Use of oil flush

[MikeT]

Some say oil flushing an old engine can create problems either cleaning out muck the engine has come to rely on, or through the blocking of small passageways.

So flush or not?

I'll run this as a 3-day poll.

[myglaren]

It wouldn't let me vote, must be a glitch.

I'd go with the 'better safe than sorry' approach.

If there is a load of gunk in there just waiting to clog up fine oilways, let it stay where it is, it isn't causing a problem so why encourage it to do so?

I used to change the oil & filter once a week in my Xantia for a couple of months, it was dirt cheap - bought cheap oil from Asda which had the required spec. As it wasn't in for long enough to 'wear out' it didn't matter.
It gently flushed the system. After that I went to changing the oil & filter once a month. I did used to add STP to it too.

The car had high mileage when I bought it but had been very well cared for, there was nothing broken on it, cosmetic appearance was almost as new and servicing had been more frequent than required by the manual.

The engine was like new too.

The tw*t that wrote it off for me should burn in hell, it would have lasted for years and years.

I would be hesitant to flush it until I'd had the sump off and removed any accumulated gunk from there first.

[reblack68]

In my opinion frequent oil changes and a brisk driving style are all the cleaning an engine needs.

[steviewonder7]

It wouldnt let me vote either.

I'm no expert...but would say if the rocker cover and valve gear and sump pan looked generally covered in that burnt on oil look and looked like the oil had not been changed for a while(nothing against you Mike...could be previous owners),then I would defo give it an oil flush. Who knows what state the oilways/pipes/orifices are in in the above instance.
It might reveal a few leaks and other things etc...
this is only my opinion

Regards Steve

[MikeT]

It wouldn't let me vote, must be a glitch.

I found that when a previous post had the same options so it might not be my fault this time

If there is a load of gunk in there just waiting to clog up fine oilways, let it stay where it is, it isn't causing a problem so why encourage it to do so?...

The pro argument is pretty straightforward - it's an unknown engine with a scattering of service receipts (of which some even claim to have given it a gold service including change of spark plugs and HT leads but they missed the failed glowplugs ) and has had serious failures and repairs that may have been assisted by a problem that has not yet been rectified. Even without that incentive, I think anyone would choose a clean engine over a dirty one, particularly if they're going to invest a lot of time and money in the hope of being rewarded with reliable carefree motoring.

So that's one for and one against so far. 8)

I would be hesitant to flush it until I'd had the sump off and removed any accumulated gunk from there first.

That is a good tip, is it an easy job on these cars (or does the entire front suspension, wheels, brakes and driveshafts have to come off first? )

[MikeT]

In my opinion frequent oil changes and a brisk driving style are all the cleaning an engine needs.

I tend to think the same and would rely on that principle to keep it clean but this poll is being asked from the standpoint that it's 168Kmiles old, has a sketchy service history, has needed new clutch, radiator, rear discs, (maybe more) and currently has a failed head gasket and a suspect corroded matrix, possibly evaporator and condensor for all I know. The A/C has been doormant for many years blah blah blah

You may recast your vote if you wish

[MikeT]

if the rocker cover and valve gear and sump pan looked generally covered in that burnt on oil look and looked like the oil had not been changed for a while ,then I would defo give it an oil flush.

If I find that much muck, I would not hesitate to flush.

[reblack68]

I'm sticking with my vote. My Escort TD had a patchy service history and the engine steadily improved in the 45k miles I did in it, that was just with 5k oil changes and a damn good thrashing.

[MikeT]

Two for, two against. Still a dead heat.

[CitroJim]

Oils are so good these days that even neglected changes rarely cause massive sludge buildups that require a strip or the use of flushing oil. I've had engines apart in the recent past that have been massively neglected in the servicing department and not really fould that much sludge or rubbish. My Lads Fiesta that he blew up had 125,000 miles on the clock and had never had a lot of love and attention and was spotless inside. It blew up because he ran it out of oil as it started burning a drop and, as lads are, he did not top it up until the red light came on going round corners.

My original 205GTi engine was again massively neglected but there was no significant sludge in it. I've had the tops off enough XUDs to know they don't significantly sludge in the face of neglect either.

So, I'm firmly in the camp that flushing oil is not needed. Better to do as Myglaren suggests and do some rather frequent oil and filter changes using supermarket oil. I have done this on every car I've had and it has proved successful. You can see the oil remains clear for longer each time. Note that a diesel will blacken its oil very quickly so colour is no indication of oil condition in a diesel. It can be clear one day and as black as a coal mine the next.

Just one cautionary tale: many, many years ago I acquired a very badly neglected Volvo 340. It had gone 60,000 miles without an oil change. It still ran well and quietly. I drained the remains of what was in it and refilled with nice 15W/40 and it knocked something shocking. I refilled with a can of cheap 20W/50 and a can of Wynns and the knock went. I used to change the oil each time the knock returned and put another can of Wynns in. That car soldiered ion for another 25,000 miles like that and even towed a small caravan to Paris and back!

[MikeT]

Three-two against.

[jonnydrumm1967]

Change the oil using the correct grade for the engine,Iwouldn't go any thinner than a 15/40, put on a genuine Peugeot/Citroen oil filter,close the bonnet,job done.
It'll hardly use any before the next change circa 6k unless the engine's goosed.

It simply won't need any additive at all.

[lexi]

At that mileage I wouldn`t flush. Frequent changes will gently clean it through without chance of dislodging something and clogging it.

[MikeT]

5-2 against

Frequent changes will gently clean it through

.....and I like this option.

[elma]

If I think I've got a good engine I flush to see if I'm right.

Beware though, if wrong they usually die within 5k.

Comma lush oil in green tub is my preference.

Any dodgy noises from bottom end, suspect piston rings and don't bother though.
Also try 50/50 veg oil in the fuel with clean oil, if the oil in the sump thickens don't bother. That was my warning sign which I didn't notice.

It makes a lot more difference to flush than to do regular oil changes, if it works.

Personally I'd say no until you've done at least 10k and got to know the engine.