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Stu 94 740i
09-06-2001, 04:14 PM
Posted awhile ago about oil leak, oil coming out on cats and mostly burning off, negligible oil loss. Someone (Mark Petry I think) suggested the oil pan, had mechanic (not stealer) look at it on last oil change. Said it may be the main bearing oil seal or intake manifold - almost 900.00 to fix! Also said it could be a breather(?). I can live with the leak, never have to add oil, occassionally a drop on the driveway, his real concern was the oil fouling the O2 sensors. If kept clean can you rationalize the repair cost? Input anyone, Thanks.<p>Stu<br>94/740i/70k - US model

Kevin
09-06-2001, 07:16 PM
Stu,<p>I had this problem a while back... rather embarassing to see the wafts of smoke when you're at a stop light... my problem was related to the lower oil pan gasket and also to a leak around the stud that holds the cover on the timing chain tensioner. Both fixes combined cost me about $190 and I have a totally clean engine.<p>This may or may not be the source of your oil leaks. Essentially any oil that is leaking gets blown back onto the cats. The other notorious sources are the valve covers... they typically leak at the rear of the engine. Sometimes a little additional torque on the nuts will reseal them, but a number of the nuts are occluded by the intake runners and are hard to get to. If the problem is the crank seal in the rear, you should see oil (wetness) on the vent in the bottom of the bell housing. If the leak is on the front of the engine, you should be able to see oil on the cross member under the engine as well as on the plastic cowell that is under the harmonic balancer.<p>Where do you see wet spots on the motor?<p>Kevin<p><i><br>Posted awhile ago about oil leak, oil coming out on cats and mostly burning off, negligible oil loss. Someone (Mark Petry I think) suggested the oil pan, had mechanic (not stealer) look at it on last oil change. Said it may be the main bearing oil seal or intake manifold - almost 900.00 to fix! Also said it could be a breather(?). I can live with the leak, never have to add oil, occassionally a drop on the driveway, his real concern was the oil fouling the O2 sensors. If kept clean can you rationalize the repair cost? Input anyone, Thanks.<p>Stu<br>94/740i/70k - US model<p></i><br>

Stu 94 740i
09-06-2001, 07:38 PM
Kevin - <p>They really cleaned the engine off today. I plan to run it a few days and then crawl under it again to see EXACTLY where it is coming from. Thanks for the pointers in where else to look. I'll let you know what turns up, at this point more of an annoyance than major mechanical (I hope).<p>"Wafts of smoke" - could call it a 'BMW performance feature' to the uninitiated.....'venting combustion gases from the afterburner to maintain sympantonic balance in the overdrive system' or something like that. <p>****, its just plain embarrasing.<p>Thanks

Rainman
09-07-2001, 02:15 AM
<center><img src="http://wsphotofews.excite.com/028/Vi/Oh/cd/8z90128.jpg"></center><p>

Lou
09-14-2001, 09:38 PM
<i><br> may be the leak you have.<p><p><p><p>Stu<br>94/740i/70k - US model<p><br></i><br>


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