Xavier Corral

Hello all. Working on a 99 civic for a friend. Car is losing coolant out of the overflow and then getting hot. Car has a new radiator and all associated hoses. Changed the oil and saw no signs of coolant. Rented a block tester and the fluid showed presence of hydrocarbons in the radiator. Did not see any smoke out of the tailpipe. I then performed a compression test. Dry: I saw 150psi out of cylinder 4 and 120 out of 1-3. Then poured 2 caps of oil into cylinders. Saw crazy amounts of compression around 200+. Discontinued the rest after two cylinders. Afterwards I saw tons of smoke out of the tailpipe.

My theory: the Headgasket was letting go and the extra compression from the oil blew it out completely. Did I perform the test incorrectly? I'm planning on tearing down soon. Any advice or opinions?

ezone

Head gasket is leaking combustion gases into the cooling system.

180-200 PSI is about what I expect to see on these engines during a normal dry compression test when done my way and with my own testers.
Seems like most people don't do it my way, so your results may vary.

Oil makes a ton of smoke when introduced into the fire. You didn't hurt the head gasket with it. Belching a huge cloud is totally expected.


Have head checked for warpage by a professional machinist if you don't have access to a precision straightedge.
Use an OEM head gasket.
Replace the heater hose under the leaking distributor.

If it has been an oil consumer, now is the time to address or replace the piston rings.