brianhed

My 2008 TL 85k blew the #5 spark plug. I drove it 30 miles to a repair shop with the plug out. Sadly, A week earlier I started getting cylinder 5 misfire codes but didn't do anything about it.

I had an insert installed. After that, it immediately started having all the cylinder misfire codes. (P301-306). Of course, I was too busy again to get it looked at... I drove about 500 miles with it having crappy idle and low power at low idle. The other day it stalled on me for the first time. I restarted a couple of times but could only get far enough to park it.

I had it towed to a shop that said exhaust is coming out of the oil fill which means I have a hole in the cylinder head or a bad valve. They recommend engine replacement instead of valve replacement.

Would I be wasting money trying to see if it's just the valves instead of replacing the engine? Did I damage it driving it with a missing spark plug?

Turbonut

iTrader: (1)

Could also be a hole in the piston, broken rings as they saw discharge out of the oil filler. Do a leak down test, or just connect an air hose into the spark plug hole, inject air and see where the air exits, throttle body, exhaust, oil filler, but sounds like the engine is toast.
As far as driving with the plug out and injector not disconnected, not a great idea, especially when fuel is being delivered into the cylinder and not burnt, as it can wash the walls, no lubrication. Also, if debris was remaining in the cylinder, that could also be a cause.

feldmanbd

My vote would be replace the engine. You could have all kinds of problems with what went on there (high blowby, damaged cylinder liner, damaged piston, damaged valves, damaged valve guides, high oil consumption, etc.), and trying to chase them down and fix them all could end up much more expensive than an engine swap. If you have the manual transmission you may as well replace the clutch while you're at it.

Also note that at 8 years/85K you're about due for a timing belt replacement anyway. Any time the head comes off the timing belt has to come off anyway, so any work there is not going to be cheap.

Being an 8 year old car - there are plenty of used J-series engines out there you could swap in.

screaminz28

iTrader: (1)

You didn't list Type-S, so I'm assuming this is a 3.2? I'd say just get a motor and install it - most junkyard motors will come with a start-up warranty and a 30/60/90 day warranty. That would reduce your costs to just the engine and R/R, which would probably be cheaper than a tear down, inspection and repair of the current motor.

It shouldn't be too difficult to put a bore scope down it though and at least get an idea of what it would need - but since it appears there is physical damage, the head has to come off for a new valve - so that means head gaskets, timing belt, etc. Your labor costs may exceed the R/R.

Good luck with it!

brianhed

I had the 3.2 swapped with another. The installer found that the front precat was melted down and clogged. Also, one cylinder looked bad. (The one with the blown spark plug) The spark plug was found melted underneath the engine to one of the plastic shields.

I'm wondering what came first. The bad cylinder, blown spark plug, or the clogged precat?

Also, does the old engine have any value or should I just take it to scrap yard? It has the wire harness, water pump, intake, egr stuff.

Of course, I had both precats reamed out. No CEL yet.

screaminz28

iTrader: (1)

What most likely occurred was this - spark plug was loose, which makes that cylinder run exceptionally hot. The engine would now read the o2 sensor as lean, and add fuel to correct, which would help destroy the cat. (It could be the opposite, engine thinks its running rich and pulls fuel making it run even leaner, thus hotter - I worked all night so my thought process is a little cloudy.)

In any case, I don't think that any of the 3 things happened 'first' other than the spark plug being loose.

Now that you have the car running again, I'd check your plugs every 5 - 10K just to be safe. This motor has a tendency to loosen plugs (especially #5 it seems.)

csmeance

Old engine is certainly worth money as intake manifold, cams, etc should be good! Don't just scrap it, put it on blackmarket here, craigslist or ebay and you'll certainly get a hit.

The plug probably loosened causing the plug to eventually blow out. Plug ejects and leaves bits of material inside the cylinder and you now have a damaged cylinder. Damaged cylinder plus misfire codes and driving causes the cats to melt.

thisaznboi88

iTrader: (7)

Swap a used motor in and part out the oil one

My thought is that you drove on a rich engine for too long that All the extra unburnt fuel contaminated the cats causing them to melt down. It also didn't help that you drove on the car like that for a few hundred miles