Runaway Diesel Linde Forklift
Discussion
Hello there and thanks in advance for any help.
Had a bit a scary moment last night when my forklift's engine ran away. I'd noticed it try to run away in the past and told the guy who serviced it about it, asking for advice on cause and what to do... He said it was likely oil being sucked through the breather, and if it happens again I should run because it might explode. Well it happened last night with 2 tonnes of timber 3m in the air and this time ran away properly (the engine, not me... Although I did touch cloth). Switched it off and it was still revving its nuts off and pumping out ridiculous amounts of black smoke straight into my building. Still looked like the building was on fire half an hour later. It often puts out a fair bit of smoke on starting, but this smoke was on a whole new level.
I hopped off, and tried looking in the engine for an obvious air intake to cover up and choke the engine, but there is no obvious air intake. The hoses are nice and obvious, but the actual intake is hidden somewhere less accessible, especially when in a panic. Wanting to get away from the forklift asap, I decided I'd better move it out the way so that I could drop the load of timber. So I sat back on the ticking bomb, moved the forklift a couple of meters and lowered the pack of timber. Dropping the timber actually slowed the revs for some reason and allowed the engine to stall/stop. HUGE sigh of relief. Not just because I was still alive, but because the forklift is my single most expensive piece of equipment.
In future, if unable to shut down I will pop off the air intake hose and cover intake with piece of ply to stop the engine, but looking to solve the issue really! Could this be worn piston rings or something? Is that a big bill to get done?
Forklift is a 1996 Linde H25D-02. Noticed about a year ago that the engine oil was very thin and worryingly smelt of diesel... I thought this meant blown head gasket, but since it was running fine... if a bit smokey occasionally, I left it to it. Service engineer said he also noticed oil was thin, and also that the level was high, so pumped a bit out. No oils been added since, but I'm thinking if diesel is somehow getting in, that would thin it, and overfill it, both making it more likely to be sucked through the breather and causing runaway?
Any suggestions welcome. Happy to get my hands dirty. Technically minded, but not experienced. Who would I approach to get work diagnosed and done professionally? I'm in S
horpe area if you know anyone in particular. Don't want to use the people who did the service because they were useless. All I can think of is find another forklift service company, but wonder if there is a better option?
Also, as a side note, noticed the coolant reservoir was cold and was expecting it to be hot after running couple of hours, but now thinking maybe this is normal, with reservoir only getting hot if coolant in circulation overheats? Just looking for any possible symptoms.
Thanks again for any help!
Had a bit a scary moment last night when my forklift's engine ran away. I'd noticed it try to run away in the past and told the guy who serviced it about it, asking for advice on cause and what to do... He said it was likely oil being sucked through the breather, and if it happens again I should run because it might explode. Well it happened last night with 2 tonnes of timber 3m in the air and this time ran away properly (the engine, not me... Although I did touch cloth). Switched it off and it was still revving its nuts off and pumping out ridiculous amounts of black smoke straight into my building. Still looked like the building was on fire half an hour later. It often puts out a fair bit of smoke on starting, but this smoke was on a whole new level.
I hopped off, and tried looking in the engine for an obvious air intake to cover up and choke the engine, but there is no obvious air intake. The hoses are nice and obvious, but the actual intake is hidden somewhere less accessible, especially when in a panic. Wanting to get away from the forklift asap, I decided I'd better move it out the way so that I could drop the load of timber. So I sat back on the ticking bomb, moved the forklift a couple of meters and lowered the pack of timber. Dropping the timber actually slowed the revs for some reason and allowed the engine to stall/stop. HUGE sigh of relief. Not just because I was still alive, but because the forklift is my single most expensive piece of equipment.
In future, if unable to shut down I will pop off the air intake hose and cover intake with piece of ply to stop the engine, but looking to solve the issue really! Could this be worn piston rings or something? Is that a big bill to get done?
Forklift is a 1996 Linde H25D-02. Noticed about a year ago that the engine oil was very thin and worryingly smelt of diesel... I thought this meant blown head gasket, but since it was running fine... if a bit smokey occasionally, I left it to it. Service engineer said he also noticed oil was thin, and also that the level was high, so pumped a bit out. No oils been added since, but I'm thinking if diesel is somehow getting in, that would thin it, and overfill it, both making it more likely to be sucked through the breather and causing runaway?
Any suggestions welcome. Happy to get my hands dirty. Technically minded, but not experienced. Who would I approach to get work diagnosed and done professionally? I'm in S
horpe area if you know anyone in particular. Don't want to use the people who did the service because they were useless. All I can think of is find another forklift service company, but wonder if there is a better option?Also, as a side note, noticed the coolant reservoir was cold and was expecting it to be hot after running couple of hours, but now thinking maybe this is normal, with reservoir only getting hot if coolant in circulation overheats? Just looking for any possible symptoms.
Thanks again for any help!
cheers bdevo3 and xjay, will have a look.
Clock says 10k hours... No idea how true that is. Not sure about safety. Once I was confident I could shut it down quickly if it happened again, I turned it back on, let it idle. Idling fine I did a couple more hours shifting timber on it. Only seems to try and runaway at high revs, i.e. when lifting fast, so babied it, keeping revs low with no more runaway. Only use it approx once a month for 4hrs, and I don't let anyone else use it.
Clock says 10k hours... No idea how true that is. Not sure about safety. Once I was confident I could shut it down quickly if it happened again, I turned it back on, let it idle. Idling fine I did a couple more hours shifting timber on it. Only seems to try and runaway at high revs, i.e. when lifting fast, so babied it, keeping revs low with no more runaway. Only use it approx once a month for 4hrs, and I don't let anyone else use it.
Mr2Mike said:
If you know the oil is full of diesel, why didn't you change it? 
A knackered injector causing oil dilution could well be the cause of this, and would also cause lots of white smoke from a cold start. Is it a normally aspirated diesel or turbocharged?
I Don't know that the oil is full of diesel, it's only my inexperienced observation. Mechanic who did service agreed it seemed thin, but didn't say anything about the smell so I assumed I was being green with regards to the smell. Normally aspirated I think.A knackered injector causing oil dilution could well be the cause of this, and would also cause lots of white smoke from a cold start. Is it a normally aspirated diesel or turbocharged?
GreenV8S said:
If that was me I wouldn't turn the key on that until I'd taken enough covers off to give me access to block the air intake so I knew I could shut it down - and make sure that you have something on hand to block the intake and prove you can actually shut it down that way before you go any further. You're very lucky that loading the engine was enough to stall it this time - it might well not be next time. You might have a relatively minor issue at the moment, but it only needs to run away one more time to leave you with a scrap engine.
If you'd read my post you'd see that is exactly what I did in preparation. Ready to access and block air intake quickly. I'm not going to cause a runaway on purpose just so that I can see that suffocating the engine works. It is widely known this works already.yes running on its own oil... I assume once the ignition is off, source of diesel is switched off. And you're bob on about the manifolds/breather, that's exactly where I believe it's feeding itself. So yes, the crankcase breather joins the air intake just before the air intake manifold. I've loosened the hose here so that I can yank it off in a hurry to block air intake directly at the manifold. In theory though, just yanking it off here should stop the engine since it'll no longer be getting oil as fuel. That's enough talk of yanking off... The inside of the hose here does have a small amount of oil in it. Don't know if some is to be expected though?
I too wondered about rerouting/letting the crankcase breather go somewhere else through an easily changeable filter or something, but would rather fix the problem than the symptom. That said, the rate I use this forklift, I'd probably only have to change a filter once a year, so long as the actual issue isn't doing any more serious damage, I can live with that.
Could it be the engine is overheating, causing more vapour than normal? I popped the oil cap off after it had cooled off a bit after the runaway, and noticed there was oil vapour then... Again, not sure if that is normal or not. If diesel really is in the oil, maybe this is also causing excess vapour, so fixing that solves everything. Who would I ask to investigate a fueling issue like that? I mean I could investigate, but I'd probably be better off sticking to my day job and yanking off.
I too wondered about rerouting/letting the crankcase breather go somewhere else through an easily changeable filter or something, but would rather fix the problem than the symptom. That said, the rate I use this forklift, I'd probably only have to change a filter once a year, so long as the actual issue isn't doing any more serious damage, I can live with that.
Could it be the engine is overheating, causing more vapour than normal? I popped the oil cap off after it had cooled off a bit after the runaway, and noticed there was oil vapour then... Again, not sure if that is normal or not. If diesel really is in the oil, maybe this is also causing excess vapour, so fixing that solves everything. Who would I ask to investigate a fueling issue like that? I mean I could investigate, but I'd probably be better off sticking to my day job and yanking off.
Hadn't occurred to me to strangle the normal idling engine, thanks for that suggestion. Even if you were a bit of a tool about it. What do you know, strangling the engine works.
Also thanks for the CO2 extinguisher suggestion. I had one of those at the ready too, but was already confident about strangling so that was my second choice.
Thanks for all the useful replies and the stories and video. Sorry to all those who have ants in their pants or other limiting conditions in that region.
Also thanks for the CO2 extinguisher suggestion. I had one of those at the ready too, but was already confident about strangling so that was my second choice.
Thanks for all the useful replies and the stories and video. Sorry to all those who have ants in their pants or other limiting conditions in that region.
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