To flush or not to flush

[Joseph80]

I am carrying out a full service on my car, oil and filter, fuel filter, spark plugs and air filter. Should I flush the engine out or just drain and fill with new oil and filter.

I am being told two different pieces of advice, one to flush the other not to flush.

Would appreciate JEC members comments please.



Many thanks

Joseph
XJ8 (X308) Jaguar Sovereign LWB
1999 - Prins LPG Conversion. Blue.
184,000

[Orkney]

My own method of oil changing is to let it drain overnight and refill the following day or even later - not always convenient with a vehicle in constant use. I have not flushed any engine in more than 50 years of motoring. I can see the idea behind flushing but have always thought there might be a small risk of dislodging some debris which has been happily sitting in a corner somewhere for years.
With any yes or no answer to a question, there will always be two camps - as we know only too well at the moment!
With your mileage I would just change oil and filter a bit more regularly, especially if you are not sure how often it’s been done in the past.

Sorry to appear to sit on the fence but it really is your considered decision which is important.

Ian

[RichardSEL]

With 184k up I would flush.

Had good experience with engine de-contamination treatment by EDT at Powerbase in Ashford, Kent.
EDT has agents around the country.

Checkout thread: viewtopic.php?f=10&t=12498

Sold the car since (an '01MY Sport) with 143k up. Now have Exec as my daily, Oil appears to stay remarkably clean
so dunno if previous owner had done a flush treatment

Refill with fully synthetic

[Joseph80]

Gentlemen

Thank you very much for your advice, as you said bit like Brexit, there are two camps.

Will keep you updated with the outcome.

Many thanks once again for your prompt advice.


Cheers

Joseph

[Jeroen]

Just one more thought. In all honesty I don’t see that much value in flushing as long as an engine has had regular oil changes. And possible even more important, also the oil filters were regularly replaced.

So if you are buying a second hand car and you have no idea how long the oil/filter have been in there, it might be an idea to flush, just as a pre-caution.

The other time you really might want to consider flushing is when you change from a mineral or a semi-synthetic to a full synthetic oil.
Full synthetic oil are likely to to dissolve any and all debris that has collected and got stuck here and there in your engine. As long as it stays stuck it isn’t really a problem. But with the full synthetic it will become dislodged.

Or instead of a flush, just run it only say 1000 miles and give it another oil/filter change. By then your engine will be thoroughly clean.
I do all my oil changes on all my cars myself. One of them is a 1986 Alfa Romeo Spider. I always run it on just mineral oil, which is in accordance with the original Alfa Spider recommendations. Half a year ago it had to go for its MOT. And as I did not have time, I asked them to change the oil and filter. They put fully synthetic oil in and a new filter. I opened up the filter after 500 miles

Look at some of this debris that had already collected:

[Joseph80]

Thanks for your advice. I have now changed the oil and filter, rather than flush. I will change the oil and filter as you recommend after 1,000 miles.

Cheers


Joseph

[RichardSEL]

The other time you really might want to consider flushing is when you change from a mineral or a semi-synthetic to a full synthetic oil.
Full synthetic oil are likely to to dissolve any and all debris that has collected and got stuck here and there in your engine. As long as it stays stuck it isn’t really a problem. But with the full synthetic it will become dislodged.

Or instead of a flush, just run it only say 1000 miles and give it another oil/filter change. By then your engine will be thoroughly clean.
I do all my oil changes on all my cars myself. One of them is a 1986 Alfa Romeo Spider. I always run it on just mineral oil, which is in accordance with the original Alfa Spider recommendations. Half a year ago it had to go for its MOT. And as I did not have time, I asked them to change the oil and filter. They put fully synthetic oil in and a new filter. I opened up the filter after 500 miles

Look at some of this debris that had already collected:

P6293867.jpg

Well, I didn't know that That's the value of these forums! No wonder in the "Engine De-contamination Thread" (URL posted above) my oil was so black! I'd already done one oil change but then didn't use fully synthetic. It was probably the first change to fully synthetic on that car since forever!

[Joseph80]

Thanks again for your advice, decide not flush the engine but to change the oil and filter again after 1,000.

Cheers