[J8NPT]

Hi
So I’m doing approx 75 on motorway, suddenly a loud ish bang bit of smoke from engine and car dies instantly. Appears to have also lost its oil as a puddle was found on hard shoulder, and on recovery truck and various amounts on underside of car engine. No warning or warning lights or issues immediately prior to this. Any ideas? Thanks

 

[MickeyMini]

Assuming you have no oil now, next step is to identify where the oil exited the engine. Wonder if you have pushed a connecting rod out of the block, if it was a seal then the engine would continue to run until the oil had run out. I would say you are most likely looking at either an engine rebuild or a crate replacement.

 

[J8NPT]

Thank you. Yeh appears empty now. Well if the oil was running out then getting low, surely the oil warning light would have came on, but it didn’t?

 

[GEOFFSNOOK]

oil light not a good idea to wait for it to come on could have spun a bearing snapped a rod or timing chain wotld think that you may be looking at a new engine but may be lucky if there are no holes in the block but i bet it will be a few quid

 

[mike1967]

sounds like its poked a rod out the block,

 

[J8NPT]

So what causes it to poke a rod out the block? Oil level was fine as checked it just before Xmas

 

[J8NPT]

But didn’t wait for oil light to come on, it never has done as always has oil in it, I check that

 

[mike1967]

So what causes it to poke a rod out the block? Oil level was fine as checked it just before Xmas

on the r56 n14 and n18 engines the pistons can break up from being hammered a lot and lean outs , i've seen a few bend rods normally the two cylinders closest the gearbox end where first off heat is hotter behind the turbo and when aux pump fails can add to the hot spot, also might find in it past someone ran low on oil maybe, sometimes its a rods have had their day,, in drag racing cars the rods have a life span they say around 200 1/4 mile hits say, metal internals weaken over time and wear ,,

 

[MickeyMini]

Lack of oil is certainly a probable cause, the strong part of the Prince engine happens to be the bottom end which came from the TU engine. You could have just been unlucky this time and a critical component failed, perils of the Prince engine - certainly a left field lump!

 

[mike1967]

Lack of oil is certainly a probable cause, the strong part of the Prince engine happens to be the bottom end which came from the TU engine. You could have just been unlucky this time and a critical component failed, perils of the Prince engine - certainly a left field lump!

totally agree with that my dyno guy had a n18 cooper s that had been forged and hybrid this guy spent well over 7k on the engine according to and on factory crank and block made 360 bhp he phoned me up to go have a look, hmmm they sound demented like everything is coming out the cot when it rev'd up , car was so light it was trying to take off the rollers really pulling on the straps , guy that owned said he knows he will need a few gearboxes going forward lol, i've driven a few like it its strange one it spends it's time trying to visit the scenery , some get mapped wrong ie gives a power band at top end , where i go for maps and dyno he progressive maps them so much better gives the drive more control of power , one thing for sure when knocking out that power it takes one injector to lean out and things melt fast, and more so on a engine thats runs at 105c to 112c

 

[J8NPT]

Thanks for all your replies. But surely if the oil was dangerously low, why did the warning light not come on?

 

[MickeyMini]

BMW's variant of the Prince engine uses a pressure switch, so as long as the oil pump can pump enough oil to maintain the pressure things will continue.

 

[NigelStap]

Forget about the oil warning light. See the comment above. You now need to find out what needs to be fixed and how much it costs.

 

[mike1967]

on n18 n16 engines they have moved the oil pressure sensor to the oil filter housing , hmmm bad idea me thinks as you could have oil pressure keeping light off just and zero oil to the head , where the older engines is on side of head so better warning , protects the bottom end and head better, the joys of living with a engine that uses to much oil its just waiting to go bang,,

 

[J8NPT]

Would it possibly have been caused by the chain or tensioners failing? These along with the oil pressure switch was replaced before Xmas.

 

[MickeyMini]

I guess we are puzzled by the ‘pool of oil’ statement. Generally means there’s a hole somewhere caused by something making an exit from the engine at the sump level. Could be that you lost your sump plug and the oil exited that way. But loosing oil while the engine is running isn’t a good thing and I think you will need major repairs

 

[J8NPT]

Ok thanks, will have a look tomorrow to see if sump bolt is still there.

 

[ExclusiveWorkshops]

Thank you. Yeh appears empty now. Well if the oil was running out then getting low, surely the oil warning light would have came on, but it didn’t?

the light is low pressure not low level, almost a 'too late' light really,

several things could have happened including driving over something, could well be a rod but that is likely to be consequential, chances are it may have made other noises beforehand that you might not have detected, issues can include a spun bearing, snapped cam/bolt, jumped chain, blocked oil pick up, oil pump failure or chain, broken valve or damaged piston etc.

damage can be severe especially with motor speed and the weight of the car behind a failure at motorway pace, really the investigative part is as it gets taken apart if no external damage is obvious

if it has a large puddle and oil elsewhere then it implies it wasn't necessarily terminally low on oil

 

[J8NPT]

So news is in. Oil was fine. One Conrod failed, and on next turn of engine, it forced it through the block, blowing the engine. It’s now a write off.
Anyone know of an engine going for sale?

 

[GEOFFSNOOK]

Do you know why it failed did they say if they good see any issues?