I want to raplace the thermostat in my 1990 740-GL Wagon. B230F (non-turbo)
engine with automatic and California emissions (egr). I live in southern California where temps range from a low of 30 degrees (unless you go to the mountains in the winter) to a max of 110 degrees F in the summer. Because California has crap gas with up to 10% ethanol and other additives that theoretically reduce smog but at the same time reduce the amount of heat energy in the gas -- thus reducing mileage, I want to get maximum mileage from the car so I do not want to run it at a lower temperature than it was designed for.

My Volvo owner's manual TP3056/1 (Canada and USA) dated 8/89 says on the Cooing system Specifications on page 118, that the thermostat begins to open at 189F(87C)on the GL and GLE-16 Valve. It says that the Turbo uses a 198F(92C).

This is reverse of what I thought I had gleaned from the FAQ and the many posts I read on the board where I thought the consensus was that the official Volvo recommendations were 92C on a non-turbo B230F and 87C on the Turbo.

The problem with internet boards like this one is that the expertise of those giving answers is variable. Until you figure out who knows what they are talking about and who doesn't (like the guy who recommended spending money on a air impact wrench instead of a counterhold tool to both remove and replace the
harmonic balancer when doing a timing belt). My Chilton's book is almost useless as an authority.

So -- is my owner's manual the last word? (or is there an addendum sheet with the correction of the two temperatures swapped) I'm still confused as to which thermostat to order up.