esixtyone

Ever see this one before?

I replaced my oil filter housing gasket the other day with a friend of mine on my '09 528i, and things went great right up until they didn't. A mile into the test drive I started losing coolant. Come to find out I cracked my cylinder head near the front-most bolt for the oil filter housing. We used a torque wrench to get the other two bolts to 22Nm but we used a ratcheting E10 torx on the bolt in question. How likely is it we over-torqued this enough to cause this result? Surprising to me given the small wrench and we only had a couple of awkward inches of wrench travel.

Also, I used the "High Performance" Bavarian Auto gasket made of DuPont Viton sold by ECS tuning. Hard to believe using a non-OEM gasket could play a role but thought I'd mention it. I also replaced the bolts during the job.

I've spoken with one mechanic and got a quote to replace the cylinder head. Another mechanic thought it may be able to be welded. Any thoughts on what may have gone wrong or thoughts on options to fix?

Thanks.

scottalexander

If you hold up the new bolt you bought next to the old bolt that originally came out of there is there anything to learn? (e.g. is it a different length, etc).

Regarding the fix, we have all heard of miraculous problems that have been fixed by JB Weld and similar compounds.

audiophool

Thoughts? Perhaps the non-OE viton gasket was thicker than the OE, requiring a lot more compression until you could achieve torque, causing the flange to be overstressed. Might be a tough angle to put a full bead of weld, but that would be my choice. JB Weld may be strong AF, but I doubt it would work here.

esixtyone

Bolts were identical to the original ones so that wasn’t it. My friend and I do suspect the other two bolts weren’t torqued down enough, maybe in some part due to thickness/strength of the non-OE gasket.

The car is now at a shop where they think they can weld it. Some things in the front will have to be removed to get the welder in there. Will switch to BMW OFH gasket. Expecting to have the job done in a week or so.

scottalexander

Regarding the crack mystery, there is a coolant hose with 2 bolts attached to the front of the block (referred to as the Mickey Mouse hose). Its next to the cracked mount.

When you tighten the bolt that ended up cracking the mount, was the coolant hose next to it still bolted on?

One guess is if the hose was still attached when you were tightening the bolt, and you didn't have a straight on connection. The torque wrench might not have been giving you the correct reading.

There have been many torque wrench tests done when using swivels and extensions. Those additional components can give a torque wrench the wrong reading. If that happened it was over tightened.

scottalexander

I was just watching a Youtube video of an Indy shop performing a gasket change on a BMW oil cooler and oil filter housing.

He claimed the torque on the oil filter housing bolts is not the same for all three bolts.

He stated the top 2 bolts on the oil filter housing are 22nm as you mentioned earlier. However, he says the bottom bolt (near the mickey mouse hose) is only 19nm. That's the bolt that cracked your head.

Was your mechanic able to successfully weld back the little cracked piece on the head?

esixtyone

The coolant hose was still bolted on. I used a ratcheting torx wrench to get in there, and therefore wasn't able to torque it to spec. It seemed to me like even the swivel socket would not have been possible to use in there with the coolant hose attached.

Thanks for this. I believe 19nm is the number I have for the oil cooler bolts. Interesting if that third housing bolt is different. What's a good source of truth for these specs?

My mechanic said he should be able to get to it near the end of this week. Haven't heard anything yet. I'll keep you posted!

esixtyone

Got the car back. The weld and the seal between the housing and cylinder head seems to be holding up fine but I have what appears to be a leak at the coolant hose flange. I have a new aluminum flange and o-ring on order from FCP Euro due to arrive later this week.


Cylinder head after welding and grinding.



All buttoned up. I think the bolt is hitting some of the weld on the back side and thus isn't completely flush. The mechanic also said he was afraid to tighten it down too much.



Leaking mickey mouse flange?

scottalexander

The weld job looks pretty good considering what he had to achieve. Yes, you can see there is a slight space between the bolt and the fitting. Hopefully he tightened it to 19nm.

Regarding the new coolant leak, if its not one thing, its your mother.

scottalexander

Quick thought:

One of the oil cooler gasket jobs I did a while back leaked a little from that bottom bolt we've been talking about (about 1 week after the job was completed).

I cleaned the area and applied Permatex "the right stuff" they refer to as cheese whiz sealer.

It stopped the leak. It doesn't look so pretty, but it works.