Ford 8N dribbling coolant out of radiator overflow, not overfilled.

[sixdogs]

Just keep it simple. These run with near zero maintenance and keep going with all sorts of neglect.

After it drains down two quarts, does it overheat or run at the correct temp?

 

[BossofBBQ]

Seems to stabilize around 200 degrees or so, with my 180* thermostat. No overheating problems so far, but I’ve never really worked it hard or anything. Ambient temps have been in the 70s here in Colorado.

 

[sixdogs]

will your radiator hose only go on one direction? I recall, from the 1970's that mattered. I think the thermostat went in the hose, right?

 

[John0829]

Did it do this before you replaced the thermostat and the other things you have done to it?

 

[BossofBBQ]

Yep, the thermostat is in the upper radiator hose, and the pointy end is going towards the radiator. I didn’t run it much before I serviced it; but the guy I bought it from was running it without a thermostat in place.

I’m honestly not sure if it leaked before- I only drove it onto my trailer when I bought it. Directly after that I did a coolant flush and installed a thermostat.

 

[sixdogs]

Is the thermostat closest to the engine?

 

[BossofBBQ]

My temperature sender is closest to the engine, and thermostat is after that, directly in the middle of engine and radiator in the upper hose. I thought long and hard about doing it the other way, but then my temp gauge wouldn’t read anything until after the tstat started to open, just because of the direction of coolant flow.

 

[ultrarunner]

Maybe someone knowledgeable on 8N thermostat position can confirm?

My understanding is the OEM 160 thermostats point to the radiator.

Many use aftermarket 180 that are designed the opposite and point to the engine.

Seen some use a 180 degree stat used OEM for Renault.

In the old car world 160 degree minimizes the old alcohol base antifreeze boil off…

No such problem with modern antifreeze.

 

[sixdogs]

My temperature sender is closest to the engine, and thermostat is after that, directly in the middle of engine and radiator in the upper hose. I thought long and hard about doing it the other way, but then my temp gauge wouldn’t read anything until after the tstat started to open, just because of the direction of coolant flow.

I don't remember mine from years ago but search some Ford site that mentions where to put it. It did matter here it was in the hose but I can't recall.

 

[4Liberty]

Just curious, can you post a pic of the new cap? It’s almost as if the seal on the cap isn’t doing it’s thing. It’s hard to see in the pics, is it possible the neck is damaged/deformed where the seal seats? I wonder if the top being deformed is holding the cap up and not letting it close all the way? I’m assuming that it does this on level ground and not moving? Because with the cap off completely in those conditions it would sit there all day running and no water should push out if the level is correct

 

[gstrom99]

3) I have attached detailed, close up photos of the radiator fill neck. I believe it to be the correct radiator for the tractor. The fill neck is noticeably bent, which myself and my brother now believe is the cause of my issue. How would I go about straightening it? Would this kind of repair require a radiator shop?

Good pics. 2 quarts down is too much to ignore. The cap may have a hard time sealing on that distorted neck. A radiator shop (these are getting hard to find now) can advise/repair on that neck. What kind of sender is it, that goes in the hose? May be an extra restriction there. Try taking your t/stat and temp sender back out, going back to square one...

 

[careyo63]

Good advice IMO. Havent read all the way back but seen no mention of it?
Has there been a pressure test of how much pressure is in the radiator running. Should be 4 PSI cap. TSC has a 7 PSI. cap. Been awhile. Is it a 9n Radiator causing a problem.
This is true as I recall.

1939 9N radiator was UNPRESSURIZED until about 1942 at which time Ford changed to 4-psi radiator system. Ford also issued a field advisory, that it was ok to upgrade to the 4-psi radiator for non-pressureized 9N's. All ya haffta do is change the radiator. (and cap)

NOTE: pressurized and un-pressurized radiator caps are INCOMPATIBLE. So you have to change the whole radiator.

 

[BossofBBQ]

I have no idea how much pressure the radiator has, I’m also not sure if it’s an earlier 9N radiator or the proper 8N one. I attached photos of the temp sender I have. Because of its design, it does cause some restriction, but I wouldn’t think it’s a lot. Also, I have included a photo of my new radiator cap next to my old cap. The new one is shiny chrome, old one is standard black.

I will remove the tstat and temp sender sometime tomorrow to see if it makes a difference, as I am not currently by the tractor today.

 

[flyerdan]

Without a recovery system you'll always have air in the radiator due to thermodynamics. I would put a 2 liter bottle with the overflow tube submerged at the bottom, take a scotchbrite disc and clean up the top seal on the neck, and verify that the radiator cap has a rubber seal at the top and bottom, so when it cools down it has to draw fluid back in, rather than atmosphere. The bend in the filler neck shouldn't be an issue, unless there is a crack that would allow air back in.

 

[4Liberty]

I have no idea how much pressure the radiator has, I’m also not sure if it’s an earlier 9N radiator or the proper 8N one. I attached photos of the temp sender I have. Because of its design, it does cause some restriction, but I wouldn’t think it’s a lot. Also, I have included a photo of my new radiator cap next to my old cap. The new one is shiny chrome, old one is standard black.

I will remove the tstat and temp sender sometime tomorrow to see if it makes a difference, as I am not currently by the tractor today.

I don’t think the new cap or that sender are contributing to your problem. I was interested in seeing what the seal on the new cap looked like. Both the seal and brass cover on the cap look correct for the type of system you have.

 

[4Liberty]

Also the thermostat needs to be as close to the head as possible.

 

[BossofBBQ]

My brother, father and I think the filler neck is “bowed” upwards just enough to cause the seal leak.

Radiator is not overfilled, I always top it off to maybe 1-1.5” above the fins. Attached is a photo of a straight edge lined up over the fill neck. There is a sliver of light in the middle, showing the bend. Could this be the cause of my issues?

 

[John0829]

The 8N tractors want the coolant to barely and I do mean barely, to just cover the tubes of the core. Anything more than that and they will puke it out, even the NAA and hundred series tractors are picky about the level.

I went back and reread your description and I now think you indeed have compression getting into the radiator. You said you held your hand on the neck but could feel no pressure, you would not, the pressure if any would have exited out the overflow tube unless you had it somehow blocked.

At this stage I recommend you do a pressure test of the system. You should be able to borrow a tester from one of the auto parts stores near you that have a tool lending program

 

[BossofBBQ]

Right- I will borrow a tester from our local Autozone shortly. I’ll update yall with the results. It might be a few days; I’ve been swamped at work lately and haven’t had much time to tinker on the ole girl.

I never thought my first thread would be 6 pages and have 10k+ views- TBN continues to amaze me. Thank you all for your valuable insight and suggestions, I’m proud to be a part of the N tractor world!

 

[gstrom99]

I never thought my first thread would be 6 pages and have 10k+ views- TBN continues to amaze me. Thank you all for your valuable insight and suggestions, I’m proud to be a part of the N tractor world!

Same here. We all love mystery problems (when they're someone elses...)