E38 740i 4.4 v8 Thick smoke problem
Printed From: Bavarian-Board.co.uk - BMW Owners Discussion Forum
Category: Technical & Model Specific Forums
Forum Name: BMW 7 Series
Forum Discription: This forum will deal with any issues on the BMW 7 Series (E23, E32, E38, E65, E66, E67 & E68)
URL: http://www.bavarian-board.co.uk/forum_posts.asp?TID=40108
Printed Date: 01-May-2024 at 23:10
Topic: E38 740i 4.4 v8 Thick smoke problem
Posted By: stheaney2007
Subject: E38 740i 4.4 v8 Thick smoke problem
Date Posted: 28-January-2008 at 14:34
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Hi there My mate has a 1999 T reg, BMW 7 series e38 740i which has the 4.4 alusil v8. Its an absolute beatutiful car, not a scratch or mark. It has beautiful interior with tv etc. Big alloys too. I can buy this car for £1500, as he's my mate and he cannot afford to run it. When he bought it, it always had a smoke problem, the mileage is average, recently had a new gearbox (over 2 grand). When you start the car within minutes the whole road is covered in smoke, you cannot see anything. I MEAN THE WHOLE PLACE IS COVERED. Ive never seen a car smoke so bad. The car drives and sounds superb. A lot of mechanics have looked at this car and many have failed to diagnose or fix the problem. Im not sure if this v8 has a cyclone valve but i think thats been checked as well. Should i buy this car and hand it in to BMW, could be a new engine. Please help, does anyone know what this is!!!!!! thanks |
Replies:
Posted By: BeemaBoy
Date Posted: 29-January-2008 at 05:14
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Aahh...a fellow..or friend of a fellow E38 4.4L owner Not sure what you mean by a cyclone valve, but the problem could be the PCV cover letting oil into the manifold and causing all the oil to be burnt? What did you friend do during the ownership period? Did he replace anything, or service the car? BTW 1500pounds for a 99 740I in as good condition as you describe is chicken feed! I would buy it anyway, even if it means putting another 1500 pounds into it!!! BB ------------- 87 E30 320I 95 E34 525I Auto, Executive Package, Arctic Silver 98 E38 740I Steptronic, Silver |
Posted By: stheaney2007
Date Posted: 29-January-2008 at 11:55
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Thanks for reply mate, Ya the car is well worth 1500 no matter what. well he wants 2 grand but i can get it for 1500. the is as immaculate as i said. he doesnt really know much about the internet and that(selling wise), so bonus for me, as i do really want the car. You said u didnt understand cyclone valve.....all the m60 v8 (nikasil) had a cyclone valve on the back of the bulkhead. when u get a smoking problem, u have to clean the gunk out of the valve or replace, common problem. lots of people have ripped out their engines thinking the rings were gone when they seen all the smoke!! he hasn't serviced the car or got anything done to it. its just really baffling what this could be, im told about 10 different mechanics have looked at it, even some have stripped the engine. nobody can diagnose this problem. cheers |
Posted By: BeemaBoy
Date Posted: 29-January-2008 at 12:46
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Not at all... I think the cyclone valve and the PCV cover valve are the same things...I have never heard of anyone cleaning them out though as the diaphragm is a sealed unit... See this link...part number 2 is the one... http://www.realoem.com/bmw/showparts.do?model=GF82&mospid=47517&btnr=11_1537&hg=11&fg=40 - http://www.realoem.com/bmw/showparts.do?model=GF82&mospi d=47517&btnr=11_1537&hg=11&fg=40 You are right, and this does cause a lot of smoke. If your friend has not done anything to the engine though, it could simply be a few bad plugs or even a dodgy MAF? You say that the car drives perfectly even though it is gushing smoke? Does the smoke get worse or better when the car is warm? Is the pipe that attached to the PCV valve attached? It would be number 7 in the following link... http://www.realoem.com/bmw/showparts.do?model=GF82&mospid=47517&btnr=11_2254&hg=11&fg=15 - http://www.realoem.com/bmw/showparts.do?model=GF82&mospi d=47517&btnr=11_2254&hg=11&fg=15 Did any of the mechanics that looked at the car perform a fault diagnosis on the OBD-II computer? That would bring up any reported faults with any of the sensors... Thanks BB
------------- 87 E30 320I 95 E34 525I Auto, Executive Package, Arctic Silver 98 E38 740I Steptronic, Silver |
Posted By: Dave E
Date Posted: 30-January-2008 at 14:22
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In 2001 my 1994 E32 V8 suddenly started throwing out an oil cloud. It was found to be a faulty non return valve at the back of the manifold that was sucking oil from the crankcase breather into the manifold to a depth of 5mm.
Replacing the PCV valve cured the problem. |
Posted By: stheaney2007
Date Posted: 30-January-2008 at 23:32
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Thanks for the replies It seems the cyclone and pcv are the same thing. i remember reading on total BMW mag that the cyclone valve causes this. I might just buy the car anyway, i mean £1500 for a machine like this. i wonder is it a big job to do the pcv. does anyone know!! cheers
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Posted By: BeemaBoy
Date Posted: 06-February-2008 at 11:08
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Hi stheaney2007 Sorry for the late reply...been really busy at work lately!!! It is a fair job in that, if you want to do it properly, you will need to pull the intake manifold off... I recently did this, and by recently, like 2 weeks ago... It is not really a difficult job, but it is time consuming. To replace the PCV valve on my car and replace the valve cover gaskets took me about 6-7 straight hours... I will look for a link for you that details how to complete the task... BB ------------- 87 E30 320I 95 E34 525I Auto, Executive Package, Arctic Silver 98 E38 740I Steptronic, Silver |
Posted By: BeemaBoy
Date Posted: 06-February-2008 at 11:15
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Okay...first you need to do this... http://www.e38.org/intake/bmw740_intake.html - http://www.e38.org/intake/bmw740_intake.html Then this... http://www.bimmerboard.com/forums/posts/233246 - http://www.bimmerboard.com/forums/posts/233246 The guy here talks about not removing the manifold. I think that the space is too tight to do this without pulling the manifold...and this is me, with my girly hands and wrists Removing the manifold will also give you a great chance to check all the vacuum lines for leaks... Just shout if you have any questions... BB ------------- 87 E30 320I 95 E34 525I Auto, Executive Package, Arctic Silver 98 E38 740I Steptronic, Silver |
