I nee d to replace thermostat on 2003 bmw 325i how

The key to searching for information about your BMW is to identify the chassis code. In this case, you have an e46.
Check out the Wiki: https://en.wikipedia.org/wiki/BMW_3_Series_%28E46%29

As for your thermostat, Google search: e46 thermostat diy

Join the following forums and search the e46 sections for more help: Bimmerforums.com Bimmerfest.com

Remember, it is a Bimmer, not a Beamer ;)

change the fuel pump relay it could be any one of the pins

A8 is thermostat needs replacement, i just had mine done at Peter pan dealership

That plastic hose is where the thermostat is located.
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BMW OPS for IBM T30

Potential causes: Low coolant- fix by adding coolant Thermostat stuck closed- would also cause engine to overheat Thermostat stuck open- would eventually blow at least luke warm air Heater core plugged- Get it backflushed or replace it These are the most common causes

If it makes no noise when you try to start it but the lights, radio, etc. all work, replace the starter.

remove fana nd fan shroud, disconnect the upper and lower hoses, disconnect the connection from harness,remove the 13mm bolt and 3 10mm bolts,pull the t stat housing away from the cyl head,clean surface and examine for pitting (ie small cavities) on sealing surface, once cleaned install new part and fill with coolant and bleed air from system,

I have 2003 bmw 325i and I took my car to the dealer, and he said my car does not need any code.

You have to take the trunk liners off of both sides. There will be 3 13mm nuts on each side for the shocks, and under the car is a 16 or 17mm bolt that has to be removed. I hope this helps.