@bcredliner,

I respect your points too. But you are obviously not familiar with M52/M54 cooling issues. These components (reservoir, WP, radiator etc.) fail like clockwork.

Indeed, my cousin owns an exclusive-BMW indy shop in L.A. and he recommends the same thing every 110K (i.e. cooling overhaul), simply because he was tired fixing things in bits and pieces. Not to mention head gasket job, which he hates doing day after day. The items (reservoir, WP, radiator etc.) fail like clockwork.

I am a contributor writing technical DIYs on bimmerfest E39 section, and this is all I can offer: do a cooling overhaul before they regret. People of course have the option to listen to my advice or not: their car, their choice.

It is very easy math: cooling overhaul ~ $400-$600 vs $4000 for a blown head gasket. It does not take a PhD degree to figure this out.

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1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT