325i running... cool?

[somecarguy]

Yes I realize I shouldn't complain but still it seems odd- was doing spirited driving on hilly country roads, mid 80s and humid. On some long downhill sections I saw coolant temps alllmost touch the blue bar area. Never crept above the first tick. i was pulling hard up hills etc. have swapped both coolant sensors. Prev owner did a comprehensive cooling system refresh before selling to me. Now im wondering if maybe the thermostat is too low or faulty? Or should I be happy to have a nice cool running e30 and stop asking questions? No probs getting up to temp in the CT winter btw so if the thermo is funky it still works.

[bluptgm3]

Sound like thermostat is not functioning as it should.


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[actletpone]

thermostat may be stuck open. The e30 coolant temp gauge can be finicky to begin with, it is common for the gauge to jump around / give inaccurate reading due to the grounding nut on the back of the cluster coming loose, a google search of e30 coolant temp grounding nut will provide more information. One way to verify coolant temperature is with a infrared temp gun pointed at the thermostat housing, these are fairly inexpensive.

[Uturn540]

Before anything else, get a IR temp gun and take a reading on the block and thermostat to find out the actual temperature. It is possible that if the SI board got service that the needle on the gauge accidentally got moved. If it has you may be chasing an issue that not exist. That was the issue with mine.

[jclausen]

Also it's common for the metal strapping that holds the thermostat together to break.

[mybimr]

Also be aware that there are at least two possibly three thermostats for our engines, each with a different temperature "setting". The hot version will keep the needle at mid point (straight up) the cool one should hold around the first tick, and the middle is the goldilocks

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[somecarguy]

Thanks for all suggestions will check thermo with my IR.

i had the cluster out recently to replace bulbs should have looked at ground nuts - can they be reached with the cluster in place?

i see Pelican sells thermostats at 71, 75, 80 degrees from Wahler, Behr and Vernet. Any intel here besides the comment that the middle one is the goldilocks?

[thejlevie]

I prefer the 80C thermostat because a hotter engine runs more efficiently. If the cooling system is operating properly the needle will about half way between the first tic mark and the half way point. It may rise to the half way point in slow traffic on a hot day.

[somecarguy]

Makes sense and matches the spec in Bentley. On another long drive today with the ac on I saw the needle flirting with the blue zone on hill descents. I see amazon has Mahle will try this.


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[actletpone]

Thanks for all suggestions will check thermo with my IR.

i had the cluster out recently to replace bulbs should have looked at ground nuts - can they be reached with the cluster in place?

i see Pelican sells thermostats at 71, 75, 80 degrees from Wahler, Behr and Vernet. Any intel here besides the comment that the middle one is the goldilocks?

The temp ground nut can be reached with cluster in place by removing kick panel and looking up under the dash. It is not easy though, I think for memory you have to remove the black plastic panel behind the steering wheel aswell.

[somecarguy]

With the dash gauge at exactly the first tick Im getting about 77deg c at the thermostat housing / hot hoses. How does that compare to what you all are seeing?


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[somecarguy]

Drained the coolant and pulled the thermostat today. 71 degrees. That explains things nicely. Wonder if someone was trying to make up for a cooling system problem or just presumed lower is better. Replaced with an 80 degree unit and curious to see how she performs in the heat.