Engine Flush

[Sudesh]

Now that my car is out of action till I get my new drain plug, I was wondering is there any point in doing an engine flush? If so whats the best way and what would you use? Its pretty much drained at this point and by the time I get my new plug Monday/Tuesday it will be well drained lol!

Would it be worth while running some cheaper thinner oil through the engine and letting it drain taking out any remaining old black stuff?

[markc]

This is one for the the Opie Oils forum :)

I know there is conficting opinions on whether it's good or bad. My view is that a well maintained engine that's always used decent oils wouldn't benefit from a flush.

Over to Opie....

Mark

[Senninha]

^^ as Mark says.

What history do you have around the servicing / change frequency? Would be good info to pass to Opie

Please let us know their response

[simonprelude]

Honda engines have been known to react negatively to engine flush.
All the small particles that help line the bores etc will be washed away.

Or so Mr Spoon says (not the one from Button Moon either)

[Papalazarou]

I don't like doing work stuff on this forum, but this subject always winds me up a bit.
It's one of those things that few people understand but everyone has an opinion about.

When people talk about engine flush, very often they are getting it confused with flushing oils which worked by draining the oil, adding a cleaner, then running the engine and hoping nothing happened. these products haven't been used for 30-40 years.

There's also normally a guy who knows someone who used a product which killed his engine. This engine however, had done 90K without an oil change and flush was the last thing he put in it before it expired!

Modern 'good quality' engine flushes are added to oil and the engine is run for around 10 minutes, then the oil is drained. The product represents only 6% of the oil volume and uses the oils lubricity whilst cleaning. However, it also contains an EP (extreme pressure) additive, which works as an extra protection whilst the engine is being flushed.

The main reasons for using a flush is to clean the engine of dirt and contaminants before adding the new 'expensive' clean oil. By flushing the engine, the oil will stay cleaner for longer.

For instance; if you drained dirty oil into a a white bucket, then poured that contents into another receptical. There would be residue left in the which bucket. In some cases the oil left may contain sludge and other contaminants. Now pour your clean oil into this contaminated bucket.

Basically, modern, and I stress 'good quality flushes' are designed to safetly remove contamination by dissolving dirt particles, holding them in suspension before they are drained out with the oil.

Markc's comment about changing oil often is a valid one. This should be done anyway; the NSX handbook recommends changing the oil at around 4K miles if the car is driven hard. If you decide to flush the oil at the same time you will remove harmful contaminants that would normally be left behind.


Cheers,

James.

[markc]

Thanks Papa, well worth pointing out the differenace between old style "Flushing oil" and newer style "Engine Flush" additives.

For the sake of discussion and of course to play devils advocate...

Firstly, you can still buy and therefore use "Flushing oils". No-one seems to like the paraffin/kerosene it contains but at least one "expert" (a Chemisty PHD on a web forum) prefers this to the "Engine Flush" method.

Second, the "Engine Flush" additives seem to be comprised primarily of the very same detergents that any decent engine oil already has. So would adding a litre dose of this stuff immediately prior to draining the old oil really be very differant to adding a litre of new engine oil and draining that?

No mainstream oil manufacturer recommends using ANY additive with their oils. Now I know that "Engine Flush" isn't an additive in the same way that Slick 50, Molyslip or indeed Wynns Super Friction Proofing is, but they're additives all the same and may adversely effect the oil's ability to keep the dirt it had collected held in "suspension" during it's life?

It seems to me that unless you know you have a problem with excess dirt and contaminants in your engine, and want to try to fix it without stripping the engine, you probably wouldn't need to use either?

Just a couple more observations and questions to try to help cover all the bases.

Cheers

Mark

[simonprelude]

If it was me, even at £50 for an oil change, if I was worried about contaminants I would just do an extra oil change after say 100 miles.

Most of the oil change flushes seem to be £10 to £20 a go, so it's not as if they are cheap against an oil chnage ??

[Papalazarou]

Thanks Papa, well worth pointing out the differenace between old style "Flushing oil" and newer style "Engine Flush" additives.

For the sake of discussion and of course to play devils advocate...

Firstly, you can still buy and therefore use "Flushing oils". No-one seems to like the paraffin/kerosene it contains but at least one "expert" (a Chemisty PHD on a web forum) prefers this to the "Engine Flush" method.

Second, the "Engine Flush" additives seem to be comprised primarily of the very same detergents that any decent engine oil already has. So would adding a litre dose of this stuff immediately prior to draining the old oil really be very differant to adding a litre of new engine oil and draining that?

No mainstream oil manufacturer recommends using ANY additive with their oils. Now I know that "Engine Flush" isn't an additive in the same way that Slick 50, Molyslip or indeed Wynns Super Friction Proofing is, but they're additives all the same and may adversely effect the oil's ability to keep the dirt it had collected held in "suspension" during it's life?

It seems to me that unless you know you have a problem with excess dirt and contaminants in your engine, and want to try to fix it without stripping the engine, you probably wouldn't need to use either?

Just a couple more observations and questions to try to help cover all the bases.

Cheers

Mark

Ok, one thing at a time;

First of all, flushing oils 'may' have improved, but the principle is still a risky one in my opinion. These products provide little or no protection for the engine and although they clean well it's a large gamble. I put this kind of product clearly in the 'old tech' catagory.

Secondly, regarding what flushes comprise of; the good ones are a mix of detergents and dispersant. They work by breaking down gums, varnishes and other contaminants and carrying them in suspension at which point they are drained from the engine.
The detergent found in engine oil is not designed to clean the engine in the same way an engine flush is. Engine flush is considerably stronger and as a result a workshop grade product should not be run in an engine for any considerable time. They are designed to be run for 10-15 minutes only.

With regard to oil manufacturers not recommending additives; This one has always been contentious. Without going too far off topic; the first additive companies..Wynn's and STP developed additives in the late 1930's because oils back then did not contain an additive package. It was only when oil companies went from straight oils to multi-grades that they saw a need to add pakages to oil to prevent foaming, sludging etc. However, these additive packages were not sufficient hence the gap in the market.

In the present day, oil is more sophisticated, it has a good additive package, but good quality additives can still enhance the performance of these oils without detriment.
In fact with the advent of 18/24K servicing and the inability of modern oils to cope with these extended oil drain periods (especially in diesel engines), it can be argued that selcted additives and of course engine flush is a necessary requirement.

It may interest you to know that Castrol and Texaco manufacture their own engine flush.
furthermore, many car manufacturers over the years have worked with some of the better additive companies to solve certain problems.

With regard to Marks last point; flushing the engine is about making the engine environment clean for the next lot of new oil. If you use your car as it was designed, oil will degrade quicker and contamination will increase year on year.
Personally, I wouldn't put expensive good quality oil in an engine that wasn't clean.

[quote]
If it was me, even at £50 for an oil change, if I was worried about contaminants I would just do an extra oil change after say 100 miles.

Most of the oil change flushes seem to be £10 to £20 a go, so it's not as if they are cheap against an oil chnage ??
[quote]

Doing an extra oil change after 100 miles will not clean a lot more contamination from the system, you'll just waste the nearly new oil.
Oil on it's own does not have the cleaning power to remove dirt from an engine.
The price of engine flush shouldn't be any more that £10-£12.00 even on a franchise service.

If anyone decides they want to flush their engine, try to get hold of a Wynn's or Forte product from a workshop or a factor. Other products might be ok, but these are the best.

[dan the man]

this is a very interesting thread. Ive well enjoyed reading it. My views are that every honda ive changed the oil at mAX 4k intervals as it dont cost a lot and its the lifeblood of the car.. and at 8k rpm the blood always needs to be healthy. Always used VERY good oil, IE- Motul 300V power or silkolene PRO S, which are high ester Oils that put magnatec to shame.

Although magnatec at 4k intervals will probably be good and wont be degraded by then anyway but i just like good oils that are stable when hot and dont shear and all the rest of it.


Thee ONLY time ive usede addative in an engine- it went pop. PUG 106 XSI when i was 19, picked it up in halfords, read it thought yes, i want to protect my engine. Bamged it in and remember thinking this is quite thick....

2 days later bang it overheated and the headwent... slick 50? who knows.. never used it again tho.

[Papalazarou]

Thee ONLY time ive usede addative in an engine- it went pop. PUG 106 XSI when i was 19, picked it up in halfords, read it thought yes, i want to protect my engine. Bamged it in and remember thinking this is quite thick....

2 days later bang it overheated and the headwent... slick 50? who knows.. never used it again tho.


Slick 50 contained a lot of PTFE which could and did block oil-ways and cause problems. I believe they were taken to court at some point.
anything with PTFE is best avoided but not easily available now.

I'm not defending slick 50, at that time it was not a good product, but just because it was the last thing to go into your Pug doesn't mean it was responsible for the engine failure.


Cheers,

James.

[markc]

Thank you for the excellent explanation Papa :)

One last thing, and this is the one that always worries me about any additive, what about the last little bit that is left in the engine after it's drained?

I appreciate that it's a very small amount, but is there any chance that it could impair the operation of the new oil? Assuming were only talking about using high quality full synthetics from the specialist guys (Redline, Motul, Fuchs, Mobil etc) and full or semi syns from mainstream boys Esso, Shell, Total etc is the "Engine Flush" safe with these oils?

Cheers

Mark

[Sudesh]

Thank you for the excellent explanation Papa :)

One last thing, and this is the one that always worries me about any additive, what about the last little bit that is left in the engine after it's drained?

I appreciate that it's a very small amount,

Mark

Mark my car has now been sitting since Thurday evening with no drain plug in it, and right up until yesterday it was still draining out oil! It may not have been "gussing" out but there is quite a large pool left in the tray I placed under it since doing the initial drain. I will take a look later today to see if that has risen any since yesterday and I might just take a measuement of what dripped out since Thursday and let you know. This is one of the reasons why I thought an engine flush with some cheaper new oil frist, might be a good think, or as Simon mentioned I might just do another oil change after about 100k of driving.

Papa Thanks for the great write up!! Very interesting to read.

[markdas]

Yep an emotive subject and I too have gone through differing opinions on oils etc. (and every car forum I belong too, has this question crop up every week or so).

I think its already been mentioned that if good quality oils are used in this very hitec engine at short intervals 4-6k miles, then sludge, dirt, contaminants etc are pretty few and far between....its really sludge from degraded oil or coolant from cross contamination that causes any serious issue (or excessive intervals)

Any engine has ledges and hold up points and this is generally not considered as a problem....if its flushed with one of the thinner type cleaners mentioned, then this is left of the engine ledges and will immediately diute the nice expensive stuff we put in later...which could be a problem!

4-6k interval, genuine Honda filter, good quality oil, let the engine warm up before high revs = no problems.

Mark

[Sudesh]

Read this old thread on the GTR forum one guy said;

"There is only one way to truly 'flush' (i.e. clean-out thouroughly) and that is to get an ultra fine filter (1.0um) and some ultra thin oil.

Drain your existing oil...
Remove and discard old oil filter...
Get some thin oil... not flushing oil!
Do the change job...
Run the car around for 30 miles (max)...
No racing but use a good range of revs...
Perform a normal oil/filter change after that 30 miles only drain for 30minutes!...

That is the only way (short of a re-build) of performing a proper flush..."

http://www.gtr.co.uk/forum/upload/7414-engine-flush-redex.html

[Papalazarou]

In answer to all the questions on this page in reverse order;

1. The GTR club method could work, but why not just use a good quality flush for £10.00 in the original oil rather than changing the oil to thinner oil then throw that away also?

2. sludge and dirt are not the only contamination; gums and varnishes accumulate on many surfaces, this can be a problem in vehicles with hydraulic tappets where it can impede proper operation. A good example is Subaru which had issues with lifters (lash adjusters) and solved this by using Wynn's engine flush, then using a hydraulic lifter additive which is added to the new oil. The lifter additive is like a diluted flush and designed to be left in the engine without a problem.

3. Left over flush in the system represent such a small volume of product that there can be no detrimental effects. Consider that the best flushes are developed in state of the art laboratories where they are tested in many engine and compared with each other. Companies like Wynn's and Forte are not going to make prducts that could interfere or damage the engine they are meant to enhance. The cheaper end of the market is a different matter, they have no R&D and are often crude.

4. Engine flush is safe with all oils. I can't speak for other additive manufacturers, but the Wynn's products are designed not only to mix with all known oils (except maybe Castrol R??!#) but also to mix with each other, i.e; if you put a friction proofer in the engine then add a rubber seal rejuvenator you will not suffer any problems.

5. just in case anyone was wondering; the difference between the Wynn's flush you see in Halford and the product you get in the workshop is this; The workshop product has more cleaner and less high pressure additive. The retail product has less cleaner and more high pressure additive to protect the engine in case the DIY car enthusiast put it in the engine and doesn't drain the oil!

6. Whatever people think, draining the oil twice in 100 miles really isn't going to remove much more contamination.

7. Finally, flushing engines is an industry norm. Most independents and a 'considerable' amount of franchises use flush, even the ones that do not recommend the use of an additive, but as we have established, flush is not an additive it's a cleaner and conditioner.


Hope this helps,



Cheers,


James.

P.s, I'm pretty good with A/C disinfecting products if anyone has any questions;-)

[Sudesh]

markc:

I finally got around to finshing my oil change and installing the new bolt. I checked to see if the dripping had stopped and the oil pan on the car was dry from my final wipe of last nite. So to give you an idea of what extra oil drained out from thursday evening to today; it was just shy of 1/4pint!! So there was quite bit that dripped out over those days.