I'm in two minds about using an engine flush before oil change on the 1.5 tdci focus.

Is it worth it or is it just better to use a good quality oil and regular oil changes?

If you're unsure I always use the cheapest same grade oil and just drain and fill the oil. No filter

Run it for 100 miles on the clean oil

Then change the oil & filter

And then change the oil more often if you want to

13 minutes ago, DaveT70 said:

If you're unsure I always use the cheapest same grade oil and just drain and fill the oil. No filter

Run it for 100 miles on the clean oil

Then change the oil & filter

And then change the oil more often if you want to

That's a good idea. I never really used engine flushes but it always seems to be a mixed opinion on them.

I always thought using good clean oil with regular changes was the best way to keep things clean

44 minutes ago, sonic113 said:

I'm in two minds about using an engine flush before oil change on the 1.5 tdci focus.

Is it worth it or is it just better to use a good quality oil and regular oil changes?

I've had diesels for over 20 years and never felt the need for the engine flush, it's likely a personal preference, I do recommend oil and filter change yearly, irrespective of mileage.

Marmite!
Always flushed for over 20 years and found Mk1 Mondeo internals very clean when the head had to be removed (plastic rim of idler failure) which confirmed my habit.
Definite yearly oil and filter change at least.
Probably not if it has never been flushed or no/poor service history.
Not for wet belts of course.

I'm not a fan of engine flush on modern cars. High risk, minimal reward, in my opinion.

Also wouldn't waste new oil running it through. I just stuck to a yearly oil and filter change with decent branded items.

46 minutes ago, TomsFocus said:

I'm not a fan of engine flush on modern cars. High risk, minimal reward, in my opinion.

Also wouldn't waste new oil running it through. I just stuck to a yearly oil and filter change with decent branded items.

I think I will just forget a out the flush and stick to regular oil changes with genuine filters ect. I'm afraid incase using a flush creates problems or issues

46 minutes ago, TomsFocus said:

I'm not a fan of engine flush on modern cars. High risk, minimal reward, in my opinion.

Also wouldn't waste new oil running it through. I just stuck to a yearly oil and filter change with decent branded items.

I think I will just forget a out the flush and stick to regular oil changes with genuine filters ect. I'm afraid incase using a flush creates problems or issues

2 hours ago, Shearers said:

Marmite!
Always flushed for over 20 years and found Mk1 Mondeo internals very clean when the head had to be removed (plastic rim of idler failure) which confirmed my habit.
Definite yearly oil and filter change at least.
Probably not if it has never been flushed or no/poor service history.
Not for wet belts of course.

But the unanswerable question is: What would the internals have looked like, if you had only carried out yearly oil and filter changes?

I was warned off engine flush over 50 years ago by my local garage proprietor and never used it.

Have used Dave's technique a few times on cars with an uncertain history, though.

To each his own but the oil DEFINITELY stays cleaner for longer (but still not very long)

The issue is I cannot be 100% of previous service history so want to keep things right or as much as I can.

Got oil and filters today but I plan to change oil more regularly than the stated interval, probably every 8000 miles.

So instead of a flush would it be better just to use the castrol oil and do oil changes and oil filter changes at my chosen interval?

Would that be enough to take out or break down any type of sludge or carbon deposits from inside that the engine may have from previous?

Either way I think regular oil changes would be safer that a chemical flush.

I have a 2.0 TDCi, but in the case of an engine flush, it should be pretty much the same.

I bought the car with 90,000 km on the odometer. I didn’t use any engine flush until it reached 150,000 km. The engine oil was always black, even right after changing it.

Now the car has 200,000 km, and for the last six oil changes (at 150k, 160k, 170k, 180k, 190k, and 200k), I have used an engine flush every time. Also, at 200,000 km, I removed the oil pan and cleaned it carefully.

Now the engine is perfectly clean inside, and after 1,000 km, the oil still looks almost new — as if it had just been changed.

The choice is yours, but in my opinion, an engine flush is a great thing.

2 hours ago, cezarg1410 said:

I have a 2.0 TDCi, but in the case of an engine flush, it should be pretty much the same.

I bought the car with 90,000 km on the odometer. I didn’t use any engine flush until it reached 150,000 km. The engine oil was always black, even right after changing it.

Now the car has 200,000 km, and for the last six oil changes (at 150k, 160k, 170k, 180k, 190k, and 200k), I have used an engine flush every time. Also, at 200,000 km, I removed the oil pan and cleaned it carefully.

Now the engine is perfectly clean inside, and after 1,000 km, the oil still looks almost new — as if it had just been changed.

The choice is yours, but in my opinion, an engine flush is a great thing.

Fair point. What brand of flush did you use? Had you any issues with seals or oil pressure after using a flush?

I would say the manual sump clean would of helped a lot with keeping the new oil colour clear. That's something I am also considering at some point.

2 hours ago, cezarg1410 said:

Now the car has 200,000 km, and for the last six oil changes (at 150k, 160k, 170k, 180k, 190k, and 200k), I have used an engine flush every time. Also, at 200,000 km, I removed the oil pan and cleaned it carefully.

If you had to clean the sump manually after 5 engine flushes, surely that proves the engine flush doesn't remove sludge?

1 hour ago, TomsFocus said:

If you had to clean the sump manually after 5 engine flushes, surely that proves the engine flush doesn't remove sludge?

Have you ever seen what the sump looks like, especially around the drain plug area? Do you know that after every oil change, more than 0.5 liters of old oil remains in the sump?

I didn’t have to clean the sump — I just wanted to. The oil color was already much better after five changes, even without removing the sump. I simply thought that after such a long period (with using flushes), the engine was probably clean, so I should clean the sump as well.

I could upload pictures showing what the engine looks like inside, but I assume that no argument will change your mind.

1 hour ago, sonic113 said:

Fair point. What brand of flush did you use? Had you any issues with seals or oil pressure after using a flush?

I would say the manual sump clean would of helped a lot with keeping the new oil colour clear. That's something I am also considering at some point.

Oil always Millers 0W30 with Ford approval.

Engine flush from Liqui Moly.

No issues with seals - it is some kind of urban legend.

Just now, cezarg1410 said:

Have you ever seen what the sump looks like, especially around the drain plug area? Do you know that after every oil change, more than 0.5 liters of old oil remains in the sump?

I didn’t have to clean the sump — I just wanted to. The oil color was already much better after five changes, even without removing the sump. I simply thought that after such a long period (with using flushed), the engine was probably clean, so I should clean the sump as well.

I could upload pictures showing what the engine looks like inside, but I assume that no argument will change your mind.

Yes, thanks. I have stripped several Peugeot and VW diesel engines with 100,000 - 200,000 miles on them. Some with full dealer history. Some with no history at all. They were all pretty clean inside.

Diesel oil does go black quickly after changing, but the colour is mainly from soot. That doesn't really bother me with regards to lubrication. The bigger issue is fuel and moisture contamination which does reduce lubrication, and attack seals and wetbelts. So I would recommend a regular oil change to get rid of the moisture and fuel, but I am not fussed about the sooty colour. Each to their own, of course. 🙂

17 minutes ago, TomsFocus said:

Yes, thanks. I have stripped several Peugeot and VW diesel engines with 100,000 - 200,000 miles on them. Some with full dealer history. Some with no history at all. They were all pretty clean inside.

Diesel oil does go black quickly after changing, but the colour is mainly from soot. That doesn't really bother me with regards to lubrication. The bigger issue is fuel and moisture contamination which does reduce lubrication, and attack seals and wetbelts. So I would recommend a regular oil change to get rid of the moisture and fuel, but I am not fussed about the sooty colour. Each to their own, of course. 🙂

I totally agree with regards to the fuel and moisture contamination that's the reason I want to do more regular oil changes at around the 8000 mark.

On that note would you suggest filling the oil to the Max or just lower to allow for any fuel contamination?

I was told that some BMW techs fill it a bit less to allow for the fuel contaminated oil level to rise but just enough to be in a safe zone before it's changed out at next oil change. The reason for this is it won't put pressure on seals ect by having the oil level over filled.

I always had a petrol and the oil was always changed at 12000 and it was always clean and stayed nice and brownish. So when I do the oil change on the diesel if it goes back after a day or week is that normal and is it still doing its job?

I think I will skip the chemical flushes and just stick with regular oil changes.

26 minutes ago, sonic113 said:

I totally agree with regards to the fuel and moisture contamination that's the reason I want to do more regular oil changes at around the 8000 mark.

On that note would you suggest filling the oil to the Max or just lower to allow for any fuel contamination?

I was told that some BMW techs fill it a bit less to allow for the fuel contaminated oil level to rise but just enough to be in a safe zone before it's changed out at next oil change. The reason for this is it won't put pressure on seals ect by having the oil level over filled.

I always had a petrol and the oil was always changed at 12000 and it was always clean and stayed nice and brownish. So when I do the oil change on the diesel if it goes back after a day or week is that normal and is it still doing its job?

I think I will skip the chemical flushes and just stick with regular oil changes.

I tend to fill half way between min & max personally. Then you'll see whether the level increases (due to post injection) or decreases (due to burning/minor leaks) over time.

After the first year you might choose to do it differently based on the evidence of your particular engine.

I've never had a BMW so don't know if there's anything specific to them.

I don't worry too much about the mileage unless you do more than 12k a year. I find it's easier to remember a yearly change as it's always around an annual event such as MOT or a holiday.

Yes diesel oil will go black again within a week. I personally don't believe that's affecting the function of the oil but others might disagree.

1 hour ago, TomsFocus said:

I tend to fill half way between min & max personally. Then you'll see whether the level increases (due to post injection) or decreases (due to burning/minor leaks) over time.

After the first year you might choose to do it differently based on the evidence of your particular engine.

I've never had a BMW so don't know if there's anything specific to them.

I don't worry too much about the mileage unless you do more than 12k a year. I find it's easier to remember a yearly change as it's always around an annual event such as MOT or a holiday.

Yes diesel oil will go black again within a week. I personally don't believe that's affecting the function of the oil but others might disagree.

Thanks Tom, I will refill halfway and keep an eye on it and take it from there. Appreciate all the input.

ive just changed the oil and oil filter last month after doing around 10k, i will need to chnage it more often like couple people on here are saying like every 8k.

also i never use flush.

As I don't have the oil dilution issue, I keep it at the full mark and may have to add 200 ml during the year.
8k miles would be a year's motoring for us (change every August when it's "warmer" - joke!)

I'm still happy with my regime so I'll not post any more on this.

I am totally untechnical when it comes to matters such as this.

But I have been regularly told never to use a chemical flush if one has a wet belt ... apparently can speed up the belt's deterioration.

I now have a modern Focus with a chain and recommended oil change at 18,000 miles or two years. But I still change the oil every 9,000 miles or one year.

5 hours ago, Linds said:

But I still change the oil every 9,000 miles or one year

You still have a wet belt for the oil pump drive of course, so I think that's wise.

The Fiesta ST is annual service anyway, but I'd still do it annually if not as I did with my previous 1.0.