8N with oil in the coolant, how long can we run it this

JerryLook

Member
My dad has a 1950 8N (front dist) that he uses for mowing a small field a few times a year. He probably puts 20-30 hours a year on the tractor. Hes getting a little older, and Ive been helping him catch up on some maintenance on it.

One thing I noticed is there is oil in the coolant. The coolant is pretty scummy and brown. He says he changed the coolant a couple years ago, so this build up has happened over not much time. There isnt coolant in the oil, and Ive read on the forum that the oil in coolant is caused by a bad head gasket letting blow by get into the coolant. So thats the first issue.

The second issue which I think is also related is it overheats. He says when he mows he can only make it about 1-1.5 hours before the tractor starts running hot (Im not sure what hes basing this on). He says the tractor starts losing power, until it eventually shut down, and wont run again for a few hours. Im thinking this issue could also be head gasket related. But could maybe also be ignition related?

So Ive read about it, and it seems like a pretty easy job to change out the head gasket. As long as the head isnt warped or anything else. So should I push him to change the gasket, or can he keep running it this way for a while longer? I dont want to wait too long and damage something else.
 
This is one of those deals if you know beyond a shadow of a doubt its oil then this is not something that will fix itself and it should be dealt with sooner rather than later. Later will likely cost you a lot more. Could be a head gasket could be a crack too.

I would make triple sure its oil and go from there.
 
(quoted from post at 11:22:17 08/04/21) My dad has a 1950 8N (front dist) that he uses for mowing a small field a few times a year. He probably puts 20-30 hours a year on the tractor. Hes getting a little older, and Ive been helping him catch up on some maintenance on it.

One thing I noticed is there is oil in the coolant. The coolant is pretty scummy and brown. He says he changed the coolant a couple years ago, so this build up has happened over not much time. There isnt coolant in the oil, and Ive read on the forum that the oil in coolant is caused by a bad head gasket letting blow by get into the coolant. So thats the first issue.

The second issue which I think is also related is it overheats. He says when he mows he can only make it about 1-1.5 hours before the tractor starts running hot (Im not sure what hes basing this on). He says the tractor starts losing power, until it eventually shut down, and wont run again for a few hours. Im thinking this issue could also be head gasket related. But could maybe also be ignition related?

So Ive read about it, and it seems like a pretty easy job to change out the head gasket. As long as the head isnt warped or anything else. So should I push him to change the gasket, or can he keep running it this way for a while longer? I dont want to wait too long and damage something else.
y 1950 8N has been (& still is) running for 20+ years with some oil in coolant. I suspect that there is some combustion products leaking into coolant, but it cant be great, as almost never needs coolant or oil added and runs fine.
 
I suspect as it gets hot, the coil 'tar' is melting and the coil is not working. I'd replace the coil and try on a hot day again.
 
Or you might make sure the gas tank is vented well through the cap. Just in case vaporization is taking place in the gas tank.
 
It is a flat head. No oil up there like
there is on an OHV engine so far more
likely it is by-products of combustion
you're seeing in the coolant.
A leakdown compression test - if you have
the guages would tell you where it is
coming from.
I don't have a leakdown tester.
So I would just weld an air fitting onto an
old spark plug and pressurize each cylinder
at TDC (valves closed) and look for air
bubbles in the radiator.
 
Im pretty sure it is oil. Its the color of used motor oil and smells like it too. The coolant.

I dont have a test set to check compression, but have always wanted a reason to get one. Ive read something about run the comp check, get the first set of numbers, and then put some oil in the cylinders. If the rings are worn the oil will raise the comp. if its a head gasket the comp will stay pretty much the same. Does that work for these engines?

I was reading on here and was telling my dad we should check it for spark one time after it shuts off. The would tell us at least why its quitting. I bet it is the coil.
 

https://forums.yesterdaystractors.com/viewtopic.php?t=1083559&highlight=byproducts

Is it worth going the extra mile to dial in on the issue well yes if your pockets are loaded with cash are you are tooled up well. If your time is free the cheap way out may be to put a head gasket on it and hope for the best. In this post they have a building full of old cars I know if I do not do a good evaluation on the engine they will be back and not happy its all on me. They have been back on other vehicles I told them look at the evaluation it full explains the engine is worn out I am out of tricks.



https://forums.yesterdaystractors.com/viewtopic.php?t=1191074&highlight=combustion

For the record I don 't think any head gasket is a positive seal add in age like on a old ford tractor at the top of the combustion event combustion byproducts will escape past the gasket. What you see did not happen yesterday its been going on for quite a long time its catching up with ya. Will this contribute to overheating yes and no the only way to truly know is go the extra mile testing. In my world I want to know exactly where the issue lye's YMMV.
 
Every 8N I have ever used had what looked like oil in the radiator.
If it ever had stop leak put in, that is what you are seeing.
 
Oil in radiator, common problem and it is combustion byproducts as there is no possible way for any unburnt oil to get to radiator. Not a big jub to change that gasket. If you like working in tight places and it has head bolts instead of studs you can replace that gasket without removing hood and gas tank. With studs you cannot raise head high enouth to get over bolts. Pretty soon it is going to blow out completely and tractor will not continue to run. And the fuel and air from being exaust going into radiator can raise heating problems, same as pipimg the exaust over the radiater, the hot exaust will raise radiater temperature.
 
One thing none of you guys have mentioned about the overheating is what kind of condition the radiator is in. Are the fins clogged? Do you have a good flow of coolant visible from the top of radiator with the
engine running? Just my thoughts but I would blow out the radiator fins and check coolant flow before I even thought about replacing head gasket. Especially if the head is fastened by studs. Those suckers are
real easy to break off. Also is the fan belt loose?
Good Luck with it and let us know the cure when you find it.
 
I still believe it is the gasket as for the time to start overheating that he has given us. If radiator was like you are saying overheating is verry possible but it would not take an hour and a half to start overheating, Would be doing that in under a half hour. Mine did not get to the point of overheating by time we tore it down but can verry possibly see the overheating just before starting to miss on running.
 
If you have a helper, taking the hood and gas tank off is pretty easy. Just remove the fuel line to the carb(after you make sure
the gas is turned off), remove the bolts from the dash and the bolts from the front of the tractor, and you are off! Taking the
head and gasket off is also very easy(and seeing inside the motor is really cool). Just make sure to remove the bolts in an
alternating pattern, or the head will warp. Best of luck!
 
Ok. Im going to order a head gasket and a new coil. Both are pretty cheap. I can get help taking the hood off, so it shouldnt be too bad.

The only thing that will suck is the tractor has a loader on it. Makes everything more difficult. Ive been telling him to ditch that loader.

I drove the 8N today and I noticed on start up it smokes a bit from the exhaust manifold area. Im thinking its either the manifold gasket, or where the exhaust attaches to the manifold where the leak is.
My dad had mentioned that he always smells really bad like exhaust after mowing, and now I know why. Haha.
So maybe I should figure out whats leaking there before I order parts.
 
JerryLook ,If I were you I would get and use a Fel Pro head gasket,a much better gasket.Napa has them.also manifold gaskets.
 
(quoted from post at 22:35:38 08/06/21) JerryLook ,If I were you I would get and use a Fel Pro head gasket,a much better gasket.Napa has them.also manifold gaskets.

Fel-pro 7277 B?
 
JerryLook Yes that's it Fel-Pro 7277B or pickup the head set NAPA
Part #: FPG HS7277B and it is 20% off sale.20% off Flash Sale
Has head, manifold,carb valve cover,dist,governor gaskets

This post was edited by Den N Ms on 08/06/2021 at 10:04 pm.
 
Our 49 8n had oil in the coolant for over 40 years. It got worse and looked like grey pudding in the
radiator, tractor started and ran fine just smoked. We checked oil level daily and added STP each oil
change. I tore down the engine about five weeks ago(tractor has not run since 2003) and was surprised
that the engine wasn't sludged up, just a small amount in the drain plug. When I removed the block
drain, it bled brownish grey goo. I flushed the block and head thoroughly and I bought a new radiator
from YT last fall. After close inspection, it seems the head gasket failed between two of the cylinders.
We never found any evidence of coolant in the oil over the years. The last time the engine was rebuilt
was in 1966.
 

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