Best engine care products to care for an engine with high mileage?

[brandon_k_w]

Originally Posted by rubix777

synthetic oil in a high mileage motor is not recommended as it'll break down some of the carbon deposits that might be filling in the cracks. Running synthetic would break down those deposits thus giving a possibility for leaks.

Some brands make those oils specifically for High Mileage. Saying they contain additives which help seal cracks. Are those gimmicks also? I think Pennzoil makes a high mileage oil

[TechX]

I will never use those products again. I just makes sense that some can of oil cannot make your engine like new again. I once used engine restore in an old engine and it made the car smell like I was running 110 octane. I think they must but something in those cans that will just burn like high octane because they know you are going to burn some oil in an old engine. Maybe that is how you get the feeling of more power. I don'
t know really but I do think it is a scam. If you have an old engine just use thicker oil like 20-50 or something similar.

[SaabJohan]

Originally Posted by rubix777

synthetic oil in a high mileage motor is not recommended as it'll break down some of the carbon deposits that might be filling in the cracks. Running synthetic would break down those deposits thus giving a possibility for leaks.

Synthetics contains the same cleaning agents as mineral oils do, so there is really no difference.

Some synthetics can however follow the surface of a material better, which means that they can more easily can find their way out of the engine in bad seals, the seal problem is however not caused by the oil, it was already there. These properties does also make the synthetic a better lubricant.

[tercelboy]

Originally Posted by SaabJohan

There are a lot of tales of what will happend when you go from mineral to synthetic, there are no truth in these tales, at least not with modern synthetic oil.

Z-max is also just another "snake oil" product, any gains are just "imaginary". It is also not good for your engine.
http://www.ftc.gov/os/2001/02/speedwaycmp.pdf

Dammit! That was a waist of damn money. I guess I noticed something because i put it in with a new oil change. That sucks, thanks man.

[SUPERMANG]

Originally Posted by rubix777

synthetic oil in a high mileage motor is not recommended as it'll break down some of the carbon deposits that might be filling in the cracks. Running synthetic would break down those deposits thus giving a possibility for leaks.

I think this would apply to older engines rather than higher mileage engines. I would thik that a 4-5 year old engine with highway mileage would be relatively clean of any deposits like that. I'd run synthetics. My $.02.

[RandomTask]

The only additive I will stand by is that Restore stuff you can generally get at any auto store. I was running around 160-165 PSI in all my cylinders, ran that stuff for one oil change and gained 10 points on all cylinders. It also helped for quicker startups. I would recommend it for older engines. For newer ones, regular oil changes and don't beat the motor up all the time.

[clawhammer]

Also, do those fuel injector cleaners do anything, or are they a waste of money? Is there any better way of cleaning the fuel injectors?