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Hi all - long time lurker, I've made a few posts a few years ago, but am a big fan of using the "search" feature of the site, so I don't have to revive multiple threads, or start any new ones: Until now:
528xi, 2009, with the trusty (ish) N52 engine. Got about 145 on the clock, and am replacing my oil cooler gasket for the second time. The first time, it was slowly leaking to the exterior of the part, and getting everything just a little grungy. Replaced it, and all was right in the world.
The other night, I was out on a date, and pulled in behind someone, on a street parking spot, and noticed a huge plume of smoke as they were leaving - thinking to myself, "Man, they've got some car problems!" - I get out of my car, and notice, "Man, I've got some car problems!" Coolant expansion tank detonated, and there was not only coolant - but OIL everywhere under the hood. Oh boy. Thinking this could be a head gasket, I opened the oil filler cap - and things were just squeaky clean in there, absolutely zero foam, or milkiness *whew.* Now that can only mean one thing (well, it could mean a few things, but we start with the obvious).
Get the car towed home the next morning (yesterday), and begin the cleanup / teardown. I take the oil cooler off, and waddya know, there's the issue. The funny thing about it is though, with the three chambers that the gasket seals up / off, the top two were fine (oil), and the bottom one was TRASHED. Like, I was pulling the old gasket it out, and it just crumbled.
Decided to replace the oil filter housing gasket as well (since I'm in there, and I'll probably do the main belt / tensioner pulley in the next week or so), but the oil filter housing gasket was in mint condition (original, again with about 145k on the clock).
The question I've got is - why is that part of the gasket falling apart, when just on the other side of the port (on the oil filter side), the gasket is (was) in prime condition? Coolant type? Variance in gasket material from the factory? I'm stumped!
I'll be doing a full coolant / oil change when I get it all cinched back together as well.
I'm thinking it is the material. Do you remember what you bought band wise and where?
Looks like it's at the hotter part of the gasket which is closer to the engine
I actually got it from the dealership, about a year and a half ago (maybe 20k miles ago?) - and I'd definitely agree that it's a hotter part. However, if it's getting this hot, maybe a thermostat isn't opening up as needed?
Originally Posted by scottalexander
The first thing I noticed from your picture is the female bolt hole threads in the OFH.
Take a look at all the metal filings inside the threads.
This should tell you the torque on the aluminum bolt was too high and it started to strip the housing inside threads.
Good eye! I looked at the part just a minute ago, and the threads on both the bolt and the OFH seem to be fine - don't even look stretched. The bits of particle in there are bits of corrosion from near the part of the gasket that went awry. Maybe the coolant didn't like it (yet seems to completely ignore the rest of the system?) - the OFH has since been removed and all squeaky clean.
Parts came in today, all installation took about 18minutes. Not a huge job at all - if it weren't for the oil getting in the coolant. Used the drain plug at the bottom of the radiator to drain out the rest of the coolant / oil mixture. Used water to fill 'er back up, bled the system, drained it, filled it... etc, about 4-5 cycles, 'til there wasn't much in terms of oil left. Used a little bit of soap to help break down the remaining oil, which really helped, then did the pure water flush a few more times. (all while the reservoir cap was off). Got it to where there was no more bubbles from the soap, and then did the same thing again with coolant (about 3 cycles). I reckon that's good enough to get it to a shop for a full on flush, rather than a drain and fill, right?
10-16-2019, 07:06 AM
Oil Cooler / Expansion Tank BLOWOUT!
