So I did the key trick on my truck the other day and got this list of stored fault codes:

12- Battery Disconnect
17- Engine too cold too long
21- O2 sensor error

According to this page:
http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

CEL lamp is NOT illuminated when the engine is running and I am driving around.

The code 17 probably has do do with a stuck thermostat or something. The T-Stat is new, but i have a funny feeling that it may be a 180, but I do not know if that was stock for the 8.0L...

I had an overheating issue before I pulled the block drain plugs, flushed the cooling system, replaced the fan clutch, replaced thermostat, filled it with straight water for a flush, and now I am having problems with it running too cool...go figure...

Just for clarification, I am running straight water in the cooling system now, planning on switching over to some G-05 before it starts getting cold here... if that matters.

As I understand, a code 17 will not always trigger the CEL, but a code 21 will...which brings me to my question:

Are these pending codes anything to really worry about? If they were serious I should think that the computer would illuminate the CEL lamp and start protesting?

I am assuming that the truck is running pig rich right now, but the funny thing is, I can't tell a difference in MPG because it has always sucked so bad! HA!

Performance does not seem to be effected.

Just thought I'd get some opinions before I start ripping into the old girl.

 

Code 12 is not one to worry about.

Try replacing temp sensor first, see what it does.

 

That's right! I had forgotten about the temp sensor...it's been a couple of years, so Maybe it's due?

I got it up to temp - a hair below 200- today, but it took a while to do so, like 15-20 miles.

I don't really know how long it should take it to get up to temp with a healthy cooling system, seeing as the fan clutch was pretty much shot since the day i got it.

Maybe its just a large engine that needs a long time to completely warm up? I usually use it for in town driving, Home Depot and wood runs, etc with a few long trips scattered over the course of the year, so it's not doing long hauls or anything like that regularly.

 

+1 on the ECT sensor. And what brand t-stat did you install? Stant Super Stat is what you want.

 

5 Miles should be enough to warm it up at 40MPH or more avg speed.

 

don't run without antifreeze, it can start to rust your cooling system, or boil the water and explode your radiator, heater core or something worse, i did run plain water in my ram and a neon at the same time, trust me in less than a week i was replacing both radiators and heater cores

 

^ +1 on that

 

It is a Stant, I got it from Napa. Not sure if it's a 180 or what though...

Any chance the O2 and coolant temp codes are related? I doubt it, but you never know...

 

Ya, so either I'm not getting the correct readout on the cluster, or the engine is, in fact, taking abnormally long to warm up.

 

FWIW I am running the water temporarily as a flush for the cooling system. I see no point in mixing up a 50/50 batch of antifreeze only to drain it and toss it after several hundred miles...

It is almost September, soon I will be draining the water and mixing up some G-O5 for the coming winter.

I have been mixing 50/50 coolant mixtures for two of my vehicles for 6+ years with water from the garden hose and concentrate with 0 problems. I have heard the stories but have yet to experience any negative effects from such practices.

Just sayin