My secondary cooling system had to be topped up twice now in the last month. 600ml first time and 350ml second time. Had couple trips hauling my rv through the mountains here. It's been warm to hot. I've done this trip in the past with no loss of coolant that I remember. Engine runs fine. I watch my gauges religiously, nothing seems out of the ordinary other than I thought my trans temps are running slightly higher than what I'm used too. Maybe 10-15 degrees. I know it's the secondary running through the trans cooler, if that even means anything. Anyone have any experience with coolant loss or evaporation in the secondary system? Thanks.

 

No, my 2013 secondary would run 115 to 130F. What were the tranny temps?

 

If you are not seeing any coolant leaks or drips, you might be burning the coolant. The secondary system does flow through the inner cooler or the egr...

 

Sounds like a bad egr cooler. Pull the cold pipe and inspect it. See if there is any soot build up inside the pipe and intake housing.

 

Well, I am deleted, but only plated off. Don't know if this makes any difference.

The trans temps in the past have always been 10-30 degrees cooler than the oil and coolant temps, which have been within 10-15 degrees difference of each other, depending on my driving. Now they're almost always the same. And the tranny seems to heat up quicker now.

 

perhaps the oil cooler should be looked at.

 

I just had this same issue with my truck, and my temps would run 230 in the city on some days, and I knew that couldn't be right; I took it to the shop, and I was told my intercooler needed to be replaced. I asked if it could've been the thermostats and was told no, it was the intercooler; fast forward a year later, and I'm still having temperature issues. I took it back in because I was getting a code about my intercooler, they looked it over and determined that indeed my intercooler went bad again, but it was covered under warranty. So now the shop has lost money and needed to figure out what's causing the problem, as it turns out my thermostats in the secondary coolant system one was working, and the other wasn't.

Problem Solved! Now my trans temp never goes above 203 degrees.

I remember when I was young working with my dad on our trucks whenever a water pump was leaking or needed to be replaced, he always told me to change the thermostats. Since you already had the fluid drained and are in the engine, it's cheap insurance so that you don't have to crawl back into the engine.

Have a shop look at your intercooler and thermostats that's the issue.

 

That's interesting. I will definitely research that. Thanks.
You mean 'oil cooler' or trans cooler?

 

Two different animals. Oil cooler bolts to the side of the upper oil pan.

Also, oil cooler uses the primary cooling system, not the secondary system.

 

I agree with you guys on the engine oil being cooled by the primary system. I'm not sure that I follow you on your statements of having the oil cooler looked at? It's the secondary system that I'm losing coolant. My engine temps are ok. My tranny temps seem to be catching up to oil temps lately. My tranny temps have always been cooler that I remember.

 

Since you do not have the EGR any more, I would suggest having the CAC tested for leaks. They are known to leak at times.

 

Well, I'll definitely consider this Larry. Just need to make the time for it now, Thanks.

 

Sorry for the late response, yes it was my Charge Air Cooler that was going bad but I believe it was the thermostats going bad that caused the CAC to go bad aswell.

This fixed all of my transmission temp issues.