Diesel running backwards

A strange thing happen yesterday, nothing to do with gasification, the trucks are running great and I have been working the soup out them doing farm work.

I was using my little wood chunking tractor in the hay fields to fluff and rake hay yesterday afternoon. ( Farm Pro chinese made tractor, two cylinder diesel) I started the tractor and there was just a little kick back with the starter. I put it in a forward gear and the tractor went backwards . I put it in another forward gear and the tractor went backwards again . I put it in reverse and the tractor went forward . The motor had a different sound to it and I shut it off quickly. I realized the motor was running backwards . This has only happened with me one other time with a D6 cat that I let roll off to start and I accidentally had it in a wrong gear and spun the motor backwards . On the D-6 the air breathe is right in front of the operator and the dust covered me and I shut it down quick.

I restarted the little tractor and it seem to work fine and I was preoccupied getting across a road with traffic etc and ran the tractor about five minutes before I noticed zero oil pressure . It is hard to tell with the diesel sound but there may have been a little rattle in the motor . I shut it down and used another tractor to finish up the day.

I haven’t had time to investigate the loss of the oil pressure . I know years ago I rebuilt a motor and realized the oil pump had to be primed before this type would function . I think all the oil may have been pumped out of the oil pump and needs some type of priming. Also it has an electrical oil sending unit and maybe pulling a vacuum damaged it or oil filter plugged when the flow reversed . Maybe oil pressure relief damaged? Damaged or broken oil pump shaft or gear?

Has anyone ever heard of something like this happening?

That’s interesting! Apparently diesels do run backwards on occasion, particularly simple ones with an injector pump.


Some folks have suggested that the oil pump running backwards will suck all the oil off the bearings. Seems like it would put it back once started back correctly though. Doubtful that you broke a shaft, but something certainly could be clogged or need to be primed again.

Do you have a compression release handle you can pull out while cranking with another gauge at an oil pressure point? Sounds like you thought of all the possibilities otherwise. Are parts available for this tractor?
Don Mannes

Pressurize the crankcase while starting. That’s a dumb idea isn’t it??!!

Hi Wayne,

the early famous Lanz Bulldog tractors didn’t have a reverse gear. Their engines had to be reversed to drive backwards. No problem, since they were diesel 2-stroke-engines (low rpm, too), easy to do. But not to be done for a long time (all the things you mentioned: no oil pressure, no intake air filtering through the exhaust…and in addition, exhaust gases through the crank case), only for switching (?) and inching (?)!

I’ve seen a truck engine (diesel 4-stroke) that had been running backwards when the truck had gotten stuck. Heavy loads are not an option for a reversed high rpm modern engine! The lack of lubrication soon turned the crankshaft and connecting rods in a colored mess (temper and annealing colors!). It seized after a very short time - I guess the english word is write-off, or is it?
But in your case the engine didn’t stall and you didn’t put heavy loads on the engine running in reverse. Therefore, you should be save. I am not sure if priming is necessary. But I would try one thing that is fairly easy:

If you unplug your oil pressure switch and take it out, you can try to seal the opening with your thumb and start the engine. If the oil goes by your thumb, I would guess your switch didn’t like the vacuum, but your pump is still OK. If it doesn’t come out, I would shut the engine off and investigate that priming issue more seriously…(and screw the switch back in…). Or maybe you can use that opening for the switch for trying to prime the oil pump first? Might be easier than pressurizing the crank case…? But Carl’s suggestion would be my next one to be tried - might be easier than taking off the oil pan and stuff…

Best regards and good luck!


Hi Wayne,

General rule is to pull the pan & check bearings after any type of lubrication failure. Yes, PITA, but usually much gentler on the pocketbook.

Hi Wayne,

there you have it! Listen to Peter and forget anything I posted! We have a saying in German with the meaning of “Children should be seen and not heard!”, I guess. I try to translate word by word:

“When the cake is talking, the crumbs are having a break all together!” Does this translate?

Best regards,

Sam (breadcrumb enginewise…)

WTF ???

Hi Wayne
you can remove the oil filter, and squirt oil in hole that feeds the filter, it goes strait to the oil pump.
you can crank it with the filter loose or removed,it should pump oil immediately.
hope this helps.

Thanks to all for the advice on the little tractor.

I pulled the oil sending unit out and released the compression and spun the motor, no oil would come out so I knew I had what might be a bigger problem. I winched the tractor on a trailer and hauled it home.
I pulled the oil filter off and spun the motor again and nothing happened. I then did as Carl suggested with some pressure in the crankcase (via compressed air through the dipstick) and spinning the motor at the same time. All of a sudden plenty of oil. Put the filter back on and tried to block the oil at the sending unit with my finger but couldn’t. I put the sending unit back on and spun the motor without starting it and the battery alone would push the oil pressure up to normal. I started it up and let it run quit a while and all seems normal.
I found no obstructions and the oil relief valve was sealing good. The only thing I can figure is the pump lost it prime.
While I was already good and oily I changed the oil and filter and hauled the tractor back to the hay fields.

I didn’t pull the pan and look at the bearing (might wish I had later) I only drove the tractor about a hundred yards, no load and less than 800 rpm. I am assuming the oil pressure died with the reversing of the motor but it took me a little while to notice. Yes I know idiot lights are for idiots but I wish I had it.

Hi Wayne, glad it is rolling again. Maybe the rod is threaded into the oil pump and just got spun out and threaded itself back in after a few tries … Keep an eye on things in case it got cross threaded or the such and wears loose ??? Made in China … Who knows … Maybe the rod’s gear lifted over the camshaft or the crankshaft gear as well. Might be a spring or something to hold it in place that is missing or got squashed … Just thinking out loud. I never did figure out what was up with my 91 S-10 … … ML

Hi Peter,

don’t take my posts too serious! I just do realize and acknowledge that you are one of the engine experts in this forum.

And it is one thing, if I decide for myself to try to get away with restarting an engine without pulling the pan to see in what shape the bearings are in. But if I suggest this to someone else without being responsible in any way, that is a totally different story! I realized this when you mentioned the general rule of pulling the pan after any kind of lubrication failure. Imagine what it would be like, if Wayne tried what I suggested and seized the engine in the end…

Wayne, it’s sure good to hear the engine of your tractor is up again!

I attach a link to a german website, where you can see that first 12-hp-tractor with no reverse gear:


Best regards,


Hey thanks for the Lanz Bulldog links SamF.
More detail than I’ve seen before.
Good point that backwards running can be accepatable for a short time at low RPM, low loads.
Realize this had been very common for a hundred years with tractive steam.
This was still done commonly to reverse with some marine applications with IC piston engines.
AND IS done on some golf carts intentionally.
Yep. Even without oil pumps but slash lubricated the lube throw patterns are not optimal and gear drives are side pressure thrusting non-optimal.
Wasn’t just you who recommended try-it ideas. CarlZ and JimG did also.
We are all adults here responsible for taking our own risks.

When I’ve had my own engines backfire, or back start run on me and I knew to load stall it stop quickly. Then let it cool and settle. Then drain the oil and check for metal. Pull the spark plugs and look for metal splash and piston crown damage.

Not a runs backwards incident; but an early twenties in a fuel milage streaching “how much ignition timing is too much?” learning incident: Aluminim piston crown splash onto the spark plug tips IS TOO MUCH timing advance! That particular engine a German Ford water cooled V-4 never ever would audibly ping - just damage itself. Everything mine pervious to then I could set up winter versus summer “ping” settings.
Wifes current 160cc Single overhead cam Honda push mower is a fuel saving dream 1/2 loaded putting around the yard 4 inch mowing down to 4 inch cut height. Pushed to 80%-100% load out on on high grass it death rattles badly. W-o-o-sie! It also looses 30% power above 80F days. Double weak W-o-o-sie!! IF I can work through 80-90F days my damn engines better be able to also! The yard Pro’s are correct - Honda’s outdoor equipment are are weak sisters in thier hoursepower ratings. Want gutsy, balls-ie engines use the Kohlers or a Kawasaki or even the higher line Briggs and Strattons for the 4-strokes. Stihl and Husquvarna for the 2-strokes. These WIll ALL work hard loaded hour after loaded hour when cold, hot, in the rain or the shine.

All of course just my own sweat learned opinions
Steve Unruh

good to see it didn’t seem to cause any major damage

diesels running backwards is something that my father told me about…years ago about once a year somewhere in the local district a truckdriver would cockup a gear change on a hill and the truck would roar off backwards at (normally due to grinding up the hill at the time) full noise…generally happend when the truck was heavily loaded with an trailer which resulted in a jack-knife under power, with all the resulting mechanical carnage as can be imagined.

don’t hear about it happening here now because all the inline injectors pumps have to have a sprag clutch on their input…i think VE type rotary pumps are immune to it because of the lift pump not pumping backwards…cam actuated unit injectors run backwards but i’ve never heard of a problem outside of the results of idiots mistreating the awesomeness of the Detroit Diesel (which is the most epic diesel ever made btw)

Hello Callum,

I remember my uncle ( a life long truck owner operator ) back in the sixties telling me the Detroit was the only truck spoken about in the Bible. He claimed it said something to the effect “ a creature screaming to the top of it’s lungs and moving at a slow rate of speed.”

I think he was referring to a four banger , I have driven one of those myself long ago. Straight exhaust , no muffler and I wonder why I am hard of hearing!

Hi Wayne

I will admit that the 2 smoke Detroit non turbo motors are a bit on the obnoxious side noise wise when they have a straight pipe…years back we dropped an ex military 8-53 in a D7 dozer…lol and we thought the dozer was loud before we swapped donks over…the running joke after that was that we needed to find the dumbest operator ever to drive it…they wouldn’t notice not being able to hear themselves think.

How does your little chinese tractor go?..

We are starting to get a bit of machinery from china recently due to the Free Trade Agreement signed a few years back making them easy to import…lol from what i have seen(and i know it’s still early days) if you pay 75-80% of what a western or japo costs you get a machine that is easily the equal of any good name unit (hitachi,komatsu,sumitomo,cat etc).

However the old story applys… if you cheap out (as management has a tendancy to do when buying new equipment) the chinese are the world leaders in producing heaps of s#@$ delivered in (almost) your desired colour

One of my 1970s projects. 1958 Ford Panel Delivery with a 6v 53 Detroit, 285 Clarke 5 spd, divorced dana transfer case, Dana 60 front & rear end.

A bread truck! Fantastic! I guess the bottom line is: Anything will fit in anything, if you know how.

Awesome !!!

love the rectangular head lights