RenSL

Hi,

Fingers crossed for some help here.

​​​I had a compression / leak down test done for a 996.2 Turbo (40k miles) I'm looking to purchase. Here are the results:

1. 150/20%

2. 150/22%

3. 146/25%

4. 150/22%

5. 148/25%

6. 142/20%

Mechanic told me that this is a good result and within spec.

What I can tell from searching the forum/google:

a. Compression is good but not excellent (almost within 5% of each other).

b. Leak down numbers are bad (20%-30%). Slightly good sign that they're within range of each other.

c. Some claim leak downs shouldn't even be done if compression looks fine. Feels like this is a minority opinion.

d. Some claim that leak downs should only be done in specific conditions (eg after X miles) due to lubricants providing better seals. So potentially this could be a high reading.

e. Saw an article re how carbon deposits (common in cars that aren't driven and especially wrt 911 boxer engines) will move leak down numbers up. If this is the case, then fuel addictives might help.

​​

​​​​​Am I missing anything in my purchase consideration? Seems like the majority view will be to walk away but thought I'd ask the crowd once bc otherwise the car is looks/drives clean (and I'm a bit fatigued in trying to get these cars to PPIs).

​

​​​​Thanks!


​​​

vtec_

The compression numbers look good. All within 5% of each other.

How much is the car? is it stock?

40K miles is like new.

Carlo_Carrera

To me those numbers look fine. I will page some super knowledgable folks for their input.

@powdrhound @993GT @theprf

RenSL

Still negotiating the price but likely to land around 70. Not stock--it has the RUF 550 package.

vtec_

Nice, I believe that package has k24s.

I think you'll be okay but there are ppl mentioned aboved who have alot of experience with these engines and I believe @powdrhound car had a RUF550 package at one point.

These engines are pretty reliable.

RenSL

Awesome, thanks for the note of encouragement!

QwikKotaTX

I would be more concerned with 2nd gear pop out or synchro issues. The transmissions are very expensive to have repaired if 6 speed.

RenSL

So far so good on that front!

vtec_

When/if you get it and if the coolant lines haven't been pinned, pull off the alternator and wiggle the coolant fitting behind it! If its loose, you can fix it in a myriad of ways (pinning, jbweld,etc) until you do the rest of them.

theprf

Those look high. More important is, where is the air going?
Also, I wonder just what the tech did. Typically leakdowns are written like 78/80. Meaning, 80 psi applied through a calibrated orfice and 78 psi shown on the cylinder.
My car with almost 180k miles is around 68-70/80 and I find that high.
There's really only 2 places air can go in a properly conducted leakdown test, through the exhaust valves or the rings.

RenSL

Update in case anyone is curious is that I ended up passing on this one. The search continues!

Bernard IV

If you PPI another car have them do the exact same leak down test to compare. When I pulled apart my 60k engine it did have some pitting on the exhaust valves and some slight leaks from it.

lawrence1

Would be nice if you shared which car this was so no one else gets stuck with a problem.

vtec_

Why did OP pass on the car?

Carlo_Carrera

IMHO there was nothing wrong with this car. The OP spooked himself with "data".