250* coolant temps

2000wa250 · Feb 17, 2012

Today on the drive from WA to CA I got a chance to play with my AE a little bit. On a whim I data logged my ECT. From my understanding because I have a 6-speed my AE can read accurate ECT. Much to my surprise I saw ECT of 240-250. I have DieselSite's 203 t-state with rotella ELC in the truck. Once I saw the ECT I pulled up my EOT and it was staying steady right above 200. I was under the impression that with a 203 t-stat I would be seeing higher temps, but I thought that they would be in the 215-220 range, not 240-250.

This occurred on completely level ground, at a constant speed, and unloaded other than myself and my two dogs. Unfortunately I have only had AE for a month, and this is the first time I have checked my ECT read out on it so I have no idea if this is a new issue or not.

I just installed a set of 250/200 injectors from FFD. I have had the 203 t-stat since august. I only data logged ECT once on the trip, but was viewing live data from it a number of times and it seemed to stay constant right around 245. Lowest I remember seeing it at was 230.

Is this something I should be worried about? I didnt hear my fan kicking on at all, but I also only have a downpipe on my truck and had the music on to keep from going insane with the drone. I can get more data logs tomorrow if need be. I am going to dual termies soon and want to make sure that I dont have a cooling issue.

Also what problems could coolant temps this high cause?

Dieselboy. · Feb 17, 2012

FWIW my scan gauge always tells me 210-213 on ECT. My Tstat is a 195

dp42 · Feb 17, 2012

Is the water level ok? I wouldn't drive it that high anymore.

2000wa250 · Feb 17, 2012

water level is right between the marks. I dont get why it was so high, does this mean that I have a defective t-stat or fan clutch maybe? Its not like I was driving in intense heat, there was actually some snow and hail coming down while I was seeing these temps.

I have to turn around and do the same drive on monday, so I have limited options...right now I think I'm leaning towards grabbing a stock 195* t-stat and seeing if that makes a difference....if not then it may be another issue..

Also, the idiot gauge was in the same place that it always has been since I've owned the truck.

dp42 · Feb 17, 2012

I understand that ambient air was cool. Maybe that thermostat is stuck. I had that problem on my 6.0 once. Went through 3 thermos before i got one that worked worth a crap.

2000wa250 · Feb 17, 2012

Great. Kind of what I was afraid of. Any one have any suggestions on switching it out without making too much of a mess?

dp42 · Feb 17, 2012

Dont take my word on that, im just guessing based on a 6.0 because its 330 am. Someone will come along though with the right answer tmw im sure.
Good luck.

2000wa250 · Feb 17, 2012

thanks man. I'm not quite sure what problems that high of temps can cause, but they seemed abnormal to me for sure and i definitely want to get it taken care of ASAP

BigAlsPSD · Feb 17, 2012

I replied to what I think is your other thread on another forum, but will add some info here to. IIRC the manuals use 2 sensors, one for the PCM(which the autos don't use) and one for the gauge, maybe check once cooled down overnight against ambient temps to see if the sensor is biased? Good luck.

Ron's Power Stroke · Feb 17, 2012

if i remember right, AE can not read ECT,the sensor is for the dash gauge only..,what does your oil temp say?

2000wa250 · Feb 17, 2012

Oil temp was right at 201. Varied by .25 on either side. As I understand it ECT is not accurate on Auto's but on Manuals it is. As big al said, the manuals have a ECT sensor that sends to the PCM where the automatics do not. I will check tomorrow morning what it says.

Ron's Power Stroke · Feb 17, 2012

201 falls just right for your thermo stat..id say your ECT is good..a good mechanical gauge would be very handy.. .interesting on the hand shaker vs auto.waiting on a reply..i thought not reading temp was with all 7.3's

2000wa250 · Feb 17, 2012

I had the wiring diagram pulled up on the computer a few minutes ago, I'll find it and get it up here tomorrow. I believe it has something to do with the fact that the auto's can read tranny temp at the PCM so it takes the spot of ECT.

As far as oil temps at 201, this was on flat level ground cruising at about 63 MPH and 17xx RPM. 201 still seems a tad high to me. Now if I was seeing 201 pulling a grade and it came down a bit afterwards I would not be concerned. However, I pulled into a rest stop after I did the data logging (alright lets face it it was awhile after) and checked again and they were sitting around the same place. Watched it while the truck was idling for a couple of minutes and still did not see any noticable change, which is when I started to be a little concerned about it.

Granted I did drive the truck for 14 hours straight today, and for 250/200's it was feeling a little underpowered and seemed like my EGT's were a little high even pulling small hills. Gotta check for boost leaks tomorrow to see if the EGT's were due to a lack of air or the ECT....

and the list just keeps growing...

On Edit: I was under the impression that EOT should be higher than ECT not the other way around...otherwise the idea of an oil cooler seems somewhat pointless....unless that oil cooler is doing such a great job that it is transferring all the heat from the oil to the coolant, which brings me back to a issue of why isnt that coolant dissipating heat better, after all that is the entire point of it. Hopefully some more people will chime in on this...really starting to get on my nerves specially with a set of twin termies sitting on my work bench ready to go in, last thing I need is a heat issue before putting those bad boys in

dp42 · Feb 17, 2012

My oil runs dead nuts with my coolant. 190*
Lets put it like this, 250 is scalding. Something in your cooling system is the culprit, or your getting a false reading. My first thought is your burning the coolant so I think thermostat. No circulation builds heat and its obviously not heat from your motor. It would have to be eot - 235+ to heat the coolant like that under normal flowing conditions.

2000wa250 · Feb 17, 2012

dp42 said:
My oil runs dead nuts with my coolant. 190*
Lets put it like this, 250 is scalding. Something in your cooling system is the culprit, or your getting a false reading. My first thought is your burning the coolant so I think thermostat. No circulation builds heat and its obviously not heat from your motor. It would have to be eot - 235+ to heat the coolant like that under normal flowing conditions.

Ok this makes sense to me. A stuck stat would cause the same coolant to basically super heat, effectively turning the oil cooler into an oil heater. In turn this would cause a viscous circle where temps just kept climbing.

Second part of the question. Other than this being incredibly bad for the longevity of both the oil.and the coolant, as well as many of the associated parts, what other effects on the engine would this have? I felt like I was seeing elevated egt and lack of power as well as throttle response, however duty cycle and icp still seemed to be fairly normal.

Lastly, easiest fix....pull stat housing try not to get coolant everywhere, put in a stock 195* stat and replace, refilling coolant. Do I need to change my oil as well? Probably huh. Oil is only about 2000 miles old rotella t6.

Thanks for the help guys.

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Tom S · Feb 17, 2012

I would not freak our for a second until you verify that the coolant temps are really that high.

2000wa250 · Feb 17, 2012

Tom, what do you suggest as verification? Im going to head out and put the AE on it here in a second and check temps after sitting all night. I would assume that a biased or faulty sensor will show me something the does not coincide with what could be considered normal.

Im assuming that after sitting all night and if I don't start it up my coolant temp and air intake temp should be relatively close.

Only reason I asked above about next steps and possible side effects of this is because im down here to see a dying family member and only have so much time. I want to know the next step assuming that something is wrong other than the simple explanation of a faulty sender so that if it isn't the sender I already know where to go next instead of wasting the precious time I have down here trying to chase down where to look next.
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2000wa250 · Feb 17, 2012

Also last thing I want is to have a messed up fan clutch take out my water pump on the drive back up and end up either changing it out on the side of the road or having to get towed somewhere

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powerstrokenstang · Feb 17, 2012

My sd says 400 or so usually in ae, i think you are fine lol.

2000wa250 · Feb 17, 2012

powerstrkenstang, do you have a manual or automatic? Supposedly the manuals have 2 sensors for ECT, one that goes straight to the PCM and one that goes to the idiot gauge. So far I have only found the one sensor located on top of the water pump next to the housing.

I guess a better question now should be this, should I be worried about oil temps right around 201, since it seems like we have reached a consensus that unless I have an additional sender, the coolant temps from AE cannot be trusted?