[dannyjones]

Just finished my OFHG (and OFCH) gasket replacements on my 335i N55 and wanted to share for others who attempt it in future. Mine weren't leaking badly but grime was starting to build up (very slow leak) so I thought I'd give it a go, especially considering the two gaskets were $50 but a mechanic quoted over $500 labour...

All in all it wasn't too difficult for a newbie like me, but was time consuming, taking 6-7 hours total, but I was working at a slow relaxed pace with breaks. I even broke it up over two days, day 1 to get the OFH removed, and day 2 to clean it up and reassemble.

A few random thoughts, differences and tricky things I found compared to the DIYs I read:

• The third bolt for the housing (the one facing the opposite direction), was not e-torx on mine but was a regular 10mm bolt, which should have made it easier. Unfortunately I didn't have a box wrench, only a normal socket, so I still had to remove the engine coolant hose
  
• The engine coolant hose was a real pain to get back in. My first attempt, I thought I'd done it (plastic plate was bolted down), but as soon as I started to fill with coolant it poured straight out and all over my belt because it wasn't in properly. I'm still unsure if its in properly, but it doesn't seem to be leaking anymore.
  
• Definitely use a magnetic tool when dealing with the intake manifold. I dropped a bolt even though I was using one. Luckily I could see it and extract it.
  
• I did not drain oil nor coolant. Quite a bit spilled when I disconnected things, but I generally managed to catch it in a small tupperware container. I also had my alternator covered in a plastic bag. Some got on the belt so I sprayed it down with some water when I was done.
  
• After doing the bleeding of the coolant system, I had some white froth in the top of the coolant reservoir. I'm not sure if this is from oil contamination or was just bubbles from the bleeding. I syringed it out as I was over the max anyway, and will keep an eye on it.

That's pretty much it. The DIYs are very good and I'm glad I did it myself.

For info I relied on this one, and the one it references:
http://www.e90post.com/forums/showthread.php?t=938455

[MrToastywaffle]

Originally Posted by dannyjones

Just finished my OFHG (and OFCH) gasket replacements on my 335i N55 and wanted to share for others who attempt it in future. Mine weren't leaking badly but grime was starting to build up (very slow leak) so I thought I'd give it a go, especially considering the two gaskets were $50 but a mechanic quoted over $500 labour...

All in all it wasn't too difficult for a newbie like me, but was time consuming, taking 6-7 hours total, but I was working at a slow relaxed pace with breaks. I even broke it up over two days, day 1 to get the OFH removed, and day 2 to clean it up and reassemble.

A few random thoughts, differences and tricky things I found compared to the DIYs I read:

• The third bolt for the housing (the one facing the opposite direction), was not e-torx on mine but was a regular 10mm bolt, which should have made it easier. Unfortunately I didn't have a box wrench, only a normal socket, so I still had to remove the engine coolant hose
  
• The engine coolant hose was a real pain to get back in. My first attempt, I thought I'd done it (plastic plate was bolted down), but as soon as I started to fill with coolant it poured straight out and all over my belt because it wasn't in properly. I'm still unsure if its in properly, but it doesn't seem to be leaking anymore.
  
• Definitely use a magnetic tool when dealing with the intake manifold. I dropped a bolt even though I was using one. Luckily I could see it and extract it.
  
• I did not drain oil nor coolant. Quite a bit spilled when I disconnected things, but I generally managed to catch it in a small tupperware container. I also had my alternator covered in a plastic bag. Some got on the belt so I sprayed it down with some water when I was done.
  
• After doing the bleeding of the coolant system, I had some white froth in the top of the coolant reservoir. I'm not sure if this is from oil contamination or was just bubbles from the bleeding. I syringed it out as I was over the max anyway, and will keep an eye on it.

That's pretty much it. The DIYs are very good and I'm glad I did it myself.

For info I relied on this one, and the one it references:
http://www.e90post.com/forums/showthread.php?t=938455

Good job
At what mileage did you replace your OFHG/OFCH?

[dannyjones]

Originally Posted by MrToastywaffle

Good job
At what mileage did you replace your OFHG/OFCH?

Around 68k miles. Only owned since 52k and not sure if it was done before. The different bolt I mentioned makes me think someone changed it, or maybe bmw changed it on later models to make it easier to access (mine is 2011)

[Abax335]

Next time and for anyone reading that ever removes a line with an o-ring like the oil cooler lines or that coolant hose that was a pain to get back in. Please use a light coat of silicone paste so you dont pinch or year the o-ring and cause more problems

Think warranty pays about 1.9- 2.5 for this.

[dannyjones]

Originally Posted by Abax335

Next time and for anyone reading that ever removes a line with an o-ring like the oil cooler lines or that coolant hose that was a pain to get back in. Please use a light coat of silicone paste so you dont pinch or year the o-ring and cause more problems

Think warranty pays about 1.9- 2.5 for this.

Not sure I understand the comment about the warranty.

But thanks for the tip on the silicone. It's not too difficult to get at that hose again so may replace the o ring completely and do as you suggest. What kind of problems could I have if it's not in properly? Just a leak or something more serious?

[Abax335]

Originally Posted by dannyjones

Not sure I understand the comment about the warranty.

But thanks for the tip on the silicone. It's not too difficult to get at that hose again so may replace the o ring completely and do as you suggest. What kind of problems could I have if it's not in properly? Just a leak or something more serious?

Every component that requires replacement pays a certain amount of hours. So at the dealer level we get paid under warranty about 2.5hrs for this car. So if we do it slower we are really losing money since we only are there for 8hrs a day and are supposed to yield 110% of the hours we are there.

But that o-ring isn't available separately. Have to replace the entire hose, they get brittle and I found this out years ago the first time when removing it, it crumbled in my hand.

Slow pinhole type leaks that may not be seen to easily, but mostly referring to other orings on any vehicle. I had a buddy who was assembling an engine and the oil pick up tubr requires a small o-ring that he didn't lube and it split.......cause low oil pressure on a 6k pull and soun a bearing. Engine and crank had to go back to the machine shop for a .35 cent o-ring

[dannyjones]

Originally Posted by Abax335

Every component that requires replacement pays a certain amount of hours. So at the dealer level we get paid under warranty about 2.5hrs for this car. So if we do it slower we are really losing money since we only are there for 8hrs a day and are supposed to yield 110% of the hours we are there.

But that o-ring isn't available separately. Have to replace the entire hose, they get brittle and I found this out years ago the first time when removing it, it crumbled in my hand.

Strange, some of the diys suggested replacing the o ring and had a part number which I did find on fcpeuro. But perhaps they were talking about a different one.

2.5 hours must be tough... But I guess possible with the right tools and experience. But my indy was quoting $450 before tax, which must be at least 4 hours

[Abax335]

Yeah warranty time differs from customers. Generally its time and a half times warranty minimum sonhis quote was accurate.

Good to know. At least nothing is available OE.

[dannyjones]

One other small point... My old gaskets looked like new. Nothing like the crumbling flattened mess I've read about. Really surprised it was leaking to be honest

[PhaseP]

If I were you I would replace the accessory belt at the earliest convenience. Oil contamination on that belt can cause havoc, even ending the belt being sucked into the engine from the front crank shaft seal. It is not worth risking.

[Sambonjo]

I recently did the OFHG. 2011 N55 also. Ratcheting box wrench really helps although I can't see any way of avoiding taking off the intake manifold. I combined this with an oil change so there wasn't much spillage. Just a half quart or so of coolant. My gasket also looked like new but I could see oil leaking from it before replacement. I'm a noob when it comes to working on cars so it was a tense moment when I had everything all put back together and ready to push the start button. Worked fine though thanks to everyone who wrote the DIYs I looked at on here. What a great resource this forum is. Saved me over $1000 in maintenance costs so far by doing some things myself. For anyone thinking about doing this OFHG, you can do it! Just go slow, label your sensors if you need to so they go back in the right spot and double check everything.

[dannyjones]

Originally Posted by PhaseP

If I were you I would replace the accessory belt at the earliest convenience. Oil contamination on that belt can cause havoc, even ending the belt being sucked into the engine from the front crank shaft seal. It is not worth risking.

I don't think any oil got on it, or if it did it was a tiny amount. But quite a lot of coolant got on it, as I started filling coolant and it ran straight out from that pipe that should go into the engine. Can coolant be as detrimental to the belt as oil? What would oil (or coolant) damage to the belt look like? The belt seems in very good condition to my untrained eye.

Thanks

[NOITALL]

Originally Posted by dannyjones

I don't think any oil got on it, or if it did it was a tiny amount. But quite a lot of coolant got on it, as I started filling coolant and it ran straight out from that pipe that should go into the engine. Can coolant be as detrimental to the belt as oil? What would oil (or coolant) damage to the belt look like? The belt seems in very good condition to my untrained eye.

Thanks

You can't tell. The belt will be a little more prone to busting or shearing. I wouldn't worry about it more than the usual occasional visual inspection.

[catcher22]

Congrats on replacing your OFHG! It's definitely a longer and more laborious process than other maintenance items or modifications, but definitely doable with the right tools, prep, and instructions.

Glad you mentioned the result of not having to drain anything. I've read a lot about OFHG DIYs, and until now, nobody else has mentioned the amount of fluid that comes out if the oil and/or coolant is not drained first. Good to know you were able to deal with the amount with just tupperware (and I assume shop towels or the sort). I have been contemplating whether to drain fluids or not when I perform this DIY.

As for the belt, since you're not leaking anything right now (oil or coolant), why don't you just give the belt a good power wash and monitor it from there? Especially if the belt is newer, or still in good condition, there's no reason to replace it when you can just wash it clean. Coolant on the belt won't give as many problems as oil on the belt anyway. Coolant viscocity is much less and almost all of it will burn off whereas oil deposits will sit on the belt for a long time.

[dannyjones]

Originally Posted by catcher22

Congrats on replacing your OFHG! It's definitely a longer and more laborious process than other maintenance items or modifications, but definitely doable with the right tools, prep, and instructions.

Glad you mentioned the result of not having to drain anything. I've read a lot about OFHG DIYs, and until now, nobody else has mentioned the amount of fluid that comes out if the oil and/or coolant is not drained first. Good to know you were able to deal with the amount with just tupperware (and I assume shop towels or the sort). I have been contemplating whether to drain fluids or not when I perform this DIY.

As for the belt, since you're not leaking anything right now (oil or coolant), why don't you just give the belt a good power wash and monitor it from there? Especially if the belt is newer, or still in good condition, there's no reason to replace it when you can just wash it clean. Coolant on the belt won't give as many problems as oil on the belt anyway. Coolant viscocity is much less and almost all of it will burn off whereas oil deposits will sit on the belt for a long time.

I actually covered my alternator in a plastic bag (to be safe) and yea, managed to catch almost everything with a small tupperware. Note that I only really lost oil when disconnecting the two oil lines from the oil cooler housing which mine has, and these hoses were then easily directed to the tupperware. Keep them wrapped as more will ooze out afterwards.

Then, the coolant does come quickly when you remove some of those pipes, so you need to be quick and will splash some but its mostly manageable. Probably is better to drain a bit if you can, but I didn't because I wanted to work on my drive which is on an incline, rather than on the road, and I couldn't really drain without putting it on ramps which is not possible with the incline.

For the belt, I did give it a spray with a regular hose when finished. Don't have a pressure washer. Also didn't want to get too much water on the engine, but I guess its all sealed and shouldn't really matter. (Like I said, I'm a newb )

[Abax335]

Originally Posted by catcher22

Congrats on replacing your OFHG! It's definitely a longer and more laborious process than other maintenance items or modifications, but definitely doable with the right tools, prep, and instructions.

Glad you mentioned the result of not having to drain anything. I've read a lot about OFHG DIYs, and until now, nobody else has mentioned the amount of fluid that comes out if the oil and/or coolant is not drained first. Good to know you were able to deal with the amount with just tupperware (and I assume shop towels or the sort). I have been contemplating whether to drain fluids or not when I perform this DIY.

As for the belt, since you're not leaking anything right now (oil or coolant), why don't you just give the belt a good power wash and monitor it from there? Especially if the belt is newer, or still in good condition, there's no reason to replace it when you can just wash it clean. Coolant on the belt won't give as many problems as oil on the belt anyway. Coolant viscocity is much less and almost all of it will burn off whereas oil deposits will sit on the belt for a long time.

Draining the coolant or oil won't effect the amount of oil that sits in the cup. Best bet is cracking the filter cup loose and letting that drain as much as possible. The oil in the sump is not effected nor will it leak out when you do the OFHG. As far as coolant it may help but you aren't loosing much.

[Rosetta Stoned]

Originally Posted by dannyjones

One other small point... My old gaskets looked like new. Nothing like the crumbling flattened mess I've read about. Really surprised it was leaking to be honest

Same here, from the amount of oil gunk in the area I was assuming the gasket would be pretty ragged, it was not. Using a pick it came out in one piece and wasn't brittle at all. I wonder if some of the leaks could have been fixed with a retightening of the 3 bolts. I was at 68k miles and only 2hrs of work $30 in parts (replaced bolts too) so at least have the piece of mind and cleaner engine bay.

[Rosetta Stoned]

As Op stated this work should be done without bothering to drain oil or coolant unless you are due for a change. All you have to do is open the coolant fill cap to relieve the pressure. Then put a sealable ziplock bag under the coolant hose attached to the OFH. Then pull that clip/hose off and point it into the bag, only about 1 liter comes out not even half the gallon bag fills. For the oil just pull the filter off and suck out the oil using a syringe as the DIY's say. No mess at all this way.

Additionally the intake for the N54 doesn't need to be removed, just the air filters to make some space and then the intake bolts removed. Then just pull the intake off enough to get to the one bolt. (Being very careful not to get anything into the intake ports). For the 3rd/smallest bolt I had to use a 5/16 wrench and worked perfectly, the others the E10 socket fit on no problem. So no need to remove the smaller coolant hose on the block.

Using these shortcuts the job can be done in less than 2 hours, at least for a N54 without oil cooler.

[catcher22]

Originally Posted by dannyjones

I actually covered my alternator in a plastic bag (to be safe) and yea, managed to catch almost everything with a small tupperware. Note that I only really lost oil when disconnecting the two oil lines from the oil cooler housing which mine has, and these hoses were then easily directed to the tupperware. Keep them wrapped as more will ooze out afterwards.

Then, the coolant does come quickly when you remove some of those pipes, so you need to be quick and will splash some but its mostly manageable. Probably is better to drain a bit if you can, but I didn't because I wanted to work on my drive which is on an incline, rather than on the road, and I couldn't really drain without putting it on ramps which is not possible with the incline.

For the belt, I did give it a spray with a regular hose when finished. Don't have a pressure washer. Also didn't want to get too much water on the engine, but I guess its all sealed and shouldn't really matter. (Like I said, I'm a newb )

Thanks for the pointers! My issue with draining oil and coolant is more logistics. I only have ramps, so I must drain the fluids while the car is on ramps. How do I get the car OFF the ramps to work in the engine bay and after the fluids are drained? It is way too high up to work in the engine bay while the car is up on ramps, and it's not like I can turn the car on and drive it off the ramps with all the fluids drained. And pushing the car off the ramps while in Neutral just seems unsafe...

So it may be easier anyway just NOT to drain the fluids and catch whatever drains out (as you did). Ideas?

[dannyjones]

Originally Posted by catcher22

Thanks for the pointers! My issue with draining oil and coolant is more logistics. I only have ramps, so I must drain the fluids while the car is on ramps. How do I get the car OFF the ramps to work in the engine bay and after the fluids are drained? It is way too high up to work in the engine bay while the car is up on ramps, and it's not like I can turn the car on and drive it off the ramps with all the fluids drained. And pushing the car off the ramps while in Neutral just seems unsafe...

So it may be easier anyway just NOT to drain the fluids and catch whatever drains out (as you did). Ideas?

Exactly the same for me, with the added complication of only being able to use the ramps on the flat road, not on my inclined driveway.
I would go for it without draining and catch as much as you can. Then afterwards, either top-off or do a flush when you're finished with the OFH if you're concerned about cross-contamination (depends on the state of your current gasket).

Also, remove the oil filter and clean out the housing first as a previous poster mentioned. This step is already in the DIY guide though.

Note, most of the coolant will come out of that hose which is secured with a C-clip. So you can easily position a container before pulling it off.

[gotturbo]

I had mine up on ramps for that job and a walnut blast. When I got the ofhg all done I just reached my jack in there to the central jacking point and picked the car up while I removed the ramps and then set it back on the ground to finish blasting and all reassembly. One thing to be sure of is make sure your jack handle is all the way down when you start to turn it and let car down. Ask me how I know! Everything with my jack fit just perfect if the handle were to be down. Not so much if it was up. By the time I got my head out of my ass it was all too late and my bumper got a bit of a wrinkling. Was so pissed at myself for being a veteran mechanic making what seemed like a rookie mistake, but it's not bad. It bounced back really well and didn't break the paint at all. Nobody would ever notice it, but I know.

[catcher22]

Originally Posted by gotturbo

and picked the car up while I removed the ramps

I know what you mean but that just sounded funny, picking up a car. I actually lolloled from reading sentence, thank you for that!