Despite people saying to go thicker to reduce consumption...
What I've seen with people running very thick oil (20w50 and thicker) in more modern engines (1995-pres) is they seem to burn oil badly amongst having other internal problems, compared to those running thinner oils (xW20-30/40max)
I've seen a comment on here before regarding all cars burning ridiculous amounts of oil in Costa Rica where 20w50 is the thinnest oil readily available to most people apparently.
Same goes here I guess where most people do still believe thicker is better, especially after a couple hundred thousand KM! To the point that the local oil companies such as Nulon and Penrite still make 40w70 (!!!) While they both also make 20 weights and Penrite even make a 0W16.
Now the people I speak to running the correct grade oils, usually between 5w30 and 15w40 in most local cars with their larger engines (4.0 I6 and 5.0 V8 in the Falcon, 3.8 Buick V6 and 5.7/6.0 LS V8s in Holdens) seem to burn no or at least minimal oil between service intervals, yet the people that run 20w60-40w70 are topping it up with the nightmare inducing viscosities every week, even if they have less mileage on the engine!
I have seen an older UOA of an early 90s Falcon with just 30,000km on it's engine when it was near new running 40w70!! The iron number came back at around 480ppm!!! This indicates massive cylinder bore wear.
My last UOA on my Falcon running 10w30 for 8,000km returned an iron number of just 4ppm and all other metals were between 0-4, and burns no noticeable amount of oil between OCIs while being driven fairly hard at 250,000km.
I know a couple of people with very high mileage Falcons. One of them has a 2002 with a staggering 960,000km on it's original engine with all it's original internals. It has run 10w40 dino since new at 10-15k OCIs. The other I know had 790,000kms last time I knew and that thing has only ever run 10w30. Both engines still run perfect and don't require a top up in between OCIs, despite the notion over here that "oh you have over 150,000km on your car, here have some 20w50" "oh yours has 250,000km, here try this 40w70!" And I believe this ill advice is where excessive oil burners originate!
My guess is thinner oil can get past the rings and slightly line the cylinder walls and prevent wear and metal to metal contact, increasing the life of the engine and help retain compression.
Thick oil can't get past the rings and lubricate the bores, causing cylinder wear from metal to metal contact. Another confirmation of this is I've seen an engine that used 40w70 being rebuilt after the pistons and cylinders completely scorched from metal to metal contact!
I think there is a happy medium but 20-40 weights are good for 99.9% of engines.
I had to add 20w50 Maxlife to slow and engine leak about a month or two ago. It made my engine feel smooth but started slowly on colder mornings, sapped power and I lost nearly 100km per tank! I fixed the leak which turned out to be the timing chain tensioner that had unscrewed itself loose a bit so easy fix.. I changed back to 10w30 and it was even smoother still, which confirms to me it was the MoS2 I started adding since the 20w50, and not the oil being thicker that has made my engine feel and rev much smoother!
I would like people's opinions and experiences on this
What I've seen with people running very thick oil (20w50 and thicker) in more modern engines (1995-pres) is they seem to burn oil badly amongst having other internal problems, compared to those running thinner oils (xW20-30/40max)
I've seen a comment on here before regarding all cars burning ridiculous amounts of oil in Costa Rica where 20w50 is the thinnest oil readily available to most people apparently.
Same goes here I guess where most people do still believe thicker is better, especially after a couple hundred thousand KM! To the point that the local oil companies such as Nulon and Penrite still make 40w70 (!!!) While they both also make 20 weights and Penrite even make a 0W16.
Now the people I speak to running the correct grade oils, usually between 5w30 and 15w40 in most local cars with their larger engines (4.0 I6 and 5.0 V8 in the Falcon, 3.8 Buick V6 and 5.7/6.0 LS V8s in Holdens) seem to burn no or at least minimal oil between service intervals, yet the people that run 20w60-40w70 are topping it up with the nightmare inducing viscosities every week, even if they have less mileage on the engine!
I have seen an older UOA of an early 90s Falcon with just 30,000km on it's engine when it was near new running 40w70!! The iron number came back at around 480ppm!!! This indicates massive cylinder bore wear.
My last UOA on my Falcon running 10w30 for 8,000km returned an iron number of just 4ppm and all other metals were between 0-4, and burns no noticeable amount of oil between OCIs while being driven fairly hard at 250,000km.
I know a couple of people with very high mileage Falcons. One of them has a 2002 with a staggering 960,000km on it's original engine with all it's original internals. It has run 10w40 dino since new at 10-15k OCIs. The other I know had 790,000kms last time I knew and that thing has only ever run 10w30. Both engines still run perfect and don't require a top up in between OCIs, despite the notion over here that "oh you have over 150,000km on your car, here have some 20w50" "oh yours has 250,000km, here try this 40w70!" And I believe this ill advice is where excessive oil burners originate!
My guess is thinner oil can get past the rings and slightly line the cylinder walls and prevent wear and metal to metal contact, increasing the life of the engine and help retain compression.
Thick oil can't get past the rings and lubricate the bores, causing cylinder wear from metal to metal contact. Another confirmation of this is I've seen an engine that used 40w70 being rebuilt after the pistons and cylinders completely scorched from metal to metal contact!
I think there is a happy medium but 20-40 weights are good for 99.9% of engines.
I had to add 20w50 Maxlife to slow and engine leak about a month or two ago. It made my engine feel smooth but started slowly on colder mornings, sapped power and I lost nearly 100km per tank! I fixed the leak which turned out to be the timing chain tensioner that had unscrewed itself loose a bit so easy fix.. I changed back to 10w30 and it was even smoother still, which confirms to me it was the MoS2 I started adding since the 20w50, and not the oil being thicker that has made my engine feel and rev much smoother!
I would like people's opinions and experiences on this