M30 oil pan removal...calling Hector and George M
Well, I will most likely be lifting the engine in my 1991 535i tomorrow to attempt to remove the oil pan. Over the years, I always snugged up the pan bolts when I had it up and it looks like the gasket right at the front has "squirted" out enough that it's leaking terribly. I spent today taking pieces off and loosening others per Bentley and other posts from the board. But before attempting to lift the engine, I have a couple of questions.
1. Is it necessary to completely remove the nuts that connect the middle exhaust to the headers? I have the nuts backed all the way to the end of the threads right now so the exhaust is still loosely connected to the headers.
2. When I get ready to raise the engine, will I be able to use a single jack with the lifting head positioned against the oil pan, or will I need two jacks? Also, if I can use one jack, exactly where does it need to be positioned to evenly lift the engine? Does the aluminum oil pan really take the weight of the engine? For that matter, when I get ready to lower the engine back onto the mounts, will all the engine's weight on the new pan gasket cause problems for it once again?
3. Will I only need to drop the oil pump in the pan to be able to slide the pan out?
I think that's all the questions I have for now. I've searched the archives and read about every post on this job. It doesn't sound like much fun. But the huge oil leak I have isn't much fun either, so I'm going to just get it done. After that, I just need to figure out what's causing the slight miss at highway speeds and I'll have my car in great shape. Of course that would be a great time to sell it and buy a Honda or Toyota or something that didn't need fixing all the time. Just kidding...sort of. That Infinity G35 sure would be nice....
Grace and peace,
Robert K
1991 535i
Well Robert, it looks like you started biting the bullet...
for this pain in the butt job.
1. If I recall correctly, the studs on the exhaust manifold are threaded to mid length so you may have to take the nuts completely off or else this may put a limit on how high you can raise the engine. You should get at least 2" of clearance between the bottom of the engine mount bracket and the top of engine mount puck when you lift the engine. I agree with George, loosen the tranny nuts from their mounts as much as you can but don't take them off.
2. I can see why you would prefer to use 1 floor jack but personally, I wouldn't lift the engine by positioning a floor jack against the oil pan. The oil pan may be quite sturdy but I wouldn't wanna run the risk of denting it... If we considered for a moment that you were successful in replacing the gasket with 1 floor jack against the pan, then after lowering the engine (assuming the jack head is somewhere against the front of the pan,) I think the weight of the engine would cause the cheap cork gasket to ooze out from the front of the oil pan. Man, don't risk it unless someone else here on the board chimes in on this method. Remember to get the paper gasket.
What I did was I bought 2 cheap 1-ton floor jacks from Wal-Mart, about 8 to $10 apiece and from positioning one against the AC compressor and the other against the power steering pump was able to lift the engine evenly. This technique was suggested by Martin. Then I dropped the x-member on the passenger side while keeping the driver side loosely bolted. Also, had to loosen the rear stablizer bar (it connects to each side of the subframe with 3 bolts per side) to allow the x-member on the passenger side to drop a bit more. If you use this technique, you will need a jack to raise the x-mbr on the passenger side and make sure the dowel pin in the x-mbr goes back into its mating hole in the subframe when it comes time to bolt the x-mbr back on. If front-end misalignment is introduced, I would expect it to be minimal. Can't see why this would be an issue when the appropriate suspension components that have been dropped/loosen fit back in their place nicely. I haven't driven the car to check for this yet. I believe the mechanic I go to from time-to-time uses the drop-the-x-mbr method to change the gasket.
3. To drop the oil pump in the pan the engine has to be raised as high as possible otherwise you will have a hard time getting the pump out. The trick is to first loosen the sprocket nut and slightly dislodge the sprocket from the oil pump shaft. Then remove the oil pump bolts, jiggle and twist the pump to pull the sprocket off, and the pump is free. Make sure not to gouge the engine block mating surface when doing this.
HTW
I lifted the motor with the floor jack under the ac compressor bracket only.
The power steering pump was unbolted & swung out of the way. I left the big floor jack under the compressor bracket. Do check the bracket bolts before all this.
I'd suggest getting the napa paper gasket over the stock cork piece.
Robert, like I said, I did lift the engine by placing...
floor jacks under the AC compressor and power steering pump. It really works!! You have to disconnect the belt from the PS pump and swing the pump up and to the right (as you face the front of the car) so that the pump is out of the way. No need to remove pump. I jacked up the engine using the AC/PS pump jack points 4 times for various reasons (long story) so I know this well. Tonight I'll try to take a picture of how I had this setup. Maybe a pic will make a bit more sense. I didn't use wooden blocks, I kept the engine jacked up all along during the job.
HTW
Some pics to raise m30 engine. m=>
The right floor jack was actually replaced by the jack of my Mazda. This jack had a slot in the middle of the head so that I could wedge it right under the bolt carriage (indicated by red arrow) in the power steering pump for a more secure fit.
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HTW