Cracked Valve Cover?

[928]

Hi everyone,

I had my 2010 335i xdrive sedan (86,000 kms or ~54,000 miles) at the dealer yesterday to get a new key programmed (old key intermittently acts flakey with comfort access). The tech also looked the car over and reported that the valve cover is cracked and leaking. Upon hearing this I asked for an explanation. The tech showed me evidence of some oil on the exhaust and he said that the cause is always a crack in the valve cover. I don't get any burning oil odour either inside or outside of the car, so not a big leak (yet). The tech seems certain that it's a crack but he couldn't see a crack because the car was assembled so that leaves me wondering which of the following situations this could be:

1. Cracked valve covers are so common that it's a safe bet/guarantee that's the source.
2. the labour for the replacement of just the gasket is so expensive (same regardless of whether they are replacing the valve cover; $1,000) that they just replace the valve cover ($750 for the part) to be safe.

So, I'm curious what the brain trust here says. Would you order a gasket, remove the valve cover and inspect for cracks and if you don't see any then just replace the gasket? I would assume a crack in the valve cover that's big enough to create a leak would be visible, no?

TIA for your advice.

[jclausen]

Replace the cover and gasket there is also the pcv valve in the cover

[dworthy]

Yes the N-5x motors have plastic valve covers, and they do like to crack or warp. More than likely it's a bad valve cover gasket, but as the CCV is in the valve cover it too is getting to the end of it's life.

As for the cost, you can always check out euro only shops in your area to see what they would charge for labor, as this tends to be a 3.5 hour job.

[928]

Thanks very much for your replies. I wasn't aware that the pcv needs replacing about now anyway. I'm going to do the job myself so thankfully will save on the labour (I have the Bentley manual and have watched some of the excellent youtube videos). My oil filter housing gasket (probably also oil cooler gasket) is leaking so I guess I'm going to fall down the slippery slope of while you are at its... oil filter housing gasket, oil cooler gasket, oil cooler line o-rings, thermostat, waterpump, complete new coolant. The quote from the dealer for replacing just the valve cover and oil filter housing gasket was $3,000!

[928]

Actually, it looks to me like my car doesn't have the two small oil cooler lines attached to the front of the oil filter housing. So I guess there's no need to mess with the coolant to do that job on my car?? I know it's unrelated to my original post, so can start a new thread, but figured I'd ask here first.

[White94RX]

There is still coolant flowing to the oil filter housing. The cooling system will be opened when changing the oil filter housing gasket. Thus necessitating filling/bleeding the system when done.

[928]

Thanks so much for pointing that out. Guess I'm back to doing the full Coolant change, WP and thermostat WYAIT. It seems that most people loosen the intake manifold, but I watched a FCP Euro video where they completely removed the intake manifold. What is the conventional wisdom on this?

[928]

Spoke with a service advisor this AM and his suggestion was to replace the coolant but to leave the WP and thermostat until one or the other goes kaput. Does the brain trust agree?

[bmwbob89]

I'm not sure if this apples to the 335 but this socket lets you replace the oil filter head gasket without removing the intake on a 328.
https://www.turnermotorsport.com/p-558766-e10-female-torx-swivel-socket-14-drive/

[928]

Thanks for thinking to pass that along. My understanding, based only on reading/watching videos, is that the intake manifold completely covers that bolt on the n54 and so it needs to be at least loosened to access the bolt. If anyone knows differently, please advise as that would be great.

[White94RX]

The N54 intake needs to be unbolted and pulled back from the head to access the bolt. The N52 intake does not need to be removed/unbolted/pulled back/etc.

Is there anything wrong with your water pump? Any fault codes or overheating? How many miles? I do agree with preventative maintenance, but if it doesn’t need it.....


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[928]

Thanks for confirming that. That raises another question: do you think it's okay to just pull the intake back a bit and then reinstall it rather than completely removing it and replacing the intake gaskets? I guess I'm wondering if the intake gaskets need to be replaced once unseated.

No problems with my waterpump/thermostat. The car is 10 years old 86000 kms/~54,000 miles. The waterpump/thermostat and coolant are all original. My thinking was that because I'd be removing the coolant to do the OFH gasket then I should just replace the waterpump and thermostat based on age. On the one hand I welcome the idea to leave well enough alone. The location of the pump and thermostat look like not the easiest to get to and I worry that disconnecting the various hoses could actually create a leak. On the other hand, I'd like to ensure that the car is reliable going into the future. I'd hate to take a long road trip and have the water pump die on me in the middle of nowhere (though I guess that could happen with a new one too). Any thoughts to help with my decision-making based on your extensive experience are much appreciated.

[gusm325]

928, I replaced the Oil filter housing gasket with out draining all the coolant, however I ran the bleed procedure afterwards and topped it off. You will get a "splash" when you pull it back away from the head, (hence lots of rags all over the belt); dry off all the oil in the filter housing as it would get messy otherwise.
No need to disconnect the water hose nor the intake manifold as 94rx stated. Just use small socket and lots of patience on the bolt under the intake. Remove the air box, intake plastics and the engine cover.
Lots of videos on Youtube.
Clean surfaces good, get new bolts and it's no big deal.

[dworthy]

Just pay attention to the car, for if the cooling fans start running full tilt all the time, that is an indicator of the water pump starting to fail.

Anytime you pull an intake you need to replace the gaskets, unless it's been pull a year or two ago. The rubber will harden to the surface and they will not mate back together properly.

[928]

Good point that the cooling fans activating give some warning that the water pump is on its way out; presumably buying time to get the parts and do the job.

Ok, then I guess I'll replace the intake and TB gaskets (@gusm325 I assume you have an N52; please advise if otherwise).

I want to change as much of the coolant as I can so will drain the radiator. I understand that draining the rad requires removing the intercooler. The Bentley manual says to use some antiseize on the o-rings, but it specifies a non-grease type of antiseize (only antiseize compounds. I asked at the dealership and they said they've never heard of that. The FCP video said to put some oil on the o-rings for the intercooler connections. If anyone disagrees/knows better, please advise.

[dworthy]

I just use coolant on the o-rings inside the coolant hoses, that tends to lubricate them just fine IMO. You can use oil for the intercooler lines like you noted. Not sure why you would need to pull the intercooler to drain the coolant, for AFAIK there's a drain on the lower left side of the radiator.

[928]

Thanks for those tips for what to use on the lines; will do.

I was basing the intercooler removal on a couple of the videos I watched (including the one by FCP) which removed the intercooler to access the drain on the radiator... All the better if that's not necessary.

[928]

Here's a link to a relatively short video showing the coolant drain procedure: https://www.youtube.com/watch?v=YFO5ycZuZlY

[dworthy]

Ah, yes that's correct. Work on too many models of BMW's and tend to forget the fine details about each one.

[928]

I finally had a chance to do this job. Seems to have gone fine as I don't notice any leaks. So many vacuum and electrical connectors etc. And that black electrical box that sits under the intake manifold is a PIA! Many profanities may have been uttered when trying to remove it. My car is an x-drive and what I think is the thermostat and waterpump (it was very difficult to tell from the view I had) look to be very difficult to get to. If anyone knows of a write-up specific to an x-drive model I'd appreciate you posting here as I have yet to find one.

Thanks again to all who posted for your advice. Merry Christmas!

[928]

I found this relatively recent video that nicely details the WP & thermostat job on an N52 Xdrive (https://www.youtube.com/watch?v=DA4JAEfSVTY). For anyone that has done this on an N54 Xdrive, is it the procedure the WP & thermostat replacement the same on the N52 and N54 Xdrive models?