Why do so many Americans hate European trucks?

Of course you know how oil works, but my point was that many people (incl. professional mechanics) think that thicker oil is better, and that's not the case. What you would like to have is the thinnest oil possible, as long as metal-on-metal contact is prevented.

If you switch to 10W30, you should use the best oil you can get. Personally I always use the best oil I can get, and for my car that's Mobil 1 ESP 0W30. Over here Mobil has the reputation of having the best motor oils.

So when I look on the Mobil web site for engine oil for recent DAF MX engines, they advise Mobil Delvac 1™ LE 5W-30 as first choice, and Mobil Delvac XHP ESP 10W-40 as second choice.
The drain interval is between 30,000 km and 90,000 km with standard oil drain, and between 60,000 km and 150,000 km with the Extended Oil Drain Pack, which seems to be a 48 litre crankcase instead of the standard 40 litre crankcase. The Mobil Delvac 1™ LE 5W-30 oil has 3 stars for fuel efficiency, and the Mobil Delvac XHP ESP 10W-40 has 1 star. Ok, those are commercial ratings, but there will be some truth in there.

 

Better mpg is not an indication of better lubrication, or less engine wear, it is just an indication of friction over time. If mpg is better, the friction over most of the time is lower, but it does not mean that lubrication is better in all conditions.

The strength or thickness or reserve of the oil film determine if there is metal to metal contact or not, and depends on several parameters, among them:
relative speed of the 2 surfaces (rpm in case of crankshaft)
oil supply (oil pressure and flow)
oil viscosity
load on the oil film (torque)

Now with the lower viscosity oil you may gain a small percentage in friction in msot of the operation conditions which results in a small gain in mpg, but in other (more severe) conditions it may lead to lubrication problems.

An oil with higher viscosity will provide a thicker oil film between crank journal and bearing surface.

Below is an example of a racing engine, not a truck engine, but the effects of oil viscosity on oil film thickness will be similar:


Now think of a situation where engine speed is low, and torque is high (for example a driver who lugs the engine down too low, clumsy with the clutch and taking off in a tall gear or the automated transmission being too late/slow to make the gearshift)
This will result in a condition where the relative speed of the surfaces is low, load on the oil film is high, and oil flow and pressure are low (low oilpump rpm).

In these conditions a higher viscosity oil will have provide better lubrication and better protection against metal-metal contact, simply because of the thicker, more stable, oil film.
A too low viscosity oil may lead to damage, either in short term, or in the long run.

The time an engine spends in these borderline conditions will normally be very small, and overall you may see better mpg, but it may also result in shorter bearing life, or even lead to catastrofic failure.

 

"No need for pre-trip, it's mechanics duty to check the truck on daily basis".
4100 km one way from home (2500 miles).

 

How many days does this trip take to complete....??

 

Left home yesterday, today/tomorrow re-loading in Osnabruck (Germany), Tuesday he should arrive in Lisboa with first unloading place (out of 5), last place is 50km from Gibraltar.

Then 24h weekend break and reloading back with potatos.

So 6 days really, but it's not 1-1 load, but many more involved on the way.

 

Looks like a nice drive. Well I have never been to Spain, but I kind of like the music. Watch out, I here the ladies are insane there....

 

Yeah, everyone in company is jealous, I only found out that out yesterday that he is going to Portugal. If I would know that earlier, propably would go myself. It's windy and raining here for a week

 

Thanks for that. the distance & time taken is very similar to our Sydney to Perth Trip...

 

That’s similar to New York to Los Angeles. Probably take six days too with all the stops.