My 1990 300zx Twin Turbo build by megaDan

3 minute(s) of a 731 minute read

Oh boy.

Fears were confirmed. Its something serious. At this point I'm hoping its ONLY the headgasket. I did a coolant pressure test again after discovering a drip from the upper radiator hose. Lost ~7psi overnight, just a little worse than before, which was frustrating. Elected to take it to work anyway and tried starting it and it stopped mid-crank. My IMMEDIATE thought was 'this sounds like a physical obstruction' but I took a second, popped the car in and out of gear, and it fired up. Odd. Took it into work and felt great, aside from when i pulled into the parking lot. It wasn't idling well, but not to the point where it was alarming. It's a 300zx afterall.

Long story short, the idle/low speed issues became more prominent on the way home so I did a boost leak test and that was fine. With all the other things I've been dealing with I jumped right to compression test. Let's answer the 'headgasket' question thats been nagging me once and for all. I pulled all the plugs and they looked great, except for Cylinder 5 which was a little wet.

Damp

I started here with the compression test and saw roughly 185 which is MUCH higher than expected. Tried again, same result. I moved to cylinder 3, saw about 150, but noticed water in the spark plug tube of cylinder 5. Crap. A lot of water.

Struggling to get video thumbnail working. Took a video down the spark plug hole while cranking. Neat and sad all at the same time.

Discovered this around 8pm last night. Tidied up the garage and moved the car into place last night.

Hopefully I have enough room for the engine hoist

Got up at 5 this morning with the goal of having the motor out by 8. I only got 2 hours of work in, but everything is drained and disassembled and the next step is removing the transmission, and then the engine.

I wish this were under better circumstancesAt least I had some help

I think best case scenario is bad headgasket. I'm real worried about a cracked block. Cross your fingers for me.