Official Caterpillar3116/3126 Thread

CAT 3126 Thermostat Temp and part numbers. Not a question here just sharing what I learned. Over the winter I had the 23 year service done and cleaned the heat exchangers, after coolers, replaced hoses, belts everything that could possibly need attention. I even painted the engine room, changed the septic hoses and replaced water heater. The thermostats were replace with OEM CAT parts the prior # for 180 degree thermostat. (I do not have the number the Diesel mechanic did this work) I used to run a solid 180-185 degrees with one creeping higher due to aftercooler or head exchanged blockage. They are now running a steady 195-200. As it turns out, CAT decided that these engines should run a bit hotter in order to get cleaner combustion and better fuel burn. They kept the old part number but now its a 200 degree thermostat instead of 180. I am OK with the higher temps because the diesel mechanic says its ok and If CAT says its better than running cooler, who am I to argue. So its possible someone can be chasing a temp issue, replace a thermostat and still see higher temps. Maybe this post can help someone out down the line
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I also put in a new thermostat in 2019, and I run right at 200* on my dash ga, but my understanding was there are 2 part#s, a 185* and a 195*.

I was hoping to go back to the 185 for no other reason than to give myself more headroom to quickly shut down in the case of a cooling system issue.

However I don't think it really matters as my engine have a rock steady temp running on plane and any deviation to the hotter side is my indication to pull back/shut down.
 
I have the 190’s on my bench at home as well, need to put them in. I don’t mind a cleaner burn and being in freshwater the cooling system stays fairly pristine so buildup and blockages are minor.

I’m just putting off the job. a friend of mine cracked the housing tightening it down and had to weld it since cat wants $2500 for that tiny part. Be careful on reinstall to not break anything
 
Been running the higher temp thermostats here in SW Florida for a year now with rock solid results.

BEST !

RWS
 
Pull the dip stick and have a blue paper towel in the other hand. Place the end of the dip stick on the paper towel and kind of roll it out of the way without moving it up/down or left/right. You can see the level on the paper towel. Ask me how I know...

Bennett
A flashlight helps as well, or one of those head mounted LED lamps.
 
I have the newer thermostats on my boat and have never installed them for the same reasons others haven't installed them. 200 in my opinion is getting real close to the alarm temperature, which I think is what 210?
 
I have the newer thermostats on my boat and have never installed them for the same reasons others haven't installed them. 200 in my opinion is getting real close to the alarm temperature, which I think is what 210?
Plus youre going to loose a good amount of coolant at the top of the engine and make a mess.
 
I have the newer thermostats on my boat and have never installed them for the same reasons others haven't installed them. 200 in my opinion is getting real close to the alarm temperature, which I think is what 210?
The new temp is 195 and it took me a little getting used to seeing that while running the boat, it was a double take, WTF, and oh ya that's right...
 
Plus youre going to loose a good amount of coolant at the top of the engine and make a mess.
Yep this is exactly another reason why we didn't replace them last year when we were doing maintenance. My girlfriend's brother-in-law, the Caterpillar diesel mechanic, said wait until you change out the antifreeze.
 
Bringing the ENTIRE cooling system back to snuff and then continuing to PROPERLY maintain it is the prerequisite to a successful change out.

BEST !

RWS
 
I just attempted to adjust my idle. The crew in the side of the governor will not move in or out. Am I missing something?
 
I just attempted to adjust my idle. The crew in the side of the governor will not move in or out. Am I missing something?

Do you have a picture of what your attempting? If you feelin' crazy, some video of what your doing would the GREAT!! I need to adjust mine...looking to follow a pathfinder!!
 
the screw head is smaller and set deeper than you think, it looks like the blade is binding in the hole. Try a smaller screwdriver, it takes very little effort to move.
Thank you. Will try. On another note. This engine idles at 740 ish. When push in fwd or reverse it slows down about 100 to 150 RPMs (to 600 give or take). Then comes back up in neutral.
Any ideas
 

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