June 24, 2018, 11:49:48 AM

Author Topic: MC8 Temp Guage or Sending Unit  (Read 1919 times)

Offline Melbo

  • Hero Member
  • *****
  • Posts: 1203
  • MC8 under construction
MC8 Temp Guage or Sending Unit
« on: May 28, 2006, 10:32:02 AM »
I have an MC8 manufactured in Dec of 77. It is a 78 model. It has an 8V71 and standard transmission. When I bought the coach I took it to Stewart and Stevenson for a complete service and asked them to tell me anything that they thought should be done ie air leaks fuel system etc. One thing they found was that the radiators were in need of attention. I took them out and took them to Commercial Radiator where I was told that they needed to be recored. I had them recored and replaced all the rubber seals around them. I also replaced the air divirters at the squirrel cage fans and the rubber seal where the belt passes through from the engine to the radiator comparment. When I replaced the radiators I completely drained the system and replaced the antifreeze with the expensive Detroit Diesel premixed stuff so I didn't have to worry about it later.  I have only driven the coach 20 or 30 miles at a time and every time I take it out the temp guage goes up to about 210 or a little more. This was a cause for major concern because I did not want to have to replace the motor from overheating. Finally I bought an infrared non contact thermometer. I operated the coach til the temp guage came up to the normal 210 or so and then I parked and went to the engine compartment and checked multiple locations on the motor. Intake at each cylinder and the exhaust manifold at each cylinder the side of the block the radiators the hoses to and from the engine. Pretty much had a ball with the new toy and the bus. Nowhere in the engine compartment could I find a temp over 190 degrees. I am not a diesel mechanic so I am not sure what the temps should be but from this experience I am guessing that either my temp guage is bad or the sending unit is bad. There is a mechanical guage in the engine compartment but it is not connected to anything the bulb end of the guage is just hanging there and I could not locate the place to hook it up. As I am starting to get things ready to work on and upgrade the dash I thought if the guage was bad this would be a good time to replace it. Any thoughts would be greatly appreciated.

If it won't go FORCE it ---- if it breaks it needed to be replaced anyway
Albuquerque, NM   MC8 L10 Cummins ZF

Offline ChuckMC8

  • Sr. Member
  • ****
  • Posts: 288
  • 1977 MC8 and 1993 102C3 Temple Ga #322 F&AM
Re: MC8 Temp Guage or Sending Unit
« Reply #1 on: May 28, 2006, 11:56:36 AM »
Melbo, I can send you a photo if you'll email me. Click on my name for addy. The photo will not load here, I get an error message that the pics too large-
Far better is it to dare mighty things,to win glorious triumphs,even though they may be checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much,because they live in the gray twilight that knows neither victory nor defeat.  Theodore Roosevelt (1858-1919)

Offline FloridaCliff

  • Hero Member
  • *****
  • Posts: 2459
  • "The Mighty GMC"
Re: MC8 Temp Guage or Sending Unit
« Reply #2 on: May 28, 2006, 01:58:01 PM »

Go to the Board Help board and their is a topic about resizing photo's.

Has a link to a free resizing tool


1975 GMC  P8M4905A-1160    North Central Florida

"There are basically two types of people. People who accomplish things, and people who claim to have accomplished things. The first group is less crowded."
Mark Twain