How to drain out every last bit of oil?
 

In an effort to get an accurate oil analysis baseline, I'm trying to drain every last bit of oil from the car. My plan (I'm on step 2):
1) Oil pan
2) Oil cooler lines (I'm only disconnecting the inner line at each cooler)
3) Oil filter

And so far I'm not getting near the amount out of the oil coolers that I thought. Regular drain/fill amount with filter is 4.0 qts, dry engine amount is 5.7 qts. Obviously the balance was not all in the oil coolers. If I can't, I'll have no choice but to run the new oil for a short time and change again to dilute the remnants, which is far from optimal and extra expensive.

Where is the rest of the oil hiding? Any reasonable way I can drain it all?

Dave

I suppose if you have an air compressor you could try pushing the oil out. I don't think you'll get "all" the old oil out without using some sort of pressure to force it out. I would think that draining the oil pan, removing the filter, and then removing and draining the oil cooler(s) would get you 95% of the way their though.

No air compressor, unfortunately, but an interesting idea. I think that would help a lot.

Aside from removing the other oil cooler lines, I wouldn't think removing the whole cooler will help. But I'll try it.

You've pulled/torn down an engine - where is that extra oil hiding? It's pretty hard to hide over a quart of oil, methinks.

If the thermostat in the cooler(s) is closed, is the oil still sitting in it? You can always do like a certain other FD owner did and crank the car without putting a filter in place. It pretty much blew out the contents of the oil cooler. Into the engine bay. The cleanup afterwards was a bit of a pain. :D


-b

You'd be surprised how much oil is packed up in those coolers. I pulled my stock one off years ago and I think it's still dripping oil today. ;) From what I've seen, your list hits the major areas since a majority of the oil drains back into the pan. However, I still think you'll need to either remove the oil coolers or blow some air though them to force out the extra oil. A lot will drain out from the oil cooler lines, but the coolers will still be hording quite a bit of oil.

is it really worth it?

if oil is changed frequently it's cleanliness is indicated on the dipstick. You run the car it's going to get dirty.

deposits and buildup should probably be cleaned off car at rebuild.

I have to agree with Mahjik...I think you'd be surprised at how much volume of oil actually is STILL remaining in the lines, and literally what coats every surface of the engine. You could probably get a quarter of a cup if you squeegeed the pan, for example.

Air thru the lines is the way to go. I won't take much pressure, even a shop vac blowing into the lines would work. I use a rag as a filter so you don't get any crud in the lines.

The 911 race cars with front mount oil coolers have schrader valves in the lines to remove all the oil

Sounds like a lot of effort.. Why not just change it, drive it for couple of hundred miles and change it again?? Time wise, it might be cheaper.

what about the oil inside the rotors?

I use this to change my oil..

http://www.rotarycarclub.com/showthread.php?p=23#post23

What is your goal Dave? This seems like a lot of effort.

Unless your going to be moving the oil cooler around to help the air collect the oil, once the air clears out a couple tubes it will only follow that path (least resistance) and won't get all the oil out any way. About the only way you'll do it is to remove and flush and drain. These cars seem to be prone to blow by and the oil turns black very quickly, you could change the oil every 200 miles and never have the oil look as clean as it does in say a propane or natural gas powered vehicle with considerably more millage on that oil change.

Most of the oil you are missing is in the rotors/e-shaft, a fair amount sits inside them even when the system is drained.

Change the oil, run the car, then change it again if you want a semi complete flush.

Dan

+1. And the oil pump, and OMP and OMP lines.

Ugh, oh well. I'll definitely remove the coolers to at least drain them.

My intention is to do some oil analysis to compare Mobil1, Idemitsu, and RLI Biosyn. The Idemitsu and Biosyn are around $10/qt, so I'd much rather turn bolts to get as much drained out as possible. If I have to do a short drain/replace it in between it will almost double the cost of this little project.

Dave

Dave,

I honestly don't think it will make any difference between quality oils, as long as you change it regularly. Our engines don't fail because of oil related problems.

This is all true.

I'm curious about two things: will running a thinner oil increase engine wear? (I'm currently using Mobil1 15w-50, and if you look up the numbers the ZDDP additive counts have been reduced substantially in the thinner/more modern oil weights), and how quickly is fuel dilution deteriorating the oil's viscosity?

The RLI Biosyn supposedly does very well at maintaining viscosity and reducing wear in the face of fuel dilution. Idemitsu of course would be tested due to the fact it's supposedly the primo choice for a rotary. It was a little project I had in mind that would have cost about $150 for the oil analyses plus the oil. At my current mileage it would take a year if I put 2k on each oil type. There's a lot of talk about oil but nobody thus far has shared oil analysis data.

I drained the other cooler lines and only a little more oil came out. Perhaps it would have worked better if the cooler thermostats were wide open, dunno.

So it looks like I'll have to do a flush run of each new oil before calling it a baseline. I guess that's not a big deal, since I can save that lightly run oil 'blend' and use it in another vehicle.

Dave

Dave, if you want to try blowing it out with an aircompressor like Mahjik said, I have one that I could bring up to you. it's not great for trying to pull a transmission, but it should be able to get the job done for what you need.

Ya know, this may have been discussed before, but for trusted/knowlegable forum members who are willing to go to the trouble on projects like this, I'd be willing to chip in a buck or two via paypal to to help off-set costs.

It's pretty chilly in my garage: if the oil cooler thermostat is plugging up the works, would it work to nuke the cooler with my hot air gun? (I'd just do it, but I think my hot air gun is in the storage unit)

Dave

I couldnt beleive how much oil i got out of my car. I drained the oilpan/both coolers/all lines/filter. Then the next day i found that there was still oil in the coolers/pan, so i drained them again.



And after all that i still got oil puked on me when i flipped my engine over on the stand:lol2: . Oh well, at least i know its all out.



I can truely see why changing oil every 3000km is a must. Its amazing how much oil stays in there after you 'drain it'.




=Ben

You would be surprised how much oil sits up inside of the engine after you drain it.

I had the front eccentric shaft bolt come out on the highway, so I "power drained" the majority of my oil in about 2 seconds. Then I drained what was left in the pan and the oil coolers.

Once I got the engine up on a stand it still puked out a ton of oil. Plus there was still a decent amount in the pan (remember, it has baffle tanks).

Honestly, I think the best method is to do a quick flush run like you mentioned.

Guys, I think he's trying to get as much oil out "without" taking the engine apart. I'm fairly sure he understands that the shaft and the rotors will contain some oil. ;)

Dave, I'm definately interested in your results and greatly appreciate you doing this for the community. As someone mentioned before, if you would like a couple bucks to help out with the project let me know.

I've followed the Biosyn threads about it helping with the fuel dillution in DI engines and am very interested in seeing how it performs in the REW.