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What is normal operating temperature?


twilmotte

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My '04 RT has been running a little hotter since I had the valves adjusted and switched to 20W50 synthetic. I'm concerned the valves may not have been adjusted spot on. Would too little or too much of a gap cause engine to run at 6 RID bars in city (stop 'n go) traffic in mid 80's outside temps? Before my last valve adjustment and fluids change my bike ran at 5 bars even in mid 90s temps and very seldom got to 6 bars unless temps were in mid 90s and then only in stop 'n go traffic. Is it OK for the engine temp to be at 6 bars for extended periods? I'm concerned about what it's going to read this summer when temps in Texas are mid 90s most of the day. I'm thinking about taking the bike to another BMW shop in San Antonio and having the valves re-adjusted to see if that makes it run cooler. Do I need to get my compressor out and from the rear side of the oil cooler blow out any bug fragments from the oil cooler fins? The cooling fins don't look very "buggy." I'd sure feel better if it were running as cool as it used to. What do y'all think? confused.gif

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I was told this after I was concerned about heat damage when I got stuck in heavy traffic and pegged the temp gauge.

 

"No one knew R-motors got hot until they installed a temperature gauge on them"

 

The difference between 5-6 bars on the gauge pretty much means nothing. I don't even start paying attention to it until I get up to 8-9. When it starts making a ton of racket, I will either shut it down (if stopped in traffic), or find a shady spot to stop and stretch for a few minutes.

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My '04 RT has been running a little hotter since I had the valves adjusted and switched to 20W50 synthetic. I'm concerned the valves may not have been adjusted spot on. Would too little or too much of a gap cause engine to run at 6 RID bars in city (stop 'n go) traffic in mid 80's outside temps? Before my last valve adjustment and fluids change my bike ran at 5 bars even in mid 90s temps and very seldom got to 6 bars unless temps were in mid 90s and then only in stop 'n go traffic. Is it OK for the engine temp to be at 6 bars for extended periods? I'm concerned about what it's going to read this summer when temps in Texas are mid 90s most of the day. I'm thinking about taking the bike to another BMW shop in San Antonio and having the valves re-adjusted to see if that makes it run cooler. Do I need to get my compressor out and from the rear side of the oil cooler blow out any bug fragments from the oil cooler fins? The cooling fins don't look very "buggy." I'd sure feel better if it were running as cool as it used to. What do y'all think? confused.gif

 

 

Tom, I’m not sure a higher oil temp on the rid is a bad thing.. I don’t have an oil flow chart in front of me here but if I remember correctly the oil gauge measures the oil temp LEAVING the engine… Seeing as most synthetic oil’s pick up latent engine heat a little better than most Dino oil’s it wouldn’t surprise me if more heat was being carried out of the engine with the oil & if that is the case you are seeing the extra heat being carried out on the oil… Better the heat carried out than remaining inside the engine.. Now If it were measuring the oil temperature in the engine oil sump the higher temp showing would be a bad thing..

 

Those valves would have to be so far out of adjsutemnt to measurably increase oil temperature..

 

Twisty

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Stan Walker

Tom, I’m not sure a higher oil temp on the rid is a bad thing

 

For a change, I disagree with you.

 

The temperature of the oil leaving the engine is controlled by the oil thermostat and should be unchanged regardless of oil type used. Only running conditions should affect it. A higher oil temp leaving the engine implies that the engine is generating much more heat than normal or that there is some type of malfunction in the cooling system.

 

My personal experience is that the oilheads tend to run cooler under heavy loading when filled with synth oils than under the same condition with dino.

 

Also they tend to run at the normal 5 bar temperature even when the ambient is cooking me. This assumes a normal speed with reasonable airflow. All bets are off in stop and go traffic.

 

Stan

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Stan, My oil temp is fine (5 bars) when crusing and air is flowing through oil cooler during mid 80s ambient temps. When you say, "All bets are off in stop 'n go traffic," can I assume that my 6 bars are normal and not a cause for concern?" Also, can I assume that the recent valve adjustment is probably not the culprit if the bike seems to running fine otherwise? I just switched to Mobil 1 20W50 "V-Twin" synthetic (from BMW dino) ... I don't think syn oil would make the engine run hotter under any circumstances. confused.gif

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Stan Walker

My oil temp is fine (5 bars) when crusing and air is flowing through oil cooler during mid 80s ambient temps. When you say, "All bets are off in stop 'n go traffic," can I assume that my 6 bars are normal and not a cause for concern?" Also, can I assume that the recent valve adjustment is probably not the culprit if the bike seems to running fine otherwise?

 

I think your OK.

 

Stan

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Tom, I’m not sure a higher oil temp on the rid is a bad thing

 

For a change, I disagree with you.

 

The temperature of the oil leaving the engine is controlled by the oil thermostat and should be unchanged regardless of oil type used. Only running conditions should affect it. A higher oil temp leaving the engine implies that the engine is generating much more heat than normal or that there is some type of malfunction in the cooling system.

 

My personal experience is that the oilheads tend to run cooler under heavy loading when filled with synth oils than under the same condition with dino.

 

Also they tend to run at the normal 5 bar temperature even when the ambient is cooking me. This assumes a normal speed with reasonable airflow. All bets are off in stop and go traffic.

 

Stan

 

Stan, your are correct in that there is an oil thermostat but like similar water temperature thermostats in an automobile it doesn’t control oil temperature but just makes sure the oil is AT or OVER a certain temperature before opening & allowing oil flow through the oil cooler.. Once open it has no further control over oil temperature until the oil gets back below the closing threshold.. (that is unless your are saying the thermostat holds the oil temp to 5 bars & we know that doesn’t happen) ..

 

Twisty

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Stan Walker

that is unless your are saying the thermostat holds the oil temp to 5 bars & we know that doesn’t happen

 

That is exactly what happens as long as the cooling capacity isn't exceeded.

 

My 2 rt's run at 5 bars virtually all the time (excluding stop and go traffic).

 

My cars run at a consistant water temp according to the gauges.

 

When the temp starts to go up the thermostat opens and allows the cooling system to bring it back down. When it starts to go down past the set point the thermostat closes and allows the temp to rise. That's the way thermostats work.

 

Stan

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that is unless your are saying the thermostat holds the oil temp to 5 bars & we know that doesn’t happen

 

That is exactly what happens as long as the cooling capacity isn't exceeded.

 

My 2 rt's run at 5 bars virtually all the time (excluding stop and go traffic).

 

My cars run at a consistant water temp according to the gauges.

 

When the temp starts to go up the thermostat opens and allows the cooling system to bring it back down. When it starts to go down past the set point the thermostat closes and allows the temp to rise. That's the way thermostats work.

 

Stan

 

Stan, so those cooling fan(s) on your automobile are just there for grins??? Automotive thermostats are just not that reactive to be used for finite temperature control.. They are pretty decent to allow a min temp to be reached before opening but very lousy at closing reaction to temperature or time.. I have no reason to believe the BMW oil control thermostat is any tighter controlled.. Your car runs at a fairly constant temperature due to cooling fan or fans coming on at the request of the engine temperature fan discrete switch either electronically modulated on newer vehicles or a simple fan control switch on older vehicles.. On the mechanical fan vehicles the fan operates all the time but most newer versions have a thermostatic spring & a viscous clutch.. The older vehicles had a fixed fan or flex blade fan but on those vehicles the water temperature would range the gauge.. Obviously in real cold ambients the T-stat will retain the coolant in the engine until it’s opening temp is reached but once open those T-stats have a very large overlap before even thinking of closing..

 

That BMW boxer oil thermostat is just a simple spring/plunger/restrictor affair with no specs given for opening temperature.. There is no spring specs given or even a temp that it opens at so I’m pretty darn sure there would be no closing temp specs given or even controlled to.. That system is pretty crude to allow it to be finite oil temp control..

 

If you think that simple spring/piston oil by-pass can control the oil temp to a narrow operating temperature range I’m all ears.. Explain to an old skeptical automotive engineer like myself how that system can hold an engine operating temperature range.. My guess is it is more reactive to oil viscosity than oil temperature..

 

Twisty

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I like to stay and argue, but I'm off to Torrey.

 

Stan, not arguing,, discussing.. If we were arguing we would be shouting & throwing things..

 

Twisty

smile.gif

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ShovelStrokeEd

I gotta say, and it seems I say it pretty often, Twisty is right on this. The thermostat does nothing more than insure that the oil temperature will reach a certain point before allowing full flow through the cooler. BTW, all thermostats have a small bypass built into them else the warm oil/water would never reach the very simple sensing element. Kinda puts paid to the oil dance, but, I digress.

 

In fact, the thermostat and oil temperature sensor have nothing much to do with each other and are on different sides of the oil cooler to boot. The sensor is in the hottest part of the oil circuit (that leaving the engine enroute to the oil cooler. The thermostat is located on the other side of the cooler and controls flow back to the sump.

 

Given that the main function of the thermostatic valve is insure that oil is quickly brought to and then maintained at a temperature where it will evaporate condensate (water primarily but other contaminants as well) it probably opens somewhere in the neighborhood of 90 deg C. Anything below that and the rate of evaporation of water is just too low to keep the oil clean on short trips. Wouldn't surprise me to find that 5 bars is somewhere around 120 deg C or a little higher. Nothing to worry about, btw, the oil can take it and lots more.

 

I base the above on watching the coolant temperature thermostat operate on my Honda when riding both normally and in the rain. Coolant temperature, different from oil temperature I know but indicative of the way the valve works, rises at a pretty precipitous rate to 175 deg F at which time the thermostat opens. On cool days, it will stay there so long as I don't idle overmuch or get too close to a car in front of me. From there, it (the bike) maintains coolant temperature at that 175 degrees plus a differential for ambient temperature based at about 75 deg F. Hit some rain and the temp will, briefly, drop into the 160's at which time, the thermostat closes and it cycles back up. The rain provides additional efficiency for the radiator and thus the drop in temperature. This puts the hysteresis of the valve at about 15 deg F. Pretty normal for these things.

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The sensor is in the hottest part of the oil circuit (that leaving the engine enroute to the oil cooler. The thermostat is located on the other side of the cooler and controls flow back to the sump.

 

Wouldn't surprise me to find that 5 bars is somewhere around 120 deg C or a little higher. Nothing to worry about, btw, the oil can take it and lots more.

 

Well, I'd feel more comfortable if the engine were running as cool as it was before the valve adjustment and the change of oil, but I guess I won't worry about 6 bars in stop 'n go conditions since other boxers seem to do the same. Thanks for the "lively discussion" of how the system works!! I love this forum!! wave.gif

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Well, I'd feel more comfortable if the engine were running as cool as it was before the valve adjustment and the change of oil,
Indeed. Regardless of the thermostat diversion (we like those) the question as to why the oil temp changed hasn't been addressed. Personally I don't see how a valve adjustment or oil change could cause a noticeable difference and I've never seen any variation in my bike.

 

As you certain that the change is really related to the valve adjustment? It's been getting a lot warmer here these last few weeks and perhaps that simple fact has more to do with it than anything else(?)

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ShovelStrokeEd

Aha!! Eureka!! Yaaaaa!

 

We have a winner.

 

Now add some road snot, dead bugs, possibly a pigeon or two in the oil cooler and the fact that the RID is a simple beast with maybe a 20 or 30 degree C range for each bar and rounding between them. The bike, which may have been running anywhere from 4.6 to 5.4 bars before is now running somewhere about 5.6 bars so, being unable to display those fractions, it just notches up to the 6th bar.

 

In other words, forget about it. Hey, I wonder what would happen if you hooked a Datel voltmeter to the temperature sensor? Probably wouldn't get a number that meant anything in terms of temperature scale but you should be able to get some sort of number and from there be able to compare when and where bars change. I'd look for a 5 volt one with two digits of precision.

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[quotePersonally I don't see how a valve adjustment or oil change could cause a noticeable difference and I've never seen any variation in my bike.

 

As you certain that the change is really related to the valve adjustment? It's been getting a lot warmer here these last few weeks and perhaps that simple fact has more to do with it than anything else(?)

 

I don't think it's related to the recent increase in temps due to approaching summer. Even last summer in mid 90s Texas heat, I seldom saw 6 bars (except during an Iron Butt run to El Paso and back in 90 degree heat at sustained 80 to 85 mph on I-10 out in West Texas).

 

I guess I'll just have to accept the fact it appears to be running somewhat hotter, but not too hot to damage anything as long as it runs no higher than 6 bars. Engine performanace doesn't seem to be affected.

 

Does anyone clean their oil cooler fins? And what is the best way to go about that chore? I would guess compressed air blown from rear of cooler through the fins to the front to dislodge bug fragments? That might make some difference.

 

Also, as Ed suggested, the sensor may not be all that accurate either to worry about the difference between 5 versus 6 bars in stop 'n go situations. crazy.gif

 

Thanks for brainstorming this with me.

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Does anyone clean their oil cooler fins? And what is the best way to go about that chore?
I just splash a little soapy water in there when washing the bike, let it sit for a while to soften up the bugs, then rinse with a (low-pressure!) water stream. Keeps everything pretty clean.
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Thanks for the cleaning tip, Seth. I'm on the road now, but cleaning the oil cooler fins is a priority when I get home next week! smile.gif

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Tom, I also had the same problem after I adjusted the valves. The bike moved up one bar on the RID just from the valve adjust. Checked the valves again, They where two tight. Readjusted the valves. I would have never guessed that it would be so critical. But I was wrong. OK, let the barb`s fly. Ride Safe Detroit

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Tom, I also had the same problem after I adjusted the valves. The bike moved up one bar on the RID just from the valve adjust. Checked the valves again, They where two tight. Readjusted the valves. I would have never guessed that it would be so critical. But I was wrong. OK, let the barb`s fly. Ride Safe Detroit

 

I does make sense as the valves control the engines 'breathing'. Too tight and it is not breathing efficiently

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