To flush or not to flush............

[Dave Wright]

Hi everyone

I've just seen a YouTube video that says that you should not use engine oil flush products.
Having just purchased my first MG, a 2000ym MGF 1.8 VVC with only 41.5K miles on the clock (and only about 5K of them done in the last 6-8 years) I was thought it would be prudent to flush/drain/replace all fluids (and filters) before any regular use and was planning on using engine oil and coolant flushing products to get things as clean as possible. However, having seen that video I'm not now so sure.

Would you guru's have any thoughts/advice on this? Your knowledge would be gratefully received.

Regards

Dave

[John SS]

If both the oil and water appear to be clear of things that shouldn't be there, my advice would be to simply replace them as per standard service procedure.
Enjoy your new acquisition.

[RobboMC]

Over the more recent years whenever I have acquired pre-owned cars I have always converted the engine oil to fully synthetic oil.

It always seemed that the 2nd oil change resulted in a much smoother engine.
An old mechanic has explained the outcome to me, and it's not my imagination!

The first oil change you do doesn't get ALL of the old oil out,
and the second oil change gets almost all the original oil that's now diluted into the 1st oil change.

So if for example the oil change gets 95% of the old oil out, then the second change gets 95% of that,
leaving just 0.25% of the original oil. After that you can't tell the difference.
( I don't know exactly what the %age is, I'm just using this an an example )

So the short of it is.... if the engine hasn't been used regularly, change the oil,
then drive it for 1000-2000 miles or so and change the oil again.

I have found this works well for cars that have only been run on mineral oil.

And in case I'm not telling you how to suck eggs,
when was the timing belt and tensioner last changed?

And don't forget the brake AND clutch fluid

[Rob Bell]

I've just seen a YouTube video that says that you should not use engine oil flush products.

That's interesting. Not heard that myself. What was the reason given for this?

I suspect that the answer may depend on how neglected your car was before you bought it. If it has missed multiple previous oil services and the oil in the cam gallery is like caramelised treacle, then I probably would use one of these products - after all, what have you got to loose?

If the oil is just black, and the inside of the castings are not orange and/or black and gloopy, then repeated oil changes with good quality oil is probably the best bet, as these are generally formulated with useful detergents.

[Dave Wright]

Hi all, and many thanks for all the replies.

John, thanks for your comments. I really am looking forward to getting my hands oily..... will take me back to when I would help my dad service his cars in the early 70's.

Rob, from what I can make out from the stack of invoices etc that came with the car it was well looked after up until around 2013, but not much paperwork since, but then that's about time the car stopped clocking up the miles as well - mileages between MOT's in only 10's or 100's.
FYI, the you tube video I was this one...... https://www.youtube.com/watch?v=WEvCKLeP3Tg

RobboMC, I have also be advised about multiple oil changes and that was going to be the approach I take. Thanks for the further confirmation.
and thank you also for your suggestions on what else I should be looking at. I can tell you the last time the alternator belt was changed..... that was today!!! (couldn't cope with all that squealing.....) but I need to look back at the old paperwork for the timing belt!.

Cheers

[Rob Bell]

Wow, that guy knows how to waffle and repeat himself doesn't he?

I am going to do some more research, but I think (*think*) the point he is making is that you shouldn't use engine oil flush products to fix an issue with the engine. That's true. It isn't a magic potion. He also says he uses it for heavy sludging - which is what I would use it for too.

I think I understand the point he was making about blocking oil ways and filters? I *think* what he is saying is that the flush will mobilise sludge deposits that could end up embolising and blocking filters and oil ways. But if your engine oil is in that bad a condition, then those filters and oil ways are likely blocked anyway.

I certainly don't get his argument that engine flush can damage your engine - he seems to think congealed oil is actually protecting your engine. Hmm. I really doubt that!!! It may potentially mask certain problems, but congealed oil can only be damaging - and if your engine is that badly worn through neglect, then it is worn through neglect... nowt an oil flush is going to be able to do.

I'll keep by my original comment - engine flush if the engine has been clearly neglected. Yours probably isn't bad - probably a few skipped change intervals on low mileage. But if you skip oil changes and are doing 10-15k miles a year, that is a different kettle of fish. As I understand it, the flush product is generally put into the engine oil for one heat cycle and then the oil is dropped and thrown away. Perhaps do two oil changes for exactly the reasons Robbo states - and indeed, I agree - modern oil is indeed a good flush product in its own right!

[Dave Wright]

Rob, Many thanks for your reply. Sorry for the delay but I've only just seen this.... couldn't get into the forum until now. Was there a problem over the weekend do you know?

Anyway..... first oil change about to take place..... wish me luck!!!

Dave

[Rob Bell]

Good luck Dave! I have been up to the elbows in a Head Gasket change on a project MG ZR for my daughter over the weekend! I am hopeful that the cylinder head will be salvagable. Fingers crossed!

PS I found the YouTube video that likely inspired the one you linked. It made a bit more sense, but really there is no actual "damage" from flushing gunged up engines: it would be more a case of exposing existing wear that may have been partially obscured by congealed oil... The Rover K-series, for it's known head gasket weakness, is otherwise a remarkably robust engine - so unless the engine has been severely neglected, it is unlikely to have significant wear... I reckon your plan for repeated oil changes is a good one!

[Dave Wright]

Cheers Rob. Oil change completed. But the time taken to refill caught me off guard!!!

From what I can see so far, the only neglect was not using the car over the last few years. Why would you have such a beaut and not be out of the road!
Still all the spiders seem to have had a good home. I've never seen so many webs!!!

[Chris Tideswell]

Cheers Rob. Oil change completed. But the time taken to refill caught me off guard!!!

That sounds like you have filled the oil using the remote oil filler and not the main one on the engine?

[RobboMC]

It's faster to remove the engine cover and refill into the cam cover than wait for the filler neck to trickle down 4-1/2 litres.

Anyway, with every oil change/service an owner should be having a general look about in the engine bay anyway.

After doing my water pump late last year I spent Saturday afternoon doing just that, after about 2,000 km since I did the work.

Too many issues with F's just fester and get worse because the owner didn't bother looking under the engine cover.

It's not that hard, just harder than other cars.

[Rob Bell]

Cheers Rob. Oil change completed. But the time taken to refill caught me off guard!!!

From what I can see so far, the only neglect was not using the car over the last few years. Why would you have such a beaut and not be out of the road!
Still all the spiders seem to have had a good home. I've never seen so many webs!!!

I suspect that those spiders are soon to get a little toasty

Good job.

[Dave Wright]

Chris you are not wrong sir. And RobboMC, more wise words. Thank you all.