online over the years in forums many seem to say these magnum engines had a real tendency to get cracked heads, some attributed that to the engine not being designed for 195, and claimed 180 was way better, this any true? I know it would use a bit more gas since it's not running to the 195 required by the computer but I'm sure it wouldn't cause any huge loss of mpg? I think I need either a coolant temp sensor or new thermostat, when I did the 3 cycle key test I got code 17, engine cold for too long. http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

https://dodgeforum.com/forum/2nd-gen...racking-2.html

"From what I have seen cracking of the heads on the 5.9L magnum motor is due to the casting. The head was made to run at 180 degree F, yet the motor is now running 195+ constantly because of emissions. The head was never made to originally run at that high of a constant temperature. They where built to run cooler so as the spacing was made. But then they heated them up but didn't change the diameter between the heads, it was a stupid engineering consequence.

So after years of heat, and/or abuse there isn't enough material between the valves to with hold the added stress or added heat so they crack. Call any good shop and that is what they will tell you, not to mention a metal worker could tell you.

It really is very easy to understand when your looking at a set of cracked heads....IMHO......That's why I push for owners to use 180 degree F T-stats over OEM."

I don't have a blown head gasket or anything, but if using a 180 stat would be some preventative maintenance I'd put a new one in. Doing reading over time, putting in a 180 stat is apparently a very common thing to do after people repair their plenum too, maybe it would be preventative maintenance to help my plenum survive longer

 

A 180* thermostat will give you that code. It also makes the PCM run the engine a bit richer, hoping to warm it up the rest of the way.......

The heads were just poor castings The decks were too thin, and even with a 180 stat, they still cracked. There are updated design heads available now, (and for some time....) that have thicker decks, so, are much less prone to cracking.

 

Thx I'll try a new 195 stat, I'm sure I'll appreciate the added warmth for the heater when needed, yeah as I read more, people said without a tune a 180 stat is just wasting gas and will end up ruining the o2 sensor

 

I have been running a 180* stat forever and no codes. The code will show up in the newer trucks because the changes in pcm. A 95 shouldn't give you that code unless there is an issue where the engine is not getting up to the t stat temp. Your location is another considering factor, If you are in Alaska no need for 180 stat but in Florida it would be a good idea. You may want to see what the actual temp is with an infrared temp gun.

 

Moparite is right!

Codes began appearing in 01 trucks for not getting to operating temp fast enough. Man, there have been some long cold mornings when my truck's coolant never thawed and I had no code. Also no cracks and I've been everywhere from TX to MN during my ownership. Heyyou is right about the castings. It's just luck that some heads last longer I guess. Remember the Cummins 53 block? Sometimes parts are just bad from new.

And tuners don't affect temps or anything. I ran Hypertech for years with a 180 but that was for ping, not the tune. I've had old mechanics say they like the 180 for these engines and won't go any hotter. New engines use what, 205? But new engineering is much better than our 1960s tech LA/Magnum series.

So I'm at 226k currently and she ran awesome all day yesterday. In the winter, I do put a winterfront on to help heat up quicker and get mileage up a tad, but that's fine with me. Always been a cold beast even with 195.

 

I could try clearing the codes and seeing if they even return, for all I know it's there from the previous owner making many short trips where the engine could never warm up to temp to begin with, a new stat is cheap enough where I could try a new one for good measure, if that doesn't fix it, the coolant temp sensor would be my next guess, but you'd figure if that sensor was messed up the truck would be running bad, read before that has a big effect on the ecm dumping fuel or not depending on its readings, and technically should throw a code 22 according to that chart I found.

weird as it was a stored code too I had to do the 3 key turn trick to make pop up, the whole time I've had the truck I've never actually had the check engine light come on, so I figured it had to be nothing too too serious

sadly I don't know any repair history on the truck, for all I know the engine and trans have been rebuilt long ago all beefed up, or not lol.

 

The older trucks do the 3 key trick? Huh, thought that began in 01. Mine doesn't.

If it runs fine, just chalk it up to a fluke and drive normally. Probably will never occur again, especially if you use 195 stat. I've never had the code in 10 years even in brutal cross winds going across SD in January.

 

The key trick skipped a few years....

 

Figures. I had to get a Hypertech to read codes. Now the mouth breather who stole it can read my codes. Stupid walking abortion. UGH!

 

I definitely miss obd2 being able to plug in this code reader I have and it would just tell me rather than counting check engine blinks like morse code and having to google what it means lol