changing oil

In the past, I've used National Tyres, with the vouchers they give out on their website / in the paper. They just drive the car up onto a lift, and drop the oil out of the sump in my experience. It's a while you wait sort of thing, so if you turn up with a hot engine, they'll be draining out hot oil.

The oil will be £1 a litre stuff, at best, which meets manufacturer specs from around 10 years ago. The filters are pattern ones. On the other hand, at least they weren't sucking the oil out through the dipstick tube last time I went...

Cheapest, yes. Is that what you really want though?

There is no way that they will take the trouble to warm the engine up. In fact, it's doubtful that they would even be aware of the need to do so. Bear in mind that the guys that work there are only one step up from fast food workers. Their training will be measured in hours, not years.

I would also be concerned that they are going to use the correct grade of oil. If your car has a need for anything other than a basic grade, forget it.

If you are unable or unwilling to do basic maintenance yourself, wouldn't it be better to ask around to find a reliable independent garage? Perhaps you could find one that would incorporate an annual service in with an MOT for a fixed price? There are certainly lots of places local to me that do this.

Chris

Some fitters in garages now prefer to suck the oil out though the dipstick hole because of bad experiences with stripped threads in sump plugs holes.

Its not what I'd do, but what's wrong with the dipstick method anyway? If you are not going to remove the sump to clean it out, might as well leave sleeping dogs lie.

Roger R

Usually due to ham-fistedness.

Letting the oil drain through the sump plug hole allows the force of the emptying oil to force more of crap that builds up in the sump to escape and leaves less old oil in the sump galleries to cause problems - and I would be rather annoyed if I saw a garage sucking the stuff out through the dipstick hole!

BTW, on many vehicles you have to carry out major works to remove the sump - and in some vehicles, the sump is actually the gearbox case.

Unbeliever

It can't be so bad a system since some cars can only be drained via the dipstick hole (such as Mercedes Smart cars)

John

If you live far enough away from the garage or big chain outlet, then travelling to one of them will allow the oil to reach its proper operating temperature. If not, then simply take the car for a drive to warm things up before get to your destination - simple!

Unbeliever

Bloody hell Mrcheerful, you must have been reading my mind to reply that fast! LOL

But I'm not rich enough to own a Merc (and got more sense to anyway) and not small enough to own a Smart car (nor do I want to) - and I believe that 'modern' is not always best in the car market.

Unbeliever

Snag is it's normally the person who did it up who was ham fisted, you only find out when you undo it & the thread comes with it :-(. Although it's an excuse to own another size of helicoil :-)

Why would that work better than (or differently from) the vacuum on the end of the pipe?

Isn't 'eradicating crap' the job of the oil filter, rather than a function of how fast oil swirls out of a hole..

Been a long while since I changed car oil but there never was much crap in the oil, BUT a look at the magnetic plug theoretically gave warning of problems if swarf appeared.

On Wed, 22 Jul 2009 19:14:37 +0100, Unbeliever mumbled:

Take it in on a quiet Saturday afternoon, with your own oil and filter. The place I take mine to seemed happy to whizz it on the ramp and change the oil for me, though I'm sure the tenner I gave them didn't go anywhere near the till...

MIke P

It happens that Duncan Wood formulated :

Well, the pipe which goes down through the dip stick hole would have to be much narrower than the bore of the drain plug. The drain plug will more likely be at a low point of the sump, aiding the oil dragging out the rubbish with it. The sucker pipe will only work while ever it's tip is well covered and the viscosity of the oil will break the suction a few mm before it is genuininly all drained out - whereas a sump plug can be left out until it all stops dripping.

You can touch the bottom on most sumps & if you've got bits bigger than the end of the tube floating about in your oil then it's far too & they're not going to come out with the oil anyway. You don't need to have the end well covered, it's a pump not a syphon.

Pump or syphon it will cause a localised dip in the oil level around it's tip and start to suck air, leaving quite a bit of oil it cannot suck out. Try draining a wide based glass of water via a straw without tipping the glass, to get the idea.

Ever since national decided to use 10/40 in my zetec engine (made it sound like a diesel & run crap when cold), I then always changed the oil myself. Since I got the picasso, after 2 changes having to drive on ramps & remove the undertray I decided to pay a garage £15 at the end of my road & supply my own oil, loads less hassle. BTW, my local National won't do oil changes on a saturday, they reckon they're too busy. They also bent my sill last time I had tyres , although it was too late to proove anything when I discovered it. They also cocked up my tracking, in fact they've never once got anything right

The same applies to the sump plug. If you're actually that worried about cross contamination you'd run flushing oil through it anyway.

Duncan Wood used his keyboard to write :

True but not quite to the same extent as would apply to suction, because gravity is working with you, rather than against you.

I've been changing my own oil for more years than I care to admit to - and have never seen any 'crap' come out with the last few drops. Or at least not on a car which has been regularly serviced.

But what do you flush the remnants of the flushing oil out with?

Me neither and I've done some real high milers