Head gasket or worse?

[Ncgreg25]

Hey guys new here! Looking for a little help... Truck won't start after overheating. I didn't compression test while cold... Hence it won't start.
First what are we working with... 97 Ford ranger 2.3 engine dual spark plugs. Checking compression on exhaust side. Cyl 1-65psi...cyl 2-65psi... Cyl 3-65psi cyl 4-150psi... Testwd all 3 times... First 2 times turning over 4-5 seconds. 3rd time 10 seconds.
So the question is will a blown head gasket cause that low psi?? Or should I be looking at valves?

 

[RonD]

Welcome to the forums

1997 2.3l SOHC Lima engine should be 170psi or so

65psi is way too low for "just" a head gasket issue

If all 4 were around 65psi then I would say timing belt slipped, but the one at 150psi negates that
Blown head gasket just looses a few PSI in the effected cylinder(s)

You can do a WET compression test, add a teaspoon of motor oil via spark plug hole and retest each cylinder
I use a drinking straw to add the oil, insert straw in oil bottle, put finger over top, lift straw out of the oil and put it in spark plug hole, release finger
PSI will always go up in WET test, but by how much tells you if its the Rings or Valves that are leaking the most

At 65 psi a wet test would show maybe 75psi if Rings are OK but Valves are not
The oil helps seal the piston rings, but does nothing for leaking valves


You can do the Glove test to see if there is a bad head gasket

 

[Ncgreg25]

Hey rond!! Thanks for replying!! Yeah didn't mention that I did add oil... No help at all... I am off tomorrow so I'm pulling the head to see what's going on and gonna replace the head gasket while I'm at it. Unless I notice a cracked head or block... Hopefully it's not that bad though. Will keep updating