Coolent

[CSavolainen]

Why does the coolant temp. rise to 180 degrees and then drop to 150 over and over again in my 1995 ram 2500?

 

[NIsaacs]

Some aftermarket do that. I recommend genuine Cummins.

https://cumminscss.my.salesforce.com/a2w4N000003sErAQAU

 

[Chief USA]

I rolled the dice and tried a Stant on my 5.9 and it works great. Pretty much keeps the temp pegged at 190. The Gates thermostat that got mistakenly installed in the wife's truck is junk. It fluctuates all over the place.

 

[GAmes]

https://www.cumminsforum.com/threads/low-or-fluctuating-coolant-temperature.449279/

 

[BigPapa]

It’s normal. Don’t worry about it. My ‘95 was doing it when I sold it in February with more than 500K miles on it. Never had anything but a genuine Cummins thermostat in it.

 

[GAmes]

I look for it. The fluctuating lets me know everything is working as it should. Nothing but genuine Cummins t-stats in my engine.

 

[CSavolainen]

Thanks all for the responses. A little history on the truck. I bought it from an estate sail in 2009 with 85417 miles on it. The previous owner filled the tank and went to his deer hunting camp. When he left for home, it was hard to start, white smoke, ran rough. He parked it in his garage in November and dies of pneumonia in December. His sister said a diesel man said the injector pump was bad and would cost $2000 for a new one. She said $3000 and I bought it. A place online told me the injector pump in the truck was built like a tank and it was maybe an overflow valve. I ordered the valve, but before it came, I taped the fuel line water filter I smelled gasoline. Removed 30 gallons of fuel, put new diesel in it and it ran perfect. I put a Boss snowplow put on it which cost more than the truck. Replaced one front hub, water pump, thermostat, and there is now 90182 miles on it.

I put a stick into the AC condenser while plowing, any tips on replacing it?

 

[GAmes]

Condensors are less than $100 on line. It is easy to access. I prefer to pay an expert to work on my AC but there are plenty of books and videos to D.I.Y. Don't forget to replace the dryer at the same time. Another $30 or so.

 

[Timd32]

Looks like if you DIY this with zero tools it would be about $500, but its a process, so for me @ say a shop said $800 I would farm it out. If a shop says $2k, get the quote in writing and see why, then price check that stuff on the internet and see what's up. But get a two or three prices if able too if it comes in super high.

Sounds like a super truck, you have not even put 5k on it!

How's the body panels floors and the sort?

I've only put a few miles on my 96 since I got it in 2015 but have double what you have, we used it on the farm for Hay but we only do like 3000 bales a year and 2 cuttings and I used it for some volunteer projects with Habitat. But man it can handle a pallet of cement bags. Have a plow but never used it to plow, that's an garage art piece in the back of the shop. Heck the entire truck is Garage Art at this point.

 

[CSavolainen]

Due to the Michigan salt marinading of the roads here, the edges of the fenders have issues. The rusting was from travel by the previous owner. The rusting has somewhat been arrested. No salt on the road we live on, and never get farther than .75 miles from home. I bring fuel with another vehicle.

I am also working on my 2001 Ram 3500 which has much more salt damage.

 

[petersonj]

I put a stick into the AC condenser while plowing, any tips on replacing it?

Since nobody really answered your question, I will. Just get another stick that looks like the one you removed.

- John

 

[Chief USA]

I look for it. The fluctuating lets me know everything is working as it should. Nothing but genuine Cummins t-stats in my engine.

I used to think the same thing too. To a degree, as mentioned above, those factors can and will affect engine coolant temperature. The thermostats are designed to fail in the open position, thus allowing coolant to circulate continuously, noted by very long times to warm up and almost never reaching full design operation temperature. In the event of a thermostat failure such as this, replacing the thermostat will address the problem. This was what happened on my truck and the wife's truck. Even with a new thermostat operating properly, extended idling, static speed driving with little to no load on the engine, and operation in very cold temperatures result in full operating temperatures not being maintain, reached, and/or fluctuation. So, to some degree, this IS normal, HOWEVER, under most normal operation conditions it is NOT. If your engine is not or never reaches full operation temperature under just about all conditions and temperature fluctuates significantly during normal conditions, the thermostat is a very likely culprit. In cold climates, many remove the radiator fan altogether or block off airflow from the grill. I close off the 4 openings in the grill with plastic inserts that I purchased many years ago from a TDR member who sells them on the forum. The lower opening through the bumper allow more than enough cooling air and in many case still too much. Reaching full operating temperature is essential for proper engine operation, longevity, lube oil life, and best efficient operating conditions. Do what you need to do to make your Cummins engine operate properly.

 

[GAmes]

Sorry Chief, I totally disagree. This t-stat isn't my first rodeo and the engine isn't the first one in the truck. Every t-stat and every engine has operated the same. I've operated in sub zero temps in northern Alberta in the winter and have never felt the need to block my radiator to get sufficient heat in the cab. A healthy cooling system, a working t-stat and a good heater core is all you need.

 

[CSavolainen]

I plowed about 8" of snow in 2 places yesterday, outside temp. was 18 degrees, cab was nice and warm. Will plow tomorrow, low overnight will be 11. I will plug it in for an hour or two first.

 

[Chief USA]

Sorry Chief, I totally disagree. This t-stat isn't my first rodeo and the engine isn't the first one in the truck. Every t-stat and every engine has operated the same. I've operated in sub zero temps in northern Alberta in the winter and have never felt the need to block my radiator to get sufficient heat in the cab. A healthy cooling system, a working t-stat and a good heater core is all you need.

You just made my point for me. Thank you!

A healthy cooling system, a working t-stat and a good heater core is all you need.

With the exception of extreme/abnormal operation conditions. You're are not debating the point with me but with Cummins. I go by what the manufacturer/designer calls for. As I said above do what you need to do to make your Cummins operation properly. This implies following the FSM and Cummins recommendations.

https://turbodiesel.cumminsnewsletters.com/2014/12/fact-or-fiction-low-coolant-temperature/

 

[GAmes]

You just made my point for me.

I'm confused. I thought your point was the fluctuation on the gauge is a sign the t-stat isn't working, or something to that affect. To wit;
" So, to some degree, this IS normal, HOWEVER, under most normal operation conditions it is NOT. " The OP stated his gauge flucutates from 150 to 180. Since a 12 valve Cummins t-stat is a 180 degree t-stat, it is normal operation. I'm not sure how a t-stat would be designed to fail in the open position either, since it is spring loaded closed.

 

[BigPapa]

The “Swing” is normal for the 1994-1998 B5.9 that the OP, Gary, and myself have. Your 1998.5-2002 ISB5.9 doesn’t “Swing” like the B. They use different thermostats.

While there are thermostats that are designed to lock open, such as MotoRad’s Fail-Safe thermostats, the normal state of regular thermostats is closed. They only open when the coolant temp on the engine side reaches the temperature it’s designed to open at. This is from the Cummins manual for the 1994-1998 B5.9.

 

[CSavolainen]

I plowed about 6" of climate change from the 2 places I plow. After the previous plowing, the coolant dropped from top line to bottom line. I filled to the top line today and after plowing and cool down it stayed at the top line. Could there have been an air pocket someplace? After thermostat change and refilling, I had to fill several times.

After the stick incident couldn't find a stick big enough to fill the hole. hi hi

 

[GAmes]

It is spelled out in the factory service manual. 12 valves have a jiggle valve that vents air out of the system when the engine is shut down. Sometimes it takes several iterations. I highly recommend you get one.

 

[BigPapa]

Anytime I opened the cooling system to replace a hose, water pump, thermostat, etc., I’d keep an eye on the coolant level for a week or two and would eventually add around a half gallon before it settled.