Thermostat temp question

[Lee22]

my coolant temp gauge rarely goes above the 1/4 mark, thats even driving in 80f ambient temps.

today when i went to long beach it was 96f with stop and go on the freeway for 30min, the temp gauge went between the 1/4 and 1/2. (in the pic)
i have only seen it reach the 1/2 mark one time in 10 years of ownership.

i'm going to switch out the thermostat next week, i live in redondo beach area, it's usually below 75f 10 months out of the year. Which thermostat should i go with?

[salvuhdor]

I would personally go with the Wahler.

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2014.cgi?command=show_part_page&please_wait=N&SUPERCAT_FLAG=Y&make=BMW&model=134&section=watpmp&page=1&bookmark=3&part_number=11-53-7-511-580-M322

My car, when running fine, would keep the temperature gauge exactly in the middle. I drove it down to Mexico then back up to San Francisco and stayed completely still at the mid mark.

For optimal conditions I believe the engine has to be running at a certain temperature and too cold may not be so good for the car. - This is regarding my bone stock 91 318is, I'm not sure about any modifications you might have.

[TobyB]

I bet you find an 81c (or something else low) in there.

Personally, I like the stock temp (91? I forget)...

Straight up and down is fine- and really, about where it should be.
But mine tends to run as your pic shows almost all the time.
Only drafting a line of cars for laps in really hot (90+, around here)
temps gets it to stand up straight. Which corresponds to about 210-220
on the 'real' temp gauge.

hth

t

[bmwman91]

The stock M42 thermostat is an 88°C one. These also tend to fail in the open position, so the issue may be either a failing one or an incorrect one.

[RCtheRed]

Are you sure you have a thermostat at all? It really just sound like you have coolant circulation the whole time from start up which won't be healthy for the engine or the cat. The car needs to be at a certain degree for optimal operation or else it will continue try to warm itself up by running rich.

88C is right for the thermostat.

[Lee22]

well i have a new thermostat in there and now the car warms up quickly and the temp gauge reads almost at the "half" mark within 5 minutes of the engine being started. I'm happy, the car is not running rich anymore.