Well that explains that

My 98 m3/4/5 has always seemed to run a little cool per the factory gauge, running steady just over the blue.  If it gets a little warmer (running up a hill or what not) it will bump up to the halfway mark and live there. 

Well, I recently got a check engine light saying insufficient temperature and I saw that it wasn’t even getting past the blue. 

I finally dug into it and found this:

It says 3/98 and is a bmw part.  I have no reason to think this isn’t a 157k mile-old thermostat. 

I got a new housing gasket but had zero luck finding a new thermostat gasket.  so I reused it and hope to clear this pesky code so I can smog it. 

I approve of the flip flop use in changing the thermostat. 

Yup, that's broken. 

I thought you wrote "miata" and thought, why would there be a '98 BMW thermostat in a '99 Mazda?

Braze it back together and test it in a pot of boiling water and be on your way...somewhere in Eastern Europe.

jfryjfry said:

I got a new housing gasket but had zero luck finding a new thermostat gasket.  so I reused it and hope to clear this pesky code so I can smog it. 

I always keep a roll of NAPA gasket paper and an X-acto knife around for just such an emergency. A set of hole punches is nice to have too.

jfryjfry said:

I got a new housing gasket but had zero luck finding a new thermostat gasket.  so I reused it and hope to clear this pesky code so I can smog it. 

Will it pass smog with just the CEL off, or do all of the emissions and evap systems have to be in ready status?  I'm troubleshooting evap on my M3/4/5 and it seems to take a lot of drive cycles to complete.  

Does the disconnect the battery trick to reset all the codes work on BMW's?    It works on my 97 Ranger and 2004 Miata.

Tyler H said:

jfryjfry said:

I got a new housing gasket but had zero luck finding a new thermostat gasket.  so I reused it and hope to clear this pesky code so I can smog it. 

Will it pass smog with just the CEL off, or do all of the emissions and evap systems have to be in ready status?  I'm troubleshooting evap on my M3/4/5 and it seems to take a lot of drive cycles to complete.  

Very likely all the evap systems have to be ready. That's how the test works in IL: plug in, if all systems report operational, good, If not, fail. 

They will recommend that you go drive 100 miles if there are no failures but not everything reads ready yet. (ask me how I know ;)  )

Well, better than failing closed or this would be a much different thread.

Most states allow 1 or 2 monitors to be not ready (depending on the year of the car).  So if all but 1 has completed and there are no codes and the CEL is off, it should pass.  

In reply to Woody :

A small ball pien hammer is helpfull

Nice. Im expecting to find similar on my E36 325. It does as you described, just never seems to hit “normal temp”. 

I always thought what I had was standard, albeit seemingly low. 

As far as monitors go, I had forgotten that one can be not ready for 96-99.  I might be good to go now!