those top-side oil change pumper thingies thru the dipstick tube?

[Kingcreek]

I have a small sport coup (Daimler/Chrysler Crossfire) that is ready to roll out now that good weather is here and I do almost all my own service and maintenece on several vehicles, tractor, mowers, and other motorized equipment. I don't put many miles on the sports car and I use synthetic oil. Problem I run into on this thing is its too low to the ground to use my ramps or floor jack and there is a belly pan shield that has to be removed to get to the drain plug. major PITA. the oil filter element is conveniently located on the top of the motor.
I had considered one of those $40-50 pumps 
http://www.northerntool.com/shop/tools/product_390306_390306
that pull from a tube fed thru the dipstick. Never spent the money because I don't need it for anything else around here and I think draining out the bottom is better.
Last week I spotted a heavy duty plastic 5 gal container in the recycling bin and I'm always on the lookout for containers I can use for waste oil so I took it home. I had a rare intelligent thought and I used 6ft of small plastic tubing (.30/ft) and drilled a hole same size in the top of the jug. The shopvac hose fit snugly into the screw cap opening and created plenty of suction.
Success! pulled all the oil into the jug in a couple minutes for $1.80 plus the cost of the oil/filter. Managed to lube with long flex grease gun. Compare to the dealer gets $130 for the oil change and lube.

[Tuco]

I see what you did there and I will spend the greater part of a weekend trying to replicate your success!!!

[RoadKingLarry]

I just can't see those things doing a good job of getting all the old oil out.

I run the Mrs.'s Mustang up on a set of ramps to pull the oil plug.

[Kingcreek]

I just can't see those things doing a good job of getting all the old oil out.

I run the Mrs.'s Mustang up on a set of ramps to pull the oil plug.

I agree with you but the hassle of getting the drain plug out and the low miles and synthetic oil make this an easy one.

[zahc]

We used to use a canister with a manual pump handle to do boats--there's pretty much no other way to get the oil out. It worked very well.

I have an old freezer compressor that I have been thinking about making a vacuum pump with for bleeding brakes, but I can't find a container that can 'hold' vacuum without collapsing. I wonder if the shop-vac method would work for a brake bleeder.

[charby]

We used to use a canister with a manual pump handle to do boats--there's pretty much no other way to get the oil out. It worked very well.

I have an old freezer compressor that I have been thinking about making a vacuum pump with for bleeding brakes, but I can't find a container that can 'hold' vacuum without collapsing. I wonder if the shop-vac method would work for a brake bleeder.

Do it from the master cylinder under pressure, they sell these for about $100 to flush your brake lines.

http://www.egrbrakes.com/power_flush_kit.htm

Similar to the link above, but I have seen them for $70-100 other places.

[White Horseradish]

I have an old freezer compressor that I have been thinking about making a vacuum pump with for bleeding brakes, but I can't find a container that can 'hold' vacuum without collapsing. I wonder if the shop-vac method would work for a brake bleeder.

5-gallon plastic buckets might work. They actually make lids with shop vac ports for them.

I have a power bleeder for my Volvo I made from a garden sprayer.

[230RN]

After I got too orippled up to climb under cars, I used a hand pump and tubing to get the oil out of my 240Z through the dipstick tube.  Seemed to reach all the way to the bottom of the oil pan, but I figured even changing 95% of the oil was better than changing 0% of the oil.

Zahc, vacuum vessels have to be a lot thicker than pressure vessels.  With a pressure vesssel, the tensile stresses tend to "spread out" around the walls, but with a vacuum vessel, the outside compressive forces seem to concentrate on one weak spot and the vessel collapses catastrophically.

If you've ever wondered why vacuum cleaner hoses are ribbed, that's why... extra strength to prevent them from collapsing under the "vacuum."  Same thing with large vacuum-packed food cans.  You'll notice a lot of them are ribbed around the middle of the cans to keep them from collapsing.

I found out about pressure-versus-vacuum vessels once when I had to design a pressure/vacuum chamber for simulating altitude differences.  A pressure vessel to handle the design pressure needed a wall thickness of only 1/16"*, but to handle the vacuum, it had to be 3/8" thick.  (Consult your "Machinery's Handbook" for details.)

Terry, 230RN

*Actually, it was a lot less than that, but one had to consider handling stresses, etc.

[Hawkmoon]

I have an old freezer compressor that I have been thinking about making a vacuum pump with for bleeding brakes, but I can't find a container that can 'hold' vacuum without collapsing. I wonder if the shop-vac method would work for a brake bleeder.

Are you near a trash transfer station? Grab an old propane tank. There's usually a stack of 20 to 40 of 'em at my town's transfer station on any given Saturday.

[never_retreat]

We used to use a canister with a manual pump handle to do boats--there's pretty much no other way to get the oil out. It worked very well.

Drain it into the hull and run the bilge pump. 

I have an old freezer compressor that I have been thinking about making a vacuum pump with for bleeding brakes, but I can't find a container that can 'hold' vacuum without collapsing. I wonder if the shop-vac method would work for a brake bleeder.

Use a length of 4" pvc pipe. Glue a cap on one end, glue a female threaded adaptor on the other. You can just screw on a cap to make it easy to clean out. Drill and tap a hole for your other tubes.

[zahc]

PVC is a brilliant idea for a vacuum chamber. I don't know why I didn't think of it.

[RoadKingLarry]

Another option for a vacuum canister might be one of those helium tanks you can get a wally world for party balloons.

[Jim147]

An out of date refrigerant recovery tank would be a real good choice for that. All of mine are good for date at the moment.

If you put the brake system under vacuum and boiled out all the moisture, would you have to change the fluid?

jim

[Nick1911]

I've made vacuum canisters out of lenghts of decent diameter steel pipe with ends welded on.

[Jim147]

I've made vacuum canisters out of lenghts of decent diameter steel pipe with ends welded on.

As we know from watching the micro gauge, it's easier to hold in pressure then it is to hold vacuum.

jim

[zxcvbob]

Instead of sucking the oil out (where you can generate *at most* about 10 psi (and there's not many square inches), why not hook an air compressor up to the filler cap and blow the oil out the dipstick tube?  

[Nick1911]

As we know from watching the micro gauge, it's easier to hold in pressure then it is to hold vacuum.

jim

No *expletive deleted*it.  Apperently difluorochloromethane molcules are bigger then diatomic nitrogen. 

[Tuco]

Explain this to me like I'm a 10 year old please.

Let's assume I've got a rigid, airtight vessel of sufficient volume with threaded and valved ports, and a hose to fit one valve and stick it down the dipstick tube.

How do I get the air out to make it vaccuum up the oil?

I have an air compressor, fwiw.


I like the idea of a 5 gallon pail and a shop vac, but for uber-engineering geekdom, a self contained vaccuum vessel sounds way cooler

[Tallpine]

Some sort of a big syringe, with a hose running down the dipstick tube 

Back in my old service station days, seems like we had a small version of something like that for getting the oil out of those old trucks with the internal cartridge oil filters mounted on the side of the engine 

You could probably use an old hydraulic cylinder for a syringe: run a hose from one of the fittings and pull the rod back to suck out the oil.

The compressed air solution would probably work pretty cleanly if you clamped a hose on the dipstick that leads into a bucket/barrel for the waste oil.  I dunno about putting that much pressure inside the crankcase ? 

[CNYCacher]

Explain this to me like I'm a 10 year old please.

Let's assume I've got a rigid, airtight vessel of sufficient volume with threaded and valved ports, and a hose to fit one valve and stick it down the dipstick tube.

How do I get the air out to make it vaccuum up the oil?

I have an air compressor, fwiw.


I like the idea of a 5 gallon pail and a shop vac, but for uber-engineering geekdom, a self contained vaccuum vessel sounds way cooler

You could build your container really small, and then with all the valves closed, stretch it to size.

Unless you have a vacuum pump (and a vacuum cleaner won't work for this), you will not be able to evacuate the air in your container.  Vacuum cleaners work on volume, not pressure.  Having the vacuum cleaner hooked to it while you're sucking the oil out works because the cleaner keeps a low amount of negative pressure in the container, but you could never evacuate all the air witha  vacuum cleaner, seal the container, then take the container over to the engine and suck the oil out.


Well, you could. . . but the vacuum would be so weak that you would probably need a container the size of your house.