I've been struggling with my TB42 S engine way to long now. But in the process learned a few things I shared and here is an other experience:
I had rebuilt the head meticulously, but realised I took a gamble :" Does it leak or not ? But living remote sending it by expensive courier to a city for testing and forking out the test fee was more expensive as at least four head bolt sets so I took my changes. If I had only known this simple self test method because on the end the head proofed to be as porous as a sponge.
This is how I tested it after the oil was again mixed with coolant:
I bought a Cooling System pressure test kit on eBay for just under $80.
Cleaned the head on the engine , made sure it was as dry as possible.
Then pressurised the cooling system to about 20Psi - double the average working pressure.
Found a small leak under a hose-clamp, easy fix.
Then observed the head between the valves:
Well that was the weirdest thing I have seen in a long time:
Coolant just appeared out of solid metal - the two photos with the coolant drops on the metal are made within a few seconds: from a small drop growing to that big one just out of the aluminium !
A replacement head is on its way...
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