960 leaking oil from valve cover?

Bear with me, as I'm not a mechanical guy. Over the years I tinkered enough with my 8n that I became fairly comfortable with some of the basic adjustments and replacements. A few weeks ago, I bought a 960 because I needed something with a bit more HP to power some haying equipment. Since I got it, I've worked it only a few times (other than just a bit of driving practice).

1.) Brush hogged about 4 acres of tall weeds. Everything worked perfectly.
2.) Cut about 5 acres of hay with a haybine. The PTO engagement lever wouldn't move without a couple of gentle whacks with a rubber mallet. Other than that, it did great and handled everything like a champ.
3.) A couple of days later, I hooked up a small square baler. About 10 minutes in I was on a bit of a sidehill (not steep but noticeable) and I noticed smoke on the left side of the tractor (downhill side). My first thought was that my "new" tractor was burning up... I took a quick peak and could see some fluid burning off on the hot manifold. I decided to pull ahead about 30 yards to a flat area where I could unhook from the baler. As the ground leveled out, the smoke diminished. My wife's grandpa, who was a farmer all of this life, was there "supervising" the process, and he was looking at the tractor and said it looked like oil was running out of the joint where the valve cover joins the engine... dripping on the manifold / exhaust and burning off. Said he thought it was probably just a bad gasket and that should be an easy and cheap fix. Well, we brought in the "plan B" tractor and finished off the baling. I used the 960 to haul hay wagons back and forth and had no more smoking.

My question is, does this "in the field" diagnosis sound reasonable? If so, is it relatively easy to remove the valve cover and replace the gasket? If not, what else might explain what happened?

When I make hay off of my small 5 or 6 acre hayfield twice a year, it's kind of a family affair. Most of my wife's side of the family grew up on farms and love to come "play farm" a couple of times a year, which kind of makes it fun. This was the first year I had "my own tractor" that could run the haying equipment, and I was kind of disappointed to come limping in on the first round with a smoking tractor.
 
Had a neighbor with that problem and he kept avoiding the fact that the engine was in dire need of an overhaul. He thought the valve area (a Ford OHV)
was pressurized. Yeah it was but not with any deliberate pressurizing device. Problem was combustion leakage around the valve guides.
 

Yes and no... its an easy job.. but the gas tank above can make it difficult to get the valve cover off.

remove, clean off old gasket. install new gasket with or with out your favorite sealer and reinstall. do not over tighten or you can bend the valve cover.

Old cork gasket probably cracked in many places so yes, when you got on an incline, oil could run out the side.
 
as said.. it's doable even with the gas tank in place, you can unbolt and roll the cover out, then clean and R&R
 
My 961 leaked considerably around the valve
seal ever since I had it and I Never really
worried. About. Just check the oil once in
a while.

Then a few weeks ago the idea popped into
my head to check the nuts holding the cover
on. Tightened them up just a bit and no
more seeping/leaking.
 
Thanks all. I think I'll order a gasket and see if that takes care of the problem. Does anyone know what the proper torque on the valve cover bolts should be? I picked up an operators manual for the tractor, but don't have anything more in depth.
 
I like to use a nut driver (screwdriver with a hex female) and screw down till it starts getting harder to turn.....Cork/cork impregnated gaskets don't use a lot
of torque as the cork breaks. Snug it down good and if it leaks snug it down some more till it stops.
 

There are way more old tractors leaking out the valve cover gasket than not. As others have said, the cover rolls out so you don't need to remove anything to get at it. First, however, make sure that just a little tightening, and I mean just a little, will not stop it. If you need to replace it get a rubber one. They will of course last much longer.
 
I did order a new gasket since it was pretty cheap. When it started smoking so badly, my fear was that the oil dripping on the hot exhaust manifold might actually start a fire. Could this happen?

Also, when replacing gaskets, does one always use a gasket sealer of some sort (high temp in this case)?
 
(quoted from post at 13:09:10 08/08/18) my fear was that the oil dripping on the hot exhaust manifold might actually start a fire. Could this happen?

That is a possibility if the engine is running hotter than it should. Under normal operating temperatures I doubt it though. A lean condition can actually cause the exhaust manifold to glow red hot, and if it were that hot then it could definitely catch the oil on fire.
 
I have a non-contact infrared thermometer and take lots of engine temp readings on different engines under different conditions. In the process I read
exhaust manifold temp and on my Ford diesels, at idle after working it is around 550F. Gas can run up to twice that.

Oil ignites (flash point) at a much lower temperature...Ref: https://www.google.com/search?
client=safari&rls=en&biw=1108&bih=581&ei=XX5rW6PUIIS6sQXNrpxg&q=what+is+the+flash+point+of+motor+oil&oq=what+is+the+flash+point+of+motor+
oil&gs_l=psy-ab.3..0j0i22i30k1j0i22i10i30k1j0i22i30k1l2.31812.37430.0.42234.36.17.0.0.0.0.1228.2851.6-2j1.3.0....0...1.1.64.psy-
ab..33.3.2849...0i20i263k1.0.2ULFCRXZUf8

Several sub questions here to answer your curiosity.

In short, not a good idea to have oil on your exhaust manifold.
 
(quoted from post at 12:09:10 08/08/18) I did order a new gasket since it was pretty cheap. When it started smoking so badly, my fear was that the oil dripping on the hot exhaust manifold might actually start a fire. Could this happen?

Also, when replacing gaskets, does one always use a gasket sealer of some sort (high temp in this case)?

Possible? yes.. likely,, no...


There are literally hundreds of thousand cars, truck, and equipment of all types that leak at the valve covers. In the 50s and 60s, 80 percent of vehicles leaked at the valve covers... Even today, lots of cars at 90,000 or more seep or leak some there. IT smokes a bit, as it burns off. Fire, no.

Possible, yes, Likely no.

Gasket sealer... works well, but will require new gasket everytime you adjust the valves as it glues everything to everything and you will tear the gasket upon removal of cover.

Correctly done, with no sealer, it should not leak if the valve cover has not been bent up or warped from over tightening. Glue gasket to groove in valve cover only on top side also works well and cover can still be removed and gasket reused in most cases.
 
(quoted from post at 12:31:39 08/08/18)
(quoted from post at 13:09:10 08/08/18) my fear was that the oil dripping on the hot exhaust manifold might actually start a fire. Could this happen?

That is a possibility if the engine is running hotter than it should. Under normal operating temperatures I doubt it though. A lean condition can actually cause the exhaust manifold to glow red hot, and if it were that hot then it could definitely catch the oil on fire.

As sotxbill said no. A teaspoon of oil is not enough fuel to burn. If, however, you had a few pounds of hay chaff and a birds nest or two in there that was soaked in oil, well then you could conceivably have a fire. Same situation as a timber skidded that has 100 lbs of brush in its belly pan. As to the gasket sealer they are not usually used, but in this situation it can help a whole lot. Get some aerosol Permatex High Tack, and apply it to the side that will be in contact with the cover only. None on the head side. Then put the gasket into the head between the outer edge and the keeper plates, and it will stay with the cover in position as you have it right side up rolling it in.
 
" None on the head side. " For years I couldn't get auto tranny pans to seal on my vehicles after changing fluid and filters till I learned that trick.....not dry, not both surfaces, just glue one surface
only.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top