It's been quite a long time since I have been on the forums as I've enjoyed my car problem free for the last 4 years. However, the inevitable day of death may have occurred. I am looking for possible diagnosis and I will post relevant mods at the end of my post. Here is the situation:

I headed out for the morning, stopped at a gas station to fill up maybe to 3/4 of a tank at the station right around the corner from my home. Headed up to the freeway, another 3 miles or so, and dutifully wait in line at the onramp traffic control signal. When it was my turn I disengaged the clutch got up to about 15mph and heard a muted pop, lost power (car wouldn’t rev with gas pedal depressed) looked in the rearview mirror to a gale of white smoke drifting down the freeway. I pulled it out of gear let off the gas and pulled over to the side of the freeway. Taking sense of the situation, I wanted to remember as many details as possible. No smoke or liquids coming off the vehicle as I got out of the car, no burning smells, no nothing! Carefully opening the bonnet (fire, hole in coolant hose etc.), I see absolutely nothing on the topside, no oil leaking from header gaskets, no coolant hoses split or torn.

I have it towed back to my house so I can get a better look, pop it on jacks. From underneath, I notice clear liquid (most likely coolant) on the driver’s side covering the A arm and a portion of the turbo (exhaust side). All of this below the actual exhaust manifold, nothing on the top side of the engine bay etc. No pooling of anything on the ground.

I also notice that I am missing nuts that hold the manifold to the engine block on both the drivers and passengers side although by this time I can see no obvious signs of a seal issue (though that will need to be taken care of) and still no sign of where coolant may be leaking from.

I've checked for cracks/lose hosing issues for both the coolant and the intercooler and have not located any issue for those systems.

A visual inspection yields no smoking gun. The only smoke comes from the exhaust.

It's a '04 g35c 6 speed with ~59,000 (43k with a turbo). It's a semi-daily driver with all of 2 track days on it from 2 years and it gets summer duty off because AZ is hot as hell.

Here is what I have on it:

1st Gen APS TT with Garret GT internal waste gate etc. (the full kit, larger oil pan etc.)
Random Tech cats
Stillen exhaust w/ x-pipe
Ceramic coating where it counts

Defi gages for EGT, Oil Temp and Boost

380-420 rwhp depending on temp/gas/boost. I try to keep it tuned at 380rwhp, which is around 7-7.5psi. I've had it retuned a few times, as the boost always seems to creep upward.

What else should I be looking for? Could a sealing/pressure issue cause this loss of power and smoke? Thoughts and comments please.

 

Have you checked the coolant hose that goes to the turbos to cool it down.
Remember APS have garrett turbo's which have a water sleeve to cool down the turbo's
so the bearings don't get caked with hot oil.

If the smoke you saw smelled sweet then yes it's coolant hitting the header and evaporating/burning off. I would heavily inspect those hoses I speak of and have those nuts that hold the header in place taken care off asap. The pop you heard probably one of those hoses letting go under pressure.

 

Ok, I haven't pulled anything apart yet. But I re-inspected the stainless steel coolant line to the driver side and it seems intact, no moisture around it etc. if there is a hole, even if its small, shouldn't I be feeling some liquid?

Also, if this were the "pop" how would that explain the sudden power loss?

After rereading my post, I think I have left out some detail. The engine sounded very lumpy during the 5-6 secs from problem to pull over and power down. I don't want to start the thing back up yet until we can eliminate other potential causes.

 

So far you've done all the right things. Check all fluid levels and color, consistency. If you're sure it's coolant, you need to find the leak. Smoke out the back of the exhaust usually indicates oil or fuel coming from the motor or turbo. That is inconsistent with a coolant leak, unless you cooked the turbo running without coolant, which blew the seal.

If you had a fluid leak in the engine bay while the car was moving, it should have sprayed the underside. If it was oil, it would still be there. Fuel you can smell. Coolant (water based) may be harder to find the source of the leak as it evaporates dry/clean. It shouldn't still have been detectable on the hotside of the turbo unless it was continuing to leak during cool down. There is a hard coolant pipe in the back and a few hoses that come off of it. You'll need to do some detective work in that tight space with a flashlight... You may need to take off the intake manifold and charge pipe to get a better look at the hoses that go to the throttle body and to look at the main rear hose connection that sits dead center at the back between and under the fuel rails.

 

Coolant levels and coloring are fine at the top of the radiator. Oil coloring is fine at the dip stick. I've debated whether or not to drop the oil and check for chewed up engine pieces while working on checking for leaks and replacing bolts on the manifold. Its just too damn hot to work outside. I am shipping the car off to the shop tomorrow for an inspection, oil change, and review of service codes.

Here's to hoping it's nothing major.

 

Did you take off the oil cap and inspect for coolant in the oil?

It sounds to me like your fluids are all pretty good which might point to internal component failure.

I feel for you.

 

Based on what I have seen so far the symptoms point to a bearing failure. Obviously, pulling the piping on both sides of each turbo will show if there is an oil issue. However, the smoke I recall didn't seem to have the blue tinge one would expect with cooked oil. I'll update when I get new information.

 

either the turbo is feeding the engine coolant or maybe head gasket. not to familiar with these cars, but head gaskets are typically problems on turbo cars. i have two turbo cars (both porsche) and one currently has a blown head gasket. it had the same symptoms, i.e. white smoke out exhaust, lumpy running engine. The coolant entering the cylinder causes this.

 

Rod bearing failure.

 

Turbo could have took a dump.Same symptoms on mine, minus the pop...The turbine wheel broke off and was sitting in the downpipe. The broen turbo acted like a cork in the exhaust track, similar to a failed Cat..Also Check the cats.