Wondering if any one can help . sometimes when I start my engine (scania r420) 1 or 2 loud knocks are heard and very thick white smoke pumps out for a 10 seconds approx. If I turn it off and switch ignition back on to set it self again then restart all is fine not a breath of white smoke seen . truck runs perfect . just get this now and again . Any ideas ■■
trucker651:
Wondering if any one can help . sometimes when I start my engine (scania r420) 1 or 2 loud knocks are heard and very thick white smoke pumps out for a 10 seconds approx. If I turn it off and switch ignition back on to set it self again then restart all is fine not a breath of white smoke seen . truck runs perfect . just get this now and again . Any ideas ■■
Cold start system fault, leaky injector etc etc…
You own it? Bring it to Scania.
You don’t? Worry about something else.
yeah I own it . could be a potentially expensive job then ?
trucker651:
yeah I own it . could be a potentially expensive job then ?
Nah, if it’s once in a while and everything else is okay don’t worry about it. Nothing is perfect.
Sounds like a weeping injector, could be the injector O rings, needs addressing though as it will cause fuel dilution in your oil and that will dramatically reduce the life of your bearings.
The last few Scannys I had (last was an 04 420) had a white smoke limiter switch on the dashboard. Symbol like an exhaust with a puff of smoke coming out. This partially engages tge exhaust brake thereby putting a light load on the engine and preventing the knock and fumes from unburnt fuel on cold start up.
probably a bit of air getting in the system overnight. injector seals, fuel filter seal/housing, perished fuel pipe.
if it has a manual lift pump, you could try pressuring the system one morning and you may see or hear a small leak.
same thing happened to the scania i drive white smoke got worse and worse turned out to be a injector gone and not a cheap job when it finally broke down in bruxelles