what's this banjo bolt on the bottom of the oil cooler housing?

[Fastguy]

I didn't get a before pic and I don't see any dangling lines to attach this too. Don't understand why they would use a banjo bolt here...but I'm guessing it was fully seated with no exterior attachments? I don't recall.

[Bigglezworth]

Need a better photo. Mine doesn't look like that....

[Fastguy]

here. in red is the bolt in question.

[Bigglezworth]

Much better photo. I can tell you that in both instances whereupon I removed the housing to install aluminum 'buffkin' pipe, I never removed this bolt. No idea what it was for and didn't go hunting trying to learn either. It was there when I removed and stayed there until I reinstalled.

[Fastguy]

Much better photo. I can tell you that in both instances whereupon I removed the housing to install aluminum 'buffkin' pipe, I never removed this bolt. No idea what it was for and didn't go hunting trying to learn either. It was there when I removed and stayed there until I reinstalled.

I removed everything. I know now I shouldn't have but did nevertheless. So, since you know the bolt I am talking about now, and you never removed yours, my second photo and what yours looks like should be the same? Just wanted to make sure that was indeed how I took it apart. I did install a new crush washer and now that I think about it, it was leaking so it needed removed. Just seems odd to have a fully seated banjo bolt like that with it not attaching any external lines.

[SteveKen]

On mine, it is an additional drain plug that I think is M4 threaded. I"m not sure why yours would have such a large hole in there and the banjo bolt you've shown looks like the one that attaches the turbo oil supply line near the oil pressure sensor. I wonder if someoene might have stripped out the drain plug and drilled and retapped with a larger head?

Sorry for the large pic

[Fastguy]

On mine, it is an additional drain plug that I think is M4 threaded. I"m not sure why yours would have such a large hole in there and the banjo bolt you've shown looks like the one that attaches the turbo oil supply line near the oil pressure sensor. I wonder if someoene might have stripped out the drain plug and drilled and retapped with a larger head?

Sorry for the large pic

No...the larger pic is great. Can really see the detail. I don't think the hole in mine is larger. It actually looks identical to that pic. So if you pull out that plug, is it a banjo bolt like mine? Or is it just a simple plug?

I should have taken better pics when taking apart, but I didn't expect to have ANY issue just re-installing a few little bolts and hoses. It just threw me for a loop when putting it back together and I was left staring at a banjo bolt in my hand and no hoses for it to attach to. If I somehow misplaced or otherwise swapped stuff around, all I can think is that I accidentially put a turbo line banjo bolt in the hole by mistake. I swear I put all the bolts for the oil cooler in one place and put them all back as soon as everything was cleaned. All the others fit exactly in the only place you would expect them to go. This is the only one I'm still a little confused about. If I knew for certain it was a banjo I took out, then no issue- a banjo it is.

[SteveKen]

You know I might be mistaken. I don't remember if I even loosened it on my car when I removed the assembly to do the Bufkin pipe. I can only say that if I did loosen it, that I never removed it completely. It does make sense that if it was a drain plug that was not to be completely removed, then it should be similar to a banjo bolt. Therefore, don't' panic, as it's probably correct.

I did a timing belt and water pump service on my wife's MDX and might have been thinking of that rear drain being an M4 bolt.

I did have a terrifying moment where I saw a bolt similar to this on the workbench and thought that I might have forgotten to put it back in before I put the car together, but you can actually see it on my car with everything bolted up. You can even get a 10mm socket onto it to check that it's tight with a swivel and some patience.

[Fastguy]

You know I might be mistaken. I don't remember if I even loosened it on my car when I removed the assembly to do the Bufkin pipe. I can only say that if I did loosen it, that I never removed it completely. It does make sense that if it was a drain plug that was not to be completely removed, then it should be similar to a banjo bolt. Therefore, don't' panic, as it's probably correct.

I did a timing belt and water pump service on my wife's MDX and might have been thinking of that rear drain being an M4 bolt.

I did have a terrifying moment where I saw a bolt similar to this on the workbench and thought that I might have forgotten to put it back in before I put the car together, but you can actually see it on my car with everything bolted up. You can even get a 10mm socket onto it to check that it's tight with a swivel and some patience.

With all the work I'm doing at once, I will be very surprised if I don't have to pull the engine a second time to iron out any unforeseen issues or leaks (I am taking my time and working very meticulously, but you never know). I'm keeping my fingers crossed.

I pulled the bolt, because I have seen aluminum crush washers deteriorate very quickly. I wanted to hit all the places as I assumed I would only have one chance to do this. Now that I saw your picture I am thinking it is actually the same bolt. I am so OCD about this, it'll probably get the best of me, and I'll pull the bolt out again and with a light figure out exactly "why" they needed to put a banjo in there. I am very curious because I've only seen these types of bolts (as you previously mentioned) on feed and return lines like on the turbos. Only problem is, when I pull the bolt, I will probably want to seat a new washer.

[Fastguy]

AH! Got it. It's a banjo so the bolt does not need to be fully removed when draining. That's my guess.