Hey everyone, I have a bit of a puzzle I need help solving.
I got a 05 civic si, 1.7 v-tech with 250,000km on it, all stock no mods, first off my coolant reservoir is overflowing after a couple days of driving which leads me to believe air is getting into to cooling system via head gasket but there's no other signs of a bad head gasket, its not overheating, no white smoke or sweet smell from exhaust and no oil coolant mixture. I did a compression test and all the cylinders are between 170-180 psi. Next i did a leak down test and this is where it gets interesting.
Cyl 1 - 70% leakage, can hear the air through the intake and air also comes out of cylinder 3 spark plug hole.
Cyl 2 - 4% leakage, can hear the air through to oil fill cap.
Cyl 3 - 69% leakage, same as cylinder 1, air in intake and in cylinder 1 spark plug hole.
Cyl 4 - 2% leakage, can hear the air through to oil fill cap
I'm guessing there is a couple burt up intake valves on cyl 1&3 but I'm really stumped as to why I can hear air through cyl 1 & cyl 3 spark plug holes, unless the head is cracked which is allowing that, also if the head was cracked could that also be the reason why the coolant reservoir is overflowing. During the leak down there were no bubbles coming out of the rad or any signs of air going into the cooling system at all. anyone have any tboughts on this,
I appreciate your input!

 

Anyone have any input on this? Thanks!

 

1st check rad to rad cap sealing surface. Get a new quality rad cap. Maybe coolant isn't flowing back into rad when cooling down.

Any signs of coolant on plugs? or tops of pistons? As you know, these head gaskets go all the time.

Unrelated, adjust valves asap.

 

Ok, im going to pick up a new rad cap tomorrow, and there is no sign of coolant on the plugs or on top of the pistons. I will adjust the valves, but I feel like there not really out of spec by much if they are, each one at TDC has a little bit of play. If they are out the tiniest bit could that make that much of a difference?

 

OP, it sounds like you didn't move each piston to TDC before applying air pressure to the appropriate cylinder. The firing order is 1->3->4->2. Cylinder 1's exhaust valves can be open at the same time as cylinder 3's intake valves.

 

Ok thanks, there is a possibility I forgot to be TDC on the cylinder I was testing, I actually think I got the firing order mixed up, if that matters. I'm going to redo the leakdown test, hopefully with better results if I did end up screwing up the first one. The thing I dont get is if a valve was burt up or out of adjustment shouldn't I hear a ticking sound or have rough idle or something cause the car actually runs really well on cold start ups to driving it hard, doesn't seem to skip a beat.

 

You can do a chemical block test, that will tell you if combustion gas is getting into the cooling system.

 

Oh I forgot to mention I did do a block test, the blue fluid never turned yellow, thats when I initially ruled out the head gasket being bad but I still couldn't figure out why my coolant reservoir was over flowing and thats when I decided to do a leak down test. Can someone correct me if I'm wrong but when doing a leak down i know you want to be TDC on the intake stroke but if your TDC on exhaust stroke could the valves still be open a bit?

 

You want to do the leak down test just like you would do a valve adjustment... this is how you know that all valves are closed in the cylinder being tested.

 

Ok, thanks JRcivic