Hi
@Jug , in Short NO, the skimmed head was still loosing coolant after I installed it last year..
Before I write more, sorry
@BobMurphy that I have been inactive here for a while (since I found out that the head repair didn't solve the coolant leaking problem), as I was a bit dejected and disappointed after the hard work of replacing the gasket and installing the skimmed head. Looking at the forum stuff just made me wanted the Prado fixed more but I was out of idea.
So back to the Head:
I spent a lot of time looking for external leak around the engine after last year head repair, but to NO avail.
Reading a lot of online information, opening and closing my bonnet looking for leak every other day (until my neighbour must have thought "he got a piece of junk there"). I nearly came to a point of stripping the heater matrix out to check for leak (but logic said its not the matrix as the inside carpet is bone dry).
Until I read in one of the hiluxes forum (I think) of checking head crack (internal) by removing the glow plugs and disconnect the fuel pump, then crank the engine to look for spray from the glow plug holes. I discussed this over the phone with the experience engine builder who helped me skimmed the head last year, and he mentioned the same method was used to check old head leak during his time.
So i did the check, and there was some mist/steam coming out of cylinder 3 glow plug hole when cranking. At that time, I was still unsure if this was the cause/problem.
Anyway, I bit the bullet and got a new (not AMC) BARE head and removed the old head (Again) and this time in Feb/March (cold outside). Once the head was removed, I checked intake 3 pot for coolant but didn't see any. But the next day, when I looked again, below was what I found (see attached photos - zoom in first photo to see the red coolant):
Coolant trace running down the intake valve! I didn't see this when I first check when the head was just removed from the car, maybe it takes time to leak out - not sure, anyway this gave me confidence.
So, I brought the new head and the old one to the engine builder and he swapped all the valves etc. over, we have to replace a few shims as the thickness were out for shim clearance.
I put everything back, and has been using the car in the last few weeks, and the coolant remains! I hope this is it.
I now can focus on other small things, after the head repair:
- The car warm up rough idle (with some white smoke) in really cold weather - not immediately after start but a few minutes after firing her up, sort of corresponded to the glow plugs "after run time" finished. So I put my old glow plugs back but nothing really changed. However, if I start her up and don't let her idle and drive away immediately, then the rough cold shaking wont happen. Its kind of happen when the idle was at around 1000rpm few minutes after first cold start, but once warm up (750rpm) idle, it will run smoothly.
- Alternator doesn't seem to charge the battery immediately after starting (cigarettes' lighter shows 12.5v right after start) - but if I drive away (accelerator pressed) then it will start charging to 14.4v. However, the voltage will flick to 15v (split second) when I drive and turn the steering wheel but immediately went back to 14,4v (mostly during the first few minutes of driving from cold). Checked the drive belt, tension is ok. But again after warm up, the voltage jump disappeared, when slowing down at traffic light (rpm decrease to 900) voltage sometime still drops to 13v, as soon as rev up it goes 14.4v.
Not sure if the above 2 are related, but I am ok with slowly working through them, at least I believe (finger crossed) the HEAD problem is sorted.
Every one told me if the head cracked, you can see it externally (either between the intake/exhaust valve, or cracking tht developed from the valve outward), But mine obviously has an INTERNAL crack/porous metal that took me awhile to find out...
Hope this might help someone out there…
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