Determining engine temp

[jimjumper]

A question that may seem simple but I can't seem to find an answer. Yanmar 240D (2 cyl. diesel), at what temp is it considered over-heating, and more importantly, where do you take that temp? I only have the idiot lights. I ran the tractor for 30 minutes in about 95' for 20 minutes and felt that the engine was getting a little warm judging from the heat blowing back on my legs. Using an IR thermometer, I checked the temp while the engine was running. Had 185-190 at the block, 165 at the oil fill cap, 170-175 at the head, 120 at the upper rad. hose, 135 at the lower, and 130 at the rad. cap. Thats a lot differences in temp depending on where I take it and I didn't find anything specific on where the best place to check is. Now this was only after 30 minutes but I've had it get hotter (I think!) when the ambient is over 105. So best spot to check engine temp to ensure I don't blow a head gasket?

 

[bmaverick]

A question that may seem simple but I can't seem to find an answer. Yanmar 240D (2 cyl. diesel), at what temp is it considered over-heating, and more importantly, where do you take that temp? I only have the idiot lights. I ran the tractor for 30 minutes in about 95' for 20 minutes and felt that the engine was getting a little warm judging from the heat blowing back on my legs. Using an IR thermometer, I checked the temp while the engine was running. Had 185-190 at the block, 165 at the oil fill cap, 170-175 at the head, 120 at the upper rad. hose, 135 at the lower, and 130 at the rad. cap. Thats a lot differences in temp depending on where I take it and I didn't find anything specific on where the best place to check is. Now this was only after 30 minutes but I've had it get hotter (I think!) when the ambient is over 105. So best spot to check engine temp to ensure I don't blow a head gasket?

When I was in TN and got the YM2610, the days above 95F ambient causes the TEMP light to come on and the engine lost a deal of power, so I quickly dropped the RPMs and let it work at cooling down. The light went out and the power was coming back. So, I just carefully drove it back home to park it. Ever since then, I never take it out when ambients are hovering in the upper 90s or higher.

 

[jimjumper]

The service manual says the water temp sensor closes at 212 +/- 5' and since its in the top of the water pump I would assume if the light comes on that the head is 230+. Thats awfully hot from what I understand about the head and head gaskets.

 

[ponytug]

These engines were originally designed to run in the tropics, southern Japan and Southeast Asia. The temps that you measured look in the normal ranges to me, but IR temperature readings need emissivity calibrations for accuracy. Rubber, painted steel, and bare metal have quite different emissivities and differences in thermal gradients. It is hard to compare your measurements to absolute from a distance.

I tend to look at the exhaust manifold, the block, and the upper and lower radiator hoses to get a sense for whether the engine is getting a) overfueled, b) has a cooling problem, c) whether the radiator & pump are working, respectively. Not in the service manual, I agree, but it is a quick check. I would repeat your measurements after ten or fifteen of work minutes on a cool day, just to give you a sense of how much the outside air temperatures affect your machine, given your IR thermometer.

If you aren't losing power and your high temperature light is off, I wouldn't sweat it. I also wouldn't assume that the head is necessarily at 230F when the light goes on. If it does go on, I would throttle down, and let the engine cool down for ten or fifteen minutes before either resuming work or shutting it down.

All the best,

Peter

 

[Menagerie-Manor]

A question that may seem simple but I can't seem to find an answer. Yanmar 240D (2 cyl. diesel), at what temp is it considered over-heating, and more importantly, where do you take that temp? I only have the idiot lights. I ran the tractor for 30 minutes in about 95' for 20 minutes and felt that the engine was getting a little warm judging from the heat blowing back on my legs. Using an IR thermometer, I checked the temp while the engine was running. Had 185-190 at the block, 165 at the oil fill cap, 170-175 at the head, 120 at the upper rad. hose, 135 at the lower, and 130 at the rad. cap. Thats a lot differences in temp depending on where I take it and I didn't find anything specific on where the best place to check is. Now this was only after 30 minutes but I've had it get hotter (I think!) when the ambient is over 105. So best spot to check engine temp to ensure I don't blow a head gasket?

I would take readings at the housing where the upper radiator hose connects, that should five you a reasonable coolant temp reading. As ponytug mentioned those temps are not a concern at all.

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[CalG]

Best engine efficiency happens at the highest temperatures that the sealing elements can withstand. Hence boiling temperature suppression additives (anti-freeze) and pressurized radiator caps.

Unfortunately, Lubrication oils do not like temperatures much above 230 F.

So... I figure 225 ...I see it all the time on my motorcycle. AND DO NOT WORRY!

 

[CalG]

These engines were originally designed to run in the tropics, southern Japan and Southeast Asia. The temps that you measured look in the normal ranges to me, but IR temperature readings need emissivity calibrations for accuracy. Rubber, painted steel, and bare metal have quite different emissivities and differences in thermal gradients. It is hard to compare your measurements to absolute from a distance.

I tend to look at the exhaust manifold, the block, and the upper and lower radiator hoses to get a sense for whether the engine is getting a) overfueled, b) has a cooling problem, c) whether the radiator & pump are working, respectively. Not in the service manual, I agree, but it is a quick check. I would repeat your measurements after ten or fifteen of work minutes on a cool day, just to give you a sense of how much the outside air temperatures affect your machine, given your IR thermometer.

If you aren't losing power and your high temperature light is off, I wouldn't sweat it. I also wouldn't assume that the head is necessarily at 230F when the light goes on. If it does go on, I would throttle down, and let the engine cool down for ten or fifteen minutes before either resuming work or shutting it down.

All the best,

Peter

Well PRESENTED!

Give that IR heat gun a through look around on a COLD engine, when you know the ambient temperature before you jump to conclusions about it's representation under elevated temperatures.

IR "heat guns" are just about the must fickle things ever created.

 

[Williy]

You will hear between 180 F and 225 F however IMHO
190 F to 200 F is a good temp you want to keep a temp
that will help keep the engine to burn clean so you don't
have to regen so often

willy

 

[winston1]

The 2000 and 226 both use the same sensor. The 226 manual states the red light comes on at 230F so according to Yanmar 230F at that location is to hot. Both tractor use a 13# radiator cap.

 

[careyo63]

My Temp lights been coming on from a bad circut for 16yrs.. I checked the heat temp. with a Thermal gun and Thermometer of the actual coolant when it started happening. I stay in the Low 190's even when the light decides to come on. I mow in 80-90+ Deg. temps. regularly. In Ga. summer temps get up there.

 

[California]

Your readings match what I found on my YM240 and posted here.

Oil & Fuel - Low oil pressure? No, bad sender!

I sometimes see questions here about what should temperature and oil pressure gauges show, and what causes the oil light to flicker. Maybe this longwinded narrative will answer some of these questions. I have owned my YM240 several years now with no issues at all, after an initial month...

www.tractorbynet.com

As CalG said, a diesel is most efficient at the hottest it can run without damaging anything.

Seems to me Yanmar's ultra simple design concept for the 240's intended that light as nothing more than a boilover warning.

How simple are these? There's not even a thermostat. Regen? Didn't exist 50 years ago. Fuel gauge? Nope. The three warning lights and the tach cover the essentials. The operator manual even allows running without a battery. A simpler machine for simpler times.

Edit - added:

 

[careyo63]

It came up on here no long ago about the Temp. light. Last week was one of the quickest it's ever came on before. Low 80's So I didn't even bother to look at the overflow bottle. Turned the key switch off and cut 2+ acres more. Actually forgot to turn it back on and make sure the Battery had a full Chrg.. Sure enough when I went to shut it down and noticed it. Turned the key switch back on " NO Temp. Light On"

 

[CalG]

The Fordson E27n (gas) doesn't have a warning light. As a matter of fact it doesn't even have a thermostat. The radiator top and bottom tank are both cast iron. Suggested coolant from the operators hand book is "clean water". Drain if there is a danger of frost." ;-)

Dang thing seems to do OK with the cloth radiator blind pulled up in winter, down in summer. If the coolant boils, I add more ;-)

 

[etpm]

A question that may seem simple but I can't seem to find an answer. Yanmar 240D (2 cyl. diesel), at what temp is it considered over-heating, and more importantly, where do you take that temp? I only have the idiot lights. I ran the tractor for 30 minutes in about 95' for 20 minutes and felt that the engine was getting a little warm judging from the heat blowing back on my legs. Using an IR thermometer, I checked the temp while the engine was running. Had 185-190 at the block, 165 at the oil fill cap, 170-175 at the head, 120 at the upper rad. hose, 135 at the lower, and 130 at the rad. cap. Thats a lot differences in temp depending on where I take it and I didn't find anything specific on where the best place to check is. Now this was only after 30 minutes but I've had it get hotter (I think!) when the ambient is over 105. So best spot to check engine temp to ensure I don't blow a head gasket?

Using an IR thermometer can give false readings, and these readings depend not only on the material but on the surface finish. Check out this link: Emissivity and Its Effect on Infrared Thermometer Readings - ennoLogic
readings/
I actually ran into this problem today. I was heating some brass parts for a shrink fit and knew that the parts were hotter than the IR thermometer was showing. I then remembered about emissivity and used a contact thermometer instead. I even tried the dull surface on the parts but it was apparently too shiny to give an accurate reading. In any case the contact thermometer did show the proper temperature, which was much hotter than the temp I was shooting for and the parts went together very easily. I'm sure that when I machine the assemblies tomorrow the two part assemblies will behave as if one solid piece.
Though I didn't answer your question my answer may explain the wide differences in your temperature measurements. I suggest you take some contact temperature measurements at the same places where you took your IR measurements and compare them. This way you can use your IR thermometer and correct for the emissivity difference, so you will know what the actual temp is.
Eric

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[CalG]

Using an IR thermometer can give false readings, and these readings depend not only on the material but on the surface finish. Check out this link: Emissivity and Its Effect on Infrared Thermometer Readings - ennoLogic
readings/
I actually ran into this problem today. I was heating some brass parts for a shrink fit and knew that the parts were hotter than the IR thermometer was showing. I then remembered about emissivity and used a contact thermometer instead. I even tried the dull surface on the parts but it was apparently too shiny to give an accurate reading. In any case the contact thermometer did show the proper temperature, which was much hotter than the temp I was shooting for and the parts went together very easily. I'm sure that when I machine the assemblies tomorrow the two part assemblies will behave as if one solid piece.
Though I didn't answer your question my answer may explain the wide differences in your temperature measurements. I suggest you take some contact temperature measurements at the same places where you took your IR measurements and compare them. This way you can use your IR thermometer and correct for the emissivity difference, so you will know what the actual temp is.
Eric

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Yup! Post #7 suggested this same thing. Nothing better than a second opinion!