| Author |
Message |
David Anderson (66.90.194.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 8:50 pm: | |
I drove the bus today and got it up to temperature to check the accuracy of my water temp gauge. My gauge on the dash and in the engine compartment never go above 160. I used a laser thermometer and pointed it at the head where the temp probes are screwed in and it shows 180. So, I don't know what to do. Add 20 degrees to my gauges or replace both.
At what temperature does a thermostat open on a DD6V92 Silver engine? 180 seems a bit low to me.
David Anderson |
Ear-8-Ky (209.250.62.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 8:56 pm: | |
David the thermostat will open at the temp that it is desigened for. 180 is ok. I run 170 degree themostats in my MC8. |
David Anderson (66.90.194.18)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 9:00 pm: | |
Forgot to mention. The laser thermometer showed the water temp on the inlet side of the water pump, after exiting the radiator, to be 120 degrees. That is a 60 degree differential. |
Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 9:00 pm: | |
David, The first thing you need to do is to get a calibrated thermometer that you trust, and go from there checking it against your IR thermometer and your gauges. Boil some water and see what the IR says, it should be 212f, making any corrections necessary for barometric pressure
(see http://www.biggreenegg.com/boilingPoint.htm )
... to me it sounds like you just have 1, 2, or 3 measurement devices of which none have known calibration.
It's also very possible that "some" outside metal parts of the engine including your head could be hotter than the water inside. A better place to measure would be the pipe coming out of your engine on it's way to the radiator...
Laser thermometers are neat toys and can be very useful, but they're not the most accurate items when trying to measure something that's hiding behind a quarter inch of metal. I'd check the gauges first against a pot of hot water and a good calibrated thermometer, and then you know....
Cheers
Gary |
Jack Conrad (Jackconrad) (204.193.117.66)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 9:15 pm: | |
The IR/laser thermometers measure the temp. of the surface that the "dot" is contacting, not any deeper. Also these have an "aspect ratio". My $89.95 gun has an aspect ration of 6:1. At 6" from surface it is measuring the temp of a 1" diameter circle, at 12" it is measuring a 2" circle, etc. If you are holding the gun 2 foot from surfce it is measuring and averaging the temp of a 4" area. This can give a false reading. I measure temp of the sending unit body near the threads which screw into the engine, holding the gun about 2-3" from the surface. My IR/Laser and engine compartment mechanical gauge are within about 2-3 degrees, electric gauge in dash reads about 7-10 degrees hotter, probably due to resistance in roughly 40' of wire from sender to gauge. YMMV Jack |
augerdogger (192.100.51.131)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 9:28 pm: | |
Water boils at 212F only at ses level. You most correct for elevation. The higher the elevation the lower the boiling point. Water boils at 180F at the elevation I live, around 7000 ft. |
David Anderson (66.90.196.163)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, December 11, 2002 - 9:47 pm: | |
I just checked the laser thermometer on a pot of boiling water. Barometric pressure =30.04 Calculator says water boils at 212.11 degrees. Laser thermometer showed 211 degrees. one degree off. So I guess it works ok.
Tomorrow I will pull off the t-stat in the engine compartment and put the probe in a boiling pot of water to see where it's at.
I'll let you know what I find.
David Anderson |