BRIAN2SUL

OK I'll try to keep this short but bear with me. I'm looking for advice on how to approach this dilemma. I bought the car long-distance, from a Porsche dealer, had a PPI done which came up clean, except that there was some story about 'the right codes not being set' preventing a DME over-rev report to be provided. I had already flown out to see the car when he told me this. 2003 996tt with barely 21K mi. Car is nearly perfect cosmetically. Recent records. Clean Carfax (2 owners). Ran great. Sounded great. Idles like a watch. Nothing to complain about, so I made it mine. Shipped home, bought my Durametric. Sure enough, about 28,000 1's and 2500 2's. last ones about 3 hours before my test drive. Crap. Now I'm sweating bullets but what else can I do except put some miles on it and keep my fingers crossed. Couple weeks go by, and get an oil level sensor failure. Indie shop says there's wire harness damage from rodents. Great. Now I'm hating low mileage cars. Few more weeks go by, get about 30 hours on the car, and I'm starting to feel squeamish about not being able to check the oil level, and it was coming up on 1 year interval. No leaks or smoke btw. So I decide to get the wiring harness addressed, which required pulling the engine. Indie suggests doing plugs/coils while the engine is out, so I say OK, you know while you're doing that why not give it a leakdown test, since both of those are about 2x the cost with the engine in the car. 5 cylinders come out perfect, 0%. Cylinder #5 has 35% leakage. He can hear it coming out the intake. So what do I do now?


These are different lines of thinking, I don't know if they're correct or not:

1. Put it back together and drive it, it runs well, 35% is not that bad and having 90-something % of power is plenty. Don't sweat it.

2. That's a bad sign, something worse will happen soon, better open it up and find out what's up with the leak, and with the engine already out, it's about a $3000 exploration instead of $6K (once engine is back in)

2a. Maybe it's just a very slightly bent valve, or even corrosion on the seat or something trivial that only costs 1 valve/seat/guide replacement, pay up and move on

2b. If he takes that head off he's bound to find/suggest $1,000's of 'prudent' repairs to do, but it's all good because I'll have to do them soon anyway. Bend over and pay another, what $2K? $5K $10k?

3. There's no way it's only going to have 1 bad valve and that's it, this is a sign that the engine is hosed and needs a complete rebuild because the timing chain is stretched, etc, etc - see choice #1


There are probably more options but this post is already too long. What is the best course of action? I should mention, my original intent was to drive the car sparingly for a year or two, and enjoy a bit of price appreciation in the 996tt market, and hopefully come out even or maybe even ahead a little. Obviously that plan is trash now, but putting $20K into it and (mentally) amortizing it over the next 10-15 years is not too appealing.


Thanks for your best advice!

docwyte

35% leakdown is significant, is the car smoking at all?

techweenie

There's a notorious problem in leakdown testing: a bit of carbon gets dislodged when the plug is unscrewed and ends up on the valve seat, producing a huge leakdown percentage. If the engine is in the car, the solution usually is to put the plugs back in & drive. Not so sure with engine out. But a big aberration like that calls for a second test before you spend in the high 4-figures!

theprf

I'm with him ^^^^^. If it truly had 35% leakdown it would run like poo. If the engine is out take off the intake for that cyl and look inside, a bent valve or corroded seat will be visible.

993GT

maybe he hasn't got it correctly at TDC? 35% it would be running like a bag...
I'd maybe pull the intake manifold and do a visual, but if it was running well before...

fpb111

BRIAN2SUL

docwyte

Not sure I'd put much validity into the test then. Also really hard to get 0% leakdown, there's usually a tiny bit and you end up with 1-2% on a healthy motor.

BRIAN2SUL

32krazy!

you need a different shop

Kevin

I'd spend a little more monies and re-glue and pin your coolant fittings to gain some extra value with the engine drop and wiring harness change. I'd get the car running and re-evaluate the situation and leakdown in 10K miles or so.

BRIAN2SUL

pfbz

Ahhh... A perfectly running, perfect sounding car that you already own.
But do a few diagnostic tests and all of a sudden FUD creeps in! Send in your oil to Blackstone and maybe you can get an anomaly on that to freak you out a bit more!

Honestly though, the car is yours. If there is a significant engine issue (unlikely), there isn't much you can do about it anyway other than tearing into it, and that's a bit crazy on a perfectly running engine. Pin the lines, put it back together, change the oil every 5K and run your Turbo another 100K miles.

If the seller over-rev'ed the crap out of it and sold you a ticking time bomb, the cost of an extra engine drop is the least of your worries (again, extremely unlikely!)

pfbz

I made my last post before I saw your most recent.

Revised plan: Second opinion from a different shop. Double-talk and incorrect data are NOT what you want from a shop evaluating your engine for a tear down. It sounds like the biggest risk for your car is a bad mechanic.

No smoke (other than a bit of typical startup)? No noises (than a bit of typical Mezger rattle)? Runs great? No codes? Get it back in the car!

Third-Reef

Put it back together and drive it a bit. then with a Durametric you can shut down each injector individually. Someone with a good ear can tell the difference between a good and bad cyl and provide a sanity check. The over rev report only tells when the last overrev count happened. The 2s might have only been i count 3 hours ago. Those # are very subjective. if you had a bent valve or bad rings you would see some telltale signs. I will check my overrev report tonight and post it here for comparison (how bad it can get and still be a good running well loved turbo)