I put them in an Opel Astra H 1400 instead of its "bad" original GM 10/40.
No difference at all..
I wonder about all the so many good reviews..
Either this is just a simple oil, or GM's are just fine and people can badmouth them all they want...

Very high-quality oil at a very good price. I put it in a Lancia Y 1.1 8V from '96, for which it no longer makes sense to use the well-known recommended Seleni@ oils by the company, which I still consider to be clearly better. The engine sounds nice and doesn't struggle to start. The result of how well the engine works with it will, of course, be seen at the next oil change.

As soon as I put it in along with a filter change, the engine stopped growling like a beast. I have a Nissan MICRA, the K12 model from 2003. Incredible oil, at idle you can't hear it at all, and doing a test on the car where with previous oils it would growl at 120 kilometers, now I hear nothing—normal, like all cars. So buy it without fear, and the price is unbelievable when in the Heraklion region I couldn't find it for less than 60 euros for four liters!!!!!!!!!!

Excellent oil for years now, tested in races and demanding cars. And the shop where I bought it is very good, excellent fast service and good prices.

I recently changed my car's oil to Castrol Magnatec and I can say that the difference is immediate. I noticed that the engine runs smoother and quieter. It is truly top-notch in protection and for this price, it's worth every euro!

I prefer it and buy it often because it burns the car... Unfortunately. My mechanic also recommended it to me, Toyota Aygo 2010

I had oil in the M50b25 vanos engine of poor quality, vadol, do not buy it even for a gas engine. I was losing oil from the sump. And probably it was burning it. I used 5w30 and then put in this 5w40, 1.5 liters of Castrol, and I no longer lose any oil at all. It doesn't burn oil; it's as if I have 5w35 in there. Normally, I should change all the oil, but since it’s not burnt and I was topping it off, it’s new. Logically, I will stick with Castrol or switch to Liqui Moly. In an Audi A4, also 20vt, it is the best there is, just like the same brand I use in BMW F30.

After the mandatory service of the Skoda, for the next 16 years I use the magnatek 10/40, the engine runs like a clock.

Good oil, I have tried many in general. I have a Fiat from the '20s as you can understand. I can say that this is one of the very good oils in terms of price. Better than Motul. Not on par with Selenia and maybe Total.

Good oil for an old Getz 1.3. The engine accepts it well and sounds quieter compared to others. The other Castrol oil is also good (supposedly cleans the engine). It takes a little time to warm up and I have noticed faster warming up (and quieter, but let's not mention that here).

I would buy both Castrol oils again. As for durability, I don't know personally because I change the oil in my Getz at 8,000 km with rural driving, not at the 15,000 km that the manufacturer recommends. It's good up to 8k, it maintains its properties.

P.S. If your engine burns a little oil, this doesn't change. And with this oil, it will burn a little (maybe a little less) but it is good oil, the engine doesn't sound like with others.

One of the best lubricants. I used it on a ten-year-old car that used to overheat a bit, and with this, it doesn't overheat at all.

In my Honda Civic 1991, I used Castrol Semi-Synthetic Magnatec 10W-40 A3/B4 4lt and a new filter, of course. The engine runs so smoothly that I didn't expect it. For now, it's working very well, but we'll see in the future. We all know that Castrol is a reliable brand.

I put them in an Alfa 156 with a naturally aspirated twin spark engine after repairing the head gasket because they are much more affordable than the expensive synthetic Italian oils that I used for years, and also because they have various chemicals that clean the engine. Basically, I used them because of the head gasket repair with the intention of changing them after a couple thousand kilometers, doing their job, which is to clean the engine, because you never know what can arise in the engine from such serious repairs. The result? Yes, they are good. I don't know in the long run if I need to top up the oil (with the Italian ones, I only topped up in extreme situations when the car was running in the red). The engine is quiet, no noises are heard, the idle is normal, the temperatures are as they should be, no white smoke comes out of the exhaust, in other words, what I mean by this is that they fit well in the rings, valves, and oil pump. The result? They are very good oils.

Mitsubishi Carisma 1300cc 16v. I have used it many times and everything is good. However, when I went on the Attiki Odos highway the last time on a trip and I pushed it to 160-180 km/h with 5000rpm/min for about an hour, it consumed about half a liter of fuel. The engine is excellent and has never had any issues from one oil change to another. On a previous trip with a different brand of oil (Liqui Moly) and traveling at 140-150 km/h, it didn't consume a gram.

I change oils every December, around 6,000km. I used this specific one in a Yaris 1.3 (2sz-fe) and it has burned about 2mm from the oil dipstick. (Before, I used the Aral Blue and there was no problem.)

It is an oil, with very good viscosity for most engines and is aimed at forgetful drivers who change oil every 11-12 thousand km IF they remember. I have been using it since the first year it came out in the Greek market because my engine (Nissan Almera sedan '96) was making "strange" noises during gear changes without any damage being detected in the gearbox by 5-6 different workshops. Immediately after replacing the old oil, the car returned to normal. During oil changes (at 7-8 thousand km), it always comes out clean, does not burn, and even in freezing temperatures, without preheating, the engine runs smoothly as if it had been preheated for 10 minutes. Incredible product. I highly recommend it. "Dog" oil for "dog" engines.

In the Fiat Punto 1.2 16v, it had good behavior indeed in terms of noise and steering, but it burned about 300ml in 10,000km. Another oil (Lidl W5 10w40) doesn't burn a drop and has almost the same behavior. I would probably say it's overrated

Excellent value for money. It easily lasts for 5 or even 7,500 kilometers. I changed it to try a cheaper and full synthetic oil from another manufacturer and I probably won't go back even though I had no complaints.

Many say it's the best, but for me, it's not. Maybe it's true that there are schemers who tamper with the product. I put it in my Fabia 1200 and it made strange noises. I threw it away after 2,000 km. I won't put it in my car again

Very nice lubricant and at an affordable price. In an old car, the engine really works smoothly and doesn't burn much compared to other lubricants I used in the past. I highly recommend it!

Amazing oil, I recommend it. It reduced the engine noise and no longer burns oil. I have a Yaris 998 2009 model!

I put this specific one in a seat ibiza 6l (2003) with 189000 kilometers and the car feels more relaxed and produces greater power (it is good to mention that the previous one was completely black, so this may have some relation)

Very good oil, compared to others it remains clean for more kilometers, plus I don't know if it's just me but it calms the engine, its price is very good for what it offers

Very good oil with a small objection, under pressure it bites a little more around 500ml at 10,000 changes. In contrast to the professional magnatec which has not burned yet at 8,000 kilometers and under pressure the car. I will come back as soon as the change kilometers are completed

2020: I bought it because the mechanic told me that the engine is old, it has tolerances, etc., and I should use semi-synthetic oil. I haven't tried it yet "at high RPMs" as they say, but at some point I will.
In the first few kilometers, I heard the engine better, but this may be due to the fact that the previous oils had a lot of kilometers on them, especially in the city.

2021: I tried it a few times "at high RPMs" with 2nd, 3rd, and 4th gear on the highway, unfortunately the steering is not as smooth as with full synthetic oils. My car is a stage A modified, so for an everyday driver who occasionally takes a calm trip, it is a good choice.
Note: After 5000 km in the city, it started emitting smoke from the back and took longer to warm up in the winter, which is not a good sign (fuel consumption also increased), so I decided to change them.

This particular oil, which was placed in a Hyundai car of the Getz model, immediately stopped the engine from burning oil. It is truly unbelievable and I am sharing this publicly for those who doubt Castrol. It must truly have incredible ingredients to stop the engine from burning oil after five years.

Tip for every buyer: only buy Castrol. All others are second and third in the category, with varying prices of at most 5-10 euros. The oil is worth it as its ingredients protect the engine in the long run.

We just need to be careful where we buy it from, as there are also recycled Castrol oils that destroy engines.

In an MG 25 years old now, the tappets were making a lot of noise & none of the various additives I used helped. For the past 7 years since I started using this particular oil, the annoying noise stopped immediately & never came back, regardless of ambient/machine temperature.

With the purchase I had made of a car, it sounded as if it was running on diesel. As soon as I put this oil in, the engine smoothed out and the noise was no longer heard