Heat Gauge

[Tomah]

I live in the State of Maine so have a few cold days, I bought a new RTV 900 with cab and heater, great machine, love it.
I have a small problem.
When I first used it the heat cauge never moved, I took it out on a few short trips of about five miles and there was no reading, I thought it was the sending unit on the engine so called the dealer and he sent a new one, came to-day ( I have not put it in yet) and now do not think it is the sending unit.
Yesterday I decided to take a long ride of about 50 miles see that I had enought hours on it for the break in. I noticed that when I would make the engine work a little harder going up hill on an unplowed road with about 5 inches of snow in it, and temp of 15 above, the gauge would go up to what would be about normal. the min I would reach the top and going was easier the gauge would drop back down in the black with no reading. The engine gauge does not have a reading when the engine is idling or working easy the gauge never moves.
I have a feeling that this diesel should have an operating temp, and engine should heat up until the thermostat opens even when the engine idles.
The question is, has anyone noticed that the gauge comes up to normal when they start their machine and let it idle for a warm up before driving it.
One of the hardest things on a diesel is running cold, and this is a sweetheart of a machine and do not want to have anything happen to it.
I am leaning to no thermostat in engine or it is stuck open.
125 Miles from dealer.

 

[Dargo]

I've heard that before on the RTV. I've battled it for 8 years with my Cummins Diesel Dodge 1 ton 4X4 now. On my pickup, I can take the fan off, and cover the entire radiator with cardboard, and if I get on the highway, the gauge buries itself at cold and I have no heat! I've changed several thermostats and have found on the Dodge Diesel web sites that my problem is common with the 12 valve Cummins engine. It sounds like the Kubota RTV engine may be similar. Maybe we shouldn't complain; I've several friends with the 12 valve Cummins with well over 500,000 miles on them without a single problem! /forums/images/graemlins/cool.gif

Actually, during hot days this last summer (temps in the mid 90's), the temp gauge on the RTV went to the middle of the normal range and I heard the electric fan kick on. Since it has been cold, I haven't heard the fan ever kick on.

 

[bczoom]

Tomah,

Welcome to TBN.
What you're seeing/experiencing with the RTV temp is pretty normal. Unless working the machine hard, I rarily get a temp reading.

Here's what I got from the dealer (I believe it's from Kubota to dealers).

"Since its been getting cold outside we have been getting calls about the temperature gauge not working. The RTV has a large metal transmission and a heavy cooling system in the hydraulic loop. This holds the temperature of the engine and tranny down for a rather long time. Expect at least 20 minutes of run time before seeing any movement of the needle (170 degrees)."

I thought it was already posted out here but can't find it.
Attached is a document outlining the steps to test the cooling system. I too was getting no reading and the fan wasn't kicking on so I went through these steps and all checked out fine.

I think with the temp gauge starting at 170 degrees, you have to work it pretty hard to get it to that temp or higher.

 

[Tomah]

Thanks for the reply on the gauge problem both of you guys.

I guess what you are saying is Kubota puts in a thermostat that opens lower than 170 degrees which is when the gauge starts to read.
The thermonstat should not open until the engine temp. reaches what ever is in there for a thermostat, so if it working right it has to be lower ten 170 degrees.
The capacity of the radiator and transmission should not effect the engine until the thermostat opens and lets colder water in.
The other thing that I can not understand is that I get some heat out of the heater without any reading on the gauge and the heater hoses are on the open side of the thermostat, so that may be the problem that the thermostat opens before the gauge starts to read.
I will install a direct reading gauge on the engine that starts at zero to 200 degrees and see what the engine runs at under normal operation and when the thermostat opens.

On the 12 cyl. Cummings that will not heat up, I am not sure that you have one or not, but make sure no one installed a block heater on it and connected one end of the hose on the block and the other end beyond the thermonstat housing or into one of the heater hoses, that way the hot water circulates through the radiator and can not stay in the block and get the water hot enough to give you heat, and give you a reading on the gauge. The engine will not heat up because it is circulating the water through the radiator all the time. it is like not haveing a thermonstat in the engine. I have seen this happen three times two Detroits, and one Cat.

Thanks again for all the help.

 

[bczoom]

I hadn't dug to much into the cooling how and why but if you do some testing, let us know your results.

 

[flyingn]

I had mine out the other day in 36 F degree temps. Running it for an hour at a normal laod. No wide open or much hill climbing I found the gauge reading about 1/3 way up most of the time.. If i went wot or climbed a long hill it went up to a little below 1/2.. Then back down to 1/3..

Frank

 

[flyingn]

was outh this moring in the 8 degree F temp and the temp gauge went up to 1/4. could not get it any hotter.. Heat worked great. I found the temp stayed higher if I droove in low gear and kept the rpm higher..

Frank