Temp gauge

[Daleb]

Is this the normal spot for the temp gauge to run or should I try replacing the thermostat?

[dave110]

No that's not normal. Just kidding. I never realized there were celcius temp. gauges. Mine runs at 190-195 F. on a 190 degree F. t-stat. When you buy a t-stat up there do they come in celcius? Just curious.

It does appear to be a little cool according to the normal range on the gauge.

Edited May 1, 2019 by dave110

[Bullet]

A stuck open thermostat will cause it to run too cold and take forever to warm up.  Looks like you might have one. 

[015point9]

Watch the torque on the bolts when you put them back in.  over the years I broke two of them

[Daleb]

1 hour ago, dave110 said:

When you buy a t-stat up there do they come in celcius? Just curious.

R no they come in F. Thanks for all the reply’s I will get a thermostat and see if it makes a difference. 

Dale

[Mopar1973Man]

Optimal is 190 to 200 degrees. Below 190 you start losing efficiency.

[98whitelightnin]

Your KPL must be horrible! had a problem like yours years ago and my mpg went up over 3 mpg when I got it back up to operating temp

[Mopar1973Man]

Optimal temperatures...

 

Coolant temperature: 190°F to 200°F

Intake Air Temperature: 100°F to 140°F

Fuel Temperature: 100°F to 140°F

 

Coolant temperature needs to be as high as possible to keep thermal efficiency as high as possible. When coolant temperature is too low the burning fuel will lose energy to the cold coolant jacket. Even 200°F thermostat is better than 190°F if you can get one from a 6.7L. Heat is naturally heading towards the coolant jacket cooling the flame front out and reducing the amount of work. 

Intake Air Temperature needs to be above at least 80°F. Below this ECM kicks up an extra 4° of timing advancement which typically you lose efficiency hence where the MPG fooler came from. Optimal temperature range for MPG is 100 to 140°F. Warmer air vaporizes fuel easier and ignites quickly. Cold air kills MPG numbers. Racing is a different story where you need cold air to control EGT's but with MPG game you need hot air to get the fuel to burn completely.

Fuel Temperature is a tight balance being the fuel cools the VP44. Typically the IAT and Fuel Temp follows nearly exactly the same temperatures. Warmer fuel vaporizes easier and ignites quicker. In all the time I've ran the Quadzilla I've never seen the fuel temp over 140°F yet. Above 150°F you start leaning on creating Asphaltenes. Getting closer to the flash point of the fuel makes it burn better.

 

Like on my morning startup I'm still in the 20s and 30s. I lose quite a bit of MPG number till the IAT and Fuel Temp rises. Now on my return trip home my temperatures are much better and Engine Load is much lower and EGT's are nearly rock bottom. At 55 MPH I've seen as low as 400°F to 450°F with cruise control set on flat ground and engine load float about 16%. 

Edited May 2, 2019 by Mopar1973Man

[kzimmer]

13 hours ago, dave110 said:

I never realized there were celcius temp. gauges.

 

Just about every country in the world, other than the good old USA, haha.

[Daleb]

I will get a 190 installed this weekend and see if that brings the gauge up. The gauge might be off also I have heard some aren’t real accurate. I should plug my edge in and see what in getting at the diagnosit plug. 

Dale

[Mopar1973Man]

Actual the coolant gauge is typical right on the money.

 

Volt gauge drop to 8V at 11.9V.

Oil pressure gauge can go up or down vs coolant temp.

[Dieselfuture]

You can maybe use IR temp gun on the thermostat housing

[Mopar1973Man]

Just now, Dieselfuture said:

You can maybe use IR temp gun on the thermostat housing

Actually point it the brass side of the temp sensor. Thermostat housing will most likely show cooler. It the temperature on the other side of the thermostat that counts.