Oil drain plug flew out on highway

So I found coolant leaking from my new engine the other day. Took a while to track it down, but finally found it coming from a coolant hose reducer (?) thingy. After taking the car back to the shop, the manager told me the JDM engine in my car doesn't have an EGR valve, so they had to use that reducer (and I assume some adhesive). Since that wasn't working, they removed the reducer and spring hose clamp and just used a worm gear (screw-type) hose clamp with the original hose. That seems to be working. Still, I'll carry some extra clamps and coolant with me.

In the second picture, the hose reducer has a red dot on it.

coolant leak.jpg


coolant hose reducer and clamp.jpg
 
Yeah, it's a pretty simple procedure.

So it has finally cooled down in Dallas, so I put the car on ramps and tried to replace the donut gasket. I really struggled trying to put the gasket on straight, and it looked like removing the J-pipe is necessary to do it properly, at least with the Rock Auto gasket. It was simply too snug for me to slip it between the two end flanges and tighten it up and have it remain straight.

When I went to remove the J-pipe, I looked up and saw something curious: A washer similar to what's shown below on only one of the three "two-piece" bolts. Since Mazda would never have used one random washer and I didn't put it there, I knew it was from the engine replacement and that it was a workaround. When I touched that washer it moved, so I knew that the bolt there wasn't tight. With the engine running and making the weird noises, I pressed the super-duper thin metal gasket just above the J-pipe (shown below), and the noise stopped. I added another washer to keep the bolt from bottoming out in its hole and that allowed the two parts to join flush. No more warbling/duck exhaust noises. I put the original donut gasket back in because it's a little more substantial than the replacement and I had kinda' damaged the replacement trying to install it without first removing the J-pipe. A slightly better repair would be to adjust what I'm calling the "two-piece bolt" to effectively shorten the bolt so that it doesn't bottom out, but I was afraid to damage the threads by doing that, hence adding the additional washer.

The two springs on the other end of the J-pipe that join it to the downstream exhaust: If they had to be fully compressed while tightening to get to their recommended torque values, are they shot and in need of replacement? There doesn't seem to be much flex in that joint with those springs fully compressed.

1600660948577.png
 
The other mounting stud that hasn't got the washer with it, has been hammered on! 🤬
Looks like someone had trouble removing the stud properly and just smashed it on instead. Not sure what the third stud (not in that photo) looks like, but that stud could be the only one that is sealing that joint. The other two studs are doing nothing.
 
The two springs on the other end of the J-pipe that join it to the downstream exhaust: If they had to be fully compressed while tightening to get to their recommended torque values, are they shot and in need of replacement? There doesn't seem to be much flex in that joint with those springs fully compressed.

That could mean that the springs are sagging and don't need as much torque to compress them, but it is kinda hard to give a torque spec when you're working against spring pressure.
The springs aren't supposed to be fully compressed because they would be bottomed out, then the joint would have no flex, and you might break your flange off.

I figure that if you back off your spring bolts a bit, so the coils have room to move and the joint isn't leaking, then you should be fine.

The only problem I could see with weak springs is that the joint may not be held together tight enough and leak or the nuts and bolts may vibrate loose and fall off.
 
Jazzy, the other "stud" looks good (see pic below). I wasn't sure why that stud and the stud with the washer were deformed. Thanks for that probable explanation and also for the word; I didn't know what the heck to call that "two-piece bolt" thingy. I did remove all three studs and their threads were intact and I was able to reinstall and torque them to their 38 - 51 Nm spec, so I imagine the threads in the pre-cat flange (or whatever it is) are also intact. The problem that I could detect is that that one nut doesn't tighten enough on the bolt, so I needed two washers to tighten it down. It definitely fixed the exhaust leak.

PCB, I'll go out and loosen those spring bolts today. I received them fully compressed from the oil change place, so that's how I re-tightened them. :( Since the donut was not the source of the original leak, I can probably loosen them without too much worry. I really thought the leak was coming from the donut gasket area. Time for me to invest in a stethoscope or better ears.

Thanks guys.

1600694690453.png
 
The nut on the stud with the washer is probably seized.
That's probably why it isn't threaded on all the way.
It's probably better to use a washer than to bottom out the stud and hope the nut starts turning.

Having the springs fully compressed could have weakened the springs a bit.
Having them fully compressed would be the same as just using nuts and bolts without springs.

That joint needs to flex.

This is my redneck fix for my flex joint. Lol

My flange rotted off so I used some muffler clamps, bolts, and strapping to resemble it.

It is still spring-loaded. Lol


 
Well, something (or someone) in your car is loaded... :)

OK, I loosened those spring-loaded bolts a fair amount to introduce some gaps within the coils. I rapidly went up and down the steep ramp to our parking garage and heard some new noises, so I put him back up on ramps and tightened things down so that there was still some gap in the coils. I sped up and down the ramp and I did not hear the noise - nor did I hear a previous noise that may have been caused by the springs being completely compressed. Fingers crossed.

I've added two exhaust springs to my cart at Rock Auto for an upcoming purchase. I'll need to do my end links and bushings soon because the greased-filled boots on my links have been split for years (they're original). Hearing YouTuber ECTG1's recent rant about Moog hasn't helped my opinion of them and I may want to look elsewhere.
 
  • Like
Reactions: pcb
Back