Pulling a question from the archives for today’s article, we found an interesting message we got from @linkypinky87 on Instagram.

LinkyPinky Said:

“I had this in my fuel, weird black sludge down the bottom. Even the 98 petrol looks a little off compared to straight 98. Ended up draining as much as possible, doing 200ml of Fuel Doctor, and saved another 50ml for next tank. Instantly better!”

@pinkylinky87's Dirty Fuel

Our Reply:

“Great to hear you got that snot out, Pinky, always best to physically remove what you can. However, I can’t stress enough to follow the instructions with 1 x 500ml (up to 100L tank) shock treatment for each 100,000 kilometres the vehicle has done. Fuel Doctor will work best at this rate and clean the gunk out that didn’t come out with the flush. It’s even safe to double that to 1 litre per shock treatment. This is really important because that gunge will stick to the insides of your tank and lines etc.

The higher ratio for shock treatments is designed to clear that out. Also, it’s a great idea to change your fuel filters when you go back to the 1ml per litre maintenance ratio. Then keep up that 1ml per litre of fuel added to the tank every time you top up to stop the grunge building back up.”

We never heard back from LinkyPinky so we’re betting on a great outcome, and luckily for them on this occasion, with very little Fuel Doctor (just 250ml).

While you may get away with using a little less, the manufacturer recommends the higher shock treatments for a reason, which is that an expert doesn’t get to physically inspect inside your fuel tank, or see fuel samples they know were taken correctly. Not knowing how bad the contamination is, means they recommend a higher treatment rate for the first few shock treatments to assist with:

  1. Ensuring your fuel system is optimally clean,
  2. Getting the entire problem fixed first time,
  3. Stopping extra chunks of gunk ruining your fuel pumps, filters, injectors, and carburettors,
  4. Avoiding further problems in a few days or weeks time,
  5. Guaranteeing you don’t come back to us saying “Fuel Doctor Doesn’t Work”, because what doesn’t work is using Fuel Doctor incorrectly.

Shock treatments are a bit expensive. Things that work often are. But if you do the job right the first time, you help save yourself the risk of costly repairs that can often easily be avoided.