I posted a few weeks ago about what I felt was higher than normal ECT.

Thinking back I never really towed after I did my delete and in the middle of summer in FL. I went through a divorce 1 month after I deleted March of 2012 and did not pull the boat much to know what is normal ECT and then I got rid of old boat due to divorce.

I replaced the radiator with the mishimoto but did not have time to replace the thermostats I bought from NAPA and hope to do it this weekend. I do not think I have a thermostat problem but figured since I just did radiator might as well. If I should just wait on thermostats then let me know.

Today I towed boat with new radiator. The temp was around 199 and highest was around 204 in traffic. My defueling temp for ECT is at 210. This was in 95 degrees FL weather

Are my ECT numbers sound normal?? Should I raise the ECT defueling temp? The next step is 220 degrees.

Thanks for the help

 

I don't have a tuner or gauges on my truck but my friends that tow heavy set defuel temp to 220. Your ECT seems pretty good to me. What is your oil temp?

 

Your ECT's are plenty fine. Nothing to worry about. My defuel is set at 225. Could be 230 safely...

 

My oil temp runs around 5-6 degrees more than coolant temps

 

That is normal. It will always be a bit higher after fully warm. As long as it doesn't get to be 15-20 or more. That's a problem.

 

I see the problem is solved, but in case anyone else experiences heating on the highway, it always has the same answer - restricted flow. The engine is doing less work around town but needs higher flow through the radiator to handle the higher heat output. Typically it could be a restricted radiator or bad water pump, but there are other causes. I had it on a Mustang once and could not figure out what was happening. It hadn't been long since I had a reverse flush and radiator flow check at the radiator shop as part of regular maintenance - everything was fine. But suddenly, getting on the interstate, the needle would go on up. One day I put (another) new thermostat in it but before actually putting it in, for some reason I stuck my finger down in the thermostat housing and felt something - I got it, pulled it out and was looking at a black rubber washer with a small center hole, just the right size to get sucked up on the back of the thermostat and block flow. The damn thing must have got in there at the radiator shop. That did the trick. Another thing is old hoses have been known to delaminate on the inside and have a 'flap' that would rise on high flow and block flow. Don't forget the lower (suction) hose - they have been known to collapse, even the ones that are supposed to have the 'coiled spring' reinforcement inside. At least this you can see with the naked eye - rev the engine and see if it flattens.

 

First time I'm hearing the term "Defueling Temp". Can someone please elaborate including why a change in its value may be needed?

Thanks for any insight you can lend!

 

If you are towing heavy, it adds a bit of built-in safety. It lowers the risk of blowing a head gasket or other heat/preasure related failures.

In a healthy truck, 230f defuel is fine. If your oil cooler is plugging up, resulting in higher oil temps, you can set your coolant defuel lower as a temporary band-aid to keep oil temps under 250f.

Defueling simply reduces fuel (power) once you hit a set parameter. The engine will generate less heat as a result. Diesels like heat, but too much heat can hurt them.

 

Excellent, thank you for the schooling!!! Thinking it's not adjustable with a Spartain N'Dash anyway but my oil temps are within 15* so unnecessary at this point as well.

 

have you replaced both coolant caps?