Thicker Oil

[GQAndrew]

I know that most people state that you should only use a 15W40 with TD42's but I have noticed that over these warmer months in perth, my oil consumption is noticeable (about 1 - 1.5L / 5000kms), and the pressure when idle and hot is dropping to only just above the manufacturer min spec.

I was considering using the HPR Diesel 20W60, but numerous people state that it is too thick and wont give enough protection. Penrite now have a 15W50, and I am considering giving this a go. anyone used this one yet, would the 50 retain more pressure than the 40 when hot.

cheers

[Adsman]

How many km has the motor done?

Using a 20W60 will take away alot of lubrication from the top end - especially valve stems.

While using a thicker oil your oil pressure will increase but it will also cause more damage to your motor.

It seems that I need to explain this more, by the responses.

As I already said using a thicker oil WILL CAUSE MORE DAMAGE TO YOUR MOTOR!! The old car sales man trick to sell old shit box cars was to use a straight 50 grade oil. Sure they don't blow smoke or burn oil but they also wont last till the end of the week either.

I don't know what oil you are using but the best oil for that vehicle is a 15W40. Brands of oil are different!!

Valvoline and BP are well known for increasing oil consumption. Good oils if used in vehicles from new but no good if you add them to an older vehicle.

Semi-synthetics and Full-synthetic oil is also well known for making a vehicle use oil. When they reach high temperatures or run at constant speeds they will attribute to bore glazing in a motor. Don't stress glazing can be fixed easily if you know how.

I recommend the use of a mineral based oil. Mobil Delvac MX or Caltex RX Super or Castrol 500 are all good oils. Mobil oil is a bit more basic than the other oils, therefore it will cope with more sulphur getting in the sump oil. (Sulphur naturally bypasses the piston rings under compression)

[bazzle]

Thinner oil is not necessary bad. It flows past bearings quicker removing the heat that causes the wear (friction). Good quality ones dont shear.

bazzle

[rick130]

Semi-synthetics and Full-synthetic oil is also well known for making a vehicle use oil. When they reach high temperatures or run at constant speeds they will attribute to bore glazing in a motor.

Wrong.

A good synthetic like Mobil Delvac 1 will reduce or eliminate the chances of bore glazing. Bore glazing is caused by engines running hard before they get to operating temperature, idling too long, etc.
The detergents/dispersant's in the additive package in the oil is what determines whether the soot that causes the glazing is suspended or deposited, not the base oil. Full synthetics are also far less volatile than a straight mineral oil, meaning they don't flash off as readily in the ring area, and generally have superior deposit control in high temperature spots like the turbo bearings.

Caltex Delo 400, Castrol RX Super, Mobil Delvac MX Super , Fuchs Titan Ultralube have very robust additive packages and are excellent oils. The additive package, as well as the operator is what what reduces/eliminates bore glazing, not the fact they are mineral oils (although Delvac MX Super is now a semi-synth 10w-40)

A bloke I know runs his entire interstate fleet on Delvac 1 in Detroit's, and they are getting virtually no wear over the 700 000-1 000 000km life of their rigs. The mandatory valvetrain adjustments at 250 000km are now not needed. They recently stripped a million km engine and the unit basically measured up within new tolerances with no sludging or wear where these engines are prone to. These engines use a 100 000km oil/filter drain period, using Mann Hummel centrifugal by pass filters and Donaldson ELF full flows and the oil is regularly tested.

Used oil analysis has shown the full synthetic Delvac 1 to be superior to RX Super in wear and long term cost with far less maintenance/breakdowns. (RX Super's maximum drain period was 30 000km, then it was spent)
This bloke bloke runs full synthetic oils, including the gear boxes and diffs (Mobil or Castrol, depending on application) because he's in front big time on a straight cost analysis over the life of a vehicle. If they caused the problems you've attributed to them, he wouldn't be using them.

What's with the sulphur comment ? It's been reduced dramatically. BP's diesel is under 50ppm, and the others will be soon if they aren't already.

As to the original post, I agree with Adsman that a 15w-40 would be a lot better, and that a heavier oil could be detrimental.

BTW, did any of you know that on new Nissan diesels, an oil with a more modern spec than CF-4 (a spec that dates from 1990) will void the warranty ?
True.
Nissan claim that the more modern dispersant packages up to and including the latest CI-4 + keep too much soot in suspension and it prematurely wears out high load surfaces such as the camshaft. This has been thoroughly disproved by the oil manufacturers with testing in their own fleets, but Nissan wont budge. They also refuse to acknowledge multi rated oils, including JASO and Global DHD 1 spec oils that carry newer certifications as well as CF/CF-4.

Rick.

[Adsman]

Sorry Rick I should qualify what I said earlier my wording is not very good.

True
Synthetic Oils are good at reducing wear and tear on motors.
What I should have said was "when motors are burning oil synthetic oils are well known as the cause."

My comments were made ONLY FOR MOTORS THAT ARE USING OIL.

Part of my job is consulting with companies about oils and effective maintaince procedures. Many times I have seen motors with both low and high milage burning oil and by swapping the oil from synthetic to mineral base we have stopped them from burning oil. Once again this was only said with reference to motors burning oil.

If you know or have any further ideas please let us know.

[Adsman]

Nissan claim that the more modern dispersant packages up to and including the latest CI-4 + keep too much soot in suspension and it prematurely wears out high load surfaces such as the camshaft. This has been thoroughly disproved by the oil manufacturers with testing in their own fleets, but Nissan wont budge. They also refuse to acknowledge multi rated oils, including JASO and Global DHD 1 spec oils that carry newer certifications as well as CF/CF-4.

Rick.[/quote]

This is true according to numerous report I have seen. There is also a lot of debate about the use of synthetic oils as they also hold alot soot and contaminants in suspension. They believe that this many be why an older motor SWAPPED FROM MINERAL GRADE OIL TO SYNTHETIC GRADE OIL can sometimes have problems. These problems include scoring of the cam, failure of cam shaft bearing, failure of crank bearings expecially front and rear and excessive valve guide wear. The automotive engineers we consult with took some time to develop this conclusion. It seems that the mineral oils drop the contaminants to the sump better. Many head are scratched as to why synthetic cant do the same.

BUT ON THE OTHER HAND I HAVE ALSO SEEN MANY REPORTS THAT SHOW - Testing on new motors permanently ran on full-synthetic oil seems good. Fewer failures and better engine life with only a few exceptions these seem to follow after overheating or loss of oil pressure, etc. Lets hope they can develop synthetic some more so that they save everyone $$