Engine Flush

Jimmy · Post by **Jimmy** » Wed Oct 01, 2008 11:39 am

As I am embarking on a voyage of discovery and picking a spanner up for the first time this weekend (read: doing an oil & filter change), is it worth putting some sort of engine flush through at the same time?

If so, has anyone got any recommendations on what flush to use?

Cheers

Jimmy

Big Brother · Post by **Big Brother** » Wed Oct 01, 2008 12:09 pm

Do you mean an oil additive? I remember Stu saying once on here that a mate of his put engine cleaner in when he did an oil change, unfortunately it removed all the crap that had built up over the years and so blew the engine to bits.

Jimmy · Post by **Jimmy** » Wed Oct 01, 2008 12:21 pm

My Grandad mentioned it on the phone when I told him what I was planning to do. Some stuff you put in after you have drained the old oil, run the engine for a while, then drain and fill with new oil. It gets rid of any crap that has built up.

I don't want to blow the engine to pieces tho.

rgreenhalf · Post by **rgreenhalf** » Wed Oct 01, 2008 12:23 pm

I've never used engine flush, if you're that worried its got crap in, then just run it with some cheap oil, even mineral, and do a filter swap afterwards. Let it get upto temp, take it out on a bit of a drive (not massive) then drain it. I've often used old oil I've got laying about to make up enough to 'flush' it with.

martinholmesuk · Post by **martinholmesuk** » Wed Oct 01, 2008 12:36 pm

I did a engine flush on the E30, Went to GFS and got there engine flush. Drained my oil then put flush in then run it for a while before draining and replacing with nice oil. I think it worth it.

gltease · Post by **gltease** » Wed Oct 01, 2008 12:38 pm

I think if your engine blows up after an engine flush, well then there are issues with your engine that need addressing.

martinholmesuk · Post by **martinholmesuk** » Wed Oct 01, 2008 12:42 pm

gltease · Post by **gltease** » Wed Oct 01, 2008 12:44 pm

Or dont use Petrol as engine flush !

Jimmy · Post by **Jimmy** » Wed Oct 01, 2008 1:31 pm

A further Q after speaking with someone here in the office - do I need to get a replacement crush washer for the sump plug?

guitarcarfanatic · Post by **guitarcarfanatic** » Wed Oct 01, 2008 1:51 pm

YES! just go to volvo as they only cost pence. A new sump plug is worth the extra quid or two as well as they can get corroded etc!

Big Brother · Post by **Big Brother** » Wed Oct 01, 2008 1:55 pm

The filter and washer only cost Ã‚Â£6 from Volvo

eEm · Post by **eEm** » Wed Oct 01, 2008 3:57 pm

Can't remember what its called now but the purple canned stuff, its about Ã‚Â£6. You add it to the old oil when the engine is up to temp, run it for 10-15 drain the oil replace filter etc etc. Or, and I've never tried it by the way, drain your oil and refill with deisel and run for 1-2mins max, drain and replace etc etc. Mechanic friend of mine used to do it but I'm not convinced by the cleaning power of deisel.

Jimmy · Post by **Jimmy** » Wed Oct 01, 2008 4:13 pm

I know the stuff you mean - Engine Flush from Wynns or something.

I like the idea of giving the internals a good clearout but am slightly perturbed by the odd story of it opening up weak seals etc currently held together with the very crud I want to remove.

I guess it is a gamble, and as the car is relied upon as daily transport I had better not risk it. Sensible decision?

martinholmesuk · Post by **martinholmesuk** » Wed Oct 01, 2008 4:41 pm

I used the stuff from gsf it was 5lt for 12 pounds

eEm · Post by **eEm** » Wed Oct 01, 2008 5:08 pm

Cheaper in the long term if you flush at each oil change, 6,000 miles or 6months isn't it? Not sure which seals you'd be referring to as surely rotating seals like crank shaft, cam etc will work best if they're clean.

Cerberus · Post by **Cerberus** » Wed Oct 01, 2008 5:42 pm

If, when you drop the oil, it is filthy horrible sludge then you might
consider throwing some cheap oil in there and running that for a bit.
(only a lil while) Then change that out with a flush included.

If when you drain it out it's not half bad then bang a new filter on
and put some decent oil in it.

C

Iroll480 · Post by **Iroll480** » Wed Oct 01, 2008 9:26 pm

Synthetic or semisynthetic oil will clean the internals of your engine perfectly. My first 480 oil change was with Castrol magnatec 10/40 + filter, drove it for about 500mls, and replaced it. Kind off black sludge came out! Now after the second Castrol + filter change and 2000mls it still looks transparant and clean on the dipstick.

Brasco · Post by **Brasco** » Thu Oct 02, 2008 7:36 am

There is advise on the forum not to use fully synthetic oil. IIRC it damages the seals.

Iroll480 · Post by **Iroll480** » Thu Oct 02, 2008 10:42 am

I heard this story too about fully synthetic. I doubt that it will damage seals. Pre 80 cars used different materials such as natural rubber for the seals. Those can be affected (swelling)by fully synthetic oils. But not our 480's, in these they used the modern, synthetic compound rubbers. Synthetic oils are really good at dissolving old crud. This can cause leaks because the crud keeps the oil in. For example old, hardened oilseals that wore in on the crankshaft can begin to leak because the oil residue disolves in fully synthetic. The residue filled the gap between crankshaft and seal. This happened on my B20F (the Volvo engine, not the Renault B20F) in my '73 P1800ES. I had to replace the seal, and relocate it a few mm so the new seal runs on a unscored part of the crankshaft. The synthetic oil just made it leak sooner as it would have leaked anyway in time. Had to replace all seals with a modern type of seal. That engine is still tight after 10 years running on fully synthetic after this conversion.
The same thing can happen if you replace very old brakefluid. System not leaking with the old fluid, put in new and voila it leaks around the seals because the old crud keeped them tight. This happened twice on cars (BMW 320 and an old Toyota Carina) of mine many years ago.