Well, this all really sucks. 1999 m3. replaced the headgasket 100 miles after purchasing the car. I saw my oil light flickering and measured the pressure. 9psi using 20w50. So I figured it was a good time to replace the pump and rod bearings while at it. replaced both (kept the rod caps in their respective order). Turned the car on, oil now at 11 or 12 at idle, let it run for 30 minutes, and then suddenly it died. It wont start now. Im assuming my block is toast. What is the cheapest way for me to salvage this project? Find an m50 or s50 block and use my s52 head? Please let me know your thoughts.
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Does "it suddenly died" mean the oil pressure went to zero or there is another problem? Will the engine turnover at all? This was obviously an ambitious project, hats off to you, but we could really use some more information on what you are seeing. Oh, and did you stake the oil pump nut after you put it on? -
I had let the car run for 30 minutes. I went inside to take a dump and it had turned off on its own while i was on the can. I did tack weld and locktight the nut on. Engine turns over freely, but it won't start.Comment
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I think you have another problem. Start the normal trouble shooting procedure for a cranking engine: compression, spark, fuel. You should be able to pull the plugs then crank the engine to measure the oil pressure to see if that system is still alive. It is throwing any codes?Originally posted by charofireComment
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is it possible to lose oil pressure in the vanos? Ok, so pull the plugs and crank the engine and I can then see if my oil pressure is truly gone? Can the main bearings be replaced like the rod bearings while the crank is still in the block?Comment
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Relax! I really don't think you have an oil problem on the bottom end. I supposed you could have doinked up the HG replacement and can't get enough oil to the lifters.Originally posted by charofire
1. Pull plugs and check COMPRESSION.
2. Check Spark
3. Check fuel pressure
Start looking for things that came loose while you were reassembling the car. Like a cam or crank position sensor connector that worked its way loose.
Again, stop panicing and start thinking. You obviously have some wrenching experience or you wouldn't have even attempted a ghetto rebuild. Use that experience to troubleshoot.Comment
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Did you check the clearances on the new rod bearings? Was this pressure when you first started up the engine or after it had warmed up?Originally posted by charofireComment
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I just finished checking: I have spark and fuel. Still won't start. I pulled my oil filter and very little oil in it, so clearly while I was on the can something happened for the pressure to drop drastically. Is there a fail safe when your oil pressure goes to low that stop the engine from firing up? the 11psi at idle was after 30 minutes of running. Thanks for all your input gentlemen. I really hope i can figure this out.Comment
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The oil will drain back to the sump after the engine shuts down, so I'm not sure this is an indication of no oil pressure. Are you measuring the pressure with a mechanical guage? I would think if you pull all of the plugs and crank the engine, you should see some oil pressure indicated on the guage.Originally posted by charofireComment
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I was thinking the same thing. I was going to pull oil filter cover to verify, but the engine is to hot for my tender hands right now.Originally posted by RickO1Comment
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I have been measuring with a mechanical gauge. I guess my next step is to pull all plugs and check that way. Is it possible to replace the main bearings while the crank is still in the block? My machine shop said this is where many engine lose oil pressure if those are worn.Comment
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OK, the short answer is, "no". I don't think you can get to the forward-most and after-most bearing. It is also a really bad idea because you are very likely to score the crank journals trying to roll the upper shells out.Originally posted by charofire
If the mains are causing significant loss, why didn't this show up BEFORE you replaced the big end bearings?
I am really wondering if you have starvation to the lifters. Loss of pressure to the VANOS wouldn't cause a no-start. I can't think of a way to test for this right now.Comment
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Since I am using my friends lift, I pulled the subframe and the oil pan off. I had my buddy submerge the oil tube pick up in oil, and as i manually turned it for a while, i then had him remove the jug of oil and covered the whole. i then turned for a while. No suction. I then grabbed the old oil pump, did the same thing, except its not bolted on the block, and it had lots of suction. So it seems my new pump is junk. My question is this: the pump worked for the 1st 30 minutes, but i still only had 11psi at idle. This pressure is still low. What should I have? Any other ideas where I could be losing oil pressure?Comment
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11psi at idle is within spec. These cars don't generate a lot of oil pressure at lower rpm which is the reason BMW doesn't recommend just letting the car sit idling.
If your engine stopped running because of no oil pressure it probably would be seized right now. I think you might have other issues.Comment
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I haven't done oil pump work on this engine. Other crank driven pumps I have done required a special procedure for priming. Like packing with vaseline, or significantly overfilling the crankcase. I suspect your interesting test was not valid because the pump didn't prime.Originally posted by charofireComment
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