J.Seven

I know what is a compression ratio test, itīs to measure the compression on each cilinder, but what the leakdown test measures?

J.Seven

vrus

It's the same thing. A leak down test measures the amount of compression loss in each cylinder. Usually, you would see a 1% - 3% variance from cylinder to cylinder on a good motor.

FineProperty

A good site for this is
Leakdown Test

J.Seven

If they are the same thing, why everybody here says to make a leakdown and compression ratio test before buying any 993TT , and not only compression test

J.Seven

FineProperty, thanks for the link, now I know the difference.

enthusiast

The tests are different as you saw on the website.

The point of these tests is to get additional information on the condition of the engine's combustion chambers. Obviously, if the test results are normal that is good.

When the test results are bad, first check:

1. that the test was done properly
2. for a carbon buildup problem, carbon flaking off might cause a valve not to seal (corrective action may consist of just running the engine and retesting)

The problem with these tests on a 993 Turbo engine is the accessability to the key components (i.e. spark plugs, turning the crankshaft), is terrible. This access problem drives the labor time way way up ($$$$).

If you are a 993 Turbo buyer I recommend doing all the other important car inspections first. If those are satisfactory to you then get an agreement on the purchase price. That purchase agreement would be contingent on the results of the engine compression and leak down tests.