1G Loud pop, white smoke, leaking oil, can't tell where

[GSLENK]

I was cruising to work at around 70 mph, normal temp, normal oil pressure (I usually keep an eye on these things while driving).

Then a "pop" sounded like something dropped in/out of the engine bay, then a rush of white smoke from out of the hood smelled like a combination of burnt rubber, maybe oil, maybe coolant.

Almost immediately, I pressed in the clutch, shifted to neutral. Then after shock wore off, a few moments, I cut off the engine and cruised to the side of the road. The smoking stopped quickly (within a minute).

I can't remember if there was a knocking sound or not. There was some clanking, but I really don't know what caused it, if it was with the engine, or if it was something else. It all happened really fast.

Coolant level is close to normal, oil level is about a half a quart to a quart short of when I lest checked (I check almost every week.

The trail of fluid on the road appeared to be oil (too thin of a trail to tell), the only mess under the car is oil. Oil is green (what my valvoline VR1 turns to in between changes, always, normal...) So I doubt it was another car's oil somehow.

I cant see anything broken or loose. All hoses are tight and intact. The coolant system hoses are hard to squeeze (still appear to hold pressure fine). All oil lines are intact. Oil filter is on snug.

I pulled the plugs, all look normal. Jacked the car up, cant find anything except oil splattered randomly on the underside of the car. Most of the oil pools on the bottom of the oil pan. No major leaks, just a very small puddle of oil. Started turning the engine over by hand, no more oil drips.

I am debating what to check next and whether it would be a bad idea to start the car. Mechanical timing seems to be OK.

Don't know what to check next. Any ideas? Sound familiar?

 

[GSLENK]

Seems to get stuck every now and then rotating it by hand. then if I go reverse (CCW) just a little for a few degrees, then I can resume going forward. Makes little clacking sounds like shifting through the gears with the car off around the time it gets stuck in rotation. Seems to get stuck every 4 or so rotations of the crank, always with piston 1 at/around bottom center.

Timing belt looks fine (normal tension, no signs of damage/oil etc)

 

[Dsmkauai]

You have the balance shaft belt still? Maybe it broke bro.

 

[GSLENK]

Is there an easy way to check that? ie NOT pulling the timing cover?

I was just able to crank through 30 rotations, no cramping/stuck points.

Turbo intake pipe is clean (little oil residue because I recirc my catch can...

 

[DSMPT]

Could be the turbo is blown or damaged valve? Did you check the hot side?

 

[Dsmkauai]

Not really unless you have a small scope/camera, you can put down the top cover. It's possible with the top cover off and a good light you might be able to see.

 

[GSLENK]

I have the easy timing cover off (the tippy top one that people replace with clear versions). Does the harder top half come off relatively easy? without removing pulleys (I am fine with removing accessory/serpentine belts...)

Turbo cold side checks out no oil pushed into the compressor area. Normal sided to side play, no in/out, does not contact the housing at all. Spins freely for a journal bearing (I can flick the wheel and it goes for a little bit, just not endlessly like a BB).

Really don't want to pull the hotside. That's a lot of tight space working, gasket replacing, fluid replacing. After gaskets oil and coolant its a ~$100 diagnostic.


How else can I verify lower timing? where should the crank pulley timing marks be when all else is lined up?

 

[Dsmkauai]

You have a 2 piece or 3 piece cover? I think the middle cover requires the belts and possible water pump pulley to be removed. Been while and I switched mine to the 2 piece

 

[DSMPT]

You can see if oil leaks on hotside if you remove 2 nuts between the O2 housing and the downpipe . or maybe just remove the O2 sensor and see if it is wet with oil.
In case if the balance shaft belt is cut then the engine should be making more vibrations now.

 

[GSLENK]

Here's the best pictures I could get of the timing side of things...

1) When the cams are lined up, the timing mark on my Fluidampr seems to be off by a little bit

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2) When the fliudampr is lined up perfect, the cam marks seem off.

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I assume perfect is by looking through the headlamp area hole and not from up top as that is not a perfectly straight line of sight from up top. Through the hole pictured looks to be a perfect line of sight... It looks worse from up top.

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[GSLENK]

NBO2 sensor in the OEM location... Enough to rule out checking the hotside?

Remember the engine was shut off almost immediately after this happened.

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[GSLENK]

If I can rotate the crank by hand, am I safe to try starting? Or at least do a compression test?

I also have a 100psi leakdown tester, never used it yet... might be a good time?

 

[mtf-DSM]

Hey. Sorry to hear about your troubles... I know you stated that you checked the oil lines to and from the turbo, but could it possibly be an itty bitty pee hole in one of them that only shows it's ugly side when the pressure is high enough, such as engine running/driving conditions?

 

[GSLENK]

Good point. That's next. After I verify engine health, I think i'll start dissecting all the lines one by one.

I am skeptical of such a hole though, but i guess it is possible, maybe I ran over some debris in the road and is put a little hole in a line. The feed line is FP braided hose with a heat protecting jacket, cant imagine a pinhole happening in that and not being very noticeable. The turbo drain doesn't see enough pressure to spray. No other oil lines.

O2 housing is bone dry. Stuck a paper towel on a wire, got it nice and jammed up in the turbine wheel, came out clean as a whistle. stuck my pinky a half inch in the o2 hole, rubbed some of the inside, came out clean too. I guess the hotside and cold side are fine.

Any other ideas?

 

[GSLENK]

FOUND IT.

While setting up each cylinder for a leak down, cylinder 4 (furthest from timing stuff did not budge when I shoved a chopstick in it. pressed down on the chopstick, and I could feel the piston move down. Will not come back up.

So something with the rod... What are the odds that the cap simply fell off and nothing was harmed? (I know... none)

What damage/repair might I be looking at here?

 

[1990TSIAWDTALON]

Wow. No they're not very good. Pull the oil pan my friend. Hope for the worst and deal with what you find. Very sorry to here that piston moved. You'll be able to tell soon.

 

[1990TSIAWDTALON]

Draining the oil will possibly start to tell you something.

 

[GSLENK]

I'm gonna wait till tomorrow evening to dig in. I had this gut feeling that something pierced the oil pan up where I could not see it.

I am guessing there is not even a slim chance I can just pop a new bearing in, bolt the rod cap back on and be on my merry way .

 

[ThunderChild]

Sounds like it's time for a tear down. I'd be surprised if the crank isn't all jacked up in addition to the con-rod.

If the cap fell off, I'm sure there's some decent damage and you'll at least need to go through the bottom end to check.

Best case: no major damage, a polish and new bearings (*highly unlikely*)

Most likely case: block fine, crank journal banged up some (may need new), rod smacked up (probably need new), and all new bearings.

Worst case: motor is toast, all new bottom end (including block)

start saving, and it's a good time for a forged bottom end.

That's rough luck man, sorry to hear about that!

 

[1990TSIAWDTALON]

You said in a earlier post that you heard a "shifting" or clanking sound. Brother that sounds like a rod no longer connected to the piston. White smoke as you described is coolant, black is fuel and blue is oil. Man your situation is a tough one.

 

[GSLENK]

Oh I have savings... it looks like a beater DD and an engine rebuild are on order instead of the fancy tig welder I wanted . I'll find out more tomorrow.

I had a feeling this engine was on its way out. Never got around to the checkup I should have done (leakdown/compression). But I had a random misfire that no amount of ignition parts would fix. Hopefully whatever gave up in the engine was also that problem. I was getting tired of chasing a ghost.

White smoke was from under the hood. Honestly in the moment I couldn't tell by smell which it was. But it was definitely smoke from a fluid burning off of the downpipe. I have a vented hood. I saw the smoke instantly after the sound.

My initial instinct was coolant. But I found no traces of leaking coolant, and only engine oil.

These are the options I am considering
1) get a DD of some kind + pull engine, send to JAM for cleaning rebuild etc... (or machining then the rest DIY)
2) get a DD and a barely used/newly built 4g63 with reciepts
3) get another 1g AWD dsm and start swapping stuff over bit by bit.
4) sell as is (bad idea)
5) part out

 

[Talon96fwd]

I'm curious this is the original motor? If so how many miles?

 

[gdb1039]

While you have the motor torn apart I would highly recommend checking the valves and head. If the rod broke there is a good chance the piston kissed the valves.

 

[mtf-DSM]

Sorry to hear that. I was hoping for something simple... After draining the oil if you don't see metal flakes/chips in it and you get out the cap and other loose hardware, you COULD press your luck on throwing it back together and praying , but even if it did function, would you really want to drive an awesome car without having a peace of mind? Or not being able to destroy the hopes and dreams of a rival at a stoplight, because you're afraid of blowing up?

Just my opinion here, but along with the above statements, at the VERY LEAST; new OEM rods, forged pistons, good rings, head checked with some minor port work (since it will be off anyway), etc... Then at least you'll know that you're a very capable DSM again... And lastly, you may find something else that was getting ready to break during the tear down, which would save you in the long run. Good luck though either way.

 

[GSLENK]

I'm curious this is the original motor? If so how many miles?

Original motor
~60k miles Don't recall ATM. I only track my weekly miles and never look at the odo.

I drive my cars. Floor it whenever I want to. Drive like a granny when I want the tank to last for a week. Sees 20+psi regularly on a FP red HTA/E85.
At least a few times a week I am sure to take a pull 2nd-3rd.

Redline was set at 7500 in link. I rarely hit that limit even when spirited driving.

It popped when I was FAR from WOT. Normal cruising, maybe even on deceleration. Didn't even hit 20psi on the way to work yet. Made it 2 miles at cruising pace, then outta nowhere... pop clunk clunk smoke.

Compression seemed good last time I checked last summer.

I didn't get a chance to pull the pan today. Will do tomorrow.