News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

Measuring engine temperature with Infrared Tool

Started by bill_boos, September 11, 2020, 01:42:43 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

bill_boos

Where are the best places to measure engine temps with Klein tool infrared gun --- heads, radiator, hoses, ??

Also, what are recommended emissivity levels for various locations. Never heard of emissivity before and online tables are confusing.

Thanks, Bill
2013 SL 550
2006 Bentley GT Continental
2003 CL 600
1947 Lincoln Continental Cabriolet
1949 Cadillac Sedan (sold years ago)
1956 Cadillac Convertible (sold)
1947 Cadillac Sedanette (Just Bought Oct 2019)

TJ Hopland

What are you trying to prove or test?   Emissivity isn't something we are typically worried about when working under the hood.  The materials involved are either decent conductors or are thin enough that it wouldn't likely change the reading much.   There is then the larger factor of we don't have any sort of published chart that says what any of the temps should be so getting an accurate measurement isn't going to mean much.   Its kinda like a compression test what we are really looking for is changes over its life and retaliative differences. 

For cooling system pointing at the hoses will give you an idea how much your radiator is able to drop the temp.  Pointing at different areas of the radiator may give you clues to areas that may be clogged and not flowing.    Pointing above and below the thermostat can give you an idea what temp its working at and if its working.

Pointing at the exhaust port area on the head or exhaust manifold can give you an idea if you have a dead cylinder, one will be cooler than the others.   If you have a dual plane intake and can tell by looking at it which side goes where you could maybe identify one side of the carb not working correctly.    Pointing above and below a 'heat riser' can give you an idea if its open or closed.

Another area they can be handy is brakes.  Taking readings on drums and rotors looking for differences especially side to side can point to an imbalance. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

bill_boos

Should have said what I am trying to test. Temp guage is going all the way to H. Trying to determine whether engine is overheating or guage or sensing unit is faulty by getting actual temperature. Infrared gun requires emissivity of material being measured to give accurate reading
2013 SL 550
2006 Bentley GT Continental
2003 CL 600
1947 Lincoln Continental Cabriolet
1949 Cadillac Sedan (sold years ago)
1956 Cadillac Convertible (sold)
1947 Cadillac Sedanette (Just Bought Oct 2019)

TJ Hopland

Must be the IR10 model.   Didn't know there were models with features like that.  I don't have time to look for the manual now but I would think there would be some sort of default setting that makes it like the other 90% of the guns on the market.
https://www.kleintools.com/catalog/infrared-thermometers/dual-laser-infrared-thermometer-201

Once you figure out what number to enter for that then I would be probing around where the existing sensor is as well as around the thermostat.    Near the thermostat is where most engine temp readings are taken since its kinda that last place in the engine after both sides come together.    If the existing sensor is on one side then I would compare with the same spot on the other side.   As far as specifically where you point I just kinda probe around the general area I am interested in and make sure I find an average spot,  not a spot that seems especially hot or cold. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

bill_boos

TJ, thanks for the good advice. The Klein gun is an IR5 which has the emissivity steeings. Setting on preset models is 95. Saw one online post that said engine heads should be 92. I sent an email to Klein to confirm. I'm not so much interested in exact temp -- just want to know approximate temp when guage is pegged at H to see if sensor or guage may be faulty
2013 SL 550
2006 Bentley GT Continental
2003 CL 600
1947 Lincoln Continental Cabriolet
1949 Cadillac Sedan (sold years ago)
1956 Cadillac Convertible (sold)
1947 Cadillac Sedanette (Just Bought Oct 2019)

TJ Hopland

Good luck and let us know what you find.    Also if you figure out that setting thing.  Like I said I had no idea there was such a thing.   If you can figure it out at least as it pertains to using it under the hood be sure to let us know here just in case someone else gets a tool with the same setting options.   My guns are cheap but I have used fancy ones and I don't remember them having more buttons on em to set things but I guess I didn't look either.   

Also you should mention which car you are working on.   I'm sure someone here should know what temps you should expect vs the gauge reading.   If it was into the 60's and up I would think 200 normal and H could be as high as 260 but looks like your cars are older and seems like the older you got the cooler normal was.   What the original pressure rating of the radiator cap was may give some clues.  You can find charts from the antifreeze companies that show pressure vs temps.   A 16 gets you into that 260 range.    If your car came with an 8 cap I would expect the danger zone to be lower.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

bill_boos

TJ, thanks once again. You,re right in guessing my car is older. It is a 1947 Cadillac with a 9 pound radiator cap.  Emissivity is new to me , too. I just bought the Klein IR5 because it looked like higher quality and it seems to be.

I think I may have a bad sensor rather than true overheating -- hope so. Guage takes a long time to move off C  and the climbs slowly to H. Stepping on the gas while idling causes it to move faster.
2013 SL 550
2006 Bentley GT Continental
2003 CL 600
1947 Lincoln Continental Cabriolet
1949 Cadillac Sedan (sold years ago)
1956 Cadillac Convertible (sold)
1947 Cadillac Sedanette (Just Bought Oct 2019)

TJ Hopland

I have never owned any Klein electronics but their hand tools and bits have served me well so far. 

Charts I found are pretty terrible so not worth trying to link to but with a 50/50 mix psi vs temp says:
0 = 226
4 = 236
8 = 248
12=259
16=267
20=275

So if your original cap was 8 you know 248 would have been the top of the danger zone on the gauge so if its working and is pretty much maxed out I would expect the temps to be in that range which I doubt they are because chances of a car that old not boiling over and vapor locking if it was really that high are pretty slim.   Guessing you will find you have either a gauge issue or some sort of circulation issue. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

harry s

Bill, I thought I had seen your were working on a flathead. Your temp measurements should be done on all four corners (about two inches in) of each head and be consistent. If under 200 you should be OK. Match that temp reading to your gauge.     Harry
Harry Scott 4195
1941 6733
1948 6267X
2011 DTS Platinum

fishnjim

Stick a thermometer in the radiator with the cap off.   That's what the sensor is seeing.   You'll have to look up what the setting is for your gauge to read "hot".   The sensor and gauge can be benched by a competent instrument tech with a heating bath and calibrator.

If you're looking for hot spots, plug in any decent number for cast iron and go with it.   The numbers will be relative.   The scanning one's with the color screen are easier to use than a direct reading digital point and shoot.   

The Tassie Devil(le)

To test the temperature gauge for reasonable correctness, I would be aiming the IR unit at various places near and around the Gauge Sender Unit.

I know you cannot get to right where the sender unit is touching the coolant, but the temps in and around it should give you some comparison, and possible relieve your mind.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

LaSalle5019

For IR thermometers to be read accurately, the emissivity of the surface needs to be known. Emissivity is a measure of how well a surface emits thermal radiation. Keep in mind that an IR sensor only measures surface temperature. It can see no deeper than what is being emitted from the surface so emissivity is extremely important to get an accurate number - material, surface texture, surface finish....these all play a role in emissivity. People usually just guess a number between 90 and 100 percent to get “somewhat” close.

TJs post about using the IR sensor to look at trends and comparing similar components is spot on and the best use for this tool. Fishnjim  is correct about using a thermometer to get a true temperature reading. If you shoot the radiator top tank/neck while using a thermometer you can at least get a good idea of how close you IR sensor is measuring off a painted surface as compared to the thermometer true reading. Then shoot your cylinder head near the temp sensor and use the same correction factor and you will at least be somewhat close. The water in the head below where you take the IR reading is probably a few degrees hotter as the cast iron head is dissipating that heat to the air as there is a slight temperature gradient across that.

Jim Miller

For whatever it's worth, I do as Harry suggests. I hit the four corners about 2 inches in to look for consistentcy and reading under 200. I'm usually around 185 to 190. I also hit the neck coming out of the radiator. When diving, my gauge will read just a bit higher at 60 MPH than 30, but the increase is no more than 1/2 the letter D in COLD - scientific gut feel observations.
Jim Miller

1941 6219
1949 6237X
1970 CDV
2021 XT6
Past:
1991 SDV
1999 DeElegence
2006 DTS
2013 XTS
2016 SRX

bill_boos

Thanks for all the replies on the best locations for taking heat measurements. I had no idea so many of you use an infrared gun. I'm still looking for the correct emissivity setting.
Does anyone use an adjustable setting gun or only the presets which I believe are all set permanently to .95?
By the way, this forum is an amazing resource, not only for this question but for helping me diagnose or solve other issues that have come up on my '47. Fortunately, no major issues for a car almost three quarters of a century old --- really speaks to Cadillac quality.
2013 SL 550
2006 Bentley GT Continental
2003 CL 600
1947 Lincoln Continental Cabriolet
1949 Cadillac Sedan (sold years ago)
1956 Cadillac Convertible (sold)
1947 Cadillac Sedanette (Just Bought Oct 2019)

TJ Hopland

All the guns I have owned have 2 buttons and the trigger.   C/F and Laser on/off.   I have used snap on and the like ones but in those cases someone handed them to me or said grab it off the bench so not a lot of training.   I think I did look at the instructions that came with one of mine and all I remember it saying is do not eat it and if you use it in California it will give you cancer.   It may have also said something about if you are going to measure the temp of your retina to turn the laser off.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Cadman-iac

CLC# 32373
1956 Coupe Deville A/C car "Norma Jean"

dadscad

#16
I have a Fluke infrared thermometer.  It has 3 emissivity settings, low, medium and hi. Low is .3, medium is .7 and high is .95. The instructions say "most organic materials and painted surfaces have a emissivity of about .95. The other settings apply to different type surfaces. Such as, polished sheet steel, use low setting. Oxidized cast iron, use high/medium. The instructions also state, if possible to paint a surface or put masking tape on it and use the high setting. Keep in mind that the sensed area is relitive to the distance the thermometer is from the surface. HTH
Enjoy The Ride,
David Thomas CLC #14765
1963 Coupe deVille