Another Question on temp gauge

[adam01]

Hi all

sorry for being a pain , but as you know that my temp gauge reads 2pm/230pm when driving around town and when driving at high speeds temp goes to just a little over the middle point it will never go under the middle or stay in the middle? is there away of checking the temp from the rad as to see if the water is at a normal temp . hope you understand what i mean thanks all again

Adam

1st picture is when driving around town

2nd picture driving at high speed

[brendang2000]

If I’m not mistaken, it doesn’t matter what the water temp is inside the radiator, it’s what the temp is inside the engine that matters, anybody else agree? A few things I did to help keep my car cool (and I live in Phoenix), was go to the 320 radiator; you can find a good one for cheep in a wrecking yard. Install an electric fan, I removed the stock mechanical fan and installed an electric fan In front of the radiator (I didn’t like the clearance between the fan and pulley), you should be able to fit a 10” fan upfront if you have clearance problems as well; you’ll gain a few HP to boot! Finally install a 170 t-stat, by your last thread; this should be straightforward now.

In the mean time, if your car is running hot, put the defroster on heat with the fan on high; you’ll be surprised how well the heater will cool your car (unfortunately you’ll be sweating). I had an old Honda that the temp switch went out on my way to N.C. and the fan was not turning on, so all I had was the heater for a fan and this kept me in the clear. Hope this helped.

[Benz02]

Check the thermostat...it's probably the reason your running so hot. And, as others state, if you replace it, go a little lower than what the book calls for...I think the 70 is a wise choice also.

-Ben

[PeteinMissionViejo]

Going to the 320i radiator on my 68 1600 has my car running on the cool side now. A good rodding out and flushing of the stock radiator probably would have had the car running cooler but it was easy, cheap, clean installation, and has the car running cool with the 320 radiator.

Pete

[adam01]

Check the thermostat...it's probably the reason your running so hot. And, as others state, if you replace it, go a little lower than what the book calls for...I think the 70 is a wise choice also.

-Ben

Thanks members for all yr advice and help. i have just looked at the history of my car on the old invoices , the last time the thermostat was changed was back in 2003year with a 75 degrees (OE) thermostat so maybe that is now old and not working as it should , i have now ordered a new 71 degrees thermostat and hopefully that will do the job. i will keep you informed.

PS: What is the difference between the 75 degrees to the 71 degrees thermostat

Adam

[ingraham]

1. A cooler thermostat will not improve the cooling ability of the cooling system.

2. An electric fan will not necessarily move more air than the stock mechanical fan. Most electric fans are "auxiliary" fans, which are meant to supplement, not replace, the primary (i.e. mechanical) fan. If you use a "primary" electric fan that moves more air than the stock fan, then yes, it will cool better.

3. A used radiator, no matter the size, is better only if it is in good condition, and there is not good way to judge the condition without taking it apart.

[Guest Anonymous]

you should buy yourself a meat thermometer to check the temp. when it gets to the position that you showed in your photo..

then at least you'll have an idea of what temp you are running at..

heck you might be at the correct running temp but the gauge is wrong..

makesure to remove the radiator cap slowly =)

[adam01]

you should buy yourself a meat thermometer to check the temp. when it gets to the position that you showed in your photo..

then at least you'll have an idea of what temp you are running at..

heck you might be at the correct running temp but the gauge is wrong..

make-sure to remove the radiator cap slowly =)

excellent sounds good.

how do you use a meat thermometer and where is the point i check and what should the temp be on the reading

Adam

[Pinepig]

Also check your timing, if it's retarded It'll cause the car to run hotter water temps.

[Guest Anonymous]

hey there,

so, you get your car up to the temperature that your photo showed....then you can either keep the car running or shut it off it does not matter so long as you drain the initial hot air using vent release on the top of the radiator cap (assuming you have one) proceed w/caution

then place the stem of the thermometer down into the coolant without submerging the indicator portion...let it it sit until the needle stops raising and that should give you a good idea of how hot you are running...

goodluck

[adam01]

you should buy yourself a meat thermometer to check the temp. when it gets to the position that you showed in your photo..

then at least you'll have an idea of what temp you are running at..

heck you might be at the correct running temp but the gauge is wrong..

makesure to remove the radiator cap slowly =)

Hi me again silly me

what temp is a normal at running..

ADz

[Zenon]

Hi me again silly me

what temp is a normal at running..

ADz

88ºC. I've measured between 86º-90ºC (~186º-194ºF) at the rad filler opening and this location very closely reflects the temp as reported by the calibrated temp sensor for my EFI system that is located next to the stock gauge sender in the coolant neck on the head. My dash temp gauge stays in a narrow range less than a needle's width above or below 3 o'clock.

This is with the stock nominal 80ºC thermostat and I would regard these direct measurements and gauge behaviour as being optimal and the way BMW intended.

Listen to Curt (except about electric fans*). The lower temp thermostats are a band-aid and can actually be bad for your motor. For some special situations they make sense but street-driven non-turbo '02s aren't those situations.

*I run an electric fan only (12" "aux" fan from a 320i) and have had no problems with inadequate cooling, even on rare 36ºC summer days. In fact, a properly-sized electric fan will move more air than the engine driven fan would at idle because it spins about 3x times as fast.

It may not flow as much air as the engine-driven fan would at over 3k rpm, but by then the airflow from the road speed alone should be larger than either kind of fan. A possible situation where a good electric fan might not be enough is towing something heavy up a long hill very slowly where the engine is heavily loaded and the air speed is low. I don't think that scenario happens to many 2002s.

To be fair, I know Curt was only warning about the sizing of the electric fan and was not really saying they are bad in principle.

regards,

Zenon

Edited 'cause 90ºC=194ºF, not 190ºF

[adam01]

Hi me again silly me

what temp is a normal at running..

ADz

88ºC. I've measured between 86º-90ºC (~186º-190ºF) at the rad filler opening and this location very closely reflects the temp as reported by the calibrated temp sensor for my EFI system that is located next to the stock gauge sender in the coolant neck on the head. My dash temp gauge stays in a narrow range less than a needle's just above or below 3 o'clock.

This is with the stock nominal 80ºC thermostat and I would regard these direct measurements and gauge behaviour as being optimal and the way BMW intended.

Listen to Curt (except about electric fans*). The lower temp thermostats are a band-aid and can actually be bad for your motor. For some special situations they make sense but street-driven non-turbo '02s aren't those situations.

*I run an electric fan only (12" "aux" fan from a 320i) and have had no problems with inadequate cooling, even on rare 36C summer days. In fact, a properly-sized electric fan will move more air than the engine driven fan would at idle because it spins about 3x times as fast.

It may not flow as much air as the engine-driven fan would at over 3k rpm, but by then the airflow from the road speed alone should be larger than either kind of fan. A possible situation where a good electric fan might not be enough is towing something heavy up a long hill very slowly where the engine is heavily loaded and the air speed is low. I don't think that scenario happens to many 2002s.

To be fair, I know Curt was only warning about the sizing of the electric fan and was not really saying they are bad in principle.

regards,

Zenon

Always first check the engine for it settings as being RICH and then lean out so it sounds OK. Then measure the temp and confirm your settings.

1] The cheapest way of measuring the engine temperature (also the one least consistent) is to put a little fluid spit (Yes from your mouth) on the engine head.

When it stays for longer as 5 seconds the engine temp is to low. Change your carburator to a leaner setting as soon as possible.

When it stays for 3-5 seconds the engine temp is OK and around 100° Celsius.

When it evaporate in less then 3 seconds the engine temp is to hot. Change your carburator to a richer setting as soon as possible.

whats your thoughts on the above

adam

[Zenon]

Always first check the engine for it settings as being RICH and then lean out so it sounds OK. Then measure the temp and confirm your settings.

1] The cheapest way of measuring the engine temperature (also the one least consistent) is to put a little fluid spit (Yes from your mouth) on the engine head.

When it stays for longer as 5 seconds the engine temp is to low. Change your carburator to a leaner setting as soon as possible.

When it stays for 3-5 seconds the engine temp is OK and around 100° Celsius.

When it evaporate in less then 3 seconds the engine temp is to hot. Change your carburator to a richer setting as soon as possible.

whats your thoughts on the above

adam

Where did you find that info? What engine are they referring to, an air-cooled 2-stroke?

Why bother with spit when a suitable thermometer is as close as your espresso machine? And I'd say that messing with mixture and timing is getting well ahead of things if the engine otherwise seems to run OK.

A 2002 engine would have to be way out of tune and the cooling system already marginal for it to run particularly hot at idle because of the tuning - so far out I would say it would not run very well at all. As I recall, you mentioned your car ran cooler on the highway than at idle so I doubt that tuning is the bulk of your problem.

On 2002s, the usual suspects for a high dash temp gauge reading are:

1. An electrical fault

2. A faulty thermostat

3. A clogged radiator

in more or less that order of probability.

Low coolant/leaks should be the first thing you'd check for and immediately rectify so that's not on the list.

In my experience, the rest of the possible causes are far lower in probability. Also, if the cooling system was fully up to snuff, slight mis-tuning would not have such an obvious effect on the coolant temp. How does your engine run, anyway? Does the cooling system hold pressure?

Just measure the coolant temp directly when the gauge is reading high and report back and we can go from there. If the direct reading is in the normal range, then we will have confirmed #1 - especially if the gauge needle jumps as various electrical loads are switched on and off.

If the directly-measured coolant temp is indeed high, then I would proceed with replacing the t-stat since they are much cheaper and relatively more failure prone than rads. That is, unless the rad is obviously decrepit or gunked-up (look inside the filler, see any crusty crap?). Even then, I might replace the t-stat along with the rad anyway while the system was drained if I did not know it to be less than a few years old. (I'd also test the new t-stat in a pot of water on the stove before installation, just to be 100% certain I won't be chasing my tail.)

Of course, it is also possible to have more than one of the above in effect.

regards,

Zenon

[ingraham]

and I agree with everything he has posted.

The difference between a 75 C and a 71 C thermostat is that the 71 C is too cool for anything but a track car. If your climate is cold to mild, use 80 C. If your climate is really hot, use 75 C.