M20 UNDERheating?

[JinormusJ]

Just did the timing belt/water pump. Everything checked out, everythings good. Replaced Water Pump (Graf), Fan Clutch (Meyle) and 80°C Thermostat (Wahler/176°F)

Before the timing belt change, my needle was sitting around 11 o'clock (7/16ths on the board), but after the change, it seems to only sit right below the first "1/4th" Hash at like 10 o'clock (around 3/16ths even somtimes) on the board and only heats to barely above the 1/4th hash (5/16ths) only while sitting and idling

Finding it really peculiar: bleed the system right, heat is blowing strong, reservoir is topped off, brand new thermostat.. Leaves me scratching my head. It was idling for 30 minutes almost before I just called it a night


Maybe my temp sensors just died? Finding it really hard to believe though considering the sheer coincidence of it all and my cold starts are fine and I'm not getting any CELs


SOLVED:
Faulty new Thermostat, changed back to my old one; sits pretty at 7/16ths like is should (around 80°C mark)

[Todd Black 88]

What tstat. Was in it before?

[JinormusJ]

No idea

Looked like a generic autozone brand: it was an engine swap, and I'm just clearing up all the loose ends (Fan Clutch, Water Pump, Thermostat)
Used a Vernet 80°C thermostat before on other timing belt changes and it always heated at 7/16ths, which only means the unknown tstat had to be 80° based on similar cooling

This is my first time ever messing with the timing belt and having cooling/heating issues afterward

[JinormusJ]

M20 UNDERheating?

According to this picture
Gauge sits at 62° when it should be sitting just below half at 80°

[mitchlikesbikes]

verify your temps with an infrared thermometer then go from there

[JinormusJ]

verify your temps with an infrared thermometer then go from there

Go where from there.. Exactly..?

If it makes any difference, I checked this morning with a traditional food thermometer at the coolant temp sensor hole and it read 150°F (65°C)


Could my coolant minute have anything to do with it? I used to do 50/50 blends BMW OEM coolant, but this change I switched to 60/40 water/coolant BMW OEM mix

[EatsHondas]

Had the same problem using TWO DIFFERENT 80C Stant t-stats from Advance Auto Parts. Switched to a Wahler t-stat, bled her all the way, and now it lingers about a needle's width to the left of 12 o'clock.

[HennaE30]

Go where from there.. Exactly..?

If it makes any difference, I checked this morning with a traditional food thermometer at the coolant temp sensor hole and it read 150°F (65°C)


Could my coolant minute have anything to do with it? I used to do 50/50 blends BMW OEM coolant, but this change I switched to 60/40 water/coolant BMW OEM mix

Yes. It will. The more water you run in your car, the longer it'll take to get warm, as well as possibly running cooler. Water displaces heat better than ethylene glycol (most coolants) causing it to run cooler.

[JinormusJ]

Yes. It will. The more water you run in your car, the longer it'll take to get warm, as well as possibly running cooler. Water displaces heat better than ethylene glycol (most coolants) causing it to run cooler.

You know, you were the exact person I was thinking about when I typed this up. The whole time I was thinking.. Man, remember when I was wrong about coolant and I told Henna?

Gonna run and get myself another jug of BMW coolant and refresh the system. Hopefully that solves it

[ak-]

Don't think that gauge is accurate. Mine once sat at the "106" Celsius position for whatever reason according the picture you posted, and Tuner Studio was saying 210* Fahrenheit, which is 98* Celsius.

[CorvallisBMW]

You can test your t-stat but placing it in a pot and heating it on the stove. Use a thermometer to verify the temp that it opens at.

[HennaE30]

You know, you were the exact person I was thinking about when I typed this up. The whole time I was thinking.. Man, remember when I was wrong about coolant and I told Henna?

Gonna run and get myself another jug of BMW coolant and refresh the system. Hopefully that solves it

Here, 60/40 is worthwhile in the summer time because it gets hot (a couple years ago we have 63 straight days over 100 degrees) from April to September. But if it's not consistently how 60/40 makes no sense unless you track the car a bunch. Unless your running hot already, changing 60/40 is pointless.

And I was thinking of that instance while reading this too, laughing to myself.

[DaveSmed]

Don't think that gauge is accurate. Mine once sat at the "106" Celsius position for whatever reason according the picture you posted, and Tuner Studio was saying 210* Fahrenheit, which is 98* Celsius.

Truth. Those gauges aren't worth a damn as far as measuring. They just show relative temperature on your specific car (basically if it goes to the same spot it always does, good. If not, check it out)

They also vary signifigantly car to car. There are something like 15-18 total connections in that circuit, (around 5 dedicated) and that coupled with 25 some odd years leads to a bit of variation.

[crappycoco]

Mine does the exact same thing since i got it. I have 50/50 pre-mixed prestone coolant in there and thats it. While driving through death valley and/or autocrossing, it can get close to 12'o'clock or a hair over it.

[JinormusJ]

Truth. Those gauges aren't worth a damn as far as measuring. They just show relative temperature on your specific car (basically if it goes to the same spot it always does, good. If not, check it out)

Day before timing belt: heats to 7/16ths
Day after timing belt: heats to 1/4th

Therefore, "if it goes to the spot it always does, good, if not, check it out". So.. Then.. I digress

Don't think that gauge is accurate. Mine once sat at the "106" Celsius position for whatever reason according the picture you posted, and Tuner Studio was saying 210* Fahrenheit, which is 98* Celsius.

I never claimed these gauges were accurate, I'm posting this thread because my car is doing something it was never doing before: eg under heating to 1/4th versus heating normally to 7/16ths (which is what my car used to heat at)

Here, 60/40 is worthwhile in the summer time because it gets hot (a couple years ago we have 63 straight days over 100 degrees) from April to September. But if it's not consistently how 60/40 makes no sense unless you track the car a bunch. Unless your running hot already, changing 60/40 is pointless.

And I was thinking of that instance while reading this too, laughing to myself.

I thought of trying a different mixture because during summer here it gets consistently 100+ and on freeway days I would consistently "over"heat to 9/16ths on my gauge; whether or not that's attributed to the fan clutch; probably, but I thought having a slightly more water-biased mixture on top of replacing the clutch would be good but didn't think it would effect normal operating temperatures this much

Either way, I was close, but no cigar on adding the 50/50 mix; still heats to 1/4th when the norm for this m20 should be 7/16ths