changing synthetic oil brands
Thread Starter
5th Gear
Joined: May 2002
Posts: 5
Likes: 0
From: Oxford, England
changing synthetic oil brands
Hi
You may think this has been covered a zillion times, but I've searched/read many of the threads, but none seem to cover this particular question...
I currently run Shell Helix Ultra 10/40 synthetic in my 65000 mile 1982 930. This coming summer I want to switch to Mobil 1 15/50 (for the slightly thicker viscocity at both ends of the spectrum). So my query is as follows. I am assuming that as oil leaks/consumption are not currently a problem with the synthetic Shell oil, so they won't be with Mobil 1? Is this a fair assumption or will the engine start leaking like a colander?
You may think this has been covered a zillion times, but I've searched/read many of the threads, but none seem to cover this particular question...
I currently run Shell Helix Ultra 10/40 synthetic in my 65000 mile 1982 930. This coming summer I want to switch to Mobil 1 15/50 (for the slightly thicker viscocity at both ends of the spectrum). So my query is as follows. I am assuming that as oil leaks/consumption are not currently a problem with the synthetic Shell oil, so they won't be with Mobil 1? Is this a fair assumption or will the engine start leaking like a colander?
Intermediate
Joined: Jan 2004
Posts: 25
Likes: 0
From: Aberdeen, Scotland
Hi Toby
I run the same oil in my 87 Supersport and I am friendly with the head technician from my local OPC. He rates the Shell as a better oil and his advice was, that if no leakage was occuring at the moment, then you should not bother changing. An average oil change in a 911 takes @ 10 lts. But the tank size is 13 lts in total. Therefore if you change synthetic oils, 3No lts of the Shell would be left to mix with the new Mobil oil. A situation which he says is not the best.
I would stick with the Shell, I have used it on 944 & 911 for years.
I run the same oil in my 87 Supersport and I am friendly with the head technician from my local OPC. He rates the Shell as a better oil and his advice was, that if no leakage was occuring at the moment, then you should not bother changing. An average oil change in a 911 takes @ 10 lts. But the tank size is 13 lts in total. Therefore if you change synthetic oils, 3No lts of the Shell would be left to mix with the new Mobil oil. A situation which he says is not the best.
I would stick with the Shell, I have used it on 944 & 911 for years.
Intermediate
Joined: Jan 2004
Posts: 25
Likes: 0
From: Aberdeen, Scotland
Supersport is the UK version of the M491 option, which I believe you call 'Turbo-look'.
Also referred to as the SSE, or 3.2 Carrera SSE or 3.2 Carrera Supersport.
My car was also Porsche's press car when the model was released, featuring in a number of motoring magazine's in the UK in 1987. Copies of which I have.
Autocar took it to Rheim's, fantastic article!
Also referred to as the SSE, or 3.2 Carrera SSE or 3.2 Carrera Supersport.
My car was also Porsche's press car when the model was released, featuring in a number of motoring magazine's in the UK in 1987. Copies of which I have.
Autocar took it to Rheim's, fantastic article!
Burning Brakes
Joined: Nov 2002
Posts: 801
Likes: 6
From: United Kingdom
Toby,
Don't worry about changing the oil - you are planning to move to a "thicker" oil, problems have ocurred when going the other way. I also believe it is OK to switch oils even though some of the old oil stays in the secondary heat exchanger. I have moved from mineral to synthetic and back again without any problems. I was concerned about mixing but a careful check on engine oil condition indicated no problem. Dealers switch oil types without worrying, just based on the best deal from the oil companies.
PJC
Don't worry about changing the oil - you are planning to move to a "thicker" oil, problems have ocurred when going the other way. I also believe it is OK to switch oils even though some of the old oil stays in the secondary heat exchanger. I have moved from mineral to synthetic and back again without any problems. I was concerned about mixing but a careful check on engine oil condition indicated no problem. Dealers switch oil types without worrying, just based on the best deal from the oil companies.
PJC
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Joined: Dec 2001
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From: Manchester, NH
Toby,
Switching should not be a problem. It will take a few changes to completely cycle out the Shell, but the mixing is ok. I wouldn't worry about it.
Matt
Switching should not be a problem. It will take a few changes to completely cycle out the Shell, but the mixing is ok. I wouldn't worry about it.
Matt
