Jim: I usually have the same experience whenever I drive east on the 101. From Agoura on to Calabasas to the San Fernando Valley--as ambient temp climbs, so do engine temperatures.
By the way, in anticipation of the latest heat wave, I spent some time this past weekend re-mixing and tweaking my coolant/water ratio. Thanks to TKamiya and JimF (for their helpful hints on how to re-mix the coolant/water and for their pictures of the recalibrated Prestone anti-freeze gauge) I was able to lower my coolant /water ratio down to 40/60. The new ratio has worked wonders in keeping coolant temps down, even in 100+ San Fernando Valley (I hate it when I have to drive to the Valley).
Anyway, for those of you who want to keep engine temp down, check out your coolant/H2O ratio, most mechanics never get it right at the 40/60 ratio. If your ratio is too high, as mine was, try adjusting the mix. You will be pleasantly surprised.
Keep cool!
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Current Benzes
1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"
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