what I got it doing now. Got some PB Blaster soaking on it. Maybe it will free up soon. I havent let it get hot enough to see if it boils out the overflow tube yet. I normally shut it down when the temp gauge starts getting to the hot zone but it does seem to be staring to get ready to boil out even @ that temp so it still must be running hot. I had checked for a blown head gasket using a test kit with the blue water that use stick on the radiator and pull air. If carbons are detected it turns the blue fluid yellow. It didnt change but is it possible to still have a head gasket leak and it not leak carbon into the radiator fluid? Thanks for all the help.

Another possibility... When I took to cylinder head of my 216 while rebuilding, I found about 4 coolant ports in the head completely clogged. Is it possible that might be causing your issue. Just a thought.....

Is it possible to have a head gasket leak and not show any of the normal signs? I have used the combustion leak test kit (The one with the blue fluid you hook to the radiator while running and suck vapors up and if any are found it turns the fluid yellow). The fluid stayed blue but I have heard that depending on where the leak is at it might not show with that test kit. Any one know?

Something else to think about is pulling the radiator and taking it down to the local radiator shop and asking them for a test for open passages and flow amounts. It may be that there is some blockage in the water tube passages.
Normbc9

Deja Veau again. I just went thru a over heating prob on my 235. A hole in the thermostat is a good idea when refilling the rad, timing got a few more degrees lower and valve timing helped. I went to a 180 thermo and back to the old x fan locater 1.5 in from rad. at idle i am at 200 and on the road it gets to about 190. my rad and pump look good. I'm thinkin i just gota live withit till winter. goood luck

Any one know what websites that may have a new radiator I can purchase? I have been having a hard time locating a new one to buy? Thanks

I finally took a chance and got a new rad after some looking. Just installed it today and it seems to have been the problem all along. No more overheating, Wooooo Hooooo! Now I have one more problem that I need some help with. The wire from the temp sending unit has broke right @ the probe that is down in the block. I have tried everything to remove the probe from the block but have had no success. Its like it has swelled up inside the block and wont come out? I have some pretty good pictures of it that I will try and post in my photobucket pages so you guys can get a look and maybe give me some suggestions. I have already let it soak in some PB Blaster but it didnt budge. Thanks for any help!

I would suggest you drill a hole down the center of the probe and screw a lag bolt into it, then pry up on the head of the bolt, or pry up on Vice Grips clamped to the bolt.

Got it out today with no problems! Thanks

I suppose it is a bit late to come with suggestions now, but just for the sake of getting the information out I will write down one other idea.
We have been driving around sporadically in a 41 Chevy sedan with a 216 for many years. For a 25 year period or so the engine had a strong tendency on hot summer days to overheat quickly (according to the temp gauge.) After trying about all of the suggestions that floated by in the above posts we noticed in the owner's manual that the 216's in that period were expected to carry a 160 degree thermostat. Over the course of the years some long-forgotten FLAPS had sold us a (standard) 180 degree thermostat, and apparently the dash-mounted temp gauge thinks that anything around or over 180 is almost in the red zone.

We exchanged it with a 160 and now the gauge rests right where we like to see it. Others may have more to say on the subject, but this was our experience.

My truck has the 180 and seems to like it just fine.

It had the 180 thermo in it and if not moving @ a idle for awhile the guage would sit around 200-205 range just starting to get into the red. I changed to the 160 thermo today and now you cant get it over 190. The lower thermo has helped alot.

Try checking your stop light switch, on an AD its mounted to the firewall under the brake arm.(Not sure where its mounted on your year truck) Sometimes the lever arm brakes off.
A simple test is to remove the two leads going to the switch, touch the wires together and see if the brakes light up.


Also check your flasher on your signal switch.

You may get a better response by posting this in the Electric Bay section of forum
Let us know your results.

Good Luck