Oil Change?

[Andrew]

And then you will be hit with the "Oil Flush Treatment" scam.

[Clive Arthur]

<snipped>

Plagiarism abounds...

[Andrew]

Modern cars are designed to run much hotter than those made 30+ years ago. Such high temperatures cannot be withstood by mineral oil and hence the need for synthetic or semi-synthetic oils.

If your car needs synthetic oil then you must use it. If your doesn't need synthetic oil don't waste money (twice as expensive) on it.

[Jock]

That isn't what happened when I managed to forget to check the oil level in mine for the MOT and agreed to have it topped up in front of me. It came out of a 20l drum and there weren't a lot of those drums of engine oil.

And when you do it yourself, the operations selling the oil don't have 4 or 5l containers by car brand and model, just have about 10 different types, everythng from dinosaur oil to partly synthetic to fully synthetic and a variety of thickness grades and a few specialist oils like for diesel engines.

[Fredxx]

In the scheme of things the cost is small.

I used to skimp on cheap oils believing that it was best to change the oil and filter but now convinced that wear in engines was accelerated. Just my gut feeling. I now use Fully Synthetic oil without fail.

I also note that most service intervals are very much extended. One vehicle it's 20,000 or 2 years. 5-30W Fully Synthetic low ash oil is recommended.

[Steve Walker]

Funnily enough, my wife's 17 year old Matiz has just failed its MOT today - one of the failures being a corroded sump! It's the first time I've ever come across it and, by pure chance, it happened to be at the same time as this thread.

[Steve Walker]

Yes. I was used to thermostats opening at 82 to 87 °C and testing them in a pan of hot water. I wanted to test my current car's thermostat and found that it doesn't even start to open until 105 °C, so I'd need to use cooking oil or something similar, which is in short supply at the moment!

And if your car needs semi-synthetic oil, which is often little cheaper than fully-synthetic?

[Fredxx]

Never heard of that before, and after some googling it implies the sump is in imminent failure.

Major oil leaks are now a fail. I have been advised to jet wash the underneath. I took the under-tray off and gave everything a good clean. And of the course the under-tray.

[Andrew]

RTFM. The manufacturer knows what your engine needs.#

Using the wrong oil is a bad as running a car and doing a high mileage for 2 or 3 years without an oil change, as one of my neighbours does.

[Steve Walker]

The point is that, from what I have read before, for those designed for plain mineral oil not only is synthetic a waste, but it can actually be damaging, but for those requiring semi-synthetic, fully synthetic is usually fine and may allow longer between changes.

[Jock]

How does it sometimes damage the engine ?

I am not convinced that any engine does.