5w30 engine oil for a VT

[torch]

+ Just by the way, as bearings wear and clearances widen, the oil does flow faster, out of the wider clearances = loss of oil pressure. Might not be an advantage.

yes along with increased oil flow goes decreasing oil pressure, sometimes all that high oil pressure indicates is that the oil flow is being retarded, as when the oil too thick/cold, or not even happening at all, ie bypass valve being activated.

Its a fairly cheap exercis for engine manufactureres to put oil pressure sensor at the output of the oil pump to detect whether the oil has stopped flowing in the system. Deciding what is happening inside the engine just by the use of this one sensor is very limited.

Im fairly sure the vt specs for the v6 in the manual are 10W/30?

 

[graham7773]

Just looked in my copy of the GMH Service Information cd, this is a direct copy and paste from it.

2.1 ENGINE OIL VISCOSITY RECOMMENDATIONS

The grade of crankcase oil should be selected to give the best performance
under the climatic and driving conditions in the territory in which the vehicle is
operated. When the crankcase is drained and refilled, the crankcase oil should
be selected, not on the basis of the existing temperature at the time of the
change, but on the ambient temperature range anticipated for the period during
which the oil will be used. Use classification SG or SH viscosity grade 20W/50
for general use and high ambient temperatures. For prolonged usage in snow
areas, a viscosity grade of 15W/40 may assist starting.

 

[WogBoyz]

in my v6 i used to use nulon 10w40 and never had any problems, ran nice and smooth without any noises, it was driven hard sometimes and had 138 on the clock

 

[vxcalais_01]

Interestingly, visiting the Mobil, Shell, Castrol and Penrite australian oil sites, the overall recommended oil for the vt v6 was the 10W/30. Penrite also suggested up to xW/50 grade as their highest, but no 60 recommendation. The castrol site also listed its 5W30 syn as a recommendation, the original query in the thread. Overall oil companies are very guarded with their recommendations and dont want to be sued/taken if they provide misleading information, however, I do realise that perhaps they are covering themselves by just stating that is what the manufacturer says should be in it.

None of the sites tell us that if the motor has 150 000km+ on it that you must switch to a heavier oil, no one suggests that older engines that come with a 20w/50 recommendation should change to say a 25W/70 oil after 150000km. Why the contrast with the v6?

I could understand the advice that if the car is burning oil or showing low oil pressure, that a change is necessary, but otherwise, I dont see the logic.

The worst part about the recommendation system is that already these cars are 10 years old, and in 10 years time it will still incorrectly state 10w30. Talk to Holden, and you will know that it was revised. 5w40 is the minimum in Australia one should use on these cars.

If you call up Penrite and speak to Fiona if she still works there, she one of the chemists/engineers and if you ask her what Penrite Sin to use, they will recommend 5w60. I have spoken to Fuchs and they say 10w40. If your in Melbourne go to their plant in Sunshine and talk to them. Some people dont realise it is a general recommendation or a copy of what the manufacturer originally came out with.

 

[vxcalais_01]

I appreciate the point that the manufacturers specs are for when the engines are new, however, as I pointed out earlier we dont go putting 25W/70 oil into engines originally designed for 20W/50 engines after a 150000km unless there is something wrong with it, why the difference with the v6.

I also understand the bearing clearances will increase with wear, how exactly will using the original spec viscosity oil here cause problems, the oil will flow faster? is that a problem?

Oil flow is what lubricated an engine, not oil film, the oil needs to flow between the parts. This is also how it takes heat away etc. All being equal, the difference between the thin oils and the thick oils are at start up and in the high pressure engine parts during operation. Thinner oils flowing and reaching op temp quicker that the thicker one. The thicker one will have a higher shear resistance in the high pressure areas. Eventually as the oils get better, viscosity ranges will close or narrow in my opinion as they will be able to perform in a number of different situations. In a burning engine, thinner oil is more prone to burning away as it passes the rings easier and into the combustion chamber. In a leaking engine, believe it or not some thinner oils can be better.

 

[torch]

The worst part about the recommendation system is that already these cars are 10 years old, and in 10 years time it will still incorrectly state 10w30. Talk to Holden, and you will know that it was revised. 5w40 is the minimum in Australia one should use on these cars.
.

I've listened to the rhetoric about it being an older engine but so far no-one has addressed this:
None of the sites tell us that if the motor has 150 000km+ on it that you must switch to a heavier oil, no one suggests that older engines that come with a 20w/50 recommendation should change to say a 25W/70 oil after 150000km. Why the contrast with the v6?

Talk to Holden, and you will know that it was revised. 5w40 is the minimum in Australia one should use on these cars.
.

Perhaps Holden made a press release here? why havent they passed this "essential" info on to the major oil companies to adjust their recommendations on their australian websites, or why havent the oil companies indeed made it their business to pickup on this instead of recommending we put 5w/30 oil into Vts? Something is not ringing true here.

 

[Brett_jjj]

I've listened to the rhetoric about it being an older engine but so far no-one has addressed this:
None of the sites tell us that if the motor has 150 000km+ on it that you must switch to a heavier oil, no one suggests that older engines that come with a 20w/50 recommendation should change to say a 25W/70 oil after 150000km. Why the contrast with the v6?


Perhaps Holden made a press release here? why havent they passed this "essential" info on to the major oil companies to adjust their recommendations on their australian websites, or why havent the oil companies indeed made it their business to pickup on this instead of recommending we put 5w/30 oil into Vts? Something is not ringing true here.

Mate you can buy oils that are especially made by the oil companies for engines that have high wear/high kilometers/high oil consumption.Its usually way thicker than the recommended oil rating.Up around 30W-70 or thereabouts I think,Ive never really taken a lot of notice of the ratings of it etc.I wouldnt use it,Id just rebuild the engine if it were that worn out.But obviously its common knowledge that older engines can benefit from thicker oil ,or the oil companies wouldnt make it,or recommend using it,would they.

 

[torch]

Mate you can buy oils that are especially made by the oil companies for engines that have high wear/high kilometers/high oil consumption.Its usually way thicker than the recommended oil rating.Up around 30W-70 or thereabouts I think,Ive never really taken a lot of notice of the ratings of it etc.I wouldnt use it,Id just rebuild the engine if it were that worn out.But obviously its common knowledge that older engines can benefit from thicker oil ,or the oil companies wouldnt make it,or recommend using it,would they.

yes, i realise all that, but given how the general advice offered by several here is to change to a heavier oil becuase the car has done 100000km+, how is that addressing the question I posed:
None of the sites tell us that if the motor has 150 000km+ on it that you must switch to a heavier oil, no one suggests that older engines that come with a 20w/50 recommendation should change to say a 25W/70 oil after 150000km. Why the contrast with the v6?

 

[Irukanji]

Bump because of the good info in here.

Anyway, I'd say the type of oil you use doesn't really matter, so long as it does what you need it to. That said, something like 20W-50 is good for prolonged 100kph speeds(the same speed the Commodores and Falcons were designed for). More heat = less viscosity.(Its obvious when you start the bbq up and any old fats which have solidified will turn into a liquid and flow better as the temperature rises). If you have one of those VS's which overheat in traffic, you might want a heavier oil because of the higher temperatures(or get an electric water pump and a better radiator and solve the problem the hard way).

But really, so long as the car is moving and your cooling system is working, 20W-50 will work for anything you'd normally do. Or 10W-40(or 5W-30) if you live in the Alps/Blue Mountains during winter, because the speeds are lower but the starting temperatures are low or below freezing.

High second number for long distance highway driving(20W-50, 25W-70). Low second number for low temperature starting and average speeds(5W-30, 10W-40). Average first number and medium second number for city use(prolonged starting/stopping and above freezing starting temp)(15W-40, 20W-50).

Something like that, anyway.

 

[NeddyBear]

I'm so bloody confused when it comes to oils so I'm going back to 20W50 and give the 15W40 the flick. I'll give this a try for 10,000 kls and see if there's any difference.