Silly question about the 300 Farmall

So in preparation for cold weather I slapped on the heat houser and gave the old gal a once over. Little low of oil and the dist cap was a little green, but took care of it. Went to start it the next morning to feed, NO oil pressure! Was just about to shut it off and it starts rising slowly, and stops at 40 psi, which is normal. It hasn't been ran much so thought maybe the pump lost prime. Next morning same story, except came up a little faster.

So the question is, is the cold causing it? It was 18 the one morning and 27 the next. If so would a block heater help? Or, is it the oil viscosity? I use straight 30wt winter and summer.

I'm not too worried, as I know this engine is in good shape. Excellent compression and starts before you can get off the key. I'm just looking for a little insight on this.

Thanks, Mac
 
Have you thought about checking the oil pump or the screen? How about switching over to 5w30 multiviscosity? See what others think. Also is the oil level correct?
 
Had thought of that but don't think that's it, I had the pan off in June and cleaned the pickup screen and pan out. I'm a little worried it might be the pump, which is very expensive to replace. What I hadn't considered was the oil weight. Might change it to 5-30 and see since it's about due anyway. Thanks for your input Jeff.

Mac
 
Could be the oil pressure is fine. Problem is rather the gage - a bit of condensation (water...) is freezing and plugging the gage tube, or freezing in the gage itself.

If pressure comes up normally on a cold start after an overnight "soak" in temps just above freezing, I'd not be concerned.
 
After the engine is hot , disconnect the oil press line from the gauge and let it squirt out a bit . That would eliminate the water if any ...
 
The pump gears don't normally go bad. What does though is the plate that bolts onto the bottom of the pump. The gasket could have blown out. I would take the plate off and check it for wear. I have rubbed them on wet/dry sand paper on a level surface with a little oil and cleaned up any scars that may be in the plate. This will give it a new surface with only the clearence the gaskets makes between the gears and plate. I've done this quite a few times on the older farmalls.
 
Like others have mentioned I believe this is caused by the thick oil in the long, small tube to the gauge. The speed at which my 350's gauge registers full pressure is proportional to the temperature - when very cold the needle just crawls up and when warm it pops up right away. I'm guessing that if the gauge was right down on the engine that it would always act the same regardless of temperature.
 
if you change the oil to a lighter weight you're still gonna have 30 wt in the line to the gauge. the 30 wt will be air locked in the line unless you loosen it at the gauge with engine running to purge the line
 
Air in the tube to the gauge will also cause a response delay because far more oil must move to compress the air as the gauge gets pressure. bleed it at the gauge while running. Jim
 
Cold thick oil.... plain and simple. My 340RC does the same thing when the temps get into the 20's and 30's here. The tube going to the gauge has a very small ID.
I'd be more concerned about engine lubrication on start-up. You might consider using a 10W-30 oil, if suitable for your 300.
 
Time to drain and refill with 10W30. If you don't have hardly any hours on it I wouldn't change the filter.
 
Thanks everyone for the replies. I am going to try to bleed the oil line and change the oil to 5 or 10 w 30 this weekend when I have more time. Will try to let you all know if that helps.

Thanks again,

Mac
 
I would put a block heater on it if you plan on using it alot in cold weather. I have been thinking about getting a magnetic one to put on pan or block.
 
Add a gauge to the line down on the block and see if it comes up right away. If it does then air in gauge line. If not then several options already discussed. Thick oil,weak pump,plate worn,suspect gauge,tired bearings, and even water in line.
 

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