N52 Valve Cover Help

Slowwagon · 03-27-2020, 08:27 PM

I'm in the process of replacing my leaking VCG. It's one of the magnesium valve covers and I know from the carfax it was changed in the past by a random shop. The previous shop did a pretty poor job, all the hard to reach bolts in the back were just hand tightened, so no surprise it was a leaky mess.

I have two questions I hope someone can help me with:

1. There were no metal spark plug tube seals. Did these not come with on the magnesium VC models or did the shop ditch them?

2 The mating surfaces are a mess, especially on the head. I think the shop may have glued the gasket on or oil just baked in-between the gasket grooves, see below. I've tried a gasket scraper, all sorts of chemicals but nothing seems to work and I'm struggling to keep the debris out of the head. I had a little luck with acetone but it would take a week to get it fully cleaned at this rate. Anyone have any tips for cleaning?

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Slowwagon · 03-28-2020, 01:39 PM

Troubles continue today. The coil tube closest to the firewall has melted. Think this can be grinned smooth or should I replace the valve cover?

omadab · 03-30-2020, 04:04 AM

Damn youre having a shit time XD
The spark plug sleeves are 3$ a pop so not a big deal tbh. When I did my VCG job I forgot to put them back on so maybe they did the same. I had a plastic valve cover though. Try youtubing instruction videos for the magnesium VC

As for the cleaning, I used brake cleaner and it did the job but I only really cleaned the surface 60% no leaks so far. (Idk if you're supposed to use brake cleaner but it did the job for me)

Efthreeoh · 03-30-2020, 07:07 AM

The magnesium valve cover on the 2006 N52 does not have spark plug sleeves. The corrosion you are witnessing is common as the cover ages; the coil insulation is probably leaking and there is electrical arcing taking place between the coil and the wall of the spark plug hole. Only the 2007 and up N52 with the plastic valve cover has sleeves.

To clean the mating surface try brake kleen, or gasoline, or acetone with a 3M scratch pad. If the aluminum is stained, then don't worry too much. Use Perma-tex Ultra Black or some other high-quality gasket sealer on both sides of the gasket when you reinstall it and that will seal against any slight surface imperfections.

Slowwagon · 03-30-2020, 01:24 PM

Thanks for the replies. It took two days and I no longer have finger prints but I was able to fully clean the gunk off the head. Constantly soaking a nylon brush with acetone and rubbing over the surface then scrubbing clean with a rag worked best. I almost gave up and used a gasket sealer but I'm too anal and couldn't bring my self to do it. Since the cover was magnesium I used a carbine gasket scraper and that took quick work of everything.

I also just grinded the coil tube smooth with a Dremel and reinstalled. So far no leaks but what a PIA.

03-27-2020, 08:27 PM	#1
Slowwagon New Member 0 Rep 10 Posts Drives: 06 e91 Join Date: Nov 2019 Location: Ventura, CA iTrader: (0)	N52 Valve Cover Help I'm in the process of replacing my leaking VCG. It's one of the magnesium valve covers and I know from the carfax it was changed in the past by a random shop. The previous shop did a pretty poor job, all the hard to reach bolts in the back were just hand tightened, so no surprise it was a leaky mess. I have two questions I hope someone can help me with: 1. There were no metal spark plug tube seals. Did these not come with on the magnesium VC models or did the shop ditch them? 2 The mating surfaces are a mess, especially on the head. I think the shop may have glued the gasket on or oil just baked in-between the gasket grooves, see below. I've tried a gasket scraper, all sorts of chemicals but nothing seems to work and I'm struggling to keep the debris out of the head. I had a little luck with acetone but it would take a week to get it fully cleaned at this rate. Anyone have any tips for cleaning? [IMG][/IMG]
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03-28-2020, 01:39 PM	#2
Slowwagon New Member 0 Rep 10 Posts Drives: 06 e91 Join Date: Nov 2019 Location: Ventura, CA iTrader: (0)	Troubles continue today. The coil tube closest to the firewall has melted. Think this can be grinned smooth or should I replace the valve cover? Attached Images
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03-30-2020, 04:04 AM	#3
omadab Private 9 Rep 49 Posts Drives: 2011 328 xDrive E92 Manual Join Date: Jan 2020 Location: Montreal iTrader: (0)	Damn youre having a shit time XD The spark plug sleeves are 3$ a pop so not a big deal tbh. When I did my VCG job I forgot to put them back on so maybe they did the same. I had a plastic valve cover though. Try youtubing instruction videos for the magnesium VC As for the cleaning, I used brake cleaner and it did the job but I only really cleaned the surface 60% no leaks so far. (Idk if you're supposed to use brake cleaner but it did the job for me)
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03-30-2020, 07:07 AM	#4
Efthreeoh General 19156 Rep 19,708 Posts Drives: The E90 + Z4 Coupe & Z3 R'ster Join Date: May 2012 Location: Virginia iTrader: (0)	The magnesium valve cover on the 2006 N52 does not have spark plug sleeves. The corrosion you are witnessing is common as the cover ages; the coil insulation is probably leaking and there is electrical arcing taking place between the coil and the wall of the spark plug hole. Only the 2007 and up N52 with the plastic valve cover has sleeves. To clean the mating surface try brake kleen, or gasoline, or acetone with a 3M scratch pad. If the aluminum is stained, then don't worry too much. Use Perma-tex Ultra Black or some other high-quality gasket sealer on both sides of the gasket when you reinstall it and that will seal against any slight surface imperfections. __________________ A manual transmission can be set to "comfort", "sport", and "track" modes simply by the technique and speed at which you shift it; it doesn't need "modes", modes are for manumatics that try to behave like a real 3-pedal manual transmission. If you can money-shift it, it's a manual transmission. "Yeah, but NO ONE puts an automatic trans shift knob on a manual transmission."
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03-30-2020, 01:24 PM	#5
Slowwagon New Member 0 Rep 10 Posts Drives: 06 e91 Join Date: Nov 2019 Location: Ventura, CA iTrader: (0)	Thanks for the replies. It took two days and I no longer have finger prints but I was able to fully clean the gunk off the head. Constantly soaking a nylon brush with acetone and rubbing over the surface then scrubbing clean with a rag worked best. I almost gave up and used a gasket sealer but I'm too anal and couldn't bring my self to do it. Since the cover was magnesium I used a carbine gasket scraper and that took quick work of everything. I also just grinded the coil tube smooth with a Dremel and reinstalled. So far no leaks but what a PIA.
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