Not your usual oil thread (promise)

[RJ092]

Ok, so without getting into what oil should and should not be used blah blah blah..

I'm planning on changing the oil in my 300, but ill be changing the grade.

Now, mixing oil grades = no good, and I was wondering if the following will get ALL the old oil out :

1) running an oil flush - will this help to get gunk/ thin out the old oil making it easier to drain completely?

2) Run air through the system to remove any remaining oil ( oil cooler and pipes, anywhere else you can think of? )

3) anything else apart from flushing the system with new oil before chainging oil again??

really any opinions/views welcome. Again, this is not about what oil blah blah, just trying to get ALL the oil out the 300..

Thanks

 

[jamesmartin]

just drain and refill ,mixing wont hurt,

 

[thebiglad]

+1 - drain and re-fill. Use good quality oil.

 

[Tuskenraider]

Its not 1970 anymore

Mixing grades is fine.

Using flush however is not and will cause more trouble than it solves.

 

[RJ092]

lol. Got the info about oils from my grandad, probably why he's weary of mixing grades lol

What about trying to get as much of the old oil out as possible, obviously, the more fresh oil the better.

You guys have any ideas?

Cheers for the replies

 

[m1943]

If you're so worried about it - change the oil twice. Fill, run the engine, drain and re-fill. Mostly a waste of time and money though.

 

[pussa13]

Would it be an idea to let it drain overnight?

 

[Tuskenraider]

Would it be an idea to let it drain overnight?

Wont make much difference, you will always get hang up in the head and around 100-200ml left in the sump. As said if you are that worried but the cheapest mineral oil you can find, stick it in, start the engine and let it idle for a minute then turn it off and drain.

Although unless the old oil had been in there for ages i wouldnt bother.

 

[RJ092]

got the disco last July so I changed the oil then... been parked up since end September getting restored (started as a roof respray, ended up taking every panel off and removing all and any rust lol).

i usually do 2 oil changes, one for winter and one for summer and i thought i'd try a new oil grade this time

Again, thanks for all the info guys

 

[gemsdad]

The amount of oil left in the engine after you have drained,do it hot,is negligable.Just refill with a good make of filter,and a decent quality oil.I think your grandad has been telling you how to be over cautious really.

 

[Tuskenraider]

Incidentally what grade are you switching from/to ?

 

[Sheffield]

I think the idea of draining the oil hot dates back to the days when engine oil was thick when cold and thin when hot, but nowadays there is little change in viscosity. I therefor drain the oil when the engine is cold and has not been running for a while. this ensures as much as possible of the oil is in the sump, and can be drained, and as little as possible still in the oilways.

 

[Turboman]

I think the idea of draining the oil hot dates back to the days when engine oil was thick when cold and thin when hot, but nowadays there is little change in viscosity. I therefor drain the oil when the engine is cold and has not been running for a while. this ensures as much as possible of the oil is in the sump, and can be drained, and as little as possible still in the oilways.

Personally I always do it hot, and fresh off the road. Into the shed, drain plug out! Any contaminants should be suspended in the oil, not settled onto the bottom of the sump. Then I leave it a few hours for any to run down out of the oilways.

Like the others I never flush, just regular changes with quality oil, never had a problem when changing brands, or from mineral to semi-synth etc.

 

[trax]

i find a huge difference between hot oil and cold.. especially with an oil extractor.

re the op, multigrade oil can do both summer and winter you know

 

[doliver]

As a Granddad who has had 8 discoveries in 24 years the problem used to be if one used a detergent oil after using a non-detergent, the detergent oil could loosen the internal deposits and these could clog up the small oil-ways inside the engine. Flushing oil could loosen and break up these deposits a bit more so it did a bit of good. If you have been using normal oils then flushing could do more harm than good, just do an oil change. I use 5W 30, nice and runny.

 

[Turboman]

As a Granddad who has had 8 discoveries in 24 years the problem used to be if one used a detergent oil after using a non-detergent, the detergent oil could loosen the internal deposits and these could clog up the small oil-ways inside the engine. Flushing oil could loosen and break up these deposits a bit more so it did a bit of good. If you have been using normal oils then flushing could do more harm than good, just do an oil change. I use 5W 30, nice and runny.

Well if you looked after them so well why have you had eight? One would last that long if it was well maintained

You should always be using a high detergent oil in a diesel!

 

[Critical Mick]

There used to be an old guy in our street who used to drain the oil, stick a gallon of diesel in, take it for a 5 mile run then drain the diesel out and put the new oil in. He swore by it for clearing the accumulated crap out of the oil ways.

 

[jamesmartin]

There used to be an old guy in our street who used to drain the oil, stick a gallon of diesel in, take it for a 5 mile run then drain the diesel out and put the new oil in. He swore by it for clearing the accumulated crap out of the oil ways.

i bet it did wonders for the bearings and rings and followers too

 

[johnlad]

i bet it did wonders for the bearings and rings and followers too

Yeah but they were clean at re build time

 

[RJ092]

Thanks for all the info guys! Honestly really do appreciate it!

There used to be an old guy in our street who used to drain the oil, stick a gallon of diesel in, take it for a 5 mile run then drain the diesel out and put the new oil in. He swore by it for clearing the accumulated crap out of the oil ways.

Lol, i dont think putting diesel into an engine and running it hot is too smart of an idea, taken that diesel is only heat ignition, all be it a very high heat..
I'd much rather throw in one of those engine flush things in that case..

As a Granddad who has had 8 discoveries in 24 years the problem used to be if one used a detergent oil after using a non-detergent, the detergent oil could loosen the internal deposits and these could clog up the small oil-ways inside the engine. Flushing oil could loosen and break up these deposits a bit more so it did a bit of good. If you have been using normal oils then flushing could do more harm than good, just do an oil change. I use 5W 30, nice and runny.

Incidentally, I want to go the opposite way ( in summer that is, It's 35 deg in the shade in Malta, plus stop start traffic EVERYWHERE, and constant hills, and the truck lives outside on the road with no shade! ) Rave quotes 15W 40 iirc and I'd like to use something ~W50!

winter will see 15w40 in it again probably.. My parents get to use my truck then to go shopping or take my dog out so not much use at all..
Meanwhile i come back to study here and get stuck with an 02 plate 1.8 astra :'( (miss my truck so much! )

Incidentally what grade are you switching from/to ?

guess the above answers that question lol. Although, i dont need an oil with a large garde variance.. summer temps are 20 -40 deg.. Winter sees 0deg(never actually 0, but close ) - 15 deg.. again, in the shade not out in sun