Mixing Engine Oil

[Bling]

No point flushing a rebuilt engine anyways, not like there will be much build up.

[Heylin]

The additives sound like snake oil to me.

Trust me alot of them are, but I used to sell Proma PT5 and MBL8 and also demonstrate the products.

In regards to PT5 If you burn a teaspoon of it theres a good 2-3 mls of light grade top oil (upper cylinder lubricant) per teaspoon. So its more than just an injector \ fuel system cleaner, and at $2 to treat a tank of gas, even if it saves you half of the minimum fuel savings of 3% its only costing you $15 per bottle.

I was saving around 3 - 5 % while using PT5, I graphed my consumption for 2 years and whenever the PT5 was missed the consumption shot up.

Now the MBl8 is even more amazing, this stuff is so slippery I could apply my full 85KG weight onto the torque arm of a friction brake test machine and it would not stop the wheels from turning, even once the surfaces were wiped clean.

Basically this = cold start up protection and less friction, dry surfaces seeminly devoid of oil remain slippery with MBL8.

The other major feature is the plating action of copper and lead particles suspended in the additive (MBL stands for metal based lubricant).

I havent seen it with my own eyes but a pitted metal surface of a cylinder wall under microscope is made smooth after running MBL8 for 5000 or so Kms. The idea is that the copper and lead being soft and mallable have a plating action and are pushed into the pitted areas.

Anyway I attribute my long engine life to MBL8, mabey I would have got upto 219,000 kms without it mabey not, but by my calculation its cost about $144 in MBL8 over 6 years of ownership and 102,000 kms of driving. Good investment I say.

Did I mention the drained oil makes great lubricant for bike chains, hinges, locks and more.

[l1ttle_d3vil]

I have been trained by Valvoline and told

DO NOT MIX OILS IN ANY WAY.

is this only when mixing different grades (5w30 with 15w40) and/or types (semi with fully synthetic)?
i've got a few leftover bottles - all 15w40 - just different brands.

still not advisable?