Whats the difference between an oil pressure test and a leak down test?

[Don Poppito]

2005 Mustang GT with 143,000 miles.

Weekend car but some issues.

I know of a couple seals/gaskets that need to be replaced. 1 Valve cover gasket, timing chain gasket and oil pan gasket (and my damn plug is fooked, and only pans i can find are $300+…)

Try to make this as short as possible.

Bought car, car ran fine. Started getting Low oil pressure errors. Had it tested and fine. Year later still runs fine and find out sometimes after market start buttons can cause error. Start with key for weeks no issue. Still oil gasket leaks though (mentioned above)

So i had the oil pressure test that showed no issues. Is a leak down test the same or should i have it done as well? I love the car so im all for fixing it up but dont wanna drop money down the turrlet if the the engine is fucked.

TL;DR Oil pressure test done. Leak down test needed?

Topic

[Richard Kirshy]

A leak down test ( as I know them to be )
Is meant to test a cylinders ability to seal and maintain pressure.
There is always some small amount of blow-by which is normal.
But a leak down test will not determine a oil pressure issue.

[Don Poppito]

So even though i had the oil pressure tested i should do a leak down test as well?
Thanks for the response!

[Richard Kirshy]

As I said, one doesn’t correspond to the other.
A leak down test on all cylinders will give you a good idea on the overall health of the engine..
IE:
Rings, valves, valve seats, head gasket(s)
What it can not specify is a crack in the head or block, that would require more extensive work.

[Author]

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