To flush or not to flush?

J

Julian24110

Member
 Cornwall
Not being able to go anywhere for the last 12 months my Z4 has done a lot of short runs, mainly 5 miles to work and back. Mayonnaise around the filler cap has become noticeable as a result. She’s not had an oil change since November 19 (but only covered 3K) so this is next on my list.

What is the general opinion here on flushing these engines? Is this a wise thing to do to a 17yr old 63K engine? Should I just change the oil and take it for a long, brisk drive?
 
Julian24110 said:
Not being able to go anywhere for the last 12 months my Z4 has done a lot of short runs, mainly 5 miles to work and back. Mayonnaise around the filler cap has become noticeable as a result. She’s not had an oil change since November 19 (but only covered 3K) so this is next on my list.

What is the general opinion here on flushing these engines? Is this a wise thing to do to a 17yr old 63K engine? Should I just change the oil and take it for a long, brisk drive?
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Personally I'd change the oil, but more knowledgable folks here may advise something else....
 
For the cost of oil and the peace of mind - annual oil and filter changes are my personal choice.
High Mileage users get to do an interim oil change - instead of waiting for the 2 year or mileage limit.
Low mileage users get to drain the oil and accumulated condensation annually.
Win - Win
Doing low mileage and then storing a vehicle with emulsified oil over the winter is not a good practice.
Hence My mowers and power implements as well as motorcycles all get oil changes prior to a winter lay up.
They are then stored with fresh oil and minimal water!
 
Have used engine flush on mine when I got it and changed the oil and filter and Gearbox and Diff fluids so I knew what was in there. Used a bottle of flusher bought at a motor factors and followed the directions on the bottle. Ran the car up to temp after having added the flusher then drained and filter changed. New oil put in and that was it. No problems after doing it and it will get an annual oil change in the future, low miles as its a weekend car.
 
I’m sure the book says 2 years between service anyway? If you’re local to Gatwick you’re welcome to borrow my vacuum pump. Can do the change yourself in a matter of minutes via dipstick. I do mine in between service book stamps just to keep it fresh, whether your driving lots or not :)
 
Thanks, I’m in Cornwall so cheaper to buy my own vacuum pump 😜

I usually religiously change oil once a year but this too has been a victim of lockdowns and having converted my garage into a kitchen! It is also an almost daily driver.

I am definitely changing the oil as soon as I can but was wondering whether to run a flush through too. I have read that BMW don’t recommend it and I’m also aware it can expose worn seals in high mileage engines. This isn’t a high miler but it is 17 years old. I do want to give the new oil the best chance rather than mixing it with old Mayo / sludge.
 
I'd suggest that if you have an indication of condensation i.e. mayo in the filler cap that your problems will probably run deeper than what you can solve by an engine flush alone.
Your CCV system will probably be gunked up too, necessitating replacement.
If it's on the orignal it will only be a matter of time before it fails and condensation build-up will only accellerate/exacerbate the problem.
If not replaced you will probably experience high oil consumption, even after flushing your engine.
If you decide to replace go for the cold climate version which has thicker tube lagging but to really solve condensation buildup issues STOP doing short journeys!
 
I’ve changed the oil and filter every year (since I’ve owned it) after it comes out of winter hibernation. Change plugs and other filters every other year. :thumbsup:
 
Have you seen the lanes and hills in North Cornwall?! 😂
Ironically I am a keen cyclist but cycling regularly to work is not really practical on my commute unless you are an iron man triathlete. Making the wife walk more and taking the main family car may be better, partly as it’s a lease so not my problem!

I have tested the CCV and there’s a hint of suction at the oil filler but no more than I would expect. But I agree it’s only a matter of time so is also on my project list for this year.
 
Depends if it`s a number 1 or a number 2 and if you`re on a water meter
 
Julian24110 said:
Not being able to go anywhere for the last 12 months my Z4 has done a lot of short runs, mainly 5 miles to work and back. Mayonnaise around the filler cap has become noticeable as a result. She’s not had an oil change since November 19 (but only covered 3K) so this is next on my list.

What is the general opinion here on flushing these engines? Is this a wise thing to do to a 17yr old 63K engine? Should I just change the oil and take it for a long, brisk drive?
Click to expand...

Using a flush is fine, but be weary of which one you use. Many on the market are solvent flushes and these are to be avoided, the ones to use are detergent based flushes that use oil as a carrier. Millers is ur most popular one.

Cheers,

Guy
 
I always avoid flushes, for the chance that it will loosen debris in the engine and cause potential damage from moving around bearings and chains. Using the vehicle for such short distances and not getting to temp to clear any condensation is the main issue. Using a flush wont necessarily stop the problem or clear it either. Can you extend the drive to work, maybe a couple of times a week to try and get the engine up to temperature ? I had to take our Volvo to the local Wickes the other day as said low battery , as we aren't using it for journeys of any sizeable amount. Was 54 miles to get there and back :wink: . Its an awkward time for cars and owners still , but we are getting there. I would extend the drive for a couple of goes, then check the cap to see if the mayo is lessening and then change the oil and filter and continue.
 
I've had an oil change at the end of last year and have a bit of mayo. I clean it to remove it (as best as I can between drives). Perhaps you need to try going grocery shopping in the car, via the scenic route? Then realise you forgot the milk once you're home and go back out again :rofl: :D
 
Thanks, we’re getting to the answer I was after. I have made my 4 miles into 20 miles home twice out of 3 times this week, yesterday with the roof down 😎

Oil change kit arrived yesterday and plan on doing that tomorrow. I bought a bottle of Millers fully synthetic solvent free flush to put through first. Sounds like that was the right stuff.

Hopefully come April I can take it for a proper drive. We’ve been in some sort of restrictions ever since I bought the car and I’m itching to take it on a road trip!
 
Good to see oilman from Opie Oils chip in there with advice regarding the flush additive, good tip thre for the Millers product.
 
colb said:
Good to see oilman from Opie Oils chip in there with advice regarding the flush additive, good tip thre for the Millers product.
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Joined a while back too, so should feel pretty honoured as this was his first post OP!
 
13 years of silence broken!

So I used the millers flush today and then changed the oil and filter. No sign of anything milky in the old oil so all looks good. The two 20 mile runs this week had cleared some of the Mayo at the filler as well. Cleaned out everything I could get to so should all be good now. Just have to drive the long way home more often!

Coincidentally I bought the oil change kit from Opie Oils 🧐
 
Julian24110 said:
Oil change kit arrived yesterday and plan on doing that tomorrow. I bought a bottle of Millers fully synthetic solvent free flush to put through first. Sounds like that was the right stuff.
Click to expand...

Yup that is the stuff. :thumbsup:

The way the Millers one works (and there are others like it) it is essentially an engine oil and uses all the same detergents you would find in a normal good quality engine oil just in more quantity/concentration if you like. You can run their flush as an engine oil for a period of time if need be.

Cheers,

Guy
 
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