When I changed my coolant today, the drain plug in the block was frozen. I figured it was just rust, and kept at it (PB Blaster, breaker bar, extensions, BFH) until it started moving. But even then it was real hard to turn (had to keep using the breaker bar); at some point I thought maybe it would be better to leave it but the bolt was half out by then.

So I finally got it out and this is what I've got:





As you can see, the aluminum threads bonded to the bolt and sheared off the block. A couple of threads are still stuck to the bolt. I don't know where the other pieces of shredded aluminum went; they were swept away in the flood of coolant.

I'm guessing no anti-seize was used the last time the coolant was drained (not by me).

So the question is, how to fix it? Do they make Heli-coils that big?

 

You can use a heli-coil maybe, or you should try the expandable rubber freeze plugs that they sale at autozone until you can find a better solution...

 

Ah, I didn't know about those rubber expansion plugs. Will at least let me drive it in the meantime. Thanks.

 

It will let you drive, it may hold perm. but I would get that hole fixed and put back the proper plug, but that is my opinion only. It would suck to have it start leaking and you run out of coolant on a nice summer day...or in freeway traffic.

 

you could always retap and use a larger plug bolt. just an idea.

 

Anyone seen this before and know what to expect in terms of repair? I'm going to ask the local dealership and another shop I know. If this were a normal sized hole I would try ot retap or use a Timesert or something myself, but I can't see myself buying a 30 mm drill bit and tap.

 

Go find a longer plug, as you can see only the first set of threads is messed up. A longer plugs will catch on the new threads and its gonna be all good.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ejoner &raquo;</TD></TR><TR><TD CLASS="quote">Go find a longer plug, as you can see only the first set of threads is messed up. A longer plugs will catch on the new threads and its gonna be all good.</TD></TR></TABLE>

Good idea...there are lots of threads left. The start of what's left are definitely damaged, but it may be workable.

Anyone know what size and type this bolt is? The Helms doesn't say and the e-catalog just says 28 mm. This is not a standard metric size (closest are M27 and M30), so maybe it's a different thread?

 

So did you get this thing fixed...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8EG-T &raquo;</TD></TR><TR><TD CLASS="quote">It will let you drive, it may hold perm. but I would get that hole fixed and put back the proper plug, but that is my opinion only. It would suck to have it start leaking and you run out of coolant on a nice summer day...or in freeway traffic.</TD></TR></TABLE>

lol dont joke about, i was at the bank one a hot summer day, friday (payday). you guys know how busy at gets on drive thru... i was in line, 2 cars ahead of me. next thing you know i see smokes, oder, than the overheat. i felt so stupid but hey! cars let me through to teller.
dont let this happend to you or anyone.

problems: coolant hose crack and leaked.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8EG-T &raquo;</TD></TR><TR><TD CLASS="quote">So did you get this thing fixed...</TD></TR></TABLE>

Nope...I picked up one of those rubber expansion plugs but it was too big and that Autozone didn't have a smaller one. I'm going to try some other stores.

I went to the local dealership's service center and they were most unhelpful. The guy looked at me like I was crazy and then asked why I removed the bolt in the first place...because that's what it says to do in the service manual, dumbass. What, you guys don't the drain the block when you flush the coolant? Anyway, I did get the number of the machine shop they use but they weren't open over the holidays.

I think a longer bolt would work but I've got no idea where to find something like that...

 

Honestly my shop never removes that plug either because of exactly what you've run into. When we do a coolant service we drain from the radiator, and if we feel a "flush" is necessary we can remove the t-stat and run pressurized fluid through the upper coolant neck until it flushes clean out of the t-stat housing area.

You will probably not find any heli-coil, time sert, thread repair kits, etc. Those threads are huge, and very odd.

Imagine being a repair shop, and doing a simple coolant service procedure while a customer waits. You pull that plug out, and like you found, the threads come out with it.

"My car wasn't like that when I came in"

"Well YOU broke my engine, so YOU need to fix it"

The list of bullshit complaints would never end. It's bad enough when we do other jobs and some dumbfuuck overtightened, corss threaded, etc. bolts which cause them to snap when the next poor guy (us) works on it. All of the sudden it's "my car wasn't like that before you guys worked on it!"

Anyways you might want to take those pics to a GOOD machine shop to see what they say.

 

Yeah, in hindsight I should have stopped and left it alone once it became clear that it wasn't moving easily...but by the time I realized that it was mostly out and only hanging on by a couple threads and that didn't seem like a good idea either.

Even so, I think the Honda service guy could have said, "Yeah, we never remove that bolt because the threads are weak and prone to corrosion" or something, instead of "WTF is wrong with you? Why would you remove that?" (paraphrased LOL)

All earlier coolant changes were done by shops, not by me. If they all do it like B18C5, it's possible this is the first time that bolt's been opened, which may explain why it corroded to the block. I searched and read all the DIY coolant changes on H-T and no one seemed to have any problem with that bolt...just lucky I guess.

If you don't think it's necessary to drain the block when changing the coolant, do you think I could just get the hole plugged and welded instead of trying to repair the threads? JB Weld LOL.

 

On topic: How much thread do you have left? Would it possible to just use a really thick crush washer or something?

Off topic: When I recently drained my coolant I applied Hondabond to the threads before reinstalling the block plug, like the Helms manual says. Will this prevent me from having the problem the OP is having or should I clean the plug and use anti-seize instead?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hardedge &raquo;</TD></TR><TR><TD CLASS="quote">On topic: How much thread do you have left? Would it possible to just use a really thick crush washer or something?</TD></TR></TABLE>

You mean a really thin washer? If you look at the pics on the first post, with a bolt of the same length as original, it would only have about 1.5 turns of thread to grab onto.

That's a good idea: the stock washer is really thick, about 2 turns of thread. I've had no luck finding a longer bolt (or any 28mm bolt at all for that matter), but I wonder if I could get a new OEM bolt and install it without the washer? Use a little extra liquid gasket? And if it leaked, weld it on!!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
Off topic: When I recently drained my coolant I applied Hondabond to the threads before reinstalling the block plug, like the Helms manual says. Will this prevent me from having the problem the OP is having or should I clean the plug and use anti-seize instead? </TD></TR></TABLE>

You're probably ok... Just remember the next time you change coolant: if the bolt doesn't come free right away with a moderate amount of torque (the torque spec is not that high, 35 or 40 lb ft, right?), then it's probably seized and you should leave it alone!

 

Yeah, if you can't find a longer bolt...find a thin copper washer and then JB it in there. Does JB adhere well to aluminum though?

 

Well, it's fixed (finally).

I bought a new bolt from the dealership (reasonable price but it took a week to get here...). Dropped the cat (had already removed the radiator) to get room to work. Used a dremmel with a grinding wheel to try to remove some damaged threads, without much success.

Couldn't get the damn bolt to bite without crossthreading...the threads are really small and fine (to make a good seal) which made it tough. Eventually I just put liquid gasket on the threads and just jammed it on. It crossthreaded and wobbled back and forth between threads and stripped, but in the end it caught a thread. If I torqued it any more it would strip I'm sure.

There's no leak (due to the liquid gasket) but because there's not much good thread holding it on, even though there's not much force on it, I JB Welded around the bolt head for a little peace of mind.

 

I would have did the same thing to fix some jb weld and place that sucker back in it! I never removed the bolt either to flush the coolant system good to know that you have it fixed . A ghetto way but none the less its fixed!

 

how about buy another drain bolt and cut the threaded part of the other drain bolt and have it welded to the other to extend it? will that work?????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dee888 &raquo;</TD></TR><TR><TD CLASS="quote">I would have did the same thing to fix some jb weld and place that sucker back in it! I never removed the bolt either to flush the coolant system good to know that you have it fixed . A ghetto way but none the less its fixed!</TD></TR></TABLE>

Yeah, ghetto for sure. It actually looked clean when I first got it in...it sat flush with just a little liquid gasket squeezing out around the edge. But now there's JB Weld smeared all over and looks like crap.

But I guess you can't really see it behind the exhaust anyway...and now I'm sure it'll never come off or leak.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by el_toro_de_magnifico &raquo;</TD></TR><TR><TD CLASS="quote">how about buy another drain bolt and cut the threaded part of the other drain bolt and have it welded to the other to extend it? will that work?????
</TD></TR></TABLE>

That would be tough... Easier than that would just be grind the threads off the bolt and weld it in.

 

where is this drain plug located

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by audsyn &raquo;</TD></TR><TR><TD CLASS="quote">

That would be tough... Easier than that would just be grind the threads off the bolt and weld it in.
</TD></TR></TABLE>

I agree!!! No chance of it ever leaking then!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aziaticvang &raquo;</TD></TR><TR><TD CLASS="quote">where is this drain plug located</TD></TR></TABLE>

It's on the front of the block behind the cat. In the first pic in this thread, the blurry area in the upper left is where the engine code stamp (D15Z1) is, and in the upper right is one of the exhaust manifold bracket bolts.