Compression & Leakdown Results

[markottawa]

Just received the results of the compression and leak down tests as part of a PPI on a car I am considering buying.

Leak down: 1: 8%, 2: 11%, 3: 5%, 4: 6%, 5: 10%, 6: 12%
Compression: 1: 200, 2: 205, 3: 210, 4: 210, 5: 220, 6: 225

Car is a '93 C2 Cab with 115,000 miles, tiptronic transmission. It does not have all service records and the mechanic could not tell if the engine had been rebuilt or not. It drives nice and no smoke was present under any driving conditions. The car is in very good condition given the mileage and has obviously been well cared for. The mechanic was recommended by several people on here, Rennlist and PCA, so the test results are valid.

Could these numbers simply be a result of very good maintenace and years of easy driving? Or do they indicate that a rebuild has likely been done? If no receipts are present, should I have any concerns about the extent and quality of any potential rebuild?

[DW SD]

Hi Mark, welcome!

It is my impresion that a fresh rebuild should have consistent leak down #s of 1% to 3%, lower is obviously better. It is also my impression that numbers above ten% start to be of concern.

I also think that good engines commonly fall into that 5% to less than 10% range. I'm no professional mechanic, so weigh other's opinions accordingly.

With no records, why would you assume that a rebuild has been done?

If I had a freshly rebuilt engine, I wouldn't be thrilled to have those results.

Any idea of how much oil it consumes? Does it leak?

What did the "recommended" mechanic conclude? Is he leaving it to you to interpret?

Doug

[markottawa]

Doug,

Thanks for your thoughts. I didn't mean to suggest that the rebuild was fresh. But for an engine with 115k miles on it, those numbers are pretty good if it is indeed all original. No idea about oil consumption but there were a few minor leaks that were repaired. There did not appear to be any evidence of excesive oil leaks in the recent past. The lack of records merely leaves open the possibility that a rebuild was done a while ago which would account for the numbers.

The mechanic commented that it was in very good condition for its age and mileage. For a daily driver and fun driving car he didn't have any concerns. He feels, as much as a person can do so, that there are many miles on this engine before any major work needs to be done on it. As always, the final decision is up to me.....so....I'm just trying to be as sure as possible that a major repair bill is not waiting just around the corner.

[TibetanT]

Hello Mark:

First, welcome to the Pelican boards! Always nice to see new faces...Ha.

Anyway, I am no expert but those numbers just don't give me the warm and fuzzy feeling. If my experience serves me right, you should have compression numbers that a little closer together or consistent across the spectrum. Hmm?

Do you have the ability to get another opinion? Of course, without making the current mechanic upset. But then again, if the mechanic gets upset then maybe you should walk away for this one. How accurate are the maintenance records? Are there large gaps in the maintenance history?

Also, if the engine has been maintained properly I would have expected better leak-down numbers, such as lower than 5% across the board.

Just my two-cents.

[cstreit]

Were those leakdown numbers done hot or cold?

They are indicative of a higher mileage engine. You usually want to see the leakdown numbers a little closer together. If it wasn't done hot, ask them to do this, it could change.

A fresh engine will show consistent 1-5% numbers and older/higher mileage ones tend to see around 7-10% so it makes sense based on the mileage. These numbers wouldn't necessarily dissuade me from buying the car if everything else was right.

[hobieboy]

Mark,

Is this a local car in Ottawa? If it is, may be worthwhile to ask around if anyone knows more history of it...