BMW E87 N46 Engine and Transmission overhaul

[Jimbing]

Dear Oners (or E87ers?),

So my beloved little UDM started to warn me about low engine oil couple of months back, and I have been topping up the engine oil 1L every 2 weeks, and most recently the little guy gave a warning light on the gearbox and gear would not shift until I restarted the engine and the gearbox warning goes away.

Went to 2 different workshops for diagnostic (one of them Optimum Auto in Kayu Ara).

OA diagnosis:

Drain the engine oil to see if the engine oil is actually low, and overhaul the gearbox (quoted RM15k) as permanent solution or flush the transmission fluid (quoted (RM1.4k+ incl. GST) as temporary solution and see if the problem arise again and proceed with gearbox overhaul.

CL Auto (Tmn Melawati) diagnosis:

Drain the engine oil and do a transmission flush (RM1.2k incl. GST) - so I decided to let them to proceed to check on the car.

latest update from CLA, engine oil is low but no sign of leaking, turns out the engine is burning engine oil. They temporary solution is to change the engine oil to semi-synthetic and see if the engine is still burning oil, if yes, then they suggest to do an engine overhaul (yet to get a quote)

No sign of leak or fault from the gearbox from the diagnostics tool, they suspect the problem could be the transmission fluid has never been changed (looking at the murky transmission oil) and it caused the gearbox to misbehave. They will proceed to flush the gearbox, but they did warn that the car might run a bit sluggish due to the new oil.

Asking for advice from the inhouse sifus here, what do you think? are the diagnosis and quoted prices fair? any other solution or fixes?

 

[Herbert]

I think CLA is being honest with their diagnosis and their price seems reasonable. Can't comment much about the other workshop but I believe RM15k to overhaul a gearbox is just ridiculous.

 

[wingzee]

Not sure if the N46 still being plagued by the same issues with the N42 which the oil seals degrades prematurely causing the engine to burn engine oil. A top overhaul may solve that issue temporarily.

But yes 15k to overhaul the GB is pretty ridiculous as I was quoted only 6k few months back to fully overhaul the ZF 5HP19 GB of a E46 by a GB specialist.

 

[Jimbing]

I was kinda shocked when he told me RM15k to overhaul the GB after he plugged in the diagnostics tool, asked if there's any other solution apart from overhauling the GB, he said either to change GB with a 2nd hand GB which he quoted around RM6k or for temporary fix to flush out the ATF.

I'm reading up in other forums (overseas) some suggesting the torque converter might need replacing.

As for the engine, it has only 95k+ km to it, and just had the gasket replaced. Some forums suggest the CCV, although I cant see any smoke coming out from the tailpipe.

 

[zidee]

For 15k I will look for half cut or CKD unit of N46. Or else, I will look for CKD unit of 120d or perhaps the 3 litres version

 

[Jimbing]

A quick update.

I just got the car back from CLA, the damage: RM1800 (I'll try posting the bill later).

Flushed the ATF and no more problem on the GB.

The main problem now, they confirmed the N46 engine is burning oil. When they drained the engine oil, <1L left. They changed the oil to a semi with higher viscuosity.

When I got the car, engine oil at Max, 2 days later a notch below Max. At this rate I might need to top up in less than a month.

The workshop (CLA) warned me about this, their solution is either overhaul or get a 2nd hand engine (quoted RM8k).

Anyone know any workshop with experience on overhauling a N46 engine that's burning oil?

 

[astroboy]

U can try just replacing valve seals.. many of us N46 did the job which may set you back circ RM1.5k {parts + labor) just to replace seals that cost about RM70 for 16 pieces.

Need to open valve cover and remove both cams with a special bracket-like tool.

Mine was +1L every 2 tanks of fuel used. Problem solved after the job.

Disclaimer: the job may not solve the problem if leakage is from loose piston rings. But our mileage was about 100k km or less.. So we are betting on piston rings in good order. Otw, top overhaul necessary.. You are looking at RM3k of damage to wallet.. I don't like foreman open pistons.. too many things can go wrong if not reassemble properly i.e. pre-torque header skimming which I don't think workshop will do.. too much work.

 

[Jimbing]

U can try just replacing valve seals.. many of us N46 did the job which may set you back circ RM1.5k {parts + labor) just to replace seals that cost about RM70 for 16 pieces.

Need to open valve cover and remove both cams with a special bracket-like tool.

Mine was +1L every 2 tanks of fuel used. Problem solved after the job.

Disclaimer: the job may not solve the problem if leakage is from loose piston rings. But our mileage was about 100k km or less.. So we are betting on piston rings in good order. Otw, top overhaul necessary.. You are looking at RM3k of damage to wallet.. I don't like foreman open pistons.. too many things can go wrong if not reassemble properly i.e. pre-torque header skimming which I don't think workshop will do.. too much work.

Sifu Astroboy, can you recommend any workshop?

 

[Vincent Hor]

I did my valve seal replacement without removing the cylinder head at WP Auto. Reasonable pricing. Call Albert 012-2017792 for more details.

 

[astroboy]

Did mine at Ah Yau's place at Bamboo Garden Jalan Ipoh 019-3201125.

 

[Jimbing]

Update.

Engine oil have reduced to ~2ltr since last top up (refer prev update). After much Googling, it seems the problem lies with the Valve Cover Gasket (VCG) but since I have just replaced the VCG and the Oil Filter Gasket (OFG) the problem must be something else that resides within the engine bay that is leaking the engine oil on the the exhaust manifold, hence the light smoke and burning oil smell inside the engine bay (bonnet).

(Note: no white smoke coming out from the exhaust this rules out Valve Stem Seal)

Sent my E87 to my usual workshop (CL Auto) Taman Melawati, told them my suspicion that there must be a leaking within the engine bay. They told me to leave the car for a couple of days for them to look for the leak.

They found the culprit! :63:

It turns out the problem was the Valve Cover Bolt (refer image below) which bushing have worn out causing a bad seal between the valve cover and the engine housing which leads to engine oil to leak and drip onto the exhaust manifold. The leak was deep inside the engine bay which makes it very hard to detect from the naked eye.

I left the engine oil at 2ltr and monitoring the consumption, so far it has not reduced and it has been almost 1 week. No more smokey/burnt smell coming from the engine bay and engine running smoothly.

Glad I did not resort to swapping the engine as suggested by some workshop. As promised, I will try to upload a pic of the bills for the fix to compare the prices on the parts. :67: