We didnt start the fire

[Hicarus]

The one thing I forgot to add was the explosion effect - well it is nearly 25 years since I dabbled in this stuff!!!
Diesel fuel as a cloud will burn. That's how the damned engines work after all. But that 'cloud' of droplets has a flame wall of something of the order of 500ft/sec. That means that if there was a cloud of vapour 500ft wide it would take 1 second for the cloud to burn from the ignition source at one end to the far end.
Petrol, though. is one hell of a lot faster. Forget the film, video and cartoon explosions, a full petrol vapour cloud explosion is a short lived, wicked and violent occurrence that distinct parallels with gas explosions - pictures of which most will have seen. A petrol explosion will destroy anything it meets: diesel cloud combustion (to give it its proper name) will probably be an experience to be remembered because you survived, albeit a bit singed.
But diesel is still considered dangerous because many consider it safe and grossly underestimate is power to create havoc.

 

[NQ94]

The one thing I forgot to add was the explosion effect - well it is nearly 25 years since I dabbled in this stuff!!!
Diesel fuel as a cloud will burn. That's how the damned engines work after all. But that 'cloud' of droplets has a flame wall of something of the order of 500ft/sec. That means that if there was a cloud of vapour 500ft wide it would take 1 second for the cloud to burn from the ignition source at one end to the far end.
Petrol, though. is one hell of a lot faster. Forget the film, video and cartoon explosions, a full petrol vapour cloud explosion is a short lived, wicked and violent occurrence that distinct parallels with gas explosions - pictures of which most will have seen. A petrol explosion will destroy anything it meets: diesel cloud combustion (to give it its proper name) will probably be an experience to be remembered because you survived, albeit a bit singed.
But diesel is still considered dangerous because many consider it safe and grossly underestimate is power to create havoc.

Hicarus a great explanation and I have seen the results multiple times of your explanations. For my employer I have helped investigate, recovered and repaired a number of trucks and offroad equipment that has had fires on board, luckily most have only been repairable damage only with the total loss fires generally investigated by a forensic fire investigator (who are very interesting to talk to and learn from if the opportunity arises).

These are some of the experienced causes I have directly worked with throughout my career. The primary cause of fires on machines was poorly supported and segregated fuel, hydraulic and coolant hoses chafing causing pin holes and leaks. Generally diesel will pool in a cavity on top of the engine, in dirt or castings then start to spill onto the turbo or exhaust operating around 700°C igniting and causing a small fire that may ignite wiring, fuel or oil soaked turbo lagging blankets and sound deadening. Pressurised spray from a pin hole in hydraulic, diesel and coolant lines is another regular cause. Second to hose chafing was solid lines cracking due to poor security, segregation and vibration giving the same results as a chafed hoses. The third major cause is poor assembly of hose joints or joints that seals or ferrules have failed from age. Fires from electrical have been generally caused by battery cables and high current cables chafing then arcing due to the lack of support, security and segregation then causing a fire. Contrary to what many believe the majority of trucks and machines, older vehicles and winches have no circuit protection on these heavy cables and if the cable is fused a glancing contact or a short time contact exposure is enough to cause a fire but not enough to trip the fuses off particularly with these circuits having a slow blow fuses in some applications to avoid failure when the sudden short spike higher current draw of a starter or winch initially kicking in. Accumulated debris has been the least of our issues because of daily inspections and removal when working in the scrub.
The last total loss fire we had at work was caused by an internally fatigued battery cable junction box under the cab of a machine we could not access to extinguish due to machine location and had to leave it burn, the fire suppression and operator had done as much as they could but the fire became too intense and reignited. Offroad fire can be difficult to detect while operating because of the dust and vibrations masking the smoke, the cab being well sealed and a/c on recirculation resulting with the operator only detecting the smell when it is too late. The company I work for has a very strict fire prevention inspection regime with every machine and car inspected and recorded after workshop repairs and three monthly detailed fire assessment inspection as part of the service on all plant.
A bit long winded but I do believe this will help, especially the home mechanics when they are doing inspections at service and prior to a trip. Nearly all vehicle servicing shops, 4x4 workshops or factory service procedures DO NOT have additional dedicated fire prevention inspections or strategies and only look for possible mechanical failure points.

 

[DenisM]

@NQ94 and @Hicarus : Your clarification and endorsement of fire issues is greatly appreciated. I'm speculating here: I mentioned somewhere on this forum re. the Grenadier fire on Stockland beach in NSW the possibility of a coolant leak as the cause. @NQ94 you included coolant leaks in your post above.
The reason I'm harping on this is that it was a source of sufficient concern in the P38 Range Rover with the 4.6L V8 for JLR to issue a worldwide warning regarding the routing and securing of coolant hoses to/from the plastic reservoir (which passed directly over the exhaust manifold) and especially since many of the vehicles by then were well and truly in the hands of DIY owners !
A not too dissimilar coolant pipe layout situation in respct of hot surfaces exists with the B57 arrangement in the Grenadier....
Question: Have either of you gentlemen witnessed/investigated fires which might have been the result of coolant ignition from a "hot" surface?

 

[dreamalaska]

And don’t forget the diesel’s DPF burn process. The video referenced earlier about the Australian family with a diesel (not a Grenny) pulling their camper through what we call reed grass was sad but very educational.

One example: https://www.abc.net.au/news/2023-05-29/outback-car-fire-risk-increased-after-wet-season/102378446

 

[NQ94]

@NQ94 and @Hicarus : Your clarification and endorsement of fire issues is greatly appreciated. I'm speculating here: I mentioned somewhere on this forum re. the Grenadier fire on Stockland beach in NSW the possibility of a coolant leak as the cause. @NQ94 you included coolant leaks in your post above.
The reason I'm harping on this is that it was a source of sufficient concern in the P38 Range Rover with the 4.6L V8 for JLR to issue a worldwide warning regarding the routing and securing of coolant hoses to/from the plastic reservoir (which passed directly over the exhaust manifold) and especially since many of the vehicles by then were well and truly in the hands of DIY owners !
A not too dissimilar coolant pipe layout situation in respct of hot surfaces exists with the B57 arrangement in the Grenadier....
Question: Have either of you gentlemen witnessed/investigated fires which might have been the result of coolant ignition from a "hot" surface?

Yes, absolutely I have seen and repaired the results. Just a caveat I am not a professional fire investigator but companies I work with will give some training and use experienced mechanics to investigate small low damage fires on equipment, prepare reports, suggest repairs and order parts when there is going to be no insurance claim.
I went to suspected coolant fire on a tip truck a few weeks ago and was there within minutes of the fire being called and fire suppression activated. Very similar scenario as the P38 Range Rover a 5/8" coolant hose that ran between the rocker cover and the turbo had become heat affected and pin holed sprayed a vapour like an injector. We were lucky there was no detectable flame damage the coolant had just soaked the turbo exhaust lagging/blanket and produced a horrid acidic smoke/steam that irritates the eyes first and causes coughing and is very likely toxic. A person has to be very unlucky to see a coolant fire happen as it happens very quickly, and the coolant spray is generally difficult to see. There are various coolant formulations and certain alcohols and chemicals that are not in all coolants, so the fire potential differs. The several coolant fires I have worked on after having been caused by misting/vapour leaks where the water evaporates then the other coolant chemicals flash over quickly from a hot surface then ignites something else. Most of the fires have been picked up by fire detection equipment and limited any major fires, we just see the damage and do the clean-up. All the pouring heavy spray leaks that I have seen cools the surface and only cause lots of steam.
As for the Grenadier, and this is only my opinion, owners and technicians will have to be vigilant with hose routing, segregation and security as the car ages and comes out of warranty and the multitude of plastic joints and hose support brackets deteriorate with age and heat cycles and appear to be the vehicles main technical weakness. There are plenty of photos on this forum and other social platforms that can illustrate these potential future issues. Thanks to the people who supplied some of the best Grenadier technical images currently available.
This fire and other reported difficulties have in no way deterred me from wanting a Quartermaster cab chassis but has made me and possibly others more aware of what idiosyncrasies and possible future repairs to be aware of for the long term owner.
If you have any concerns about flammability of and fluids used on the Grenadier or Quartermaster look up the Material Safety Data Sheets (MSDS or SDS) for the product. No manufacturer can withhold this information and must either supply or direct your search to the supplier of the product.

 

[DenisM]

Thank you very much @NQ94 for your lucid explanation: Vigilance the indeed the key!!

 

[Tazzieman]

Power steering and brake fluid are also flammable. An high pressure PS hose leak can destroy an engine .

 

[NQ94]

Power steering and brake fluid are also flammable. An high pressure PS hose leak can destroy an engine .

The one everyone forgets is the pressurised R1234yf a/c gas used in a Grenadier and now nearly in every new Euro car is more flammable than the previous R134A refrigerant.

 

[trobex]

I dare you to post that on any Australian 4x4 platform
Where last century medieval beliefs refuse to die

Just like.... EV can type just as well as diesel!!! Albeit how far...

 

[Tazzieman]

Just like.... EV can type just as well as diesel!!! Albeit how far...

Type?

 

[Hicarus]

Power steering and brake fluid are also flammable. An high pressure PS hose leak can destroy an engine .

Of all the vehicle fires I have researched and reported on one or two stand out. A Range Rover with a failed (stuck) fourth gear cooked the gearbox oil to the point where an oil cooler joint failed. The hot oil sliced through the front bumper (fender) and ignited on the left hand exhaust down pipe. Another had a failed ABS pressure hose (separate HP pump in those days) and sprayed a fine mist of Dot 4 onto the right hand exhaust of an idling engine. Yet another incident saw the front of a TD5 engine cut away as though attacked with a gas axe. That was the EGR pipe loose and burning through the PAS flex hose.

The list goes on. Many seemingly innocuous fluids will ignite under the right circumstances. The wonder is that there are so few fires as a whole – it seems that “circumstances” take a while to get themselves organised, fortunately.

 

[Tazzieman]

Of all the vehicle fires I have researched and reported on one or two stand out. A Range Rover with a failed (stuck) fourth gear cooked the gearbox oil to the point where an oil cooler joint failed. The hot oil sliced through the front bumper (fender) and ignited on the left hand exhaust down pipe. Another had a failed ABS pressure hose (separate HP pump in those days) and sprayed a fine mist of Dot 4 onto the right hand exhaust of an idling engine. Yet another incident saw the front of a TD5 engine cut away as though attacked with a gas axe. That was the EGR pipe loose and burning through the PAS flex hose.

The list goes on. Many seemingly innocuous fluids will ignite under the right circumstances. The wonder is that there are so few fires as a whole – it seems that “circumstances” take a while to get themselves organised, fortunately.

Once the rubber hoses age/cook in the heat +/- the crimps rust, seepage if not blowout is going to happen. The downfall of old/classic cars with deferred maintenance.

 

[Hicarus]

@NQ94 and @Hicarus : Your clarification and endorsement of fire issues is greatly appreciated. I'm speculating here: I mentioned somewhere on this forum re. the Grenadier fire on Stockland beach in NSW the possibility of a coolant leak as the cause. @NQ94 you included coolant leaks in your post above.
The reason I'm harping on this is that it was a source of sufficient concern in the P38 Range Rover with the 4.6L V8 for JLR to issue a worldwide warning regarding the routing and securing of coolant hoses to/from the plastic reservoir (which passed directly over the exhaust manifold) and especially since many of the vehicles by then were well and truly in the hands of DIY owners !
A not too dissimilar coolant pipe layout situation in respct of hot surfaces exists with the B57 arrangement in the Grenadier....
Question: Have either of you gentlemen witnessed/investigated fires which might have been the result of coolant ignition from a "hot" surface?

 

[Hicarus]

@NQ94 and @Hicarus : Your clarification and endorsement of fire issues is greatly appreciated. I'm speculating here: I mentioned somewhere on this forum re. the Grenadier fire on Stockland beach in NSW the possibility of a coolant leak as the cause. @NQ94 you included coolant leaks in your post above.
The reason I'm harping on this is that it was a source of sufficient concern in the P38 Range Rover with the 4.6L V8 for JLR to issue a worldwide warning regarding the routing and securing of coolant hoses to/from the plastic reservoir (which passed directly over the exhaust manifold) and especially since many of the vehicles by then were well and truly in the hands of DIY owners !
A not too dissimilar coolant pipe layout situation in respct of hot surfaces exists with the B57 arrangement in the Grenadier....
Question: Have either of you gentlemen witnessed/investigated fires which might have been the result of coolant ignition from a "hot" surface?

My answer is basically ‘no’. However, my work was 23 years back plus and things have moved on since. For example, coolant was around the 25% mix in those days. Now I se some being as high as 50%. At that concentration I would guess that it is possible that a ‘contribution’ to any fire may be possible but actual ignition would not seem to be on the cards. However, there are many strange things in this world….. and what 50% coolant at 110ºC in a high ambient temperature would do is something I would love to experiment with!

 

[bemax]

In '67 this city academic with no 4x4 experience bought a S2 LR and drove for 6 months in the outback, alone, retracing an old explorer's tracks.
8 jerry cans of petrol in the back.
But he was smart enough to clear the spinifex.
This book was part of my matric English studies subject. Great book!
From a time when everything was simpler , if not as lardacious and luxurious as today.
View attachment 7858420

Thanks a lot for giving me the opportunity to buy a (till now) not known book. I just ordered it for the insane price of 38 €.