Yet More coolant issues! 84' M923

[swbradley1]

Thank U Davis, that is close to right I am sure,
but factory calibrated and certified gauges might work
a little better. It boils down to cost certainly...

I appreciate the input!

Based on Monrovia's elevation of 571' above sea level I doubt you are going to change the boiling point of water much from 100 degrees C (212F) and a couple of degrees on checking the temp of an engine is not going to matter. If it does...you are running a little too close to the edge.

Cube of ice (H2O) and boiling water just like Jeff said.

 

[tbar123]

I did say boiling water! What I should have said was I was boiling water to check the variance between the food thermometer and the temp gun. The water never really got to boil. It was close though! Other than that, I'm not sure what your saying!

 

[swbradley1]

I'm saying Artisan was worried about a lab calibrated thermometer vs boiling water or ice to test it and that isn't a good place to spend his time.

Nothing about what you did.

 

[tbar123]

Does anyone know what a "High temperature Switch" is? I seen it in the manual, but it really didn't state what it did or where it went to. I ask because my truck had one, Someone down the line cut it off. Wondering if I should replace it or not. Thanks for the info.

 

[MtnSnow]

I too found it in the 9-2320-272-34-1 TM with a mention of "high temperature switch" in the "engine replacement" section page #3-46 which is connected to Circuit #35 but I don't see that Circuit # shown in the P2P program. Need to look into the wiring schematics closer I guess.

 

[juanprado]

The early first series had a temp idiot light in the warning light row cluster over the steering wheel. They were discontinued. Later dash lights just had a blank in that hole. I suspect they used the standard temp sensor for the gauge but have not dug into it as mine does not have it. Saw it on some scrappers but did not pay a lot of attention to it.

 

[Csm Davis]

So tbar123 are you saying that your truck is fixed? If so I am glad, also to clarify your gage was misreading the temp?

 

[tbar123]

So tbar123 are you saying that your truck is fixed? If so I am glad, also to clarify your gage was misreading the temp?

That is correct. Big boy is apparently fixed. Everywhere I shot the temp gun showed the engine and all but one hose never got over 180.One heater hose reached 203.At the time the fan activated the temp gauge was reading about 260. I'm still not sure why the system still had pressure in it about 16 hours after testing it.

 

[tbar123]

Well I was feeling good about Bigboy. So I drove him to work this past Friday night and everything seemed good. I drove him for about 20 minutes to work. Parked, Got out and checked for leaks and there was none. Once my handheld computer DL'd about 15 minutes I came back out and rechecked for leaks, none. I then drove around the block to get my paperwork and hooked up to my trailer and drove real slow past and still nothing. I came back to the plant to get my second trailer and I found what is in the first picture.I took a quick pic of the actuator and as you can see something went wrong. I then drove the truck home the same distance and no leaks whatsoever. But I could hear bubbles going into the surge tank. For a very long time. I would say at least 20 minutes.So I let it cool down for 3 hours, and removed the rad cap. A bunch of air rushed out and heard a lot of bubbles coming into the tank. So today, I charged the air system and waited for the sound of bubbles...none. SO then I started the truck and let it run for 20 minutes. I then shut it off and once again listened for bubbles...none. Any advice?

 

[juanprado]

Looks like the middle of the truck so I am guessing water pump? The water pump has a weep hole that bypasses and leaks fluid when the seal and bearings are going bad. Feel under the water pump or down the front housing to see if you can feel the wetness?

 

[Coffey1]

Mine was leaking at the side caps on radiator.
It would leak sometimes the not leak.

 

[Swamp Donkey]

When you rebuilt the shutterstat, did you replace the O-ring behind the jam nut on the stem, and tighten the jam nut real good?

Did you happen to notice which pressure gauge was dropping when the bubbles were in the coolant? Only the secondary drops when there is a leak in the shutterstat.

System air pressure in the coolant can cause leaks from strange places. I'd verify the shutterstat wasn't leaking first. It's the easier of the two to check. I think you know what the other possibility is...

 

[tbar123]

Thanks Gents. I'm not sure why I didn't say this earlier, but if you look at the picture of the actuator you can see a tiny drop of coolant coming out of the pin hole. I also noticed that when the truck was cooling down, coolant would blow out of that hole with air! It also appeared that coolant was leaking out of the fan clutch. So i'm sure that's my problem, but just thought it to be weird that it would leak while cooling down ,not when it was at full temp. I think I'm just gonna try and eliminate the actuator all together. I have an idea ,but not sure if I can bring it into fruition.

 

[tbar123]

Well this is what I came up with. I'm pretty sure it's a long term "cheap" solution. I have a total of $9 bucks in it right now, but that will go over $40 when I buy the replacement solenoid for the air horn. I also would like to get a back up in case this one fails. I just couldn't help my self showing off my work foot! LOL. Of course this is just a trial set up and have to make a bracket,hard wire, drill hole in the dash and mount everything, but since it's hotter than the devils breath out there right now this is all I could muster for the day. Please give me your absolute honest opinion on this solution/conversion! Thanks in advance. http://youtu.be/3l3mc20sWGA

 

[jonesal]

I'd be a bit careful. Last time I researched air horn solenoids, they are not continuous duty. So for the short term, I think you're ok. For the long term, carry a spare in case the coil fries.

Al Jones
84 M923

 

[MtnSnow]

Just run the air supply hose up to a valve inside the cab and then run the output line to the fan clutch. No need for an electrical item and a mechanical 1/4 turn ball valve is going to last the lifetime of that truck!

 

[Coffey1]

The air horn solenoid will work.
Because it won't be on all the time.
Mine barely comes on at all then on for a very short period if time.