Mr. Molly engine oil additive?

Warning sign #1... could be legit, could know something that he wants to get rid of the car ASAP. Hard to say; how do you read the guy?

If oil companies could improve lubricity by doing that, they would. They don't. It's snake-oil / placebo effect at best, suspicious at worst.

Well, the leak will be about 4 inches above the head gasket if it's coming from the valve cover. Getting it clean will actually help so you can see the source.

It's possible that he's just convinced that it helps and it does nothing. In either case, I can't see how a moly additive to the oil would mask anything of the nature of a head gasket problem. But since you raised that issue, what's the condition of the inside of the tailpipe? Black/sooty (ok), oily not so OK), or so on?

Dave Hinz

I have never used the additive (why should someone need it if using good oil to start with)

... if it is a mechanic selling it privately "as seen" I would walk away. You also say he sells used cars. Was this his own "private" car? Can check from the logs how long he has owned it? (a few years or a few weeks?)

The addtive sounds like graphite based (which I think is what mol(l)ycote grease is) and I would expect graphite to be used as an additive in a transmission or gearbox.

Why does someone buy a SAAB (not the most economical car around) and then wants to improve its economy by 1MPG.

Sorry, you have the doubt that there is some fishy smell about the car and that is why you are asking. I am only making sure you have even more doubt.

Sorry :-(

Charles

PS. Assuming I am correct that graphite is used in gearboxes ... it might be a far fetched case that it also has a knocking engine (main or small bearings) and the graphite is used to try and lower any noise.

I missed Dave's answer somehow and the particular point you make above.

Anything you do with an old (worn) engine will come down to two points. a. It is worn (as in worn pistons/rings valves etc) and some oil is leaking into the cylinders

b. it has damaged bearings.

In any case the idea would be to use thicker oil (eg. 20-50 SAE) in the hope that whilst demonstrating the car and the engine is cold and thus the oil a bit thicker you get less noise/less smoke.

Another trick is to use brand new oil (it is not expensive as it is the cheapest cr@p) but it is at its thickest ... maybe the graphite stuff can be used to simply dirty the oil. Black (used) oil with graphite would (should?) still look black!

Are you put off or not yet? Charles

To me it sounds like it contains molybdensilicide (MoS2), which I know is used as a lubricant.

More information about Molykote can be found at

/Bengt, SAAB 9-3 5d Sport Edition 2002

Molybdenum Disulphide!

Yes, you're right and I stand corrected.

/Bengt

Sorry as well, as it is Disulfide now of course.