Last Updated on July 25, 2021 by Stewart

There are a lot of trim restorers available, some of which are temporary, and others being semi-permanent. In the case of Gtechniq C4, it is a semi-permanent trim restorer.

How To Use Gtechniq C4

As with any detailing regimen, the proper preparation is key when it comes to C4. It is recommended that it is left to cure for at least 12 hours without the trim becoming wet. This may pose an issue for some, and I have heard that those that did get it wet whilst it was still curing and the results were a bit patchy. If it is the case that you cannot be guaranteed to keep the trim dry, then I would recommend that you do not use C4 until such times as you can guarantee this.  

There are two situations to use C4 in. The first is on a brand new car where you want to protect the trim from premature fading. The second scenario is when the trim has started to fade and you would like to return it to its former glory.

After the car and the trim has been washed with a shampoo that does not contain any waxes or forms of protection and dried, the trim then needs to be prepared before applying C4. This can be done by using an all purpose cleaner. When I was applying C4, I opted to use Gtechniq W2. This is recommended by Gtechniq as the cleaner of choice. Given that this is recommended by Gtechniq, I thought it was the best way to apply the C4.

Gtechniq now recommend W5 Citrus APC. Regardless of the pre cleaner that you use, I like to use a soft detailing brush to really agitate the cleaner and ensure that the surface of the trim work is as clean as possible. For this, I would recommend the 26JNP Ultra Soft Brushes. They offer excellent cleaning power, without the worry of scratching the surrounding paintwork.

A small volume of C4 needs to be applied to the included applicator pads and massaged into the trim work. After doing so any residue should be buffed off using a short pile microfibre cloth. This will help to level the coating on the trim so that the coverage is as even as possible. Only a small volume of the coating is needed to cover the area. This is the case that less is more. After this, it’s just the case of letting the product dry and cure.  It really is a simple, straight forward product to apply to the trim.


When it was originally applied to my car, some parts of the trim where more faded than others. C4 worked wonders on turning the trim back to black, and it was a completely uniform finish. There were one or two spots that I accidentally over applied C4 to. However, it was really easy to remove this with a microfibre cloth.

What I really like about C4 though is that if I’m waxing the car or polishing the glass is that there is no white residue if it gets onto the trim. For anyone that has had the displeasure of getting wax onto plastic trim, it’s a real challenge to get it back off! Since C4 forms a chemical bond to the trim work and acts as a barrier to the elements, it means that there is no white residue should it be the case that you apply the wax by accident onto the trim.

Durability of C4 Trim Restorer

Gtechniq claim that C4 will last up to 24 months before it starts to fade. However, mine has been on for 35 months now and it is now just starting to show signs of the coating starting to degrade. It’s important to note that this coating has been through several harsh winters, as well as sitting outside in direct sunlight in the summer and in an area that is subjected to a large amount of fallout from a nearby steel melting plant. This would have caused other trim coatings to degrade rapidly, but this is not the case with C4. Of course, the duration of the C4 is dependent on several things.

The first is how well the surface is prepped before applying it. If the trim has not been well prepared, then this will have an impact on how well the C4 adheres to and makes a bond with the trim. The other factor is the condition of the trim before the C4 was applied. The fact that it’s lasted over a year longer than advertised is a huge bonus.

The last factor which will influence the durability of the C4 is how often the car is washed. If it is the case that the car isn’t washed for months, then this could have an impact on the lifespan of the coating. Likewise, if highly acidic or highly alkaline shampoos are used, this could impact the durability of this coating.

26JPN Ultra-Soft Detail Brushes - Set of 2 Ultra Soft Brushes, Car Detailing Brush, Motorcycle Detailing Brushes, Soft Brushes, Wheel Brushes, Interior, Emblems, Interior, Exterior, Air Vents
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Gtechniq W5 All Purpose Cleaner - Car Degreaser Spray for Oil, Grease and Stain Remover. Suitable for Most Surfaces and Car Wheel Cleaner, 100% Biodegradable Car Cleaning Products. 500ml
  • HEAVY DUTY CAR DEGREASER - unique citrus based formula completely removes tough stains caused by oil and grease, it doesn't just clean, but breaks the bond between the grime and the surface

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Gtechniq C4 Permanent Trim Restorer for Car and Vehicle Trim, Revitalises Tired, Faded, Discoloured Plastic and Rubber, Easy to Apply - 15ml (Sufficient for 1 Small-Medium Car)
  • RESTORES TRIM LIKE NEW - bring old, tired plastic or rubber back to life, with an invisible, exceptionally thin, coating that revitalises the colour, look and feel of all car trim, and protects from rain and UV

Last update on 2024-06-13 As an Amazon Associate I earn from qualifying purchases.

  • Ease of Application
  • Results
  • Durability


Gtechniq C4 Trim Restorer is a fantastic solution to cars which contain a lot of plastic trim. When applied properly, it last for years and makes the car look great. Highly recommended!



Really easy to apply

A cost effective, long term solution

Makes faded trim look like brand new



Needs to be dry for 12 hours in order to let it cure