“The Dog that Didn’t Bark:” Yanmar. 4L HASTE.

[oldgit]

For some time the oil pressure on one of a pair of 240 hp engines always displayed a lower pressure than its companion when hot.
OK cold start but drops away when hot, especially noticable on gauge at low idle. Needle in RED section.
At no time did the alarm sound.
First a change of oil and filter.
Much extended swapping around with old/new pressure senders, wiring from senders to gauges etc etc.
Yanmar notorious webwide for rubbish instrumentation.
Checked with mechanical gauge and half decentish pressures indicated both at high and low idle.
Attention turns to oil pumps (easy to check with feeler gauges on this engine) no wear regard vanes or pump body.

Then a very recent and very short trip to a local marina, as always a quick engine check prior to any trip including sump oil .
30 mins running and very low pressure on gauge.
Check sump oil again and oil level has risen ?
Then something clicks.
Lubrication oil being diluted by something ?, no emulsion so not water.
Only good news it was on the engine that was easy to get to.
Consult companion skippers, only one bloke to talk to apparently, a local man tucked away in a back street round the corner.
A visit to the workshop suggests he might have known Rudolf Diesel.
No elecrotrickery here, there might have been a BBC B somewhere but not on display.
Any problems, starting, smoke etc......Nope.
Told to bring in the lift pump, for him to test, 100% working no leaks..
Injectors next please , some very stone age technology. ........ All 101% knackered and dribbling. 1500 hours on log.
Told probably not worth repairing possibly money on the bits + labour could exceed cost of new.
4 x "new " injectors fitted yesterday and problem solved.
Do wonder whats going to be next ?

 

[wallacebob]

Oil dilution is common in Subaru and BMW engines, and others that use diesel injection to burn off exhaust deposits. If the engine doesn’t get a good long hot run, the fuel can’t evaporate/disperse. Many instances of Police BMW engines grenading after long periods sitting at idle, then high speed. I was warned by dealer to check oil level, and if appeared overfilled, change oil. The car also had a warning light if too many fuel injections before oil change. I always knew when the system was working, clouds of reek on overrun off m/way.

 

[oldgit]

Oil dilution is common in Subaru and BMW engines, and others that use diesel injection to burn off exhaust deposits. If the engine doesn’t get a good long hot run, the fuel can’t evaporate/disperse. Many instances of Police BMW engines grenading after long periods sitting at idle, then high speed. I was warned by dealer to check oil level, and if appeared overfilled, change oil. The car also had a warning light if too many fuel injections before oil change. I always knew when the system was working, clouds of reek on overrun off m/way.

On long runs deisel in hot lub oil was possibly evaporating out, most trips last year were fairly long 8 to 12 hours duration with only one or two short runs out.