I would say that if your car has a D.P.F. you may be best off changing the oil for the ones specifically recommended for these engines. These oils are low ash to avoid clogging DPF. Total/Elf are usually specified, but, if you can find the equivalent spec it should be ok. Good luck.

Well AJS2 i think you are confused about tempertures and high and low oil pressure!!!!!!

Oil is thicker when cold which causes higher oil pressure but possible lack of lubrication on start up when the oil is slow to circulate.high temp thins the oil out and wear is most likley to take place if the oil exceeds its temp range and the effectiveness of the oil is reduced.

High oil pressure on a cold engine can cause hydraulic lifters to "jack up" and decompress the engine. The oil pressure is controlled by an oil pressure relief valve but these can only cope within a certain range so adding an adative on a hiher grade of oil would make the oil very thick when cold causing more resistance in the engine straining the starter and possibly exceeding the oil pressure range when cold.

"Ignore the incorrect comments about it!" and then boggles goes on to say " I would consider changing the oil before tempertures drop !

Damage is unlikley yes, upping the grade of oil will do no harm especially on a worn engine but economey can be effected but the Oil addative, over and above whet the oil manufactures already use WILL make the oil thicker when cold.

The worse risk is, and does happen is shearing the oil pump drive when the engine is cold due to excess load! and on the epycyclic type pumps they are not uncommon to crack a gear. Obviously these are the worse senarios and infact some years ago some cars used to be prone to blowing oil filters actually off their housings when too thick an oil was used or addative.

Boggles I suggest you make sure you are armed with an ammeter with a 900 amp range and take a starter load test on a car at 0 degrees then add some oil addative and then take another start test reading at 0 degrees the following day and you will be shocked at the increase in starter current drain!!!!! always best to know your facts before you make contrdictory remarks!