old 944: to mineral oil or not to?
Discussion
When an engine gets old, it seems to be advisable to switch from synthetic oil to mineral oil. Is this true in the case of the 944?
I'm quite confused with this because the owner's manual says ALWAYS to use synthetic oil whereas some friend of mine already use mineral oil in his turbo...
I'm quite confused with this because the owner's manual says ALWAYS to use synthetic oil whereas some friend of mine already use mineral oil in his turbo...
IMHO Thom I cannot see where the justification is for changeing to mineral oil. Its the kind of advice I might give to greens 
Assuming huge oil consumption is not the probem then why change? If the engine is on its last legs and shoving blue smoke out then the cheapest oil posible for its last few hundred miles might make a saving. If the engine is OK then mineral oil will only breakdown and destroy the engine.
Cheers
John
Assuming huge oil consumption is not the probem then why change? If the engine is on its last legs and shoving blue smoke out then the cheapest oil posible for its last few hundred miles might make a saving. If the engine is OK then mineral oil will only breakdown and destroy the engine.
Cheers
John
Thom, if your mate is using mineral oil in his turbo, then please advise him that the blower will go bang at any time....mineral oil easily breaks down into base elements at extreme temperatures....like those you get on the blades inside a turbo. So the carbon deposits, the rotor goes out of balance and....bang ! New turbo please.
Synthetic should be used at all times with forced induction, particularly turbochargers. With regard to older engines, an oil with a viscosity rating of 0W/40 is not advisable for an older engine as it will most likely leak due to its very liquid nature at normal temperature (it runs like water). However, the big boys like Mobil 1 do sell a 15W/40 for older engines - it's labelled as much too.
Hope this helps.
GT
Synthetic should be used at all times with forced induction, particularly turbochargers. With regard to older engines, an oil with a viscosity rating of 0W/40 is not advisable for an older engine as it will most likely leak due to its very liquid nature at normal temperature (it runs like water). However, the big boys like Mobil 1 do sell a 15W/40 for older engines - it's labelled as much too.
Hope this helps.
GT
Cheers guys 
Greg, my car has been running on 0W40 for her first 60,000 miles (read since new) and was not showing any leaks when I switched to 5W50 (couldn't find 0W40 anymore).
Given that the engine is getting quite old, am I about to be the witness of leaks? 60,000 miles doesn't sound old for an engine, especially a Porsche one.
By the way when can one say that an engine is old?
>> Edited by thom on Tuesday 23 April 09:21
Greg, my car has been running on 0W40 for her first 60,000 miles (read since new) and was not showing any leaks when I switched to 5W50 (couldn't find 0W40 anymore).
Given that the engine is getting quite old, am I about to be the witness of leaks? 60,000 miles doesn't sound old for an engine, especially a Porsche one.
By the way when can one say that an engine is old?
>> Edited by thom on Tuesday 23 April 09:21
My 944 S2 has just done 100k and I run it on Monil 1 0 40 if I can get it. It did have an oil leak at 63 k and It got fixed. There is no reason for oil leaks in older engines except if seals are worn. If you use synthetic from new then the engine behaves like a new one for ages. I ran my Opel to 289k on 0 40. No leaks and no loss of performance, just a water soluble body forced me to change the car. IMO it is a myth about synthetics being prone to finding a way out of the engine. I have never experienced that. There is lots of bull talked about oil but basically synythetic is good in most engines. I did hear of a well known Rover V8 tuner claiming synthetic caused a brand new 4 ltr to blow (Couldn't possibly have been his crap engine building technique though, must have been the oil, yeh)
(Couldn't possibly have been his crap engine building technique though, must have been the oil, yeh) Thom, there is no harm running 5W50 and you shouldn't get leaks.
The problems occur when people run an engine for 60k miles on shitty oil, then chuck in 0W40 Mobil 1. This is a thinner oil, and also has detergents to clean the engine... the carbon deposits that have built up and act as a kind of seal get removed gradually by the detergent, then the super thin oil gets through the gap causing smoke.
Turbo cars should always run with at least a 15W50 rated oil, fully synth as Greg pointed out. If the oil is too thin the turbo bearings may wear as they 'float' on the oil, and need it to be relatively thick.
The problems occur when people run an engine for 60k miles on shitty oil, then chuck in 0W40 Mobil 1. This is a thinner oil, and also has detergents to clean the engine... the carbon deposits that have built up and act as a kind of seal get removed gradually by the detergent, then the super thin oil gets through the gap causing smoke.
Turbo cars should always run with at least a 15W50 rated oil, fully synth as Greg pointed out. If the oil is too thin the turbo bearings may wear as they 'float' on the oil, and need it to be relatively thick.
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