| Author | Message | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 149 Registered: 12-2009 Posted From: 69.152.168.208 Rating: N/A |
I have an '81 MC 9 w/ DD 6V92T. Standing behind the bus looking at the engine, there are two identical looking sensors threaded into the back of the passenger side head. They look like short spark plugs with threaded post on the top. I guess them to be water temp sensors or something similar. However, the outer most sensor is disconnected while the inner most sensor is connected. There is a spare wire and connector cable tied to the head. I do not find a wiring diagram for the engine in my MC 9 manual. My question, what is the extra sensor for? I'd like to understand what it's for so to determine if I should undertake to reconnect it. The other side (driver) has only one sensor on the back of the head. Thanks in advance | ||
| Van (Van)
Registered Member Username: Van Post Number: 138 Registered: 7-2008 Posted From: 68.108.81.25  Rating: N/A |
Our 692 has 2 water temp senders, 1 for the gauge on dash, the other for an engine bay temp gauge and the 3rd conection for the Alarm-stat. | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 150 Registered: 12-2009 Posted From: 69.152.168.208 Rating: N/A |
That makes sense as I see 3 sensors. Do you have any idea which is which? Or is it just a matter of tracing the wires? | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 1207 Registered: 8-2006 Posted From: 99.146.10.201 Rating: N/A |
Jim, A question which might help with an answer, does your temperature gauge work properly now? Secondly, has the engine ever gotten hot enough to cause an alarm? I think the gauge may average both head temps to protect against one stuck thermostat, but mine has one sensor for the gauge, and another which is actually just a switch to sound the hot engine alarm. G | ||
| Derrick Thomas (Thomasinnv)
Registered Member Username: Thomasinnv Post Number: 13 Registered: 10-2010 Posted From: 67.142.130.37 Rating: N/A |
my guess is that if the gauge is working then someone has disconnected the alarm-stat. they can fail and shut you down below operating temp. had one do that to me. | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 151 Registered: 12-2009 Posted From: 69.152.168.208 Rating: N/A |
Hi, The temp guage seems to work fine. I have never seen the engine temp even as high as 200 in the middle of summer running 70 mph across kansas on a 95+ degree day. I haven't ever heard any alarms for hot engine conditions. So I don't know if I have an alarm for overheat. There is certainly a tell-tale, but I have never seen that light up either. The temp guage may be averaging the temps of both heads, but how would I confirm this? How best to test the disconnected sensor to determine its function and health? Thank You! | ||
| Derrick Thomas (Thomasinnv)
Registered Member Username: Thomasinnv Post Number: 15 Registered: 10-2010 Posted From: 67.142.130.22 Rating: N/A |
How best to test the disconnected sensor to determine its function and health? Hook it up and see what it does, seriously. that's how i found a bad alarm stat on my 8v71. the wire was disconnected so i hooked it up and when it got to around 140 deg the alarm sounded and shut down the engine. I ordered another stat from Caylor Supply and all works as it should now. If yours is the alarm stat that is disconnected I would make it a point to get it working right. may save you an engine some day. BTW, on my 8v there is 1 alarm stat on the left bank and one on the right bank. there is an electronic temp sensor and a mechanical temp sensor on the right bank as well. the only temp sensors for the gauge are on the right side, no averaging between sides. (Message edited by thomasinnv on March 28, 2011) |