Originally Posted by HumanMode

I am able to update on the result here: thanks to Needs Wings my mechanic was able to identify one of the seals for the pipes entering and exiting the plate behind the timing chain. But it still required removing many parts to get to that - finally the sump pan and front block cover.

I instructed the mechanic to replace all the seals and gaskets they came across on the way there.

Fortunately it was not a cracked head gasket, but they were checked anyway. While at it, the exhaust valves were pitted on the seats so they were machined and the heads planed. Valve stem seals were replaced. Planing valves cost NZ$255.

Heads were fitted with new gasket seals and head bolts. Gasket set top NZ$202. Head bolts NZ$241. Head gasket NZ$170.

A new timing chain was fitted. NZ$724 for the chain - most expensive part. There was no clear factory timing info on the engine, and the original crank pulley was replaced. So it had to be marked up again.

Front cover had an entire set of new seals. Air conditioning was recharged - which has sorted the cabin smell and start-up water noise behind the instrument panel air con controls.

Also replaced the drivebelt (aka the serpentine?) NZ$248.

Turned out to need a new battery.

These big part costs, plus small ones and a bunch of labour, bought the cost to 50% of the value of the car. Ouch.

And soon after I got it back I needed a new OEM siren from Needs Wings to replace old one that was randomly going off before I hit my more serious water-in-oil problem. Took the opportunity to replaced RCU with OEM from Needs Wings, which had been resoldered a few months earlier - because I thought I may as well eradicate a future problem. Kept old one as spare. My auto-electrician charged $NZ100 to do both (yes, I could have done the RCU myself...).