The most reliable car I've ever owned

[Emtee]

Sorry for raking this over Miles.......am sure it was no fun in many ways.

will allow an internal bleed within the pump itself either from high pressure back to low pressure in the pump chamber, or from the pump chamber into the scavenge pump chambers.....result of this happening?


BUT...if the flush had anything to do with it.....if MDs and others flush as per the above schedule, then we would have defo heard of other failures by now......4200 is 9 yrs old now....!!!!!!!



A Maseratisti {HUG} for your pain Miles!!!


P

Don't worry P, it's worthy of discussion and it's sorted now, so the scar will heal.

Your first point............. the result of this happening is an internal oil pressure bleed showing itself as low oil pressure on the gauge.

Your second point......... When did you last have your engine flushed? Do you know? Does anyone else know whether this has been done as part of the maintenance schedule? If not, there will be considerable build-up. Do you really want to dislodge all that crud in one go?

Oh and the transmitters are cr@p! I've had three on mine in the last three months and they varied by more that a bar of pressure. Even the one that's on the car now sticks a little during the warmup cycle.

In fact I might start a thread to gauge everyone's oil pressure readings at cold and warm. Would make interesting reading I think.

Cheers, Em.

 

[Parisien]

Oil pressure bleed means what....how does it affect the engine....

Must check to see if its noted on any of my invoices and ask Marios about it next week!!


P

 

[Parisien]

Only 1 flush mentioned by an indie who did it in 2008, none on the MDs invoices.


P

 

[Emtee]

Oil pressure bleed means what....how does it affect the engine....

Must check to see if its noted on any of my invoices and ask Marios about it next week!!


P

Sorry P, it's probably just my wording to describe something that's known more widely by another name.........

I am referring to oil bleed as an escape of oil under high pressure meant for delivery to the engine, directly across to oil under lower pressure as it returns from the engine. No oil leak out of the engine, but within the engine and / or its components, in this case the oil pump. Oil is allowed to effectively circulate, but completely miss out the engine it's meant to be lubricating.

The oil pump is made up of 4 chambers that are all driven off one shaft. The same assembly and shaft also turn the water pump, so five separate elements or chambers, all driven from one (jointed) shaft being driven from the drive chains.

For the purpose of this discussion we can ignore the water pump as it's not pertinent.

So 4 oil movement pumps. One is the delivery pump and it's under high pressure, probably 7 bar at the pump (if you've ever felt 7 bar of pressure you'll know it's pretty persistent!). It delivers the oil to all the engine oil feeds and galleries, beginning at the bottom and working it's way up.
Getting it in is one thing, but you need to get it back out again, so this is where the three scavenge pumps come in. They work under lower pressure as they have the benefit of gravity and the received pressure from the oil in pump. Their job is to deliver the oil back to the oil in pump (via other components) and so complete the cycle.

Now as mentioned above, The high pressure pump is just one of four chambers all sitting side by side, all being driven by one central shaft, all of which owe their independent integrity to the seal between a steel rotating pump and it's aluminium case. VERY fine tolerances as a fine layer of oil has to lubricate the two surfaces, but steel is hard and aluminium is soft. so if ANY hard particle gets onto those two faces........ well it's obvious which face will get scored. And that score will then become a perfect oil channel, and if the score is in the wrong place, it will circulate oil within the pump, but completely miss out the engine it's meant to be lubricating.

Sorry, that's all a bit rambling, but I hope it makes some degree of sense.

Em.

 

[Parisien]

.....so indeed just like the heart....four chambered organ............if you have a hole in the heart, less oxygenated blood is circulated around the body leading to a similar effect!!!

Thanks for that Miles.....made "prefect" sense....



P

 

[RonnieMack]

Thanks from me too Emtee, I've found your thread very interesting and informative.
Cheers
Ronnie

 

[Emtee]

Thanks from me too Emtee, I've found your thread very interesting and informative.
Cheers
Ronnie

I rather hijacked Stu's thread extolling the virtues of our cars, which I do wholeheartedly agree with. They're very solidly engineered engines, and failures are very rare. I was just unlucky in that I asked for my engine to be flushed not having considered the possible consequences. My one gripe is P's example of the maintenance schedule that lists oil flush as a service item. I would bet money that most of our cars have not had this done at each service, and in not doing so, it just increases the risk of damage when it is done.

Anyway I'm pleased you found it interesting Ronnie, though I hope you never need refer to it!

Happy motoring.

Em.

 

[Parisien]

So...in reality Miles....its.......

"To flush or not to flush...that is the question!?"

Not sure what to think now!

P

 

[Budapeststu]

Wow, my thread did indeed get hijacked but it was all in a good cause as I can see, Miles. I'll certainly ask when my next service comes around if flushing is included. I'm leaning towards not flushing and leaving anything lurking where it lies.