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OT: MY Runaway diesel tractor almost gave me a heart attack today
- Thread starter tomjelly
- Start date
- Replies 60
- Views 16,194
Its an oil burner, not gas. The turbo seemed pretty naffed, when i was helping him to try and get it started a while later. The hose from the intercooler to engine was disconected, sprayed oil up the inside of the bonnet and windscreen. Later inspection found the intercooler full of oil.
If it was caused by or the cause of i couldnt say, but apparently its a known fault on this engine and not just in the saabs. I dunno.
He ended up buying the car for some silly price. Still up on stands in his driveway.
Roger Williams
Aluminum
- Joined
- Oct 18, 2009
- Location
- UK
Tdmidget, no offence, but Demon73 didn't say whether it was a petrol (gas) or diesel engined car. This diesel runaway phenomenen is quite common on cars in the the UK, and is more than likely caused by ignorant drivers who for some reason, either they don't know or can't be bothered, to let their engines idle for a short while, before switching off. Especially important after a high speed run, when the Turbo is red hot , still whizzing round at high speed and after quickly turning off the engine, no oil pressure. Worse, that small amount off oil remaining in the hot Turbo, carbonises, causing irrepairable damage. Eventually, this can cause frightening driving experiences, when the engine runs away on its sump oil. I know of a traffic policeman who's attended 8 of these, all on the motorway, who's drivers miraculously avoided collisions. All this could perhaps be averted if drivers let their engines idle for a few minutes.Cheers.
cncFireman
Hot Rolled
- Joined
- Jun 19, 2013
- Location
- Farmington Missouri
I have two Detroit 453s in a couple of 1 ton trucks. I have a shutdown on the one the other I had ran away on me and was my fault do to an governor adjustment. I literally pulled the air filter off and choked it out with my own two hands. It billowed a nice black cloud until it chugged to a stop. Those engines barely give you time to think during a runaway
dkmc
Diamond
- Joined
- Jan 13, 2002
I do wonder what RPM's are attained on a DD when they decide to head for the sky.....
Mud
Diamond
- Joined
- May 20, 2002
- Location
- South Central PA
I wonder too, and I wonder what the limiting factor is. I assume it's the exhaust valves floating?
The 6v53 was governed at 2600, 2800 if it was on an auto trans.
dkmc
Diamond
- Joined
- Jan 13, 2002
I dunno mud......those valves are pretty small......and light 
I think there are or were some truck pulling people out there that ran DD's in
"Big Rig" type pulling trucks, and they twist them up to pretty scary levels.
I think there was also a pulling tractor with a DD in it....may have been a 12V....
that ran on Methanol.......
Almost think it was spark ignition as well......
dk
I think there are or were some truck pulling people out there that ran DD's in
"Big Rig" type pulling trucks, and they twist them up to pretty scary levels.
I think there was also a pulling tractor with a DD in it....may have been a 12V....
that ran on Methanol.......
Almost think it was spark ignition as well......
dk
I think the answer is they sound like they're spinning 16,000 but they're actually running 3500.
Larger diesels like 855 Cummins, 92 DD's, 3406, etc will run 4500 for a very long time before they slowly lose power from the crank bearing wear. 5000+ is about scatter speed for big engines though. The valvetrain is so massive it can't handle those speeds. Pistons can only smack valves for so long before valve stems break and a chain reaction starts.
The thing to remember about big diesels is most have huge rods with forged steel pistons directly bolted to the wrist pins and an aluminum skirt. Even though it's a shitload of mass the materials are usually high quality and will take some incredible forces.
Ox
Diamond
- Joined
- Aug 27, 2002
- Location
- Northwest Ohio
One more 
for not stalling it in a higher gear....
----------
Think Snow Eh!
Ox
for not stalling it in a higher gear....----------
Think Snow Eh!
Ox
dkmc
Diamond
- Joined
- Jan 13, 2002
Would have done a wheelie revving like that, no way would the brakes have held. I got my special NH134 hydro oil ($84 per 5 gal!, luckily I had 2.5 gal left over from the last change) and new filters today; drained 2.5 gallons out of the rear drain plugs, the front reservoir portion was dry, so it either ingested or spilled a total of 5 gallons. The hose that split was upon closer inspection standard 5/8 fabric reinforced automotive heater hose elbows (!) unfortunately couldn't get 2 wire hydraulic hose (all I could get locally)to make such a tight bend. I installed some heater hose for testing only and the engine started right up and ran fine, so I dodged that bullet... The new version of my machine has the steel line coming in to the cooler straight on so no hose elbow is needed- just straight hose; presumably I can just get a set of the late model steel lines and the be able to use straight hose segments of hydraulic hose if necessary but I'd rather just upgrade the hose elbows. Even the OEM straight hose segments to the cooler appear to be the same heater hose material...I'm not too sure that with 2 wire hose that I could get enough clamping force with a hose clamp to seal the joint anyway though, so I would like to find an alternative to the heater hose stuff. G4H hydraulic suction hose (textile reinforced & spiral wire to prevent collapse, 1/2 bend radius of standard SAE 100r4 stuff, and can be clamped with hose clamps) sounds flexible enough for a tight 90 deg but I only see sizes down to 3/4", anyone know of a source of 5/8"? ...I suppose molded 5/8 fuel line 90 deg elbows would be a step up but I'd have to figure out where to get that as well...
Ox
Diamond
- Joined
- Aug 27, 2002
- Location
- Northwest Ohio
That may explain it!
Many (all?) hydrostats that I have seen - IF they even have a brake peddle, it is mech linked to the controls so that you cannot try to stall it.
Good catch!
--------------------
Think Snow Eh!
Ox
Mud
Diamond
- Joined
- May 20, 2002
- Location
- South Central PA
Pushlock hose bends tighter than hyd. hose, and you can clamp it. Maybe you could put a 90° fitting in the middle of the hose?
GAT Gates Push Lock Hose 5/8 for AN -10 Fittings - 70680 : Amazon.com : Automotive
3384 | Black Push-Lock Hose
GAT Gates Push Lock Hose 5/8 for AN -10 Fittings - 70680 : Amazon.com : Automotive
3384 | Black Push-Lock Hose
robmc
Cast Iron
- Joined
- Dec 22, 2009
- Location
- Rhode Island, USA
His tractor would have had a separate brake pedal and system, I think, not positive. If he was brave enough to stand on the brakes and the hydrostatic direction pedal as hard as he could at the same time....... would it stall? Maybe, maybe not. First his was a diesel running wide open... it has a lot of torque. Brakes might not be strong enough to resist that much force, might have lurched and pitched him off or worse. Bypass valve in hydro might have come into play and defeated that option, also don't know how much if any slippage is involved. The reason I say all this is because I rented an Allmand backhoe loader (4000 lbs. approx. and 25 H.P.) about a month ago, It had a Hydrostatic trans and if you tried to dig and and push too much at the same time it would just stall the engine. Granted the engine was being pulled down to ever slower RPM's, not a runaway situation and not the torque his diesel has and probably governed so people can't abuse the unit. The backhoe totally different, relief valves kicked in if breakout force, whatever, was exceeded. His post just reminded me of that situation.
It has a 3 range trans and the brake is not linked to the hydro. Regardless, at those revs it would not have stalled at full braking even in high range & what the inside of the trans would have looked like after attempting that I don't even want to know...
Deereahuler
Aluminum
- Joined
- May 27, 2013
- Location
- McCook, NE
If the hydro is losing oil, eventually it would not have enough oil to pump. A pump with nothing to pump does not create a lot of resistance, so jamming on the brakes and the hydro would not do a lot of good.
Timw
Stainless
- Joined
- Nov 8, 2005
- Location
- N E Florida
Here is a 68' Yacht stuck in reverse, docking when it ran away!!! With Pics.-
Sportfish "Silver Fox" accident at Sailfish Marina - YachtForums.Com
Sportfish "Silver Fox" accident at Sailfish Marina - YachtForums.Com
Following up on Mud's post about delivery truck diesels running away from fumes at the gas station tank filler mouth--about 25 years ago, a tank farm north of South Bend had a gasoline spill. Various fire departments were on hand in case it ignited. The fire trucks were all parked in a position to quickly respond and their engines were left idling. Fuel fumes got to the intake on one and the engine ran away. What was really bad was that hot particles of carbon began flying out the exhaust stack. Fortunately, they got the engines shut off before things went "woomp".
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