Cooling system question...

[zoner]

I think I may know what the problem is, but since I'm a noob to the ti, maybe there is something I'm not thinking of or know of...

My temp. gauge fluxuates between just off of the blue bar to just a hair past the halfway point with normal driving. If it is cool outside and I am at freeway speeds, it is on the low side. If it is warm and I am driving in the city or in traffic, it is on the high side. I always thought that at operating temperature, if the cooling system is functioning correctly, there should be little, if any, fluxuation in the gauge. I'm tempted to think that the thermostat is either too low of a temperature for the climate- it is not completely closing and giving the radiator time to do its job, or it is broken altogether (stuck open). The fan does kick on, so it would appear that the problem is not with the fan.

Anyone have a similar experience or have any thoughts on this? Or is this just a quirk of the ti?

Thanks in advance for any help... :smile:

[cooljess76]

The needle should rise to the 12 o'clock position and remain there during the entire time the car is running. If it drops, even slightly, I'd say that your thermostat probably could use replacing.

[Will'sBimmer]

Mine did the same thing. I bought a new thermostat and everything was back to working just fine. Never moves from the middle now.

[zoner]

Just as I suspected. Is there a standard factory temp. thermostat, or do they make a range of temperatures? I should probably check to see what temperature the fan switch is, just to be sure... no?

I need to get the car dialed in before I take it in for a smog check (including changing the chip back to stock this weekend).

[zoner]

OK- so I've seen 88*, 92* and 97* thermostats. Can anyone tell me what the stock temp. is? I'm leaning towards a Wahler 92*... I live in So. Cal., where temperatures are not exactly extreme (between 50* and 90*), but I do plan some occasional trips to the mountains this winter.

[CirrusSR22]

realoem.com says 95 degree for an M44 engine and 92 for the M42. You didn't say which engine you have.... It's not gonna matter either way. My coolant temp needle stays pegged in the middle from -25F to 100F outside with the stock 95 degree. Just buy whatever autohausaz or pelican has in 92 or 95.

[zoner]

It's an M42. Most of the ones I've seen for the 1995 were 92*, including the German ones like Wahler and Behr. I figured 92* was the stock temp, but when I saw the other ones I began to wonder. I'll go with the 92*. Thanks! :smile:

[weezer]

Do a little research on your Ti as well........regarding other cooling system parts. If the water pump has never been replaced, now is a great time to replace it as well. I did a complete replacement of radiator, water pump and thermostat all at the same time last year. These are all very easy to do and will extend the life of your engine. Also the temp sensor on the passenger side of the radiator......these will fail and prevent the fan from properly coming on at certain temperatures.
Also...........when refilling the coolant, make sure to burp the system............very tricky. I had overheating issues for weeks before the system was burped.
After refilling the coolant, you want to leave the reservoir cap off for at least 15-30 mins, until the coolant has the chance to circulate around the engine block; a slight gurgling sound will appear and the coolant level in the reservoir will go way down. Top off then you're done.
Good luck!

[jimmyb724]

I've read through this post because I need to replace the thermostat on my 318ti too. but after researching them, a lot come with the housing too. For those of you that have done this before, would you recommend buying a new housing along with the thermostat, or just getting the thermostat alone?

[hotmilk400]

so, i am bring this old thread back as well.

my gauge just barly leaves the blue part, even after 20 minutes of driving. it starts to go up alittle after that. also, the heater does not work that well either until the freakin needle passes that blue part.

never bothered me that much, and works fine in the summer..

any ideas? bad thermostat? pump? anything at all, i mean its cold outside, and if it is above like 50F outside, it works fine (heater heats up, and needle is in middle)

i do not wanna replace stuff that is fine, but i do not want to freeze or wreck anything too.

THANK!

[cooljess76]

I've read through this post because I need to replace the thermostat on my 318ti too. but after researching them, a lot come with the housing too. For those of you that have done this before, would you recommend buying a new housing along with the thermostat, or just getting the thermostat alone?

There's 2 different types. If your car is a '95, it has an M42 engine which uses an aluminum thermostat housing and a removable thermostat. If your car is '96 or newer, it has an M44 engine which uses a plastic thermostat housing which has an integrated thermostat(non-removable). They're not interchangeable. Find the part numbers on realoem.com and order it from either pelicanparts.com or getbmwparts.com.

After you replace the thermostat, DON'T FORGET TO BLEED THE COOLING SYSTEM:
http://www.318ti.org/forum/showthread.php?t=27983

[cooljess76]

so, i am bring this old thread back as well.

my gauge just barly leaves the blue part, even after 20 minutes of driving. it starts to go up alittle after that. also, the heater does not work that well either until the freakin needle passes that blue part.

never bothered me that much, and works fine in the summer..

any ideas? bad thermostat? pump? anything at all, i mean its cold outside, and if it is above like 50F outside, it works fine (heater heats up, and needle is in middle)

i do not wanna replace stuff that is fine, but i do not want to freeze or wreck anything too.

THANK!

Replace thermostat bleed system.

[hotmilk400]

alright, thanks alot man, will do. heat would be nice in the winter!