0W-40 Mobil1 or 5W-40 for Turbo Diesel Trucks?

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grant
.. which is a truck oil, with ACEA A7 rating adn Cummins, Detroit, Mack, etc certification.

hwoever it was recently pointed out to me that it calso carries the ACEA A3/B4 certs.

I expect that oil for diesel trucks would have more acids to deal with, and maybe more particulate matter to suspend, but, over all, woudl added suspension adn pH neutralizing capabilities be a bad thing? I dont believe so.

Grant

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MarcW
that of course is too small to be caught by the filter -- which given the overwhelming majority of these cars are not suffering from worn out engines is a solution looking for a problem -- it doesn't remove the most abrasive particulate matter in the oil and that is the aluminum oxide particles that flake off from. These alum. oxide particles are far more abrasive than iron particles.

And the factory filter doesn't have a pressure bypass. The pressure bypass is at the pump. All oil that is pumped to the clean side of the oil system is filtered oil.

BTW, in the 993 Porsche had two filters, the regular filter and a bypass filter. The bypass filter was there to remove even smaller particles than the regular filter. The concern was even the finer particles would be harmful to the zero-lash valve adjusters. Porsche found out the regular filter was quite up to the task of removing particles that could prove harmful to then engine and did away with the bypass filter for the 996 models and ever since.

Sincerely,

MarcW.

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San Rensho

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MarcW
that of course is too small to be caught by the filter -- which given the overwhelming majority of these cars are not suffering from worn out engines is a solution looking for a problem -- it doesn't remove the most abrasive particulate matter in the oil and that is the aluminum oxide particles that flake off from. These alum. oxide particles are far more abrasive than iron particles.

And the factory filter doesn't have a pressure bypass. The pressure bypass is at the pump. All oil that is pumped to the clean side of the oil system is filtered oil.

BTW, in the 993 Porsche had two filters, the regular filter and a bypass filter. The bypass filter was there to remove even smaller particles than the regular filter. The concern was even the finer particles would be harmful to the zero-lash valve adjusters. Porsche found out the regular filter was quite up to the task of removing particles that could prove harmful to then engine and did away with the bypass filter for the 996 models and ever since.

Sincerely,

MarcW.

I thought that the factory filter housing has a bypass, in case the filter gets catastrophically clogged (or have straight 40 wt oil in your car and are trying to start your car at 20 below.). While LN says a filter bypass is bad, its better to have full flow, my understanding is the factory filter bypass will never actuate under normal conditions.

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MarcW

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San Rensho

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MarcW
that of course is too small to be caught by the filter -- which given the overwhelming majority of these cars are not suffering from worn out engines is a solution looking for a problem -- it doesn't remove the most abrasive particulate matter in the oil and that is the aluminum oxide particles that flake off from. These alum. oxide particles are far more abrasive than iron particles.

And the factory filter doesn't have a pressure bypass. The pressure bypass is at the pump. All oil that is pumped to the clean side of the oil system is filtered oil.

BTW, in the 993 Porsche had two filters, the regular filter and a bypass filter. The bypass filter was there to remove even smaller particles than the regular filter. The concern was even the finer particles would be harmful to the zero-lash valve adjusters. Porsche found out the regular filter was quite up to the task of removing particles that could prove harmful to then engine and did away with the bypass filter for the 996 models and ever since.

Sincerely,

MarcW.

I thought that the factory filter housing has a bypass, in case the filter gets catastrophically clogged (or have straight 40 wt oil in your car and are trying to start your car at 20 below.). While LN says a filter bypass is bad, its better to have full flow, my understanding is the factory filter bypass will never actuate under normal conditions.

I spoke (I had a car in for service last week and spent an hour or so at the dealer in the service area) with a couple of Porsche techs and they told me the Boxster engine filter does not have a pressure relief/bypass.

In the past when I've done oil/filter changes I have looked at a filter and I do not see one nor do I see a pressure relief ball valve in the dirty high pressure area of the filter mounting area of the engine.

I'm told the pressure relief valve is in the pump or just after the pump and if the filter is not able to pass sufficient oil to keep the pressure down -- like at cold engine start or possibly with too high of engine revs with the engine is not fully up to temp -- the pressure relief valve of course provides relief by directing oil either back to the oil sump or to the intake side of the pump. My WAG is it probably the former for the latter route could have the pump heating the oil considerably.

The pressure relief could also come into play if the filter becomes clogged if left in service too long. I note that at least in the case of my 02 Boxster in the owners manual service schedule the oil changes were scheduled for 15K miles and the filter changes at 30K miles so there must be some considerable filter margin.

Compared to other filters for instance the one that my 06 GTO used the Boxster filter element is huge. The GTO's filter (spin-on) was about the size of the large coffee/tea mug. The actual filter element was of course smaller than the housing.

If a filter became clogged enough to restrict flow and pressure I would expect at hot idle to see oil pressure drop enough (below 1 bar for those cars that have a gage) to the point the low oil pressure or oil warning light would at least flash if not remain constantly lit.

An unknown though is the piston oil jets which are fed via an oil port that has a pressure relief. If the oil pressure drops too low this valve closes and the piston jets receive no oil This could work to alleviate (or mask) a very low oil pressure condition though the pistons might suffer from running hotter than normal (the oil jets says Porsche reduces piston temps by 50C).

Even with engine fully hot the oil pressure is between (based on my other car, not the Boxster -- it does not have the hardware to deliver anything other than a low oil pressure signal) 1.7 to 2.0 bar depending upon various factors. The oil pressure sensor is located quite a distance away from the oil pump. When I had my Boxster in for its VarioCam solenoid/actuator work the tech told me the oil pressure sensor is located at the camshaft cover about as far away from the oil pump as is feasible.

I have no worries about the capability of the stock oil filter. I wouldn't consider running it for 30K miles though so it gets changed every 5K mile oil change. Well, almost every 5K mile oil change. There have been a few times when I've been in a hurry and -- and the oil drains out still having some amber color to it (like after a 4-5K mile road trip with almost no stop/go driving) -- so I've not bothered to change the filter so a few times the filter has remained in service for 10K miles.

Sincerely,

MarcW.

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