My 223 in my '56 is running, but i am having a lot of problems, personal, and with the engine itself.


What is the correct running temperature for these motors? I think the thermostat is 180º.

When we would run it, and started to break it in, it started getting hotter on the gauge. I wasn't sure how hot, so I bought a mechanical with degree read-out.

It was reading 210º--took forever to get there--, and that's when I thought I had enough of watching it getting hotter....so I shut it off.


!!!!!!!!!!!!!!!The little overflow tube out of the radiator shot out steam and water like a volcano(for about 15 seconds, then it was just a little steam)!!!!!!!! I almost had a heart attack,
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I am so confused...where should this truck be running temp wise?

We have to break it in for 20 minutes at 2000 rpm...but I don't see how I can do that if it overheats uncontrollably?

We built a homemade fanshroud that is working very well, but it still isn't keeping the temp down.

 

Technically speaking, running "cool" would be anything below normal operating temperature, if the engine were to be running as hot as it would get. So if it only ever got up to, say, 160F, that would be running cool, since these engines were designed to operate in the 195F range, give or take ~10 degrees.

If you have an uncontrollable overheating issue, you could have a bad thermostat, a clogged cooling system, or a much more serious issue, like a blown or incorrectly installed head gasket, or worse yet, a crack somewhere in the heads/block. Only some good detective work will answer that question.

 

A fresh motor will run a little on the hot side 10-20degrees because of the tighter clearances. If the timing is advanced too much, it can cause it run hot. I would say a stock 223 should run between 160-185 degrees.

Did you check the accuracy of the new gauge? Are you tapped in where the old sending unit went? Radiator cap holding pressure? If there's no pressure it will begin to boil.

 

A new motor will normally run at least 10 to 20 degrees hotter at speed. But at idle those tolerances may be enough to cause it to climb constantly until it is hot HOT!

Make sure you don't sit in traffic for long periods of time, make sure you run good gas, run a thin oil SAE20 for the first 500 miles, and ensure the fan shround is on and correctly oriented to the fan.

Use a 7lb radiator cap and install a recovery tank. 165 to 180 would be normal operating temperature, but when you aren't moving very fast - 200 to 210 is not uncommon until you get rolling again, and with a new engine, it will just continue to go up if you are sitting. Remember, oil absorbs that heat too - don't let it break down.

 

Are you using your original 50+ year old radiator? Has it been cleaned and flow tested? If not it could be your biggest problem.......t/m

 

sometimes the simplest things can be wrong. Is your thermostat installed correctly? I recently put mine in backwards during a brainfart! I felt sooo stupid.

 

1)I installed the thermo correctly, I am 100% on that.However, I didn't test it to see if it opened at the correct temp as it says it should.

2) I am using the original radiator; I washed it out with a hose and it seemed to flow water out at a pretty good rate. It holds pressure no problem--lets say I let the engine warm to 150-170 and then shut it down, it'll have no leaks or anything.

3)Fan shroud is installed properly

4)I have NOT checked the gauge for it's accuracy, I need to do that next!!! The sender is taped off, however, the gauge is mechanical. I understand the electrical gauges often use the sender screwing into the head/block for a ground, but the mechanical gauges should not need a ground, so I used teflon tape to help it seal.

5)The cap says its a 9lbs cap, but I don't know if it actually holds that much, don't know how to test it.

6) coolant and distilled water is being used. I'd say something like 25-30% coolant, and the rest water(a lot spilled out when a hose wasn't connected tightly, so I replaced the lost coolant with water).



52 merc--The engine was just rebuilt, so I am sure there are no cracked components. As for incorrectly installed HG.....that'll have to be the absolute last thing to check. As for a clogged cooling system, it's possible. As for a bad thermostat, that's one of the next things to check.

These things were made to run at 195º....ahhh, that makes me feel a little better.

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From my experiences, it seems as though cooling systems in the old days just didn't cut it when sitting still. Most cars got a little hot when still, whether they were at idle , and especially when revved.

We are trying to run this engine at idle and at speed while sitting completely still--I think we are asking too much of it.

Am I right in thinking that this engine is getting hot simply because that's just the way older cars worked? No matter how hard I try, as long as the truck is stationary, it will get hot?

Or were these trucks somehow meant to keep their temp when sitting completely still while revving at 2k rpm?




I am only saying this because I don't want to waste my time fixing something that isn't even a problem, but rather the way these trucks work no matter what.

Thank you all so much!

 

Ok it sounds like you have your act really squared away. But like me when I started up my engine for the first few times, I think you are on a few pins an needles with it.

I think you are fine and have a good handle on it. But here are two things I would do:

I'd increase the coolant to water mixture to 50/50.

And second, I would NOT let a newly rebuilt engine sit at idle for any more than 5 minutes, especially after sustained higher rpm (2300+) driving. Mine used to climb through the roof even driving throught the Macky "D" drive through until I had a couple thousand miles on it.

Here's why and this is why I suggested the 20 wt oil. With a new engine there is extra friction and the parts have not "worn" in together. There will be metal "Chips." The oil is flowing through the engine and it's really having to do a job on a new engine as tight as it is.

When you are not driving but rather sitting at idle you have no flow over your oil pan to help cool the oil. And that oil is carrying off a good bit of your engine heat. The 20 weight oil helps it flow faster and pull off heat better. it will also help the parts "wear in" together a little better.

If you have to run it stationary, take a house fan or two (3, 4) and place them to blow onto the oil pan to help draw off heat. Here is a picture of my 20 minute cam break in on first start....note the fans (there are two more in front of the truck out of the picture)......it still rose to 215/220 degrees in 20 minutes, and was climbing!

It'll be ok once it has about 1000 miles on it.

 

^^Wow thank you very much for tha reply.


The machinist who rebuilt my engine had only one request that he insisted happen: Break in with strait 30 weight Valvoline VR-1 conventional oil. So that is what I'm using.

We had a fan blow on the rad, but I never thought of the oil pan! Thanks a ton.


So what am I supposed to do about the climbing temp? I have to break it in for those 20 minutes(already did about 3-4)....Should I just live with it? I mean.....it's just going to keep climbing...I know it!

PS--Oh, and this truck is far from driving on the road.....

 

I certainly wouldn't "just live with it". You don't want to burn up a new engine. Everyone here is correct that a new engine will run warmer than one that's broken in. But that doesn't mean it should automatically boil over after 3 or 4 minutes of running. If you're sure you don't have any problems with the engine, internally, and you need to do your cam break-in, have your big fan right in front of the grille, and get out the garden hose and run cold water over the radiator to help cool things.

Just to clear something up, you said originally it took forever to get to 215, but then later you said it was overheating in 3 or 4 minutes. I'm confused.

 

I was saying it seemes like it took 5-7 minutes to get the mechanical temp gauge to get to 180-190, but after that, it got to the 210 within about a minute.

All of the warm up was at idle. Once it got to about 200, we took it to about 1300-1400 rpm until it got to 210 which took about 45 sec-1 minute, then shut her down. That was the last time we ran it(yesterday)

 

One last stupid question. Did you check and refil the coolant after the thermostat opened the first time and let the coolant start to pass. If not check it - it will be way low. One last thing you can do that will draw a little heat off of it is if you have a heater installed. Turn it to full hot and turn the blower on full - like a little radiator - won't help a lot but some.

Also, do your initial couple run ups at night when it's cold and damp. Moist air absorbs significantly more heat.

 

No I haven't checked the coolant when the thermo opens.... So let me get this strait, take the cap off, let it get to 170-180º+, and look at the level? This is completely safe?

Heater is there and has water flowing...but the fan is a tiny little thing that doesn't spin very fast, I doubt it's going to help at all....but it's worth a shot.

Night runs...I've been afraid to do that since I can't see anything as well, and I'm afraid I might miss a leak or something. However, maybe that's when we'll start it next time.
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OK guys, here's my to-do list for today.
1) buy more 50/50 coolant
2)Test the mech gauge by putting it in a pot of water, when the water starts to boil, the gauge should read around 212º, correct?
3) remove the thermostat and test that.
4) if all is well, drain remaining fluid, reinstall what I took off, replace all fluid with 50/50 coolant, retry again later tonight.


eeeeesh, I knew this was going to pose a problem, so I expected to do all this work.....but I was also really hoping I would be wrong and none of this would happen.

I won't be near a comp until later this evening, so if I don't reply...I not ignoring you!

 

OK, tested the gauge, it works. It's not spot on, but really close(when water was bouling, it was reading just under 210º).

Tested the thermostat, works perfectly, opens a little at 180º like it should, and is almost fully open by 190-195º(as per the gauge).

The coolant is all drained, and I will fill it up with 50/50 tomorrow.

I am going to try setting up a few box fans, and also sprinkling a little water on the radiator cores(I'll have to be careful, since water and electricity don't mix) to see if that helps this truck stay cool.

Thanks everyone for your input!!!!

 

What I was trying to convey is that when you fill up the radiator with cold coolant, the thermostat in the engine is closed and does not allow you to add as much coolant as the engine will take.

When you start it up the first time, and it heats up enough to open the thermostat, the coolant will flow freely, but will now be low - by about a gallon or two.

Tomorrow when you fill it up with the 50/50 mixture, start it up and let it get hot. Then when it cools down, take off the radiator cap and check the coolant level - refill as necessary. You will probably need to do this a couple times.

Also, do not fill the radiator up to the top. Leave the fluid level two inches below the cap to allow for expansion.

For the water on the radiator to help cool it, a sprayer bottle (on spray, not stream) is enough. If it gets hot, about 3 squirts every minute will help cool it.