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Is it worth using Engine Flush when changing oil?

Is it worth using Engine Flush when changing oil?



Original Poster:

1,847 posts

123 months

Thursday 12th November 2009
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I tried the search function but it took AGES and didn't actually do anything.

So, as per title really?

Is it a good idea to flush your engine before an oil change? I don't know of anyone that does it but there must be a market for it because the products are out there to buy.


Edited by carter711 on Thursday 12th November 21:02


15,370 posts

113 months

Thursday 12th November 2009
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There is a theory, and i can only repeat it as a wive's tale rather than actual documented fact, that some flushing can disturb solids and crud that have nicely taken a seat inside the nooks and crannys of your engine.

Some people swear by it, but i can't think of any manufacturer that recommends engine flushing.


6 posts

98 months

Friday 13th November 2009
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with modern oils you do not tend to get the sludging problems of years ago so engine flush is not normally needed also a small build up can help on a worn engine , only exception i would say is the ford CVH engine which i would flush at every oil change as these were terrible for blocking oil ways and pick up pipe etc to the piont ford reduced the oil change shedule in the first few months of release.

Simon Says

14,790 posts

146 months

Saturday 14th November 2009
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Change the oil & filter at regular intervals and you wont need to flush wink as already said can cause more harm than good,not always noticed at 1st after oil&filter and flush well not until the sludge starts moving and blocks the ever decreasing in size oil filter(have seen this happen)with obvious consequences frown


5,710 posts

176 months

Saturday 14th November 2009
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The trouble with engine flushes is that some are good and some have a detrimental effect. So no manufacturer is going to have a carte blanche statement saying that a flush is a good idea when they cannot control which flush is to be used. The issue is one of legality and competition, with oil you can specify the grade and spec, but not the brand. Same goes for any other consumable chemical.

Flushing an engine can be a very smart idea on sludged diesel engines and it can be achieved by just using straight mineral diesel oil. But it needs to be done in very controlled circumstances.

Whether you have a diesel or petrol engine and you think you may have a sludging issue I would be tempted just to use a very high detergent oil formulated for diesels in the correct oil grade and change it after 1000 miles then revert to changing at around 50% to 75% of the original manufacturer's schedule. Oil is very cheap compared to engine rebuilds.


205 posts

113 months

Tuesday 17th November 2009
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i recall a granada 2.3v6 with low oil pressure, i used an oil flush and had no pressure after.would only use from new or prior to an engine rebuild.


118 posts

116 months

Tuesday 17th November 2009
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Many years ago I worked for a company that manufactured these products. I carried out field work at main dealers, demonstrating the benefits on older vehicles.

I would take compression readings before the oil change and after the flush and refill. In every case, a significant increase in compression was recorded.

On the other hand, when I worked at a main VW dealership, engine flush was used at the customer's request during a service. Roughly two weeks later the engine seized. Whilst there was no definitive proof that the flush caused a problem, the dealer squarly blamed the flush for having loosened some crud which had then relocated itself and blocked an oilway.

With my own cars, I never use engine flushes.For many, the cost to properly strip and rebuild an engine is prohibitive. As said above, regular oil changes are better preventitive medicine IMO and there is no such thing as a cheap fix for a tired engine. Certainly not if long-term reliability is a goal.

Way back in 1983 I bought my first MK1 Golf GTI. The car was just a year old at the time. I decided to 'fit' Slick 50 when I changed the oil. What I can say about that particular additive, is that having had 4 MK1 GTi's after that one, the first car was massively quicker and more responsive. I still wouldn't choose to use even that product on any of my cars now though.

Read into that what you will and best of luck.

Edited by MSPV12 on Tuesday 17th November 19:47 to cheak speeling mistaks

Edited by MSPV12 on Tuesday 17th November 19:50


429 posts

108 months

Saturday 21st November 2009
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i usually (mk2 golf using mk3 16v abf) flush using the cheapest mineral oil i can find (asda smartprice etc) run a 10 mile trip, then flush and refil with quality oil. i use vw synta silver. cracking stuff.

when i picked up the lump (85k), i got a full service history with it. every single oil change, with the above said oil. when i took off the sump and rocker cover, it was perfct inside. perfectly clean. no burn marks and nothing in the oil pick up.

regular servicing wins! now the oil stays golden for over 4k no probs


3,010 posts

141 months

Saturday 21st November 2009
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This topic always seems to get people juices flowing on here, a couple of previous threads for you: