[AT] One of those days

Sat Jan 24 12:26:37 PST 2026

Sounds to me like a wire with an intermittent break in it, or perhaps the
repair shop dropped something on it. Any way to run a jumper wire and see
if it fixes the problem?
Dave Maynard
Marion NY

On Sat, Jan 24, 2026, 2:33 PM Dean Vinson <dean at vinsonfarm.net> wrote:

> Oops, just re-read this:    “…if the switch were simply open there’d be
> current flow and no voltage at all…”   Obviously that should be **no**
> current flow and no voltage.
>
>
>
>
>
> *From:* Dean Vinson <dean at vinsonfarm.net>
> *Sent:* Saturday, January 24, 2026 2:31 PM
> *To:* 'Antique Tractor Email Discussion Group' <
> at at lists.antique-tractor.com>
> *Subject:* RE: [AT] One of those days
>
>
>
> Thank you, gentlemen.   It certainly seems logical that the issue is more
> likely to be the sensor or the wiring rather than an actual pressure
> failure.   I’m still not seeing an obvious explanation for what would make
> the problem suddenly pop up in between when the guys at the repair shop had
> the tractor running and when they dropped it off, but I guess that’s less
> important than fixing it.
>
>
>
> I talked with the shop again and they plan to send a technician here to my
> place to check it out.  Might be a while before they get me back on the
> schedule but I told them I won’t need to use it for anything during the
> winter anyway.
>
>
>
> In the meantime I did tinker with it a little more, trying to test the
> sender by disconnecting the idiot light wire and then using a multimeter to
> check for voltage between the tip of the sensor and the positive terminal
> on the battery.   With the engine off I got 12.57 volts, which made
> sense:   No pressure, switch closed, positive-to-ground circuit complete.
> With the engine running I couldn’t get any kind of consistent reading—the
> meter reading just fluctuated wildly all over the place no matter how
> carefully and steadily I held the test prongs.   I’m not certain how to
> interpret that, but I guess if the switch were simply open there’d be
> current flow and no voltage at all (i.e., idiot light “off”) so I’m taking
> it as an indication of a sensor failure.
>
>
>
> It’s kind of hard to get a good look at the sending unit, much less get a
> hand on it, because it’s slightly behind the power steering pump.
> Wrenching on an oily hunk of metal to get that pump out of my way, in 10°F
> weather, is not terribly high on my list of fun things to do so for now at
> least my plan is to let it sit and wait for the repair shop guy to get here.
>
>
>
> Lots of snow coming shortly, by all accounts, so that’ll keep me occupied
> for a while anyway.   Spencer, I’m guessing you might be in the
> ice/freezing rain path?   One of my brothers lives north of Atlanta and is
> tracking that risk.
>
>
>
> Dean Vinson
>
> Saint Paris, Ohio
>
>
>
>
>
> *From:* AT <at-bounces at lists.antique-tractor.com> *On Behalf Of *Spencer
> Yost
> *Sent:* Friday, January 23, 2026 8:59 AM
> *To:* at at lists.antique-tractor.com
> *Subject:* Re: [AT] One of those days
>
>
>
> I’ve had a few oil pressure sending units fail. Granted, they typically
> were full failures and didn’t work at idle either, but I could see how the
> failure mode might be vibration induced.
>
>
>
> I’d get a super cheapie oil pressure gauge at the auto parts store, or
> this:
>
>
>
> Engine Oil Pressure Test Kit
> <https://www.harborfreight.com/engine-oil-pressure-test-kit-62621.html?hftm_sc=&hftm_source=google&utm_source=google&utm_medium=cpc&utm_campaign=21901271210&campaignid=21901271210&utm_content=171677806502&adsetid=171677806502&product=62621&gad_source=1&gad_campaignid=21901271210&gbraid=0AAAAADAHb4eil-ADMAET3vLnfQyDpklM->
>
> harborfreight.com
> <https://www.harborfreight.com/engine-oil-pressure-test-kit-62621.html?hftm_sc=&hftm_source=google&utm_source=google&utm_medium=cpc&utm_campaign=21901271210&campaignid=21901271210&utm_content=171677806502&adsetid=171677806502&product=62621&gad_source=1&gad_campaignid=21901271210&gbraid=0AAAAADAHb4eil-ADMAET3vLnfQyDpklM->
>
>
>
>
>
> remove the sensor, and then hook it up to confirm if you have a real
> problem.
>
>
>
> Spencer Yost
>
>
>
> On Jan 22, 2026, at 10:44 PM, Dean VP <deanvp at att.net> wrote:
>
> 
>
> Dean,
>
>
>
> My guess would be a faulty sensor or a loose wire shorting out somewhere
> due to the vibration of the running engine.  I sincerely doubt you have an
> oil pressure issue.  Check everything around areas where your shop may have
> worked.  I think they damaged or disturbed something while working on the
> other stuff.  Is there any wiring that they could have disturbed?
>
>
>
> Dean VP
>
>
>
>
>
> On Thursday, January 22, 2026 at 08:19:55 PM MST, Dean Vinson <
> dean at vinsonfarm.net> wrote:
>
>
>
>
>
> Dean, ah, I see now how my sale of the 620 is coming back to haunt me.
> :)
>
>
>
> On the plus side for green tractors, my 3020 runs like a top and is
> standing by in the barn with the rear blade attached, ready for the
> snowplow duty that per the weather forecast looks mighty likely in the
> coming few days.  Moving 8 or 10 inches of snow with a rear blade is not
> ideal but it beats relying on my scoop shovel.
>
>
>
> (Speaking of not ideal, the high temperature for the day after the
> snowstorm is currently forecasted to be 7°F and of course the 3020 is an
> open-station tractor.   “Cab by Carhartt,” as the saying goes.)
>
>
>
> The oil pressure warning light issue on the Ford 3600 does concern me a
> little.   The idiot light comes on when the key is turned on but prior to
> starting the engine, exactly as it should to demonstrate that the circuit
> is intact and the bulb works, then goes off once the tractor starts and oil
> pressure builds enough to open the pressure sensor switch.   The only
> surprising part is that the light comes back **on** when I throttle up.
> One possibility is that there is a glitch causing a “false positive”
> warning light even though oil pressure is fine.   The other is that the
> sensor and wiring are functioning exactly as intended and oil pressure is
> for some reason dropping.
>
>
>
> Today I added about a third of a quart of oil to bring it up to the “Full”
> line on the dipstick, and I removed, inspected, reconnected, and fiddled
> with the idiot light wire where it clips onto the oil pressure sensor just
> to make sure it felt secure.  Neither of those actions stopped the warning
> light from coming on as soon as I throttle up past idle, but it seemed
> worthwhile to try them just in case.
>
>
>
> The repair shop hasn’t called me back yet, so I’ll follow up with them
> tomorrow.  The timing of this issue—literally popping up in the first few
> seconds after they brought the tractor back to me after working on it—makes
> me wonder if something they did somehow caused this, maybe by aggravating
> an existing problem enough to push it from “this is going to fail soon” to
> “this has failed.”  But maybe it’s just a coincidence.   Either way, I
> can’t use the tractor with the oil pressure warning light on.
>
>
>
> Dean Vinson
>
> Saint Paris, Ohio
>
>
>
>
>
>
>
> *From:* AT <at-bounces at lists.antique-tractor.com> *On Behalf Of *Dean VP
> *Sent:* Thursday, January 22, 2026 2:36 AM
> *To:* Antique Tractor Email Discussion Group <at at lists.antique-tractor.com
> >
> *Subject:* Re: [AT] One of those days
>
>
>
> Dean,
>
>
>
> I've had all too many days like that. it can be exasperating. As I get
> older, they seem to come more often. Lost items can usually be better
> described as misplaced items. Absent minded excellence.  I'm really good at
> that. But in your case, it is all because you sold the JD 620. If you had
> sold the M you would only have had 5 nuts to contend with rather than
> three, but the advantage is missing one out of 5 is not nearly as serious
> as one out of three.  But eventually you will see the light!  :-)
>
>
>
> But I will admit I have never had the light sequence you are experiencing.
> Probably because JD did not use idiot lights on the two-cylinder tractors.
> But it is exactly opposite of what one might expect. Is it possible that
> with your multiple tractors you have forgotten how this one is supposed to
> work? I don't recall any piece of machinery that that has worked like that
> except my JD 750 Compact Tractor.  It has a light on the dash that turns on
> when the key is turned on and stays that way and is not dependent on RPMs.
> Since I too have multiple tractors and this is the only tractor that works
> this way, it has more than once caused me to stop and question what is
> wrong. Then I realize this is the way this one works.
>
>
>
> I cannot think of an oil pressure sensor could possibly fail backwards.
> This will be interesting when you find out what is going on.
>
>
>
> The other Dean in AZ
>
> Dean VP
>
>
>
>
>
> On Wednesday, January 21, 2026 at 04:53:43 PM MST, Dean Vinson <
> dean at vinsonfarm.net> wrote:
>
>
>
>
>
> Minor tinkering today with my Farmall Super M, chainsaws, and Ford 3600.
> Nothing quite went as expected.
>
>
>
> This morning I went into town to pick up the Super M’s right front wheel,
> which a local tire shop had finished pulling thorns out of and putting a
> new tube into.   When I got home I went to put it back on the tractor,
> which is sitting by itself on the (relatively) clean concrete floor in the
> far corner of my enclosed shop.   Got the rim in place and went to bolt it
> back on, only to discover I was short by one nut.   Neat little pile of
> hardware on the floor right where I’d left it, three bolts, three lock
> washers, but for some reason only two nuts.   Couple of wrenches nearby but
> nothing else, no junk, no random stacks of supplies or half-full jugs of
> engine oil, nothing to camouflage the presence of the missing nut.   (My
> shop is not exactly short of any of those things, but they’re all over on
> the other side near the workbench where I spent most of my time, not here
> where the tractor’s been sitting.)    I got down low and looked, picked up
> the wrenches and put them back down, checked under the other front wheel,
> checked the area, nothing.   Big dang nut for a 5/8” bolt just
> disappeared.   Scratched my head for a minute but soon enough gave up and
> went back into town to visit the local hardware store for another nut.
> Problem solved, tractor is now all back together.
>
>
>
> Next task was to clean up my two chainsaws and figure out why one of them
> wouldn’t start last time I tried to use it.  I take both with me when I’m
> clearing osage orange and honeysuckle from the old overgrown pasture.  The
> newer saw cuts clean wood, and the older saw with a
> no-longer-fresh-but-still-halfway-okay chain cuts stumps down low and
> serves as the backup in case I get the other one pinched.   Last time I
> went out I absolutely could not get the #2 saw to start, but it’s been an
> egregiously long time since I cleaned (much less replaced) the air filter.
>   So today I got the saw all cleaned up, and also cleaned up the other one
> while I was at it, but didn’t see anything that looked bad enough to keep
> the saw from running.  Scratched my head for a while and then finally
> thought to check the fuel tank, which of course turned out to be bone
> dry.   Last time I went out I must have somehow forgotten to fuel that one
> up.   This was mildly funny to me today, but it had not seemed so last week
> when I was out there in the woods yanking endlessly on that starter rope
> and scaring away wildlife with a loud string of curses.
>
>
>
> Last task was to take delivery of my Ford 3600, which for several weeks
> had been at a local shop for an overheating problem.   The shop’s
> diagnosis, as written on the completed service order, was that the “coolant
> was nasty and radiator was almost plugged.”   They removed the radiator,
> sent it out to get cleaned, then put it all back together, function checked
> it, and brought it back to me late this afternoon.   After their driver
> started it up and idled it backwards down off his tilt-bed truck, I went to
> put it in the barn…and as soon as I throttled it up past idle, the oil
> pressure light came on.  I tried throttling down again and then back up,
> and shutting the tractor off then restarting, but same thing every time:
> Charging system and oil pressure lights come on when key is turned to the
> “run” position, then both go off when the tractor starts, but the oil
> pressure light comes back on at anything above a moderate idle and goes
> back off upon returning to idle speed.    I checked the oil level and it’s
> about halfway between “Full” and “Add” on the dipstick, so I wouldn’t
> expect it to just be an oil level issue.   Their driver hadn’t left yet so
> he called his service manager and gave him the rundown, but by then it was
> nearly five o’clock so the plan is they’ll call me in the morning and
> figure out the next step.   I won’t need the tractor for anything until
> springtime, but still, dagnabbit it I was looking forward to having them
> all back home and in one piece today.  :)
>
>
>
> Oh, and of course, as I walked back through the shop to close up the doors
> and turn the lights off, I stumbled across that missing nut about 15 or 20
> feet from where the Super M is parked.  Maybe I somehow kicked it over
> there without realizing I’d done so, or maybe a cat had been entertaining
> itself, who knows.  But now I have an extra 5/8” 11-pitch nut in a shop
> drawer, in case I ever need one.
>
>
>
> Dean Vinson
>
> Saint Paris, Ohio
>
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