danalex

Not sure what's going on (maybe nothing). I have a Quadzilla Commander guage. A few wks ago I replaced my 190-degree thermostat with a 180-degree. It was probably the original (85K miles). The first week or so, the 180-degree performed very well, with both the dash-guage and Commander reading in the 180-range. RECENTLY. I set a "warning" setting on the Commander to alert me if the coolant temp rises to 220-degrees. HERE'S WHAT HAPPENS: When I'm driving steady speed, the temp still reads in the 180-range. But if I'm on the highway and slow to exit, or if I'm in a neighborhood and slow to a stop sign/intersection, the Commander shows the coolant temp spike to trigger the 220-degrees alert. The dash temp guage stays pretty steady and does not rise beyond the straight-up 190 mark; actually the needle stays below the 190-mark. As I begin to then move forward, the temp will settle back down to the 180-range. It almost seems as if "gravity" is causing hot water to slosh forward to the temp sensor resulting in a temporary (minute at most) spike in temperature. Does this make sense? What about the waterpump? Does it stop or slow the movement of water if I slow down? The coolant itself is relatively new (changed it about 60-80 days ago). Could the coolant/water mix be unproportional? I replaced the gator-belt several months ago--just taking shots at this. Any ideas?

sheriffav8r

I would bet it's a ground problem.... Also check the small wire from the coolant connection back. It runs very close to the block and piping and may have frayed or have an open contact. I have the standard 190 degree and have never been able to get the needle over 200. Why'd you go with a 180? I though our trucks generally run cold, anyway....

John Faughn

Does that Quad use a separate sensor ?
Stick with the stock temp rating , diesel work more efficiently at higher temps [ 190 *F ] .
May need to do some electrical diagnosis on the Quad's wiring .

kawi600

I notice with the 190 degree thermostat I get spikes where it climbs up above 190 and dips back considerably over time. Its just the valve setting and resetting.
For running veggie oil conversions or just for plain fuel efficiency a hot motor is usually better.

Fishin2Deep4U

How did you put the gauge in the water jacket? The instructions tell you to put in the oil port. I just wanted to be sure we are talking the same thing.

If the sender is not covered in fluid, it can have wild readings.

Dave

danalex

AV8R, I'll check the wiring (ground)--that sounds like a possibility.
JOHN, The Quad uses a wire tap; into the stock temp sensor...if I don't have a ground/wire issue, I may replace the sensor. ...agree the 180 may not be mechanically logical though...just considering the climate here in South Texas.
FISHIN: Not same. The Quad's sensor reading comes from tapping the wire of the stock sensor...now the transmission temp sensor does touch the fluid (screws into the port), but not the water coolant sensor.
Thanks yall!

chainzaw

Try cutting off that little spade lug and crimping on a new one that fits into the wire tap. I was having erratic readings on my quad gauge and not my stock gauge. I found most of the wire strands on mine had broke off and was getting a bad connection. I crimped on a new one and that took carer of the problem for me. I don't think there's a problem with your temp sensor or t stat. I also run the 180 t stat and i see no difference with engine performace. I've read that the 180 is a cummins thing and the 190 is a dodge thing to help the engine reach operating temp quicker.
Does that help?

danalex

CHAINZAW: Thanks--good idea; will try it...I think I still have a packet of the wiretap crimps...somewhere.

John Faughn

From what I can gather , in the Cummins / dodge comparison , is that in most of the dodge applications [ especially the early models ] that dodge has detuned the engine [ making less heat ] so the need to go to 190 , where Cummins in the same yr. but in a truck it was designed for , runs 180 .
As an example , my truck , 94 auto=[ weak link ] 160 HP , most any box truck or standard application , 275 HP .
Since this thread started , I found that my truck was not making heat [ after I pulled cardboard out from in front of rad. , weather warmed up ] so I had a new thermostat , from Cummins last summer , on the truck , put in , and now instead of going just below half way on gauge , it tops out just above 1/4 , but only when steady driving , if I stop with traffic , the gauge goes to just above the 1st mark , and that's after putting the cardboard back in .
When the old thermostat was working , it was steady at just below 1/2 .

danalex

And the winners are: The "Harrier" guy & CHAINZAW! Checked the wire/pin connection at the sensor and it was a little loose. Also the protective sleeve (coil plastic around the wire) had slipped a bit and so the tiny wire was also probably getting a lot of direct heat. I added some protection to the tiny wire (some of that "accordian" tubing and electrical tape) so that it doesn't get rubbed on the engine block or something else really hot. Slid the connector back in snug and took it for a test drive--nice and steady around the 180 mark (+-a few degrees)--works great. Thanks yall!