There was a thread a while back that I can't find now talking about using suction pumps to do oil changes. I saw one in Europaarts for £30 and thought I would give it a go on my Mercedes. How quick, easy and clean was that?!?!
1) A quick drive to warm the engine.
2) Remove the old oil filter. This is at the top of the engine and at the front so really easy to get to.
3) Stick the new oil filter in.
4) Put the hose from the pump down the dipstick and the other end in a container, switch on and wait 5 minutes for the pump note to change as it sucks air instead of oil.
5) Put the new oil in.
I was concerned about how much oil it would suck out. The capacity is 8 litres and I refilled to the correct point on the dipstick with 8 litres so must have been pretty much empty. I guess it would have been more awkward with a difficult to reach oil filter but that is the only thing that would make it difficult. Opie oil give you an oil rag to wipe the dipstick and another to wipe your hands and that was enough to clean up with. A whole heap easier than getting the car on ramps and draining through the sump.
Sounds easy, but I think I'd prefer to drain all of the sludge and crap that accumulates at the bottom of the sump too. Can't see a pump reaching that!
Yeah I can't in my soul trust in "suck out" oil changes. Yes I know modern cars are engineered for it, I know smarter people than me have put countless hours into it, and also I know that sludge and oil can and will stay in the sump even with an old school drain. I don't care, this apparently is a step too far, the hill I irrationally die on. I want to look at my magnetic sump plug and go "hmm".
(I just took the sump off an engine with Mystery Miles on- the car had done a quarter of a million but it was at the very least the second engine and I think it'd been rebuilt too. But even so, there was enough crap in there to tarmac a driveway. The actual oil came out black but not bad looking at all, it was presumably just sitting on top of the slime. )
My MX5 has a fumoto tap on and takes exactly 5 litres, I can change the oil in minutes and never spill a drop, lovely.. Filter takes a little longer because it's in an awkward place.
Yeah I can't in my soul trust in "suck out" oil changes. Yes I know modern cars are engineered for it, I know smarter people than me have put countless hours into it, and also I know that sludge and oil can and will stay in the sump even with an old school drain. I don't care, this apparently is a step too far, the hill I irrationally die on. I want to look at my magnetic sump plug and go "hmm".
you are me. I just can’t. But I probably should.
Yeah I have to get under the car to change the filter as it's in a really awkward place.
So for me, it's just easier and cleaner to get it done at a garage.
Just think yourselves lucky you don't have a bike where you have to remove the bash plate to get at A. The oil strainer or B. The drain plug, but to remove the bash plate you have to remove the side stand (bike doesn't have a centre stand) and side stand switch and I've yet to get at the drain plug because the exhaust is in the way - recon I need to make a special low profile socket to get at the plug without removing exhaust... and breath.
Go on then STW, recommend me a pump to suck the oil out.
I’ve still got to get under my car and van to access the oil filter, do I might as well drain via the sump plug while I’m there to get as much out as possible. But sucking most of the oil out the filler tube initially would make the job a bit cleaner.
My van takes almost 10 litres and I’m not sure the manky old basin I use to catch the oil is big enough…
I've been using a marine engine oil extractor thing on my Volvo with a Peugeot based 1.6hdi engine for 250,000 miles. With oil replacement (Inc oil flush every 10k miles). It's a 2011 jobbie.
Head gasket going means I've just traded it in, but the time and effort saved is worth it.
On my Kuga, the biggest PITA is taking off the oil-soaked fibre under-panel sound reducer below the engine bay, to access the filter as well as drain plug. As Ford were too dumb to put access points in it.
By the time I've done that, I've already lifted the car onto stands and crawled under. So taking the drain plug out is the least problem (its a 1/4 turn bayonet plastic thing with an R clip to secure, not a proper threaded plug).
I did have to buy a big catch bowl as the usual 6 litre ones are too small and are brim-full = guaranteed spill when moving. Opie had a 16 litre catch pan for not-that-much, so got that with the latest oil supply.
Sealy TP9312 is what i used.
You drive the car first to sit up the oil which means most crud comes out with the oil. What didn't probably wouldn't through the drain plug either. So unless you remove the dump it is much the same.
I drained into a 5 litre can until it was nearly full, turned off the pump and used a second can do there was no spillage. Much easier than ring to drag out a catch pan without spiling any, assuming you had a big enough catch pan.
Smoother of my cars has the filter underneath so that will be going up on ramps but I will still probably drain most the oil first with the pump anyway
I feel like I'm missing something obvious here, but why would there be oily sludge at the bottom of the engine? Isn't that what the filter is for? And just to cap that off, if it doesn't suck out with a drain pump, why do you think it would drain out of the sump plug hole?
Exactly Flaperon. Even if there was thicker sludge at the bottom, you drain the oil at the bottom first and all of the rest gets sucked through as the level drops. Perhaps pull the drain plug every few years if you have fitted a magnetic drain plug but it has been proven years back that they don't doo that much anyway. If there is lots of metal swarf floating in your oil then you have a bigger issue than an oil change. I do agree that it is different to using the sump plug but most recent stuff I have seen says it is as effective and a damned sight nicer to do.
I will be doing the BMW tomorrow so let you all know if that is as easy again. The Vauxhall has its oil filter only accessible from underneath and even then access is blocked by the exhaust pipes so if you warm the engine to get out the oil properly then you burn yourself on the pipes or drip oil on the hot exhaust. That is according to YouTube so I might wait for the weeknd to do that one.
I think it's more the possibility of something being left over with a pump Vs using the sump plug. Think of drinking with a straw Vs having a hole at the bottom of the cup, there's always a little bit left with a straw
Been using the pump on my Mazda for a few years now. An absolute joy. I do changes every 6k as it's a Euro 6 diesel. I watch the oil level religiously on the dipstick and the pump pulls out exactly what I'd expect. Did a change a few weeks ago and as an experiment I removed 90% with the pump, and removed the sump plug to drain the last 10% into my oil pan, all of which came out fine with no sludge or bits to worry about
but I think I'd prefer to drain all of the sludge and crap that accumulates at the bottom of the sump too. Can't see a pump reaching that!
Why though? After the crank's been spinning above it churning it up at a few thousand RPM and the car's been driven down Britain's finest roads and over supermarket speed bumps it'll be pretty stirred up.
Then the pump is just a pipe with a hole on the end at the lowest point of the sump into which the oil flows, just like the drain plug, so even if there was rubbish in the bottom of your engine both ways of removing the oil would be equally effective.
I just took the sump off an engine with Mystery Miles on- the car had done a quarter of a million but it was at the very least the second engine and I think it'd been rebuilt too. But even so, there was enough crap in there to tarmac a driveway.
Proving that the sump drain is equally useless?
Just think yourselves lucky you don't have a bike where you have to remove the bash plate to get at A. The oil strainer or B. The drain plug, but to remove the bash plate you have to remove the side stand (bike doesn't have a centre stand) and side stand switch and I've yet to get at the drain plug because the exhaust is in the way - recon I need to make a special low profile socket to get at the plug without removing exhaust... and breath.
Could be worse, could be a Harley.
Step 1: balance the un-balanceable quarter of a ton thing on a jack stand.
Step 2: Drain the oil via the inconveniently located drain hose (why? Why not just give us a plug in the tank?). It's 20W50 so it'll take a while to drain, go make a cup of tea or proceed to step 3 if you're doing the gearbox while it's on the stand.
Step 3: Drain the primary/gearbox. This has a drain plug, just to rub it in that they did know this would be easier and more reliable than a bit of fuel hose, a plug and a jubilee clip.
Step 4: Remove the derby cover. Why? Why unlike every other bike on the planet could we not just have a sight glass?
Step 5: Fill primary until the teeth on the clutch are just submerged. This requires 3 hands, a funnel, torch and x-ray vision because wedging the funnel in obscures your view of the clutch.
Step 6: Re-install the derby cover, this will now leak so go ahead and order a new o-ring.
Step 7: The filter, which is in an awkward place because if you squint from 100ft it sort of looks like the generator on an old shovelhead. It doesn't. No amount of carboard, milk cartons or proprietary expensive funnel doodahs will stop you dumping black oil all over the front of the engine case.
Step 8: Fill the filter with oil. WTF. It goes on sideways, so now having mopped up the oil you just spilt, you're about to add some clean oil to the mess.
Step 9: Fill the oil tank. This is the only easy bit, because it's a Harley and you'll probably be doing it a lot. You remembered to put that bung back in the drain hose didn't you...........
Step 10: Be thankful it's not a big-twin engine and you don't have another separate gearbox to drain and fill as well.
There may be extra steps depending on what "custom" parts the previous owners fitted (or Harley, you'd think at least their own bits would fit, but they don't).
Why though? After the crank's been spinning above it churning it up at a few thousand RPM and the car's been driven down Britain's finest roads and over supermarket speed bumps it'll be pretty stirred up.
I'm not so sure. My experience is mainly on motorbikes tbh. I get the engine as warm as I can still manage to work on before dropping the oil*. Then I leave the sumpplug out for ages. Initially the oil flows out looking fairly clean but, if left for a few hours, there is almost always thicker, nasty looking stuff that gradually oozes out.
Granted, the inside of (motorcycle) engine sumps are rarely smooth like a baking tray. They tend to be diecast with lots of webs and pockets. Nothing, apart from a strip, will get everything out!
*My method of draining developed over the years: I warm up the engine, remove the filler plug, then place the nozzle of a vacuum vaguely over the filler hole. I can then undo the sump plug without any oil coming out and burning my hands. I then remove the vacuum and the oil flows out. Clean and easy... other than the time I got the vacuum too close!
The vacuum over the oil filler hole works on cars too, provided you have a mte up top to hold the vacuum steady, preferably a mate underneath undoing the sump plug incase the vacuum trick doesn't work.
I just took the sump off an engine with Mystery Miles on- the car had done a quarter of a million but it was at the very least the second engine and I think it'd been rebuilt too. But even so, there was enough crap in there to tarmac a driveway.Proving that the sump drain is equally useless?
Not necessarily equally, or even better or worse, who knows? Just that neither is perfect and different sumps are differently good or bad, I don't think there's even necessarily one best way but for sure there's worse ways. I can't remember but i think maybe it was maybe my uncle's sierra that when you jacked it up as directed in the manual, the drain plug was at the front so you left about a litre of oil in it every time, unless you jacked it back down mid-drain. But also if you put the advertised amount of oil in, that meant you overfilled by a litre too.
Some are really well placed. There's a lot of ways to do it wrong, there's an old jeep where they went "let's go all in and make the best oil drain ever", and they did, perfectly at the bottom and the oil change procedure included a tilt so basically every drop went to the drain... but it also meant it was quite exposed being at the lowest point, AND they put all the threads etc outside the sump as an outie instead of the more common innie, and so loads of people bumped it on rocks and instantly drained every drop out of the engine.
But yeah, I fully concede that a suck-out design could be just as good or better, like I say it's not all rational this, out the bottom just feels better.
I have a Pela vacuum pump, it works as well as draining from the sump but my cars have the filter underneath so a jack/ramps are involved anyway. At that point I always have a good nosey underneath and can spot issues starting to develop and check the rust proofing.
However I did have a MK4 Golf that had the filter on the topside of the engine so that got Pela suction oil changes.
I think I'd prefer to drain all of the sludge and crap that accumulates at the bottom of the sump too. Can't see a pump reaching that!
Second this.
Just think yourselves lucky you don't have a bike where you have to remove the bash plate to get at A. The oil strainer or B.
IIRC, the first front wheel drive Lotus required detaching the front subframe and engine from the body in order to change the oil filter. Apparently only held together by six bolts or something, but not something you want to do in your driveway with a trolley jack and some blocks of wood. I guess the dealers had a jig to hold the two halves of the car.
I feel like I'm missing something obvious here, but why would there be oily sludge at the bottom of the engine? Isn't that what the filter is for? And just to cap that off, if it doesn't suck out with a drain pump, why do you think it would drain out of the sump plug hole?
So as ever, a bunch of reasons. Partly it's that oil sludge is thick and heavy, so it sits at the bottom but also on other surfaces like internal braces, baffling etc. Almost by definition it's not mixing freely with the oil, if that happens what you get is really dirty manky oil and less sludge, like very thin sloppy wet mud, sludge is when the dirtiest and mankiest part of the oil is so bad that it settles out, like thick mud with substance at the bottom of a puddle. (in my case, I reckon it was mostly oil-with-carbon from piston blowby
Oil pans are sometimes very convoluted, to help control the oil and stop it slopping (more common on performance cars where gforce can literally push the oil out of the sump and onto the sides of the engine causing you to suck air) , or to guide it more directly down into the sump, or more complicated stuff like windage trays (to capture oil mist out of the air in the engine) and crank strippers. Plus, sometimes, reinforcement for the actual sump- alu ones tend to have webs, steel ones often will have bits welded in. And these are all places for sludge to build up.
Also, the oil pickup isn't right at the bottom- it's exactly like a straw, if you stick it right to the bottom of the glass you get restriction, the best place to have it is far enough up to avoid interacting with the bottom. (and sometimes you get a bit of room to spare, so that if the sump gets bumped it doesn't drive straight into the pickup and block it) Some pickups have holes in the side instead of the bottom to avoid this, but that in turn still means you're not sucking oil from the bottom. It's always a compromise, I doubt there's one perfect answer.
The filter can only filter out stuff that actually gets sucked up by the oil pump, so anything that's thick enough to not mix freely with the oil, or heavy enough to sit at the bottom, or that's settled somewhere away from the pickup, won't get to the filter. And tbh that's not always bad, in the sludgy engine I mentioned if all that sludge had been sucked up into the filter it'd probably block it, instead it's basically isolated itself into the bottom.
Here's a sump I took off a fairly modern subaru. You can see a couple of things- this one's pressed steel not alu, it's very shaped (more than most) so that it's basically a very deep narrow glass and a very long straw, which helps ensure there's always oil to suck even if the amount of available oil is low cos it's all off oiling, or returning to the sump. It's got a bunch of metal in it to reinforce it and to hold stuff like the dipstick in place, which can all hold slime and debris. And also, the drain plug isn't right at the bottom, and it sticks into the pan (there's a little hole at the bottom so it's not as pronounced as it seems, but, it's still not like a sink drain. You can't see the pickup but it goes into the bit where you can see the oil dregs.
So again, compromises. Internalising the threads etc for the drain makes them less vulnerable to corrosion and impact, but makes it drain less well (less of an issue with alu sumps, which are thicker walled) Likewise it's not right at the bottom, it's more protected to one side. Both the drain and the pickup want to be at the deepest part, they can't both be so the drain gets second place because if the pickup starves for a second at high revs the engine dies.
The deep sump makes the engine taller, which isn't a problem for subaru because the engine's flat, but you can't really have an 8 inch deep sump on a normal upright car engine, my MX5's sump is like 3 inches deep and has a fraction of the oil control. But also this depends on the rest of the car- the subframe and steering rack are usually under the engine so there's lots of packaging requirements, the best place for the oil drain might very well be exactly where the steering is.
@tinas that'll be reasons not to buy a Harley #125 & I like big vee twins
Just opened the bonnet on the Vauxhall Sh1tbox. You can't even open the oil filler without having to tilt the cap sideways to get it out.
https://photos.app.goo.gl/ZJ1J5eZP1N8e3RMn6
Looks like I am going to need the suction pump to get oil INTO this one!
Mercedes design the sump for suction removal.
On the om642 the dipstick sits in a well at a low point of the sump.
So suction oil removal is very effective and will remove the same amount as a sump plug drain.
Depends on the car, my Kuga retains some oil when sucked, so I do the last dribble from the plug. Still worth using the pump as it is much less messy without the initial full pressure dirty money shot.
Top tip, drain the pump slowly without it going beyond horizontal or the oil gets into the wrong part of the pump and leaves oily rings wherever it sits. There is a label to say so on my pump, which I ignored. A simple but tedious job to cure.
