At this point I wouldn't want to start it. Your looking to do a little detective work without stressing the motor or tearing it back down.

You just want some numbers, don't have to be buy the book. It's not broken in yet. Just ballpark average across the board on all 8 cylinders. If they are within a few pounds or a swing of 10 on average we might be able to rule out the hg.

Cold they should be pretty close to one another on average and a leak will be low, you might even hear the coolant gurgle. You might get a little coolant to show up on the gauge nipple..... trying to determine where the issue is, what cylinder could this issue be on from piston to plenum.

 

1. I do recall seeing something but do not remember the specific source but it spoke of applying the sealant to the bottom side of gaskets but not both sides. Do not remember the exact rationale either. Maybe some of the engine guru's could explain.

2. I am sure a compression test can and will show differences at cold vs operating temps.

 

Compression checks can be done wet (with a couple of shots of motor oil into the cylinder - best) or dry (no oil in cylinder - OK).

I'm with the others who suggested a compression check and a coolant system pressure test. Make the source of the problem show itself before digging back into it. Good luck!

 

I was actually trying to find the specs for compression tests in the RAVE but didn't see them anywhere? I do have a tester, just don't know what to expect until I find the specs.

 

Guess I was too hasty in announcing success...

All cylinders register 150-160 PSI except #3 at 120 PSI
Plug 3 was also very black

What worries me is that #3 isn't next to the water jacket like #1 and 2. Or am I wrong?

 

Called machinist. He said heads and block were perfectly flat. No specific block crack test done but the cylinders looked good when honed. Agreed that 66 lb-ft should have been enough torque on head studs. Suggested maybe coolant still getting into intake and lowering compression. Also suggested putting towel by open plug hole and cranking to look for coolant coming out.

 

I guess it's time to pull cylinder head A and have a looksee at what the hell is going on.. On the upside at least you dont have to buy new headbolts and only one headgasket and a new valley gasket.. Keep it up, there's light at the end of the tunnel and no its not a train coming

 

CYLINDER COMPRESSION - TEST
Equipment:
Compression pressure gauge
Test
1. Start and run engine until normal engine
operating temperature is achieved (thermostat
open).
2. Remove all spark plugs.
3. Disconnect both coil negative (WB) leads
4. Insert compression gauge, crank engine until
reading stabilises.
5. Expected readings, throttle fully open, battery
fully charged:
8.31:1 = 10.2-10.9 bar, 150-160lbf/in2
9.35:1 = 11.5-12.2 bar, 170-180lbf/in2


Page 114 in my version of the Rave.

 

1. Seems like overall PSI is low, for the 9.35 compression ratio engine. This could easily be age of rings. You did not do rings as I recall.

2. You can put a tablespoon of oil in #3 and retest, if numbers come up quite a bit, rings are suspect. If not, valves or gasket. But rings don't do coolant leaking.

3. Gasket failure, crease, etc. You won't know until day light hits it. What about doing a cooling pressure test (borrow from parts store) and using a q-tip in plug hole to detect moisture? May take a while for moisture to bleed in there, like after you switch engine off and cooling pressure still exists. Bet when you take coolant container cap off in morning there is no indication of stored pressure.

4. Let's pretend tests all point to cylinder 3. When you take off intake again, triple check in that area before going to the heads.

 

Thanks guys.

Everything including rings was done. Should be like new.

I tested cold engine with throttle closed so maybe that's why pressure seems low. Water in oil might lower it too.