Yesterday I was servicing my '26 coupe, tire pressure checked, all fluid levels check, all grease fittings greased and transmission brands adjusted. Next I changed the engine oil and as I always do I jacked up the front axle. After draining out all the oil I found that I had about 2qts of old oil. When I refilled the transmission it took 3qts to fill, I open the top transmission petcock and it started to drip oil. So you may be wondering what I learn from this. I had installed a dip stick and use that to check my oil every time before I start my T and even yesterday (before the oil change) it was high on the stick. Now I'm thinking that the oil viscosity is the cause of the high reading and will be double checking the oil level the old fashion way.
Ford said to install four quarts after an oil change and five quarts after a rebuild (dry engine). So, there must be a quart of oil scattered around engine and rod troughs. This oil would not appear on your dip stick or by checking the petcocks.
Unless you're using some kind of gear oil weight, I don't understand the difference you're seeing.
Did you wipe the dip stick and re-insert before reading it? While driving oil creeps up the tube.
Was the front end still jacked up when you checked the oil? Recheck it after it's on the level and has been started to circulate the oil.
Is the dipstick relatively vertical at the bottom? If it is not, I could see minor level variations making major differences on the stick.
I have never had a dipstick in a model T (unless I count myself). But I have had other cars with small tube deep reach dip sticks and found them to give erroneous readings a lot. The theory is that when the engine is running, it pushes oil up the tube. When shut off, the small tube with the dipstick hangs onto a higher level of oil than is in the engine (oil IS thicker than water). I could check the oil level hours after running it, and find it higher than it was before I drove it. Even a quick wipe of the dipstick would still show oil that had not drained out of the tube. I got in the habit of letting the car sit for a bit, then pull the dipstick out, wipe it, leave the dipstick out and the hood open for five minutes. Then go back put the dipstick in, and check the oil. That five minutes with the dipstick out allowed the oil in the tube to drain down enough to get a more accurate reading.
Other's mileage may vary.
Drive carefully, and enjoy, W2
Ken, I am going to recheck the engine oil today and take Seabiscuit out for a drive. Yes Tom, I always wipe the dip stick and re-stick before gauging. Walt, the front end was not jacked up when I checked the engine oil. Hal my dip stick is almost horizontal going into the transmission. Wayne is correct, the viscosity of the oil clings to the side of the small tube. The point I was trying to make is that dip sticks may not be a reliable way of checking your engine oil in your T. Thank you all for your helpful suggestions.
"I didn't sleep in a Holiday Inn last night, but I do drive a 1926 Model T Ford Doctors Coupe"
but I'm really happier when I'm driving Sambuca my '17
I see why you are happier, it is a time machine. Turns you into a little kid. Dan
Dan, those are my grandsons Josh and Joe. I could not begin to tell you the joy and happiness that teaching them how to drive a Model T brought to me. They live in Tucson, Arizona and where here visiting over Christmas back in 2010. When Joshua first saw Sambuca he looked at me and said "oh Grampa please promises me that when you die you will give me your Model T". He also said "can we take it for a drive" and I said "if it will start we can take it out in the driveway and drive it". I hadn't started Sambuca in over a month, so I felt it was a safe thing to say. Dam model Ts they always start no what how cold or what the weather is outside!!!!