inkatouring

I'm seriously looking at a c4s and have been talking to several shops about a PPI. Each one, when I ask if a leakdown or compression test is included, says no. They are wiling to do it -- at a significant cost sometimes, but all say they wouldn't bother unless the engine is running in an abnormal fashion.

The car has close to 90k on the clock, but had valve guides done at 35k because of SAI issues. Runs great and strong.

Thoughts?

ja78911sc

Was a complete top end done @ 35K or just the valve guides?

inkatouring

Don't have receipt in front of me, but as I recall it was guides.

ilko

Most shops charge in the neighborhood of $250 for a leak-down test. That's chump change compared to what you may be facing further down the road. Look at it as cheap insurance against a huge dent in your savings account.

inkatouring

I recall that you did one on your c4s when you purchased it. Two questions: (1) what were the numbers and (2) how much did your car cost (if you don't mind me asking, trying to figure out market for higher miles c4s)...

Quadcammer

DO IT

ilko

My car had 101K at the time. The engine had never been opened. The numbers were as follows:

1 - 2%
2 - 1%
3 - 2%
4 - 2%
5 - 3%
6 - 2%

The engine uses a quart of oil every 2400 miles or so. That number has been pretty consistent since I've bought the car a couple of years ago, initially with Mobil 1 15W-50 and now with Brad Penn 20W-50.

Cost of the leak down test was $250.

FisterD

Not sure I agree with this. MarkD's turbo had a 20% leak down on one cylinder before we did a top end rebuild on it. Driving the car you would have never known this.
I recently checked mine and all cylinders were < 3% at 69k miles.
$250 is on the mark for a NA 993 for the test.

ilko

Just re-read your question again. As far as the cost of the car it depends on a lot of factors. Mine was pretty well sorted with just about ALL the major upgrades people go gaga about here (PSS9, RS sway bars, LWF, RSR mufflers, OEM litronics, 3-spoke steering wheel, Euro front and rear bumpers, turbo S chin spoiler and brake ducts, C2S grille, etc., etc.) and the seller threw in a set of new tires. So I think depending on the car you'll be looking at a $30-40K window for one. I remember there was a red C4S in Chicago for $28K when I was looking for mine. It had 90K miles but it was pretty scruffy. That was 2 years ago. I don't know how things are now but I keep seeing people starting threads looking for a C4S in particular this year. Maybe it's back in fashion, hehe.

inkatouring

I figured your "improved from stock" car was a good comparison for the one I'm looking at because it, too, is not a stock low mileage garage queen, either. Thanks for the info.

earossi

It's been almost a year since I bought my 98 C2S with 100k miles on it. Prior to the purchase I had a PPI done on the car by a respected shop in Wisconsen which found several small things, but nothing to prevent me from buying the car. However, the leakdowns were in the range of 6 to 8% on an engine that had never been torn down. The car ran strong. The shop opinion was that the leakdown numbers in that range was about right for a motor with that many miles, and since there was not a wide disparity in the numbers, they pronounced the motor as OK. I've now put about 6k miles on the car since buying it, and oil consumption is about a quart every 1500 miles which seems ok to me. So, I am beginning to wonder about some of the leakdowns I see on this forum and wondering what they are an indicator of. An original motor with 100k miles on it and a leakdown of about 1% is significantly different from what my motor tested out at, yet both engines are stated to be running well and strong.

Quadcammer

A 1% leakdown on a 100k mile car would be unusual. Keep in mind that not all testing equipment is perfectly calibrated.

That said, the 1% leakdown car would make more power, run cleaner, and use less oil. They can both run well, but all else being equal, the car with the lower leakdown will perform better.

ilko

Anything under 10% is good in my book. Anything over 20% is bad.

MDamen

Do leak down results change with engine temperature? I recall that a compression test should be done with the engine warmed up so you see the proper clearances. Is this the same for leak down?

Quadcammer

yes, leakdown should also be done warm, but its difficult on some cars to reach the plugs without getting burned to hell on a hot motor (993TT for instance0