Oil Changes

survey

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I believe that many garages now remove old engine oil by sucking out the oil rather than draining via the sump plug. Is this to be recommended as surely when oil is removed via the sump plug there is a better chance of old oil residue in the sump being removed than via sucking/pumping out? Should one insist that the garage drains via the sump?
 

Number_Cruncher

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>>Should one insist that the garage drains via the sump?

IMO, no.

If you have such a significant amount of debris in your sump, you have bigger and more fundamental problems than whether the oil leaves via the plug or via the dipstick tube.

A vacuum pump will get more oil out than draining via the sump plug, and the vacuum pump can also be used to remove oil caught in the traps inside the filter housing on some models.

I have never seen any evidence to support or to damn either method - as far as I know, there is no reason to believe that sucking the oil out will reduce the life of the engine in any way.

So, where's the evidence?
 

television

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Any residue will stay in the sump with draining, and flushing a little would be the only thing to do, but this is not done.

Many of the experts and hands on guys say that sucking out does a very good job
 
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survey

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Any residue will stay in the sump with draining, and flushing a little would be the only thing to do, but this is not done.

Many of the experts and hands on guys say that sucking out does a very good job

Thanks for your opinion. I did just wonder which method was more efficacious for the longevity of the engine.
 

duncanh

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Personally, I suck the oil out of my Mercedes, but drain it out of my other cars.

Why? - Purely for convenience. With the Mercedes I need to get right under the car to take off two large sheets of plastic. Other cars in the family don't have them, so it is easy to get the sump plug out. With my Peugeot I don't even need to jack it up.

With the suction method there is also no need to remember to buy a sump plug washer.

I believe that I get all of the oil out by suction. My 611 engine will take all of the 6.5 litres that I gave it without complaint. (I used the engineering menu on the dash, it read 6.5 litres after refilling).

The question about whether any nasty residue is left behind? Should not be a problem, the oil filter will stop it reaching anywhere it shouldn't. I don't see any long term issue, my car has done 185,000 miles and the engine is likely to outlast the bodywork.

I had a look underneath at the rear last week when I changed the rear ARB bushes. Much surface rust to be seen on the rear subframe and elsewhere. The paint is flaking off the rear wheel arches. It has only just turned 7 years old. I have a tin of POR-15 on order. That will be my next job.
 
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survey

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duncanh - I have the same scenario. With an excellent Peugeot 205 diesel it was easy to get at the sump plug. The wife's Skoda has an undertray and yes you have a point that one doesn't have to remember to have a sump washer at the ready with the suck-out method!
 

anisamy1

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I believe that many garages now remove old engine oil by sucking out the oil rather than draining via the sump plug. Is this to be recommended as surely when oil is removed via the sump plug there is a better chance of old oil residue in the sump being removed than via sucking/pumping out? Should one insist that the garage drains via the sump?

It happens at many place but it is not recommended.
 

Myros

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I've been a sucker since I joined here

as MJTray told me where to buy the relevant kit.
I have to jack the SL up to get the filter off, but can get at teh others from on top.
I've been sucking the oil out on all the cars since about 2004. No problems encountered. And I change the oil well before the indicated time anyway, despite using synthetics.
 

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