low compression after rebuild, 2006 volvo v50

goatkeeper · Post by **goatkeeper** » 22 Sep 2013, 10:06

The car overheated when I was driving it as a result of the coolant reservoir cracking on a road trip. The system lost pressure, coolant evaporated and the car overheated. I had the head checked, and it was warped but that's it. It did not blow a head gasket. I checked the compression before tear down and numbers were all over, some as low as 35. I just finished bolting the engine back together to the point where I could do a compression test. I got 95,80,65,65,120. I tried adding oil to the cylinders and it didnt make much of a difference. I replaced the head gasket, head bolts, used copper gasket spray, and cleaned everything very well. Will the compression even out and go up that much after I get it started and warm the engine? Thanks, any help is much appreciated.

goatkeeper · Post by **goatkeeper** » 22 Sep 2013, 10:46

Can I swap a older 2.4i into this car from another chassis?

Post by **JDS60R** » 22 Sep 2013, 11:45

Perform a leakdown test to confirm where the pressure is being lost. With compression numbers that low on a wet (oil added) test I would think you have a bad leak or the valve timing is incorrect.

I would verify cam timing using the proper test for a VVT engine and if correct I would perform a leakdown test.

Remember - pass TDC and turn another 90-180 degrees. Then turn counter clockwise to TDC. Then inspect cam and crank marks for proper set. This procedure places the VVT in the correct position for checking. VVT = variable valve timing.