[AT] Radiator situation

[Tyler Juranek]

Hi All,
 Last Saturday, June 8, I took my Oliver 88 on a tractor ride. I have
been on this ride for five years, and it In the first, and hopefully
the last, year I didn't finish.
 I had just put an electronic ignition on it with a new coil, spark
plugs, wires and cap. On the ride, I rode for quite awhile, (I don't
remember how many miles), and stopped for a break. I started it back
up, and we kept going. The tractor was running like a sewing machine.
Just purring away.
 And then all of a sudden, at full throttle, I am running, running,
running, and then it died. No smoke, no leak, nothing. It just quit.
 So, they pulled me with another tractor to the side of an elevator.
One of the guys said, "Tyler, try starting that again. Might just be a
vapor lock." So I pushed the button. Sure enough, it started again! It
ran like an Oliver for another 8 miles, and did the same thing again.
This time, some antifreeze leaked on the bottom, but it was a "drip
drip" and then it quit. So it got towed to a guys house, of whom I
knew, and I hopped on a people hauler to finish the ride.
 I went back, and started it, and had someone drive it onto the
trailer for me. (Remember, I'm visually impaired). It ran fine then
also.
 So I brought it home, put it into the shed. I took both hoses and
clamps off, and found a half galon of coolant came out.
 Anyway, we cleaned the fittings up, put new hoses and clamps on, and
bought some water in the gallon jugs at the grocery store. (We had to
replace the pump in our well, and so there's a lot of rust in it now
and didn't want to put that in). Anyway, a few days later, I proceeded
to fill it. My father brought over a funnel that had a little oil on
it. I wanted to clean it, but he said it wouldn't hurt. So when I
dumped the third gallon in, it made a small screech. We realized that
the radiator was full! It uses 4.5 gallons according to the book. It
was filled almost to the brim. (That's too full). So then I went to
start it. My father suggested that we leave the cap off so we could
see what was going on inside the radiator. So we started it, and like
always, it fired right up, and ran fine. However, I had filled the
radiator so full, it was a wet mess. So we left it outside for the
night so that the excess could just leak out and didn't make a mess on
the shed floor.
 Yesterday, (Sunday) my grandpa, (The one who gave me the tractor),
was over for a meal and to visit. Grandpa obviously had grown up on
both an Oliver 70 Hart Parr, and an 88 like I have now. So all three
of us went out to look at it. We checked the radiator. It had
obviously leaked down to a "happy point." We added a pint of water,
just to make sure it was over the core.
 So here again, I started it, it ran like an oliver the whole time.
However, in both instances I ran it, there have been air bubbles in
the radiator. Both times in running, there is no white smoke, the oil
looks great, and, as my grandfather said, both hoses are the same
temperature. I must also mention that when I had the hoses off, I
flushed the radiator 4 times. There is also supposed to be a
thermostat in the tractor, but apparently it never has had one since I
have had, or my grandfather has had the tractor. It never got hot. So,
this is what we know so far.
 1. The day of the tractor ride, it obviously got overheated a bit.
(We are all in agreement that somehow it had to be low on coolant.)
 2. My grandfather highly doubts its the head or the head gasket,
because the oil is fine.
 3. After 40 minutes of running each time, it didn't get overly hot.
(The temp gauge has never worked on this tractor, but just by feeling
the cap, it only felt "engine warm"
 3. It's not the water pump, because water is circulating just fine
and not leaking.
 4. It isn't boiling out on the sides of the radiator or anything
after running for awhile.
 So, why might it be bubbling? There has to be an air pocket or
something somewhere that's causing this. The other thing that I am
wondering is, "Did the tractor always do this, and nobody realized it
until now, because there was no reason to pay attention to it?"
 Should a person just run it down the road at full throttle for a
couple of miles to try to get the air out?
 What does everyone think?
 Thanks for any help, and sorry for the long post. This is my pride
and joy, and so I want to take great care of it, as always.
 Take Care,
 Tyler Juranek
 IA