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Dear All, Has anyone experience of this engine oil additive made by the excellent German company Liqui-Moly? They claim that it coats the engine internals and manages to reduce friction and thus improve fuel consumption. I was cynical until I made some research and so I have now added it to my van engine just to see how she performs.

Any comments, experiences and reactions please???

Thanks Simon
 

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I'm not a fan of adding stuff to oil. These days, good oils are very very good. They are designed to do what they do under widely varying conditions. So if you use the right oil for your engine, it will do the job. An additive pollutes the oil formulation, and we don't know what that will do to the original function of the oil. So, you might have an additive that does "coat" the metal, but it is in a carrier fluid which might negatively affect the performance of the motor oil. The active ingredient might make it harder for the oil to leave a film where it is needed, thus increasing wear during cold starts, or increasing piston wear.

I am not an oil engineer, nor an engine engineer, so this is just my opinion. Now back in my father's day in the 1930's, yeah there was a lot of room for improvement with oils and engines! Nowadays the tolerances are so tight that the oil is part of the design process, with film strength part of the consideration.

As far as economy gains, I doubt you can make any measurable improvements. Car manufacturers are under so much pressure to improve fuel economy that they take to all kinds of crazy shenanigans. If a simple oil additive would give them a fraction of a % gain, they would put it in.

Now if your motor is getting worn, additives might mask the symptoms for a while and delay major maintenance. That's a different animal altogether.
 

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I tried CeraTec. I don't have any long-term experience with it, but as with every new oil change, the engine felt like it revved easier. But that could just be in my head. Definitely no noticeable improvement in fuel consumption.

The problem with CeraTec and their other additive, MoS2 is that they both flush away when you change the oil. That means you need to keep adding them with oil changes. CeraTec is supposed to last a little longer because it's supposed to stick to the metal better, while the MoS2 definitely goes away with every oil change.

So I am now trying their new engine oil, MolyGen 5W-40 It is VW 502 and 505 compatible. The additives are already in the oil, so I don't need to buy additional additives. It's probably a combination of MoS2 and CeraTec additive. So far, for about 1000 miles, so good. Engine is smooth, revs free, and no evidence of oil burning (as some have complained). I haven't noticed any improvement in fuel consumption though.

It's a fun experiment, but I think the ultimate best thing to do is just changing the oil every 4 - 5000 miles. I have an oil extractor, so it's easy to change the oil often. I change the oil filter every other oil change (approx 8000 miles). The engine's has 91,000 plus miles now, and it still drives very well.
 

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Discussion Starter #4
Thanks guys very interesting and I kind of agree with you both. I am not looking for nor expecting snake oil miracles of course cos I am too old for that, I just seek to give my engine some extra care I guess. Thanks. More comments and or experience???
 
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