Percolation? Heat soak? Don't drive during summer??
I kinda suspect that too. Its possible the sensor is in a bad spot and getting heat from somewhere besides the water. Hey I'm glad we could finally agree on something!! Haha sorry I got a little irritated earlier. I was at work and was having a bad day. No hard feelings!?
None! I don't get angry at people, but I can be flippant ;) the internet doesn't convey enough subtext to form a valid opinion of any one person.. At least IMO.
In my line of work, I never trust a single source of info - if the temp reads high on one gauge, but not another, all that means to me is I have two suspect gauges. Consilience is necessary, which is why I bring up an IR temp gun.. They have so many uses, it's an expense I can justify suggesting.
@billsdartgt has some good points (especially about doing the FREE stuff first), and I didn't notice that it used to be 185 and is now 200+, which moves the needle on how important a solutions is.
I've read mentions before from I don't remember who that some headgasket brands have improper hole sizes/placement? Could be something to that? The heads did come off, if I remember right. But it's hard saying, not knowing... As the man says.
Still, until the hot temp is confirmed, I'd go by the thing which is consistent to before the engine R&R - the factory gauge.
I still wouldn't lose any sleep until the temperature really starts to run off the charts (220-230F).
