Mixing oil
Author
Discussion

nrayner

Original Poster:

3,058 posts

312 months

Sunday 11th March 2007
quotequote all
Hello all, When last serviced my 97 993 was filled with Esso Ultron. Would it be a problem to top up with Mobil 1 ?

Pickled Piper

6,452 posts

265 months

Sunday 11th March 2007
quotequote all
No real problem for topping up.

pp

hutchingsp

68,027 posts

240 months

Sunday 11th March 2007
quotequote all
From a Porsche technical bulletin:

Miscibility
The engine oils approved by Porsche can be mixed to the extent that it is not necessary to flush the
engine when the oil is changed, or another type of oil is used. This holds true for mineral oils and syn-
thetic oils.
However, since every brand of oil has a specially adapted unique composition, the same oil should be
used for any topping up that might become necessary between oil change intervals, whenever possi-
ble.

I've no idea how true that may be, just stating what it says.

slippydiff

16,441 posts

253 months

Sunday 11th March 2007
quotequote all
I spoke to the technical department at Castrol a couple of years ago, as I was worried about mixing synthetic with semi synth or mineral.
They told me that by LAW all oils have to be compatible. That doesn't mean to say it's recommended you mix them, just that they can be without a problem.

warmfuzzies

4,375 posts

283 months

Sunday 11th March 2007
quotequote all
Aren't they part of the same Exxon group?

Oh, I've never overly worried, and have never had a problem it's the spec of oil that you use which is the important bit.

Kevin.

chickenskin

22 posts

240 months

Sunday 11th March 2007
quotequote all
Nope, Castrol is owned by BP.

warmfuzzies

4,375 posts

283 months

Sunday 11th March 2007
quotequote all
No....no no no.....Esso and Mobil, don't you read the OP's Q


K

nrayner

Original Poster:

3,058 posts

312 months

Tuesday 13th March 2007
quotequote all
Thanks all - I'll dollop some stuff in at the weekend.