Thermostat Open Temperature Differs Claimed

[ningshao]

i ordered a 71C thermostat from bimmerworld a couple of days ago. in order to verify the open temperature, it was put in water with a pre-calibrated thermometer (this one is super accurate and cost about $200) and slowly heated up.

the thermostat did not open AT ALL till 76-77C and fully opened at about 81C. is this normal or it is considered significantly different from claimed? to me its more like a 80C thermostat.

[douglee25]

Hmmm...

Also interesting to note that the 71C thermostat is quite a bit more expensive too. If it's rated at 71C, it should damn better open at 71C.

Doug

[IraSummers]

$200 and it doesn't open until nearly 80*...I just paid like $40 for a new 80*... that sucks man...

[ningshao]

well, i mean the thermometer is $200, not the thermostat.

just called bimmerworld, the tech guy confirmed the temperature labelled on thermostat means at the point the thermostat STARTS TO OPEN. but they have no idea why my 71C opens at 76C

[douglee25]

well, i mean the thermometer is $200, not the thermostat.

just called bimmerworld, the tech guy confirmed the temperature labelled on thermostat means at the point the thermostat STARTS TO OPEN. but they have no idea why my 71C opens at 76C

Tell Bimmerworld to send you another one. Use your old thermostat or buy one local and see if that opens up at the correct temperature.

Doug

[Devius1]

temperature labelled on thermostat means at the point the thermostat STARTS TO OPEN.

c'mon man it's a t-stat= a spring and a seat it's not supposed to be rocket science.
give it some pressure and cycling and it should be fine. :D

BTW why a 71*

[IraSummers]

well, i mean the thermometer is $200, not the thermostat.

just called bimmerworld, the tech guy confirmed the temperature labelled on thermostat means at the point the thermostat STARTS TO OPEN. but they have no idea why my 71C opens at 76C

ok, that's better. I was hoping you didn't pay 200 for a thermostat, lol.

[ningshao]

c'mon man it's a t-stat= a spring and a seat it's not supposed to be rocket science.
give it some pressure and cycling and it should be fine. :D

BTW why a 71*

you will realize why a 71 if you live in texas.:stickoutt

i suspect even if the thermostat will work after 'break-in', actually, its more like a bimetallic spring and i dont think it will perform differently through its life.

right now what i can think about is, the ambient pressure of yesterday (when i performed the test), and the impurities in the water might have caused the problem. maybe i should test in ethylene glycol, aka coolant :D

[TH3 Shifty]

great... now you worry me... because i just ordered a 75*c thermo from them... looks like i'll be doing a pretest as well to verify

[art@rmeuropean]

I wonder if coolant pressure in the system makes it function differently when the thermostat is installed.

[Xiphos]

To get an accurate reading, I'd try putting it in coolant, then seeing when the thermostat opens.

[douglee25]

To get an accurate reading, I'd try putting it in coolant, then seeing when the thermostat opens.

The fluid medium should have nothing to do with it. 71C of water or 71C of antifreeze the thermostat should be opening.

It's like the old question, "What weighs more, 100 lbs of feathers or 100 lbs of gold?" - And I want the answer buddy! :D

Doug

[Xiphos]

The fluid medium should have nothing to do with it. 71C of water or 71C of antifreeze the thermostat should be opening.

It's like the old question, "What weighs more, 100 lbs of feathers or 100 lbs of gold?" - And I want the answer buddy! :D

Doug

Well you said should, so you dont seem too confident ;).

100lbs of feathers, because there is no way you can weigh feathers without putting them in a bag. Thus the weight of the feather plus the weight of the bag > just the 100lbs of gold which you can stack :D

[douglee25]

Well you said should, so you dont seem too confident ;).

100lbs of feathers, because there is no way you can weigh feathers without putting them in a bag. Thus the weight of the feather plus the weight of the bag > just the 100lbs of gold which you can stack :D

lol :lol

[TH3 Shifty]

i love Xiphos and his wise ass ways... always cracks me up

[Devius1]

you will realize why a 71 if you live in texas.:stickoutt


That should help keep your car in cold start enrichment mode for a while. If your having cooling issues 71* t-stat isn't really gonna fix a taxed system. :D

If 111* texas traffic is the problem lower your aux. fan switch temp. Better yet get a 3 core rad.

[Xiphos]

i love Xiphos and his wise ass ways... always cracks me up


you loooooooooove me :naughty

[MARKSS]

I wonder if coolant pressure in the system makes it function differently when the thermostat is installed.

This seems logical. I would also think that the pressure of the coolant moving through the system would help the thermostat to open.

[ningshao]

This seems logical. I would also think that the pressure of the coolant moving through the system would help the thermostat to open.

i dont think the pressure will help the t-stat open. when it opens, the valve moves towards the hot side which has higher pressure than the cold side, so the pressure will prevent it from opening.

[MARKSS]

i dont think the pressure will help the t-stat open. when it opens, the valve moves towards the hot side which has higher pressure than the cold side, so the pressure will prevent it from opening.


Oh..... ok.:)

[Moron95M3]

Jw, how did you heat up the water, over a stove?? where was your thermometer with respect to the tstat (how accurate it is is only one issue). were you mixing the water while you heated it? The bottom of a pot of water will be hot than the top of the pot. (even though the hotter water will rise, it'll still be hottest at the bottom). My opinion is that 5* difference is close to a 5% error (with respect to the 71*) which is always okay according to my Thermodynamics class, :) I'm such a dumb college kid.

I'd just bet it's due to measuring error on the accound of how different the water actually was in temperature. The producer undoubtedly tested many of these with equipment most likely better than what you used to test.

Just my 2cents, I wouldn't worry unless after you put it in it has issues. Then bitch the company out.

[ningshao]

Jw, how did you heat up the water, over a stove?? where was your thermometer with respect to the tstat (how accurate it is is only one issue). were you mixing the water while you heated it? The bottom of a pot of water will be hot than the top of the pot. (even though the hotter water will rise, it'll still be hottest at the bottom). My opinion is that 5* difference is close to a 5% error (with respect to the 71*) which is always okay according to my Thermodynamics class, :) I'm such a dumb college kid.

I'd just bet it's due to measuring error on the accound of how different the water actually was in temperature. The producer undoubtedly tested many of these with equipment most likely better than what you used to test.

Just my 2cents, I wouldn't worry unless after you put it in it has issues. Then bitch the company out.

the thermostat was put in a secondary container and the entire assembly was suspended in water. the thermometer was very close to the t-stat and they were far away from the bottom hot spot. basically my job is to play with these kinda setups and i know how to avoid these errors.

it wont give me any problems since it opens at lower temperature than stock one. but i just wanna verify everything before gets installed.

[pbonsalb]

Just feel the hose and you will feel when it starts to open significantly. I would not worry. Thermostats often take up to 20 degrees F to fully open. If it opens 10mm, I would not expect to see even 1 mm at its rated "start to open" temp.

[RRSperry]

I have to agree, thermostat isn't the answer to Texas heat. Once it's open, it's open, the cooling system will reach steady state at some higher temp. (somewhere in the 190'sF) Not to mention, in the winter, it will be at the T-stat's set point, keeping the ecu in cold start mode.

Better radiator, (increase the fluid capacity, more rows of cooling fins (3 row Al rad), Stewart pump (better flow), and a lower temp aux fan switch.

[ningshao]

i agree with ya all that t-stat wont reduce the engine temp. but since i am overhauling my entire cooling system, IMHO its a good idea to have a better t-stat.

a repeated test was performed yesterday under strictly 1 bar in 100% de-ionized water (resistivity 14-15MOhm), such that error could be controlled under 3%. everything was pre-calibrated and still the open temperature was about 75. not to worry everyone, but be aware that what claimed on thermostat may different from it truely can perform

[EricP]

The fact that this much time has been spent testing a thermostat only to find that it opens about where it says it should....... is amazing :)

Mine would've been in the car days ago and I would've moved on, methinks.

[Devius1]

The fact that this much time has been spent testing a thermostat only to find that it opens about where it says it should....... is amazing :)

Mine would've been in the car days ago and I would've moved on, methinks.

Absolute attention to detail is essential :) making sure every valve cap weighs the same and using only blueprinted BOSCH titanium piston return springs :buttrock

[TH3 Shifty]

Hey Art... got my stuff yesterday... thanks again... and you know whats odd... my radiator cap has always been really tough to take off.. it starts 1 full turn really easy. then the rest is really really tight to take off...it screws on fine.. but take off was always a bitch... its not broken or anything... and never leaks...

i replaced the cap with the new one from you... and now the temp is 10-15* cooler...???? i dont get it... but im glad i got a new one...