engine flush

[rollaholic]

i know this has been discussed before, but i thought i would chuck up this picture and see what people think.



its an engine out of a guys car from work, hes done heaps of kms in it and it recently ran a bearing. in fact it got so hot that the big end in question had burned off all the oil on it, and bits of bearing were scattered through the motor. oil starvation is the obvious issue, but im interested in where that blockage has come from.

he has been doing pretty regular servicing, but of course has no idea of the history. its a jap import mazda sp20 / familia thing.

the rest of the engine was pretty gunked up, and he did recently put a flush through it... made me think of sergei (and others probably) theory about flush potentially breaking those deposits free to cause mayhem.

curious what others think

[Dell'Orto]

We have a 02 318i with theN42 motor in at work currently, which was running well until the owner put a flush through it. They use lots of plastic components in the bottom end, and it would appear the flush has made them go brittle. Oil pump strainer fractured, and bits of it went up the pick up and jammed the relief valve partially open.
Also the oil pump chain guide snapped too when it was undone...be interesting to see the state of the top chain guides

[jacobrjett]

remember i have no smarts but personally i wouldnt do a flush, i would take the rocker cover off and get as much crap as you can out with a spoon and wire brush then take the oil pan off and give it a big wipe down then do a couple oil changes before doing an oil flush

the way i look at it you dont want all that crap loose in your oil system to clog up your filter and pickup

[rollaholic]

We have a 02 318i with theN42 motor in at work currently, which was running well until the owner put a flush through it. They use lots of plastic components in the bottom end, and it would appear the flush has made them go brittle. Oil pump strainer fractured, and bits of it went up the pick up and jammed the relief valve partially open.
Also the oil pump chain guide snapped too when it was undone...be interesting to see the state of the top chain guides

early 2000s range rovers have the BMW v8 in them, have seen a few with similar issues with the plastic chain guides failing and causing havoc. not sure that was caused by flush though.

is the strainer plastic on your N42 vehicle?

[phoenix]

hes done heaps of kms in it and it recently ran a bearing.

.... and he did recently put a flush through it...

Yeah I'd put money on it... Which big end went? furtherest from the pump?

[Bling]

Oh dear haha. I'd never do a flush, always considered it a throw of the dice. My 4age had a hard life in Japan and would put money on a flush killing it, quickly.

Obviously no way to know if the flush was 100% to blame for the engine in question. But if that's what it looks like on the inside, I can't see any good coming from using a flush. Bag of sand in the filler "flush" would likely be better

[Dell'Orto]

early 2000s range rovers have the BMW v8 in them, have seen a few with similar issues with the plastic chain guides failing and causing havoc. not sure that was caused by flush though.

is the strainer plastic on your N42 vehicle?

Used to be

[BZG Wagon]

I've always used flushes but I can't disagree with the logic on these boards.

I will say that flushing on my cars seems to result in the oil looking cleaner for longer, but that said every time I've had a rocker cover replaced (1/2 the cars I've owned) the engine looks virtually new with the cover off.

Maybe I've had a just good run?

Also once I've drained the oil, I pour clean oil through the engine until the oil pouring out the bottom runs clean. I also serviced my cars every 7,000kms (other than my GTT which was serviced every 5,000kms).

[Dell'Orto]

Regular oil changes are the best thing you can do. If it looks gunky, do lots of frequent changes, it works well. Or diesel oil if the viscosity is right

[rollaholic]

yes i cant see flush doing any harm as long as the engine is in a reasonable state to start with.

it was indeed the big end farthest from the pump.

do agree on regular servicing.

this is the closest i have seen to solid proof of flushes being potentially deadly though

[stoffa]

I just did a flush on my 3sge altezza, I used a good quality flush and left it idling to 10 minutes, I got told not to load the engine up, I dumped the oil immediately.
I refilled with some flash Fuch's GT1 Pro Flex 5w30 (ester based like motul 300v but much cheaper) im not sure if it was the flush or the oil but the car has lost a few hesitations it had. I guess something to do with the oil actuator thingies for the VVTi.

[rollaholic]

it catches me in two minds sometimes. some cars, like the VW 4 cylinder turbo in the passats n stuff has that stupid long convoluted oil feed for the turbo which gunks up. part of me sees a flush being beneficial here, and another sees something crusty breaking off and blocking it entirely.

[blindnz]

They're pretty much kerosene right? Isn't the idea to dissolve the deposits?

I don't think you would get any more "lumps" breaking off than you would by the the build up breaking a lump off by oil pressure..

[MAC_HATER]

I used to chuck flushes through my trueno every oil change, and didint think anything of it

but i haven't, and wont ever, do a flush on the supra, as it is very sludgy, black flaky shit everywhere under the cam covers, and it runs perfect, doesnt burn oil and its still reasonably clean when it comes to change time, so im not going to tempt fate

[KwS]

I know back in CHCH when i was doing work experience for a major dealer we used flush in every car that was getting a service. It was part of the standard service plan.

I do remember using flush in an old high KM Mazda Luce of mine, it did a good job of removing all the gunk that was stopping oil seeping through the seals... leaked like a bitch after that.

[rollaholic]

They're pretty much kerosene right? Isn't the idea to dissolve the deposits?

I don't think you would get any more "lumps" breaking off than you would by the the build up breaking a lump off by oil pressure..

i guess the danger is the ability to dissolve deposits means it dissolves the bond between big chunk of dried oil and your cylinder head, thereby leaving it floating around in the oil. it might or might not get completely dissolved.

we put em into almost every car at my work too.

i dont think its a problem if done regularly, but then as mentioned above regular oil changes should have the same effect anyway

[Sick Puppy]

Maybe it's that the flush is only part of the job? So would it be an idea to:
1. Perform the flush,
2. Remove the sump and rocker covers to get rid of as much dislodged gunk etc as you can
3. New oil and filter, nothing fancy, just something to run through engine
4. Drain oil, put in proper oil / decent filter

[allencr]

yes i cant see flush doing any harm as long as the engine is in a reasonable state to start with.

Then there really isn't any reason for it is there, only a choice between useless & harmful.

[Leon]

So in conclusion, the only good engine to put a flush through, is an engine that has been well serviced, therefore doesn't need flushing?

[lowseven]

Flushing sludged caked up engines can block oil galleries. usaully when a engine gets to that state there's no quick fix

We have a 02 318i with theN42 motor in at work currently, which was running well until the owner put a flush through it. They use lots of plastic components in the bottom end, and it would appear the flush has made them go brittle. Oil pump strainer fractured, and bits of it went up the pick up and jammed the relief valve partially open.
Also the oil pump chain guide snapped too when it was undone...be interesting to see the state of the top chain guides

cam chain guides break at 60-90 tho kms on those n42/6s common as problem, if you put a screwdriver down the oil filler cap hole and can move the guide its broke. there shit engines, will need 600bux worth of gear to set tdc up and the pcv valve under the intake manifold will also be blocked if it wasnt done around the 60-70km mark