Both lubricants here are fully synthetic oils developed for both gasoline and diesel engines. Here GTX specializes in cleaning the sludge and reducing its built-up.
And the Magnatec focuses on reducing the wear of the engine especially in the critical engine warmup stage where 75% of the wear occurs. We are going to analyze these oils here like never before.
GTX cleaning property is made possible by its double action formula and synthetic technology, providing 1.4 times better cleanliness than other oils of the same category.
And as for the Castrol Magnatec, the molecules of this oil stick with the metal surfaces even when the engine stops and the oil returns to the sump.
Hence the name Magnatec as they act like magnets, sticking with the engine parts and providing lubrication at the key moments when the engine is starting and warming up.
Lets have a quick look at these oils first with the help of a table.
Table of Contents
Castrol GTX and Magnatec
| Specifications | Castrol GTX Ultraclean | Castrol Magnatec |
| Oil Type | Fully Synthetic | Fully Synthetic |
| Engine Type | Both Diesel/Gasoline | Both Diesel/Gasoline |
| Available viscosity grades | 0W-20, 5W-20, 5W-30 | 5W-30, 5W-40, 10W-40 |
| ILSAC | GF-6 | GF-6 |
| API | CF/SP/SN/SN Plus | SP/SN/CF |
| Oil change frequency (Kms) | 16000-24000 | 16000-24000 |
| Additives | Anti-wear, Detergents, Dispersants, Anti-foaming agents | Friction modifiers, Anti-wear, Detergents, Dispersants, Anti-foaming agents |
| ACEA | A3/B3 | A3/B4 |
Catalytic Converter Performance Comparison
The zinc and the phosphorus compounds present inside the oil pose a threat to the catalytic converter as when the oil burns the zinc and phosphorus ash remains which is poisonous for the catalytic converter and could hinder its performance.
The higher concentration of these compounds is found in Ultraclean whereas a lower concentration is found in Magnatec. Hence, making Magnatec the best choice in terms of the catalytic converter’s performance.
| Oils in Comparison (5W-30 Grade oil) | Zinc Concentration (ppm) | Phosphorus Concentration (ppm) |
| Castrol GTX Ultraclean | 808 | 707 |
| Castrol Magnatec | 695 | 672 |
Sludge Buildup Reduction Comparison
The sludge is formed inside the oil when it is oxidized and combines with dirt to form carbon which further reacts with other pollutants, producing a thick slurry liquid, tending to block the engine or reduce its performance.
Detergents are used to fight back against this sludge.
Ultraclean has a little higher amount of calcium present along with some amount of magnesium to fight against the sludge.
The higher concentration of calcium undoubtedly makes it the best oil for reducing sludge. Its silicon concentration is, however, a little lesser in comparison with other oil, denting its anti-foam ability.
Magnatec oil has a comparatively higher amount of sodium along with a lot of magnesium but the calcium concentration in this oil is lower than the other oil because it uses both magnesium and sodium as its main detergents, making it the second-best in line after the Ultraclean oil in terms of sludge reduction.
It also contains a higher amount of silicon to avoid foam production inside the oil.
| Oils in Comparison (5W-30 Grade oil) | Sodium Concentration (ppm) | Magnesium Concentration (ppm) | Calcium Concentration (ppm) | Silicon Concentration (ppm) |
| Castrol GTX Ultraclean | 1 | 21 | 2451 | 5 |
| Castrol Magnatec | 5 | 715 | 1063 | 7 |
Comparison of Oil Burn off Protection
The oil with the higher volatility will evaporate quickly, reaching its flashpoint at a lower temperature. Flashpoint is the temperature at which the low-pressure vapors of a liquid can easily be ignited with a spark. Higher flashpoint indicates better oil burn-off protection.
The flashpoints of both these oils are almost comparable with Magnatec having the higher flashpoint compared to Ultraclean, showing its higher oil burn-off protection.
Magnatec on the other hand has a slightly lower flash point, making it a comparatively higher volatile oil than its counterpart.
| Oils in Comparison (5W-30 Grade oil) | Flash Point Temperatures (Degrees Celsius) |
| Castrol GTX Ultraclean | 200 |
| Castrol Magnatec | 202 |
Comparison of Engine Wear off Protection
The motor oils use special compounds that form a film around the metal parts of the engine. This film reduces the friction between engine parts hence improving the wear and tear protection.
A higher number of anti-wear additives and friction modifiers further improves the oil’s wear protection characteristics.
Ultraclean has a lower amount of these antiwear additives in comparison to the other oil. Thus, its anti-wear performance is lower in comparison.
Magnatec has a respectable amount of antiwear additives along with some amount of titanium compound which forms a nanolayer with the vulnerable parts of the engine, providing the best wear protection to the engine parts.
| Oils in Comparison (5W-30 Grade oil) | Zinc Concentration (ppm) | Phosphorus Concentration (ppm) | Boron Concentration (ppm) | Molybdenum Concentration (ppm) | Titanium Concentration (ppm) |
| Castrol GTX Ultraclean | 808 | 707 | 198 | 84 | 0 |
| Castrol Magnatec | 695 | 672 | 197 | 60 | 30 |
Viscosity Comparison
At a medium temperature of forty degree, Celsius, Ultraclean performs the best as it has the higher kinematic viscosity while the Magnatec has a little lower kinematic viscosity.
As the temperature increases up to a hundred degree, Celsius, the Ultraclean leads with a little higher kinematic viscosity even though its Viscosity Index is lower. Whereas the kinematic viscosity of Magnetec is lower with a little better viscosity index than Ultraclean.
In cold winter weather, the performance of Magnatec is found to be better as its pour point (free flow) temperature is lower. Whereas the Ultraclean has a slightly higher pour point temperature than other oil in comparison, making it worst in winter weather.
| Oils in Comparison (5W-30 Grade oil) | Kinematic Viscosity @ 40 o C (cSt) | Kinematic Viscosity @ 100 o C (cSt) | Viscosity index (VI) | Pour point (Degrees Celsius) |
| Castrol GTX Ultraclean | 61 | 11.25 | 148 | -38 |
| Castrol Magnatec | 60.25 | 10.25 | 155 | -42 |
Oil Change Frequency Comparison
The Total Base Number of the oil is the measure of base additives available inside that oil for neutralizing the acids formed during the combustion process. A higher number of TBN allows the oil to be used for a longer duration of time.
The TBN of Ultraclean is higher, allowing an oil change interval of 16000 to 24000 kilometers. The Magnatec has the same interval of 16000 to 24000 kilometers even with a lower TBN.
| Oils in Comparison (5W-30 Grade oil) | TBN (Total Base Number) mg/g KOH |
| Castrol GTX Ultraclean | 8.26 |
| Castrol Magnatec | 7.1 |
To Conclude
- Ultraclean, and Magnatec are both fully Synthetic oils.
- The catalytic converter performance of Magnatec is better.
- Detergents are strongest in Ultraclean compared to its competitor.
- Oil burn-off protection of Magnatec is higher than the Ultra due to its higher flashpoint.
- A higher concentration of anti-wear additives is found in Magnatec.
- Ultraclean performs better in both medium and high temperatures even with a lower viscosity index while Magnatec has a lower pour point temperature.
- TBN of Ultraclean is higher, providing longer oil change intervals.