[The Nightman]

Originally Posted by gbalthrop

ANYONE taken the time to think about OFHG leaks and have a THEORY?
George

It would be interesting to learn why BMW engineers chose the materials they did for the gaskets. At least the newest version of the OFGH (with the additional ridges) is now FKM, but it seems that the other gaskets are still ACM.

Here's an overview of different materials to nerd over: https://www.professionalplastics.com...rsOverview.pdf

[Korz55]

I have a 2009 328. Changed mine at 80,000. Super easy. My only problem was after changing a coil went bad - may have been from handling - might be worth changing those at the same time. Considering what they do, it is worth changing at reasonable intervals.

[PhaseP]

Originally Posted by freedomfries

It would be interesting to learn why BMW engineers chose the materials they did for the gaskets. At least the newest version of the OFGH (with the additional ridges) is now FKM, but it seems that the other gaskets are still ACM.

Here's an overview of different materials to nerd over: https://www.professionalplastics.com...rsOverview.pdf

At OFGH you need a material that is good with both oil and coolant. Unless someone makes one that uses different material for the oil passages areas and coolant areas. The other thing is that is one of the hottest parts of the engine except exhaust section. The gasket gets cooked there.

Had seen and help replace same thing on a Mercedes V6 of a friend of mine. Similar design same leak.

[krhodes1]

Originally Posted by gbalthrop

I AGREE! If it "Ain't Broke":
1) Do something else;
2) Have a beer;
3) Float a boat, or WHATEVER

My 2007 328xi N52KP has not leaked ANY oil from anywhere other than seepage at rear of Oil Sump, in the four+ years I've had it. Don't know WHAT prior owners did, or if OFHG & VCG are original.

I can't help but wonder if OVER-tightening Oil Filter Cover, or "ham-fisted" cover removal contributes to OFHG leak. I've done ALL my own work under hood (bonnet ;-) and always just tighten Filter Cover to "Hand-Tight". The Cap o-ring is the seal, and the cap is NOT going to loosen by vibration.

My 33-year-old XJ-S has NEVER had the cam covers off, at least in 17+ years I have owned it. It doesn't leak a drop of oil. Conventional Steel Bolts (NOT "single-use" T-T-Y bolts) can be "snugged-up" as a gasket shrinks from compression, to prevent/ reduce seepage. Can't do that (safely) on Oil Pan, but CAN on Tranny pan and OFH (steel bolts into aluminum head).

ANYONE taken the time to think about OFHG leaks and have a THEORY?
George

I have a theory. The hotter the climate your car lives in, the shorter the gaskets last. I have two 2011s with about the same miles on them - ~50K. My 128i convertible lived almost it's whole life in Austin TX, which is roughly the temperature of the surface of the sun, and now lives in SW FL where it isn't much cooler. It's needed the Trifecta of gaskets replaced already, AND it has had a set of coils. My 328i has spent it's whole life in chilly Maine, and hasn't had any issues at all.

But at the end of the day, it's a materials quality issue, IMHO. This shouldn't be rocket science, but BMW doesn't seem to be very good at specifying this stuff. When I did the OHFG last summer on my 128i, the gasket had basically turned into glass it was so hard and brittle. Supposedly the latest are better, time will tell. At the end of the day, replacing gaskets every 8-12 years doesn't bother me much anyway. Note - superficially there was no sign of leaking on my 128i when I changed it. I changed it because I was changing the oil and coolant anyway, had the airbox out to change the belt and tensioner, so there was no better time. Glad I did, because it was obvious once removed that it had started to fail - was just starting to leak onto the alternator bracket where it could not be seen. Only a matter of time before it would have been making a mess.

For contrast, my Mother's V6 Camry has 50K on it, has lived in hot FL it's whole life, and doesn't leak a drop of anything. Neither does my 17yo Volvo that has 121K on it - also in the heat it's whole life. But Volvo mostly doesn't use gaskets at all - they use just sealant with no gaskets almost everywhere - which is a whole different can of worms if you do get a leak or need to get into something. Toyota just seems to use really good gaskets.

[krhodes1]

Originally Posted by Efthreeoh

Funny, but my '06 E90 has passed 400,000 miles in 15 years and I haven't notice a fairly regular pattern or interval of failing gaskets. I also have a 2008 Z4 (N52) with 110,000 miles in 13 years, and it has no leaks at this point. Replacing gaskets before they leak is pointless. The OFHG is an entirely different and independent repair from the valve cover gasket. Given the propensity of the CCV vent hose to crack when removing the valve cover, IMO it is better to leave the valve cover alone if the gasket is intact.

I don't think mileage has much to do with it in and of itself. If anything, higher mileage would imply less time spent at low speeds meaning lower underhood temps. As mentioned, my 128i needed all three main gaskets within the first 50K miles. A car that lived in blazing hot TX and obviously spent a lot of time in low speed traffic. I firmly believe temps are the key - the lower the underhood temps, the longer these gaskets last. Heat cycles probably play into it too. Lots of short trips in South TX are going to be MUCH worse than your long commute in the mid-Atlantic. Which is certainly worse than my 328i that rarely gets driven in Maine.

I wouldn't change the valve cover gasket "just because" either, but at this point if I had to disturb it for any reason on my 328i the original is NOT going back on the car, nor would any of those hoses. After 10 years, it owes me nothing. But hopefully it will stay in place for a good while longer.

[The Nightman]

Originally Posted by krhodes1

I don't think mileage has much to do with it in and of itself. If anything, higher mileage would imply less time spent at low speeds meaning lower underhood temps. As mentioned, my 128i needed all three main gaskets within the first 50K miles. A car that lived in blazing hot TX and obviously spent a lot of time in low speed traffic. I firmly believe temps are the key - the lower the underhood temps, the longer these gaskets last. Heat cycles probably play into it too. Lots of short trips in South TX are going to be MUCH worse than your long commute in the mid-Atlantic. Which is certainly worse than my 328i that rarely gets driven in Maine.

Yup. Short cycles with short distance trips and city driving conditions are brutal on cars, hence why manufacturers have severe service schedules for these conditions.

Mileage alone isn't a good indicator of wear but you can look at average fuel consumption. The driving conditions that result in poor fuel economy are the same conditions that increase wear.

Not to dismiss 400k miles since that is still an impressive feat, but probably not representative with a lifetime consumption of 27 mpg. I only hit that kind of fuel economy coasting down the highway!

[mecheng77]

Originally Posted by gbalthrop

I AGREE! If it "Ain't Broke":
1) Do something else;
2) Have a beer;
3) Float a boat, or WHATEVER

My 2007 328xi N52KP has not leaked ANY oil from anywhere other than seepage at rear of Oil Sump, in the four+ years I've had it. Don't know WHAT prior owners did, or if OFHG & VCG are original.

I can't help but wonder if OVER-tightening Oil Filter Cover, or "ham-fisted" cover removal contributes to OFHG leak. I've done ALL my own work under hood (bonnet ;-) and always just tighten Filter Cover to "Hand-Tight". The Cap o-ring is the seal, and the cap is NOT going to loosen by vibration.

My 33-year-old XJ-S has NEVER had the cam covers off, at least in 17+ years I have owned it. It doesn't leak a drop of oil. Conventional Steel Bolts (NOT "single-use" T-T-Y bolts) can be "snugged-up" as a gasket shrinks from compression, to prevent/ reduce seepage. Can't do that (safely) on Oil Pan, but CAN on Tranny pan and OFH (steel bolts into aluminum head).

[COLOR="Red"]ANYONE[/COLOR] taken the time to think about OFHG leaks and have a THEORY?
George

Originally Posted by gbalthrop

I AGREE! If it "Ain't Broke":
1) Do something else;
2) Have a beer;
3) Float a boat, or WHATEVER

My 2007 328xi N52KP has not leaked ANY oil from anywhere other than seepage at rear of Oil Sump, in the four+ years I've had it. Don't know WHAT prior owners did, or if OFHG & VCG are original.

I can't help but wonder if OVER-tightening Oil Filter Cover, or "ham-fisted" cover removal contributes to OFHG leak. I've done ALL my own work under hood (bonnet ;-) and always just tighten Filter Cover to "Hand-Tight". The Cap o-ring is the seal, and the cap is NOT going to loosen by vibration.

My 33-year-old XJ-S has NEVER had the cam covers off, at least in 17+ years I have owned it. It doesn't leak a drop of oil. Conventional Steel Bolts (NOT "single-use" T-T-Y bolts) can be "snugged-up" as a gasket shrinks from compression, to prevent/ reduce seepage. Can't do that (safely) on Oil Pan, but CAN on Tranny pan and OFH (steel bolts into aluminum head).

[COLOR="Red"]ANYONE[/COLOR] taken the time to think about OFHG leaks and have a THEORY?
George

Considering the OEM gasket is now from Japan I think the original material was not able to handle the heat cycles and resistance to resist degradation from engine oil.

[nm49152]

The original spark plugs in my 2010 328i N52KP lasted 98K miles, when misfire was noticed. Replaced the plugs at 100K and it has been running fine (I got 31 mpg a couple times, mostly 28-29 mpg, driving local back roads with Costco 92 gas).

[C4maro]

Not to hi-jack the thread but, on the n54 once the ofhg is replaced, is it common to fail again?