Steam from Rad

[Paul in Edmonton]

Last year was a heavy snow year, and by the end of the winter, we had too much snow for the 8N to handle. We have almost as much right now, and it's not even Christmas yet...

Anyway, while trying to plow yesterday, I was having steam coming out of the radiator. Not a good omen. (The 8N lives out at my cabin, an hour north of the city.)

Background:
1. '49 8N, front mount. Pretty much original except the genny is not an original Ford. Still 6V, though. And the solenoid is wired for a key start. (I intend to fix that next time I'm ordering parts.)

2. The radiator is NOT overfilled.

3. The radiator is not designed for the 8N. It fits in place reasonably well, except the cap doesn't fit perfectly through the hole in the sheet metal. It was new when I bought the tractor a few years ago.

4. The fan is spinning and providing good air flow (pulling towards the engine). This of course means the water pump (or at least its shaft) is turning--but I have no way of knowing if it's actually pumping.

5. The temperature at the cabin yesterday was a few degrees above freezing. (Although the min/max thermometer had bottomed out at -40 sometime in the past three weeks, since I last reset it.)

6. I pulled the dipstick after using the tractor yesterday, and the oil on it looked clean--no sign of water in it.

Anyway, there were a couple of odd things I noticed at the time.

The first is that the oil pressure was decent--I've seen it a lot lower in summer. If the engine was overheating, I'd have expected the oil pressure to go lower--at least down to where it gets in summer.

The second, and more significant, is that the steam didn't seem to be coming out the cap. There's also an overflow tube coming out of the stem just below the cap, and nothing was coming out it, either. I couldn't tell just where it was coming from, since it was all under the sheet metal. Most came out from under the sheet metal where the cap protrudes, but sometimes it also came out lower, being blown back by the fan. It was only coming out when the engine was working under a heavy load (like when the plow was getting overloaded), and for a few seconds after. Running without a load--no steam. It would also spew for several seconds after I shut the engine off, even if it wasn't steaming or under load right before. I have seen no evidence of a leak in the rad--no visible accumulation of coolant below the tractor--and like I said, the rad is pretty new.

Any ideas what to look for?

-Paul

 

[Bob Harvey]

Maybe blow-by from the crankcase vent ('cooking off' accumulated moisture)? HTH

 

[kris Jensen]

From your description I think the most obvious place
to start is you hoses. had a similar experience
years ago with a car. (falcon, mine was not one of
Fords better ideas) turned out the clamps were not
really tight enough. I have also seen a weak hose
spew steam under pressure when working hard, but
seemed just fine when under low or moderate load

 

[old]

Can you take the cap off and check for good water/coolant movement?? Could be a sticking thermostat type of problems. Also might be snow coming back on the hot engine and causing steam. Or blow by out the oil fill cap.

 

[corchel1942]

Just a thought, If it was snowing or had been, maybe just the
heat melting off the snow or ice in between the fins on the
radiator?

 

[Paul in Edmonton]

Thanks for the ideas.

Pretty sure it wasn't snow. That was all gone, and it was still steaming. I also checked the crankcase vent--the steam wasn't coming from there.

Hoses seem a good possibility--they appear old and not in great shape.

I will also plan to check for water movement next time I'm at the cabin (probably not until after Christmas). How long should I have to run for before the thermostat opens?

Of course, one must be careful--I had a sticking thermostat in my 1949 Jeep, and when I wanted to check for water movement, I took the cap off (engine cold) and started it up. When the engine heated up sufficiently (with the thermostat staying closed), there was a geyser out the top of the rad. It went at least a couple feet in the air!

-Paul

 

[Joe Scribner]

You're saying it has an incorrect radiator? I'm
wondering if it is a non-pressurized rad letting
steam out the cap and overflow tube. If it's not
overheating and your coolant stays up I wouldn't
worry too much. Just keep your eye on it.

 

[Colin King]

What is the mixing ratio for your coolant? -40C will freeze the standard 50/50 mix for anti-freeze.

If you're radiator is steaming, that means that your thermostat is not stuck since the hot coolant is getting into the radiator. You'd have a blown top hose if the t-stat were stuck.

I suspect that your coolant froze and never unfroze in the bottom hose. Thus, your radiator wasn't circulating coolant, causing a build-up of overly hot coolant at the top of the radiator.

Colin, MN

PS: I haven't seen the thermometer hit -40 since '97. I'm thankful for that. Stay warm up there!

 

[Charner MS]

I would invest in a thermostat and 30 minutes labor. That is the fastest and simplest fix and might solve your problem. 40 below, how do you live, we close schools at 20 degrees.

 

[notjustair]

Had the exact same thing many years ago. Head gasket. Ours would puke when you shut it down or under heavy load. I first noticed it when the bush hog mower was hooked up. We had clean oil as well. If you aren't getting water in the oil run it just a bit more and see if it is getting worse. I'm betting it will. It is probably coming out of the cap or overflow and it is just disguised.

The water pump or coolant doesn't know of your engine is working hard or under load. They only know speed of the engine. That means you must have combustion gases pushing the coolant when it is laboring. Just idling the leak isn't pronounced. It would probably do it if you throttled it up and took out in road gear, too.

Does the coolant look dirty? Ours was carboned up and dark. Not oil, but not nice and green.

 

[Paul in Edmonton]

Replying to a few comments:

1. It was above freezing when this was happening, and had been well above -40 for several days. There is a good mix (can't say it's exactly 50/50, but shouldn't be too far off) in the system, so I really don't think it was frozen. I'll test the mix next time I'm out there.

2. Possibility of head gasket is why I checked the cleanliness of the oil. I'll have to check the coolant next time I'm there. (I didn't want to open the cap at the time.)

3. The rad is pressurized. It seems to be a good quality rad--it's just not a perfect fit.

4. You close schools at +20°F or -20°F? I've never heard of schools closing in Edmonton due to weather--though if there's a snowstorm, kids who are bussed to school might have to stay home. The policy here is: above -22°C (-8°F), the kids go outside for recess, below that, they have indoor recess. But close the school? Never. Cold's not so bad, if you're dressed for it. Edmonton has wonderful summers, 18+ hours of daylight and rarely getting over 30°C (86°F). I'll happily take the cold dark winters to get those summers. I don't know how people live in the south with the summers down there. At least you can dress for the cold.

Thanks, all.

-Paul

 

[Paul in Edmonton]

Update:

I pulled the hood today to have a look. I had planned on running it with the hood off until it got hot enough to see where the steam was coming from. I never got that far, though. There were two significant holes in the radiator. The neck was practically broken off--I attribute that to the poor fit of the rad in the hood. But there was another hole somewhere just below the bottom of the top expansion area. When I tried to top up the fluid (so it would be just above the top of the tubes, of course), fluid started pouring out...

So a new rad is at the top of my shopping list. And this one will be one made for the 8N.

On the bright side, there was no evidence of oil in the water (I already said there was no water in the oil), so it looks like the head gasket is fine.

-Paul