My car handbook lists what should be done at each service, and it does not say “engine flush” should be used. The main dealers don’t use it.

Yet most small garages seem to insist on using it at every oil change…. Why?

(It is not them trying to make more money, as they only charge about £3 for the engine flush.)

  • 2
    Unless flushes are done from new, they can cause any dirt stuck on the engine internals to be released and to then be pumped to the bearings where it can easily block oil to the journals.
    – HandyHowie
    Feb 15, 2016 at 14:05
  • 1
    You shouldn't need an engine flush if you change the oil regularly. Feb 15, 2016 at 14:21

3 Answers 3



Well, money. Even if its $3, that counts as an upsell. They will probably sell the "engine flush" to most people. Raising the average sale by a fair amount.

Follow the vehicle's manual. Don't give in to these offers.

  • It's not a offer, it just what they do for ALL services. Feb 16, 2016 at 9:00
  • 1
    You should find another place. One that does not include such things as default.
    – race fever
    Feb 16, 2016 at 19:24

Go somewhere else. It's your car and you shouldn't have to argue over the service you'd like performed. Any place that up-sells products I didn't ask for is always suspect to me. Generally they come off like snake oil salesmen...

  • I used to have an old mechanic that would call me if he found some work to do because he was checking everything, if he couldn’t reach me and the thing wasn’t a big deal he would do the extra work and not charge for it because I didn’t say "do it". He even used to keep a piece of paper with a drop of the old oil and before picking up he would show you the new one... could fix any engine, never a complaint and more clients he could handle... For as much I search, cant find one like that, they don’t care anymore, there’s little work one can do on their own today so you are stuck with them... Feb 18, 2016 at 14:08
  • Nah, you can still do about 96% of it yourself, just take the plastic covers off, and the engines still the same lol. An OBD scanner is about the only 'new' tool in my arsenal.
    – Nick G
    Feb 18, 2016 at 17:53

An additive is added to break up carbon deposits in the engine, the car is driven, the carbon is trapped in the filter and then oil and filter are changed. Unless you gunked up your engine driving in a lot of traffic (for many many km), or skipping oil changes or letting the car sit for months, you could do without. The car is yours, you should be able to tell them not to flush and they shouldn’t do it and not charge you for it, although if they are after the money they will get those £3, or more, in another way anyway.

Now, if you just bought an old car, a flush is one of the first things you should do.

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