I have used Prolong Oil Additive which I understand comes from the States in three of my other vehicles, namely a Mazda Pickup and 2 Volvo Estates
The Mazda stopped smoking and the performance was notably different
But !!!! I see in the 840 Manual that I am not to add any additives to the oil
Can anyone tell me why and if it willl do any damage if I did add Prolong to the BM
For further info on Prolong see
www.prolong.com
Thanks for your help
Chootspah