Non-contact thermometer--diagnostic possibilites? - PeachParts Mercedes-Benz Forum

kerry · #1 01-05-2006, 03:47 PM

Bought a remote thermometer today. Harbor Freight had them on sale for $50 from $80. What are the diagnostic possibilities?
I think it is useful for diagnosing bad wheel bearings, sticky brakes, and bad tires. But what else? Bad glow plugs? Non-firing cylinder? Bad turbo bearings?
I figured out my oil cooler is working and it flows from bottom to top using the thermometer. Bottom was 100 and top 80 while idling after a 15 mile drive.

It'd be interesting to compare Z's intercooled intake manifold temperature with a non-intercooled version.

ytr1903 · #2 01-05-2006, 04:03 PM

Kerry Edwards,

The radiator can also be diagnosed with the thermometer. Last summer, I used it to help determine the optimum A/C output at the vents.

Tom

phidauex · #3 01-05-2006, 04:22 PM

Non contact thermometers are GREAT. I've got one at work that I carry with me all over just to play with. (don't worry, I'm not crazy, I work at a science museum).

Automotive uses abound... Drive around the block, then quickly check the temperatures of your brake rotors. Got one that is a lot hotter than the others? Its dragging! Got one that is a lot cooler than the others? Its stuck!

Check your EGTs on a warmed up vehicle. Check pre and post turbo temperatures. Check oil temperature at the filter housing, check parts of your radiator for temperature differences indicating a blockage.

If one cylinder isn't firing, it'll be cooler around the head there.

Check coolant hoses for flow direction (like you did with the oil cooler), diagnose thermostat problems by measuring temperature on either side of it, or the temperature that its opening at.

Check wiring or batteries for overheating. Check the temperature of the top of your hood to see if your lack of a hood pad is cooking your paint.

Check your fridge to see if its cold enough (don't trust its built in thermometer).

Check the temperature of the bulbs in your house. Its fun.

Check for leaks in your windows, doors or outlets by checking the temperature around them.

Oh man, its so much fun. Enjoy!

peace,
sam

Eskimo · #4 01-05-2006, 04:22 PM

Quote:

Originally Posted by kerry edwards

Bought a remote thermometer today. Harbor Freight had them on sale for $50 from $80. What are the diagnostic possibilities?
I think it is useful for diagnosing bad wheel bearings, sticky brakes, and bad tires. But what else? Bad glow plugs? Non-firing cylinder? Bad turbo bearings?

Raytek markets their AutoPro model specifically to automotive repair folks. Take a look here, and you'll find links to the brochure and the manual for this model. The manual gives suggested procedures for a number of diagnostic activities, so it might make for nice supplemental reading to go with your new tool..

If you have access to some sort of "contact" temperature measuring device (thermocouple reader, for example), then you might want to play around some with comparing it to your new non-contact thermometer. For shiny or polished surfaces, the difference in emissivity can give inaccurate readings from your IR unit. The Raytek manual touches on this (and ways of getting around it).

phidauex · #5 01-05-2006, 04:26 PM

BTW, here is the link to the harbor freight one:

http://www.harborfreight.com/catalogsearch/result?category=&q=thermometer

Its on sale at 40$ on the website. If you buy it at a store, make sure you print out the website and bring in the copy, they don't always have the same prices, but they'll honor the lower price of the website if you bring in a copy.

Its true that they aren't always as accurate as a contact thermometer, especially the ones without adjustable emissivity, but their power lies not in precision, but in their ability to make quick comparisons.

Its hard for me to tell you what temperature a 'good' cylinder will be, but if you can check them all in the period of 5 seconds, you can notice a difference very quickly. Same with rotors. There is no specific temperature that means good or bad, its a difference you are looking for, and you need to be able to make lightning fast measurements to see those differences.

peace,
sam

Jarod · #6 01-05-2006, 04:43 PM

i got a craftsman non contact thermometer, it was on sale for $40... but when i got to the store it rang up for $25, and the guy let me have it for that price!! and its really cool, it can be used to see if your tea (yep i've got english blood) is too hot!! or if your ear is running at the correct temp, or if your ear cooler is plugged!!

Eskimo · #7 01-05-2006, 04:45 PM

Quote:

Originally Posted by phidauex

Its true that they aren't always as accurate as a contact thermometer, especially the ones without adjustable emissivity, but their power lies not in precision, but in their ability to make quick comparisons.

Understood. I only suggest that, depending on the application, it can be useful to be aware of the sorts of situations in which an IR unit might lie to one - and to know how one can make it tell the truth if necessary.

I own one, too, and think it's dandy not only for around the garage and house, but also as an educational tool/toy.

phidauex · #8 01-05-2006, 04:55 PM

Quote:

Originally Posted by eskimo

Understood. I only suggest that, depending on the application, it can be useful to be aware of the sorts of situations in which an IR unit might lie to one - and to know how one can make it tell the truth if necessary.

Oh, I agree.

The manuals for the Rayteks are good, and all thermometers of this type work in the same basic fashion, so they are definately good reading. Like all instruments, when you know more about how its working, you can better interpret its results.

peace,
sam

kerry · #9 01-05-2006, 04:57 PM

Quote:

Originally Posted by Jarod

i got a craftsman non contact thermometer, it was on sale for $40... but when i got to the store it rang up for $25, and the guy let me have it for that price!! and its really cool, it can be used to see if your tea (yep i've got english blood) is too hot!! or if your ear is running at the correct temp, or if your ear cooler is plugged!!

How can you have English blood if you think tea can be too hot?

Why are you cooling your ears?

whunter · #10 01-05-2006, 05:55 PM

Mine was damaged, now I must buy another unit.

kerry · #11 01-05-2006, 06:01 PM

You can use it to detect an intruder in a darkened room. (I just found my daughter with it)

R Leo · #12 01-05-2006, 06:11 PM

the man with two is never quite sure.

I have a Raytek and I wouldn't trade it for ANYTHING!!! On road trips, it rides in the door pocket. Stop for a break and out it comes, aimed at the tires as I walk around the car and the trailer and, at the trailer hubs too....particularly if it is hot and I'm carrying any sort of a load.

I also have a Craftsman digital VOM that can use type K thermocouples to read temps. There is quite a discrepancy between the three thrmocouples I have and the Raytek. The thermocouples vary between about 3°-5°F and they all read approximately 10°F higher than the Raytek.

I'm inclined to trust the Raytek since it reads 212° just about the time a pot of water boils (we're barely 600ft MSL) and it's low temp in the country readings have corresponded to the reported temps out at the farm.

Eskimo · #13 01-05-2006, 06:20 PM

Quote:

Originally Posted by whunter

Mine was damaged, now I must buy another unit.

Were you using a Raytek ST25? Are you planning on replacing it with an identical (except for being broken) unit, or are you going to try something different?

phidauex · #14 01-05-2006, 06:39 PM

ZyTemp makes a unit (the TN400) with a K-type thermocouple socket, and an emissivity 'learning' feature. You plug in a thermocouple, measure the temperature of the object, then measure it with the infared sensor, and adjust the emissivity until the two temperatures are the same. Cool, huh? Most units are fixed at .95, and even adjustable units usually require that you look up the material on a chart to find its emissivity, instead of directly measuring it.

Fun stuff.

peace,
sam

whunter · #15 01-05-2006, 07:11 PM

Quote:

Originally Posted by eskimo

Were you using a Raytek ST25? Are you planning on replacing it with an identical (except for being broken) unit, or are you going to try something different?

wttool.com

http://tool.wttool.com/search?w=thermometer&x=26&y=12