realcanuk

I would do a leakdown test to make sure the engine (rings, valves, etc) are sealing properly. If the tests are good, go ahead with your plans to change springs.
When you are changing springs, you will be changing the valve seals at the same time. See if that clear up the problem.

C U IN REARVEIW

For how long (leak down) test?

realcanuk

Just a quick google.... do some searching....


https://mobiloil.com/en/article/car-...-leakdown-test