Will a compression check rule out - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

alchemist · 12-14-2001, 01:12 AM

Will a compression check rule out a bad head gasket.  I'm just looking for a way to check the easy way before tearing it apart

yenpit · 12-14-2001, 10:48 AM

yes and no. sometimes it takes HEAT to "open" the small gasket leak or cracked cyl head (engine warmed up). does it still run?? However, a leak down test will also show you bad valves or valve seats, AND bad rings, ring landings or scored cyl wall. so yes it can, but there are other things to consider!

alchemist · 12-14-2001, 01:48 PM

well, it doesnt run......but the head gasket might not be the cause....it hasnt run in over a year.  I bought it like that.  I'm changing the fuel filter obvisously tonite.  See,  she feels like she wants to catch and fire but doesnt.  I was towing her last night.....dropped the clutch in 3rd to get the engine up to ~2-3K and tried flooring it....it caught but bogged down really quick even while still attatched to the drivetrain moving.  had her run that way by poping the clutch and flooring it and clutching again and flooring it,  had some smoke come out for a few seconds and stopped.  I'm going to compression test the cylinders tonite to see if there's a drop.  Oil pressure is still good though when the engine is running via the drivetrain.  Yes I know it was stupid to chance the engine to poping the clutch, but i had to to give hazard lights some power.....it aint too safe to tow a car at night with hazards dying on you.

12-14-2001, 01:12 AM	#1
alchemist Zilvia Member Join Date: Oct 2001 Posts: 192 Trader Rating: (0) Feedback Score: 0 reviews	Will a compression check rule out a bad head gasket.  I'm just looking for a way to check the easy way before tearing it apart

12-14-2001, 10:48 AM	#2
yenpit Zilvia Addict Join Date: Sep 2001 Location: Holland Michigan Posts: 798 Trader Rating: (0) Feedback Score: 0 reviews	yes and no. sometimes it takes HEAT to "open" the small gasket leak or cracked cyl head (engine warmed up). does it still run?? However, a leak down test will also show you bad valves or valve seats, AND bad rings, ring landings or scored cyl wall. so yes it can, but there are other things to consider!

12-14-2001, 01:48 PM	#3
alchemist Zilvia Member Join Date: Oct 2001 Posts: 192 Trader Rating: (0) Feedback Score: 0 reviews	well, it doesnt run......but the head gasket might not be the cause....it hasnt run in over a year.  I bought it like that.  I'm changing the fuel filter obvisously tonite.  See,  she feels like she wants to catch and fire but doesnt.  I was towing her last night.....dropped the clutch in 3rd to get the engine up to ~2-3K and tried flooring it....it caught but bogged down really quick even while still attatched to the drivetrain moving.  had her run that way by poping the clutch and flooring it and clutching again and flooring it,  had some smoke come out for a few seconds and stopped.  I'm going to compression test the cylinders tonite to see if there's a drop.  Oil pressure is still good though when the engine is running via the drivetrain.  Yes I know it was stupid to chance the engine to poping the clutch, but i had to to give hazard lights some power.....it aint too safe to tow a car at night with hazards dying on you.