Temp Gauge Straight Up?

[JMI]

Have read on the forum many times that the temperature gauge indictor should be straight up in the 12 o'clock position. Anything other than that is abnormal. This can't be true in all circumstances though, during hot summer days, for example. Right?
At some point (<180 degrees?) the thermostat will be wide open with the fan running at full speed. At this point the only variable in the cooling system is the temperature and rate of flow of the cooling medium, i.e. the air passing through the radiator.
Yesterday the local temperature was 85+ degrees. My temperature gauge was at times hovering near the next gauge mark (the mark halfway between normal and the beginning of the "red" zone) depending on the engine load and the car speed. The higher temps were occurring in stop and go traffic but once I got going again the temp returned to "normal". Later in the day as things cooled off the temperature gauge had the reassuring straight up appearance.

Do others have a similar experience or is this something I should be concerned about?

TIA

Jim

[repenttokyo]

i wouldn't worry...if it's hot out, the guage is going to move.

[t_marat]

In here it can be more than 100F (40-45C) during the summer, and my temp gauge never went beyond halfway, always at 12 o'clock. And that is with a broken auxiliary fan.

[repenttokyo]

In here it can be more than 100F (40-45C) during the summer, and my temp gauge never went beyond halfway, always at 12 o'clock. And that is with a broken auxiliary fan.


are you sure your temp guage works properly?

i can't wait to add a real temp guage to the car that will give me water temperature in degrees.

[t_marat]

I had such fears. After all it was very hot, and the auxiliary fan was off. However, the temp gauge does work correctly. During the winter to make the engine heat up more quickly I inserted a cardboard bloackage (hard paper) between the radiator and front grill and forgot about it. Then in mid march on a highway I looked down on a temp gauge and was horrified, the temp needle was at about 13 o'clock. Thought something horrible happened, like a leak in the radiator. But then I remembered about that cardboard I put in there :)
Stopped and turned off the engine, removed that blockage, started again. The temp gauge was showing an even higher temp than when I stopped! Very close to the red zone! But then it cooled down quickly to its usual position. So this proves the temp gauge does work correctly.
When its very hot the fan clutch really engages. When you rev the engine it sound like a small turbine. Sound more like a big engine.

[zman-95-540i]

Here in Texas we have many days over 100 and my gauge never went past the middle mark last year.

[70383roadrunner]

Mine never goes above the 12 o'clock position regardless of temp outside and a/c running.

[Barney Paull-Edwards]

If the gauge does anything but point to 12 then something needs looking at, simple.

[whiskychaser]

If the gauge does anything but point to 12 then something needs looking at, simple.

Second that

[Ferret]

Second that

My old 525i used to be dead on 12 o'clock, but once I'd whapped the 2.0 head on it ran about 2-3mm over top dead centre...

If it's moving about like that your thermostats most likely duff.

[Boone.Msi]

temps are over 100F here also, never went over half. Ive currently switched to a lower tstat(85 degree) and did away with my clutch fan. Temp sits at 11:00 and never goes past 12:00 in heavy traffic and high heat.

Something is abnormal if your experiencing a slight overheat in 85 degree weather. I would check your aux fan and or switch to a lower tstat.

[LunatiC]

Mine is always ever-so-slightly-left-by-a-bee's-dick from dead on 12'oclock. Depends on which angle you look at it.

I know my tstat isn't broken because I have cracked a water pump and let me assure you the car was running VERY hot.

[rob101]

Mine is always ever-so-slightly-left-by-a-bee's-dick from dead on 12'oclock. Depends on which angle you look at it.

I know my tstat isn't broken because I have cracked a water pump and let me assure you the car was running VERY hot.
mine was a little left of centre when the thermostat was screwed. when I replaced it, it was right of the centre, i think the brand and type (ie 85 or 90 deg type) of thermostat effects it.

[attack eagle]

mine also stays straight up, and my gauge works properly

I live in the desert.

[ApproachingZero]

It is probably your radiator. Either it is cloged inside or out. My corrado did the same. Normally everything was fine until it was very warm, and i was sitting. One day i removed the grill and powerwashed the damn thing. Tons of crud fell off.

Shortly after that, i took it for a spin and it drove 10 degrees cooler. I turned the AC on full and let it sit on a 95 degree day, everything was good.

I think the radiator just can't hold on to the normal temp.... might be in need of a new one

[Ross]

A fully functioning cooling system will keep the gauge nearly dead nuts center unless really extreme ambient temps. All of the BMs I've owned have been this way. A rising gauge is an indication of a marginal cooling system.

[bmwrp8]

Have read on the forum many times that the temperature gauge indictor should be straight up in the 12 o'clock position. Anything other than that is abnormal. This can't be true in all circumstances though, during hot summer days, for example. Right?
At some point (<180 degrees?) the thermostat will be wide open with the fan running at full speed. At this point the only variable in the cooling system is the temperature and rate of flow of the cooling medium, i.e. the air passing through the radiator.
Yesterday the local temperature was 85+ degrees. My temperature gauge was at times hovering near the next gauge mark (the mark halfway between normal and the beginning of the "red" zone) depending on the engine load and the car speed. The higher temps were occurring in stop and go traffic but once I got going again the temp returned to "normal". Later in the day as things cooled off the temperature gauge had the reassuring straight up appearance.

Do others have a similar experience or is this something I should be concerned about?

TIA

Jim


yesturday here in philippines it was around 115"F but still my temp is a little bit higher in the 12 oclock pos. traffic.check your e.fan and try to bleed your system

[Fred/Houston]

temps are over 100F here also, never went over half. Ive currently switched to a lower tstat(85 degree) and did away with my clutch fan. Temp sits at 11:00 and never goes past 12:00 in heavy traffic and high heat.

Something is abnormal if your experiencing a slight overheat in 85 degree weather. I would check your aux fan and or switch to a lower tstat.

Mine is always at 12:00 and it's HOT in Texas!
Boone, how did you do away with your fan clutch?
Thanks
Fred/Houston

[paul p (chi-town)]

Boone, how did you do away with your fan clutch?
Probably like this -> http://www.understeer.com/fanclutchmod.shtml

”Hang up & Drive!”
94 BMW 530iT&A 135K, ‘Helga’ ( for sale.....WHOOPS, haulin again *confused* )
92 BMW 325i 135K, ‘Rolf’ ( he’s baaaaack *woohoo* )
91 Volvo 740 Turbonium Vagon 195K ‘Thor’ ( where’s my check! *mad* )
93 Datsun NX2000 175K ‘Carla’ ( JWT clutch *smile* )
85 Toyo MR2 125K ‘Jerry’ ( dare i drive it *duh* )
“Do you want the signature on or off...............too bad." -- Captain Murphy

[JMI]

The status of the cooling system is as follows:

Coolant level is normal
System is bled of air
I replaced the thermostat about 2 months ago (engine was running cold on highway)
Main fan/clutch works
Auxiliary fan works (it runs with AC on - not certain if it runs at high water temp)
According to the previous owner's service records a new water pump was installed 46k miles ago and 31k miles ago a new radiator, upper radiator hose and coolant sensor were installed.
Radiator looks clean on the outside

The water pump is "relatively" new but from the horror stories posted on the board it may be worthwhile to change it out. Will order it soon. Any suggestions on a brand? Are plastic impeller failures still an issue?

TIA

Jim

[bmwrp8]

The status of the cooling system is as follows:

Coolant level is normal
System is bled of air
I replaced the thermostat about 2 months ago (engine was running cold on highway)
Main fan/clutch works
Auxiliary fan works (it runs with AC on - not certain if it runs at high water temp)
According to the previous owner's service records a new water pump was installed 46k miles ago and 31k miles ago a new radiator, upper radiator hose and coolant sensor were installed.
Radiator looks clean on the outside

The water pump is "relatively" new but from the horror stories posted on the board it may be worthwhile to change it out. Will order it soon. Any suggestions on a brand? Are plastic impeller failures still an issue?

TIA

Jim


check your aux.fan if it works in high mode...might be its low all the time

[Fred/Houston]

Probably like this -> http://www.understeer.com/fanclutchmod.shtml

”Hang up & Drive!”
94 BMW 530iT&A 135K, ‘Helga’ ( for sale.....WHOOPS, haulin again *confused* )
92 BMW 325i 135K, ‘Rolf’ ( he’s baaaaack *woohoo* )
91 Volvo 740 Turbonium Vagon 195K ‘Thor’ ( where’s my check! *mad* )
93 Datsun NX2000 175K ‘Carla’ ( JWT clutch *smile* )
85 Toyo MR2 125K ‘Jerry’ ( dare i drive it *duh* )
“Do you want the signature on or off...............too bad." -- Captain Murphy


Thank you very much for that nfo Paul. Living in Texas where rush hour is about 10mph and it's 100 degrees in the summer I would not do that procedure at this time.
...but when summers over I would!
:)
Fred/Houston

[JMI]

Want to close out the thread with the final resolution.
I should have known better then to assume (in this particular experience) new parts, out of the box are good. In the past, although infrequently, have found faulty new parts. Why I chose to overlooked what was staring me in the face I don’t know.
I had replaced the thermostat (with a lower temp one), water pump, fan clutch, auxiliary fan switch, coolant temperature sensor that goes to dash board, expansion tank and cap. Basically almost everything except the radiator, aux fan and hoses were replaced. Still the temperature would creep up at idle between ½ and ¾ on the gauge.
Summer turned to fall and the daytime temperature began to cool and with it my concern about the overheating problem went on the back burner, but it never completely left my mind as I would drive along.
In the last week or so I decided to revisit the issue well in advance of Spring and warming temperatures.
Bottom line: the problem with my M30’s cooling system was a bad viscous fan clutch.
After reviewing a lot of old posts and “googling” around the web I came to the conclusion that it could only be the fan clutch. I had read in numerous posts that a slowly rising temp at idle indicated a bad clutch. Also I overlooked the fact that I could stop the fan from spinning regardless if the engine was cold or hot. For that matter after stopping the fan I could spin it backwards with the engine running. I just assumed the Behr clutch that came new from BMA Auto Parts had to be good:(.
Called BMA with the expectation of having to shell out for the price of a new clutch but was pleased to learn that the part came with a one year warranty and they would ship me a replacement the same day (I received a Sachs clutch in a couple of days).
So now it looks like I will have to put the 80 degree Celsius stat back in because the temperature gauge is now spending most of its time below the straight up middle mark:D.

One thing to note: When replacing the Behr with the Sachs I examined the bi-metal strip that operates the plunger/valve stem/whatever it is called, with the non-working Behr. The strip was flat and the stem pressed in, whereas with the working Sachs the strip was bowed and the stem extended outward. Both were at “room” temperature.

What a relief to get this problem fixed.


Jim

[philbyil]

that the temperature needle is no lower than around 11 o'clock.
Mine ran just like that (below the mid-mark) for years before I changed the water-pump, thermostat (same temp) and thermo cover. After I replaced all of the above, it now runs exactly mid-mark and steady.





Want to close out the thread with the final resolution.
I should have known better then to assume (in this particular experience) new parts, out of the box are good. In the past, although infrequently, have found faulty new parts. Why I chose to overlooked what was staring me in the face I don’t know.
I had replaced the thermostat (with a lower temp one), water pump, fan clutch, auxiliary fan switch, coolant temperature sensor that goes to dash board, expansion tank and cap. Basically almost everything except the radiator, aux fan and hoses were replaced. Still the temperature would creep up at idle between ½ and ¾ on the gauge.
Summer turned to fall and the daytime temperature began to cool and with it my concern about the overheating problem went on the back burner, but it never completely left my mind as I would drive along.
In the last week or so I decided to revisit the issue well in advance of Spring and warming temperatures.
Bottom line: the problem with my M30’s cooling system was a bad viscous fan clutch.
After reviewing a lot of old posts and “googling” around the web I came to the conclusion that it could only be the fan clutch. I had read in numerous posts that a slowly rising temp at idle indicated a bad clutch. Also I overlooked the fact that I could stop the fan from spinning regardless if the engine was cold or hot. For that matter after stopping the fan I could spin it backwards with the engine running. I just assumed the Behr clutch that came new from BMA Auto Parts had to be good:(.
Called BMA with the expectation of having to shell out for the price of a new clutch but was pleased to learn that the part came with a one year warranty and they would ship me a replacement the same day (I received a Sachs clutch in a couple of days).
So now it looks like I will have to put the 80 degree Celsius stat back in because the temperature gauge is now spending most of its time below the straight up middle mark:D.

One thing to note: When replacing the Behr with the Sachs I examined the bi-metal strip that operates the plunger/valve stem/whatever it is called, with the non-working Behr. The strip was flat and the stem pressed in, whereas with the working Sachs the strip was bowed and the stem extended outward. Both were at “room” temperature.

What a relief to get this problem fixed.


Jim

[Ross]

Thanks for the follow up.