Advice with smoking rocker box

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Jdring
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Hi folks,
I need some advice - I am on the lookout for a quality run about - Merc or BMW.  I just saw a 2001 2.5 Diesel BMW 5 Series - quite nice and all checks out - EXCEPT there is constant smoking from the engine (rocker cover) along with a bit louder tapping than expected inside.  The drive is a little slow on the uptake but pokey with a heavier foot.   Its done 130k miles (only) and good BMW service up to 110k. 

Point is - what is the typical reasons for smoking Diesel engines?  I expected a little fumes out of the Oil filler cap, but not that much and not continuous.

Ideas?

Spider1V
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Re: Advice with smoking rocker box

 Not being technically mnded as some others here, this happened to me woth a Peugot 405 Mi-16, and what ended happening was one of the exhaust valves dropped into the cylinder, very expensive to fix (for the garage) as it was under warrenty! OK it was petrol, but there was smoking and a tapping noise, then 'bang, rattle'

But of the ar is a steal go for it?

Spider1V

Spider1V
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Re: Advice with smoking rocker box

 Not being technically mnded as some others here, this happened to me woth a Peugot 405 Mi-16, and what ended happening was one of the exhaust valves dropped into the cylinder, very expensive to fix (for the garage) as it was under warrenty! OK it was petrol, but there was smoking and a tapping noise, then 'bang, rattle'

But of the ar is a steal go for it?

Spider1V

Jdring
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Re: Advice with smoking rocker box

I am sure this Beemer will run for miles,and I am reading that blow-by from the cylinders and valves is more expected in diesels, but the car (525) just felt a but sluggish until pushed.  Rest of the engine looked just fine and clean.  But no point in buying a diesel needing expensive repair when there are hundreds out there.  But I'd be interested in what is 'normal' or even a link or two to a sample video.  The ones I have seen look less smoky that this one.

fixwin38
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Re: Advice with smoking rocker box

Hi
Smoke normally indicates back pressure caused by worn cylinder bores or broken piston rings allowing compression gasses into the crankcase ....if very bad this problem can blow the crankshaft oil seals (front and rear)  which generates major oil leaks......                                           sounds like a very "tired "engine.....it could have been driven "frozen" during last winters cold weather !!

phileas
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Re: Advice with smoking rocker box

hi.

Just to add to Fixwin's post, smoke from the rocker box could also indicate excess friction: i.e. blockage of oil getting to cam bearings which could cause excess smoke and poor uptake due to 'sticky' valves. I had this happen to me on a Land Rover and eventually the cam snapped.......not a cheap repair.

As always, the advice would have to be, if it doesn't feel right, don't buy it. There are plenty of other fish in the sea.

Good luck/ph

mark
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Re: Advice with smoking rocker box

 Not the main point of the thread, but thinking about quality run arounds,  you can pick up Merc 190's for very little. Old school, but I bet a 190 will cost less to maintain and last longer then later generation Mercs.
I know of some one who recently picked up one for about £600, drives like a new car.  You couldn't say that for a 4 year old C class.. ;-)

prwales
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Re: Advice with smoking rocker box

have to agree with Mark or even a w124, with a choice of body styles

http://www.ebay.co.uk/itm/1993-MERCEDES-220-CE-AUTO-BLACK-/290580781882?...

peter perfect
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Re: Advice with smoking rocker box

 I had a 190 2.0 ltr, the biggest regret was selling that car, a great motor.

Jdring
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Re: Advice with smoking rocker box

Thanks all.  I am passing as its not worth the risk although I am sure its run like that for a while and will run for much longer. 
That 220 CE looks nice, but too far to consider and anyway, I'd like to be getting 35mpg+

I think I am getting just 15mpg max from my 230GE SWB, and using it every day it's very noticeable!

prwales
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Re: Advice with smoking rocker box

I average 25 with a 300E, more on a run, the 220E is supposedly capable of a 34 mpg average. This is much the same as the multivalve 6 cyliner diesel.