Work was done at a volvo dealer. PCV, Cam seal, and spark plugs have all been done at a Volvo dealer after I got the car (yes, I know expensive, and easy to do myself but I am not at a level where I can comfortably do timing systems). When they replaced the spark plugs they ran a compression test on all the cylinders and found them to be good.- Pete - wrote: ↑Sun Aug 11, 2019 11:38 pmHmm, (Abscates punctuation has me concerned) coolant reservoir empty (you then refilled), but you never made mention of receiving the "low coolant, stop safely" message.
You can get a compression tester pretty inexpensively at HF, not super accurate, but just to get an idea if any of your cylinders are scoring better or worse than others. This here might be a noble thing to do, I mean since you're gonna have the coils unscrewed, not that much more work to take a gander at the plugs. And while doing that, just measure compression on the 2 suspect cylinders.
Low PSI on 4/5 could possibly indicate you are leaking psi into the cooling system, or elsewhere. This scenario (head gasket) is typically pretty unlikely though, as Abscate has said, but don't rule it out yet.
You also mentioned several times a "dealer mechanic" .... This was at a Volvo dealership? Or just an auto repair facility? If it was a Volvo dealership, I'd be pretty surprised if the tech used anything BUT Bosch coils & Volvo plugs (which was probably a $6-700 invoice).
I did get the "low coolant, stop safely" message. And then when I did stop it changed to "low coolant, turn engine off" or something like that.