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4.6 head gasket replacement.


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It might be more than "just" a headgasket. Have a look around on the forum for slipped liners.

I've done my HG's on my 4.6 and it's pretty much the same as every other engine (just twice lol).


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In my experience they liners only slip if the engine has been roasted.

I might think you were lucky then. 3.5V8 are known to have had slipped liners and they run lower coolant temps, by much, than the P38. Overheating isn´t nice, no doubt about that. But the liner problem also applies to later RRC as well, which hasn´t had the coolant hose / Thermostat problems of the P38.

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I've read somewhere that an engine that's overheated 3 times is likley to be cracked behind the liner. There are a number of typical failures including the top deck separating from the bore (horizontal crack) but the problem is made worse because the liners were never pushed home onto the lower register when they were made.

True indeed that later RRC suffered, the 4.2 had something of a reputation and later 3.9. The 3.5 is often thought to be a stronger block because it has smaller bores (more metal round the liner) although later service blocks were made from 3.9 castings which varied somewhat in quality, the core which makes the water jacket often moved so the cylinder wall thickness varies. later engines were built using ultrasonic testing and the best ones kept for the 4.6 engines.

However this is all talk about engines that are 15 years old now, or therabouts. |Chances are all the badly built ones have now failed, so if it's been looked after it's quite possibly a good one, which makes it all the more of a shame when one gets cooked through poor maintenence.

The hot-wire EFi engines should all run at over 80 degrees BTW which is more than the V8 was designed for originally, it's all about emissions though and if a hot-wire is running cold it will run rich.

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