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peterpete190, Auto Technician
Category: BMW
Satisfied Customers: 28768
Experience:  Over 17 years diagnosing and repairing vehicles.
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I'm working on a 1998 BMW 540i. 9 months ago the owner

Customer Question

I'm working on a 1998 BMW 540i. 9 months ago the owner of the BMW blew up the engine both rear connecting rods were sticking through the side of the crankcase. We replaced the engine with (the same type engine) a good used 4.4 liter V8 and after test driving the vehicle the customer paid for and picked up her car. Several months later the owner of the BMW blew up the engine again (same cylinders, same rods through the side of the engine) and just like the first time she didn't hear a thing, no knocking, no explosion, no noise of pistons & rods crashing out the side of the engine onto the ground, nothing. We replaced the engine again with a good used one, we drove and drove the car over a period of different days, it was smooth, it was quite, it was perfect. Her husband picks up the car, starts it up, drives it to the highway, and while waiting to go out into traffic the engine blows up again. Same rear cylinders, no noise, it just stalls right there at the entrance to our auto repair. We bring the car back and check it out, pull all the spark plugs and find anti-freeze in all the cylinders with the most in the rear two cylinders. There was not a lot of coolant in any of the cylinders that would cause a hydraulic lock but we could see it on the tip of each spark plug. This is where we are at, we checked all the service bulletins from Mitchell DIY auto repair. Is there any BMW mechanic here that has experienced this. Is there any mechanic that is familiar with this.
Submitted: 1 year ago.
Category: BMW
Expert:  peterpete190 replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

If the engine is equipped with an engine oil cooler this can have debris in it and if the cooler was not replaced and engine oil cooler lines not flushed out this will cause repeat failure if there is metal in the oil cooler that makes it way into the engine.I have seen this before and had to replace the cooler to correct this here.If this does not have the cooler or it was replaced or is not the cause let me know.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
This BMW does have an engine oil cooler. However, there never has been any very fine to heavy ground up metal in the engine oil or in the bottom of the engine oil pan. This includes before and (especially) after each of the three times the engine blew up. Also, at no time were any of the engines connecting rod bearings or crankshaft journals burnt out or damaged. Nor was there ever any knocking, pounding, clicking, etc. noise coming from the engine. And, any & all damage to the engine was always located only to the two rear cylinders. Any massive amounts of metal re-entering the engine oiling system will affect the entire system not just the two rear cylinders. I'm sorry, I don't mean to be rude, but please, I need a mechanic that is familiar with this specific problem on this specific vehicle.
Customer: replied 1 year ago.
Hello, is there any professional mechanic associated with Just Answers who can help me with my problem. Over the last 9 months the 1998 BMW 540i that I'm working on has literally blown up 3 times, exactly the same way each time. Please read my original question and see if any one has known of a similar problem.
Expert:  peterpete190 replied 1 year ago.

I apologize for the delay.

Unfortunately this is all of the info I have on this here myself.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete