engine and drivetrain which thermostat? which fan/alternator/water pump belt?

[golf73]

i have a '73 standard 2002, trying to get some parts for it. i see different sizes for the 02 and i dont know which is correct? BELT = 9.5 x 975, or 8.75 x 10?

what temp thermostat should i get, i live in a temperate climate, San Francisco? 71C OK?

Also the engine tends to get near the H when i'm sitting in traffic. goes back down when i'm on the move, how can i check what the problem is, radiator, water pump, thermostat?

Thanks

[golf73]

i meant "or 875 x 10"

[Guest Anonymous]

I only run my 02 in decent weather here in upstate NY when the temp is above 50F and runs up to the high 90's. The standard thermostat works fine for me (I have a 3 core radiator).

On the near-red zone indicator issue, my current car did that when I first picked it up, but the radiator cap never got very hot. After eliminating the thermostat, radiator, and replacing the water pump ("burped" the system) and temp sender, I concluded it was the electronics or gauge. (I also had a radiator shop confirm that, infact, the car was not "over heating") I cleaned up all the grounds and replaced fuses with no success, so finally installed a VDO water temp gauge on the dash and it works fine (I don't have the expertise to pull the instrument panel and diagnose the gauge). Also, my 525 near-over heated routinely in heavy traffic and after eliminating thermostat, water pump and fan clutch, it turned out to be the radiator, which needed to be replaced at 150K. Good luck.

Roger

BMWCCA 310877

1972 2002 VIN 2575613

1992 525i, daily driver

1982 320i, traded

1973 tii, sadly traded

1971 1600, traded

[Napes]

I think a ' 73 belt would be the same as the one for a ' 75, so the correct one is 9.5 x 875.

Bob Napier

[jgerry2002]

Depends on the pulley you are running. The longer ones are generally with the stock sized (largest) pulley. There are two other sizes available.

[ingraham]

I suggest 80 C, or maybe 75 C. The higher the rating, the more cabin heat you'll get. Don't use 71 C unless you're doing significant track time. A cooler thermostat will *not* improve a cooling problem.

Does your temp gauge normally sit at mid-scale? If so, the temp gauge behavior you described is almost certainly due to inadequate cooling by the radiator. It will be cured by boiling out, rodding out, recoring, or replacing your radiator. But first, try clearing out the radiator fins by spraying water forward through the radiator (from the engine side toward the front of the car).

SteveJ has posted a nice summary of radiator choices several times. Use the Forum Search to find it.

[golf73]

thanks for the responses, although i'm still confused as to which fan belt i need.

curt, yeah, during driving the temp gauge needle is horizontal.

if i'm at a stop light and the needle moves up into the H, and if i give it more RPMs, it will go down a bit outta the red but doesnt go back to mid-way until i get moving down the road again.

ryan

san francisco

[ingraham]

almost certainly on the part of the radiator.