When have you seen 606 head gaskets needing replaced?
 

I have a friend who's looking at a higher mileage 606. Just curious: for those of you who have had to have the head gasket replaced, what was the mileage?

There's a recent thread about someone needing it replaced at just over 150k, but I'm assuming that's an anomaly.

Anytime after 250,000 mi. Watch for coolant leakage at rear of block on the passenger side unless it has been abused. Go ahead and do timing chain/guides while in there.

My '95 had about 310,000 on it when the gasket started showing signs of external coolant seepage. I had Metric Motors surface the head, replace the valve guides, new exhaust valves, etc. The bottom end looked amazing - original honing marks in the bores were still like new.

She's now at 410,000+ miles. Unfortunately, she has just recently started to have residual pressure remaining in the cooling system in the mornings. :mad: What a bummer. I'll be investigating this further in coming weeks....