Im clearly not the car guy in my house haha, sad I know. To do a compression test does the manifold need to come off?

2007 Volvo S40
Non turbo
140K MILES

I do have an engine knock that Im currently trying to solve, I think its the lifters sticking/making the noise but Im trying to take it step by step. Any clear instructions on this? Dont work on volvo's too much. Any help would be great.

 

Nothing special about Volvos - ie the compression test would be done via the spark plug hole.

General procedure (should be more detailed write ups on a sticky) is
1) pull the fuel pump relay then crank to remove extra fuel pressure and keep fuel from dumping in when testing

2) pull the valve cover and remove all the spark plugs (ie you need to get the coils out of the way)

3) install the pressure guage in the #1 spark plug hole in such a way that you can see the needle from the driver's seat or have a buddy on the key.

4) crank the engine for a few turns to get a dry reading. Should be something in the 180 PSI range (Turbos should be in the 160 range). pull the gauge, drop a few tablespoons of oil in the spark plug hole, reinstall gauge to get your wet reading. Repeat for each cylinder.

Not sure how this would relate to an engine knock unless you are thinking a head gasket issue - sticky lifters typically gives a clicking sound - knocks could be a rod bearing or some other peripheral.

Results - low dry test > normal wet tests suggests worn or stuck rings, low wet/dry in one cylinder suggests a burnt valve, low wet/dry in adjacent cylinders suggest a head gasket (further testing required), low across the board could point to valve timing being off a notch or two.