Engine Temps rising again.

[Gary M]

Engine/Trans Temps High Again
09 Knight 38PKQ 360 Cummins 

After a month of being sick(Covid) we decided to head south to our winter hangout. Before getting sick I had the coach serviced. Motor, Genny, radiator steam cleaned. They also without telling me did an ECM upgrade they said was needed. On our first leg from Twin Falls, ID to Nephi, UT, temps were running higher than I thought they should for being 65 out and flat landscape (199-205+). 6th gear, 1700 rpm. I then brought it up to 75mph @ 2100 rpm’s and it cooled down to 188. I tried dropping into 5th at 2100 rpm 65 mph and temps dropped sometimes to183 but ran about 188 which has been normal for my coach. Motor seems to need to be at high rpm’s to run normal temperatures. Outside temp was 73. So I was jockeying back and forth to keep temps down. Still have two days, 9hrs to go. Outside temps mid 80’s till i get there which is good. 
Oh and since the service my MPG has dropped from 7.7 to 6.5 ????
Appreciate any suggestions on temps and MPG change. Pic is after I raised speed  and temps started dropping. They were around 199.

[JDCrow]

I would think running at 2100 RPM would increase fuel consumption?

As far as temps, Fan clutch? Boost waste gate? Did you have a flush with the Rad cleaning?  That could lead to air lock. The steam clean could have damaged fins, or actually pushed gunk into the fins more, and thus air flow is now decreased. 
 

This is one if those problems that can lead to a lot of parts thrown at it with no rhyme or reason. 
 

I would fine a reputable shop and start with some diagnostics to see which sensors are working correctly. Perhaps a leak down test in the radiator. 

[Ivylog]

While 200+ degrees on level ground seems high, we’re you in a high headwind situation? Would explain the poorer mpg.

[ktloah]

188' is not really hot for a diesel. Your speed shows almost 75mph, perhaps a slower speed should see lower water temps. That engine is working hard so the increase in temp. My Dynasty runs at 185-190..

[JDCrow]

Bros, when he slows down it heats up 

[Gary M]

3 hours ago, JDCrow said:

I would think running at 2100 RPM would increase fuel consumption?

As far as temps, Fan clutch? Boost waste gate? Did you have a flush with the Rad cleaning?  That could lead to air lock. The steam clean could have damaged fins, or actually pushed gunk into the fins more, and thus air flow is now decreased. 
 

This is one if those problems that can lead to a lot of parts thrown at it with no rhyme or reason. 
 

I would fine a reputable shop and start with some diagnostics to see which sensors are working correctly. Perhaps a leak down test in the radiator. 

Well the shop was Cummins and I asked for a complete diagnostic but didn’t realize that it would be 50+ pages and they only gave me 5 pgs of which I sent to Frank. Thats when he told me they were basically screen shots. Ive been in contact with the Cummins shop but no response yet on whether they are going to email the actual file so Frank can plug it into his insite software.

38 minutes ago, ktloah said:

188' is not really hot for a diesel. Your speed shows almost 75mph, perhaps a slower speed should see lower water temps. That engine is working hard so the increase in temp. My Dynasty runs at 185-190..

Tried that. 75 mph at 2000 rpm flat ground gave me the 188 which is high normal temp usually at 60-65 mph and 1600-1700 rpm. Mine also used to run 185-190 at 60-65. When at 60-65 at 16-1700 it’s running 199-206.

[ktloah]

Interesting,  perhaps fan clutch, thermostat not opening? You got me stumped....I'd like to know what others find

[Gary M]

38 minutes ago, JDCrow said:

Bros, when he slows down it heats up 

Thankyou JD

[JDCrow]

18 minutes ago, Gary M said:

Well the shop was Cummins and I asked for a complete diagnostic but didn’t realize that it would be 50+ pages and they only gave me 5 pgs of which I sent to Frank. Thats when he told me they were basically screen shots. Ive been in contact with the Cummins shop but no response yet on whether they are going to email the actual file so Frank can plug it into his insite software.

Tried that. 75 mph at 2000 rpm flat ground gave me the 188 which is high normal temp usually at 60-65 mph and 1600-1700 rpm. Mine also used to run 185-190 at 60-65. When at 60-65 at 16-1700 it’s running 199-206.

Cummins NW? 

[Gary M]

7 minutes ago, JDCrow said:

Cummins NW? 

Cummins in Boise, ID

[JDCrow]

31 minutes ago, Gary M said:

Cummins in Boise, ID

Do you have a working relationship with a Cummins dealer? I’m not sure if Cummins works like auto dealers where everything gets entered into the big database and any dealer can pull records? 
 

As I posted earlier, airflow seems to be key. Which leads me to fan clutch, or wiring for fan. 
 

With other diesel manufacturers, the computers are linked to temp. So say thermostat doesn’t kick in then temp sensor cannot get accurate reading and computer doesn’t get the info it needs and won’t know about the fan. With the 6.0 power stroke I was just tinkering with, we dropped a higher temp thermostat in it. Well the engine stayed at 186 right at the temp of the thermostat, but it wouldn’t open and keep the pup cool. The computer kicks in at 193 to turn fan on. It wouldn’t get there. It messed it up. Dropping OEM thermostat back in to see if it helps. That truck was running 200-210, Which is a bit hot considering all the work we had done to it. 

[Gary M]

37 minutes ago, JDCrow said:

Do you have a working relationship with a Cummins dealer? I’m not sure if Cummins works like auto dealers where everything gets entered into the big database and any dealer can pull records? 
 

As I posted earlier, airflow seems to be key. Which leads me to fan clutch, or wiring for fan. 
 

With other diesel manufacturers, the computers are linked to temp. So say thermostat doesn’t kick in then temp sensor cannot get accurate reading and computer doesn’t get the info it needs and won’t know about the fan. With the 6.0 power stroke I was just tinkering with, we dropped a higher temp thermostat in it. Well the engine stayed at 186 right at the temp of the thermostat, but it wouldn’t open and keep the pup cool. The computer kicks in at 193 to turn fan on. It wouldn’t get there. It messed it up. Dropping OEM thermostat back in to see if it helps. That truck was running 200-210, Which is a bit hot considering all the work we had done to it. 

Well I quit working on motors when computers got involved. The last motor I rebuilt was a 1957 Mercedes Benz 4 cyl diesel in my sailboat. Easy peasy. Finally got ahold of Cummins Boise and while their words were encouraging, their voice was not. Im getting more and more confused on what I need from Cummins. Ill check back with our Frank and get a better word on what to ask Cummins.

[Trinidaddave]

Sorry, I do not have much to add to the post.  Just for reference my CAT C-9 constantly runs at 198 deg. I do keep it between 55 and 60 MPH, but haven’t subjected it to high ambient temperatures or steep inclines. 
 

please post the resolution after you figure it out.

Thanks

[Gary M]

5 hours ago, Trinidaddave said:

Sorry, I do not have much to add to the post.  Just for reference my CAT C-9 constantly runs at 198 deg. I do keep it between 55 and 60 MPH, but haven’t subjected it to high ambient temperatures or steep inclines. 
 

please post the resolution after you figure it out.

Thanks

No problem. Plan to if it’s figured out.

[Rikadoo]

Ok so my question is when you took it in for "service" what all did they do? Things I know of cooling systems is, coolant less than 50/50 can create issue (example is less coolant more water cooling increases cavitation) so start with checking the concentration of coolant, another is a pressure cap failure or wrong pressure cap, did they replace the cap, when the engine is cold remove the cap and look at the rubber seal, is it cracked or distorted, (if a pressure cap cannot maintain pressure the boiling point drops more boiling less cooling) Use a tester and see just what the pressure is "holding" at. Next you said they steam cleaned the radiator, is it a rear mount radiator ? if so was the radiator restricted from the slobber tube and when they steam cleaned it did grease get on the belt? Being a cummins is the tensioner takin a dump? the ones I worked on as it starts to fail they will start to not run true in line with the belt, in a short while the belt shreds loosing tension just before the belt rips off. and lastly MANY a technician has been lured into a overheating problem only to discover that the sender has become biased, Is the engine really overheating? I know this sounds like im not possibly understanding the situation, but these are all the basics, and in my time as a mechanic I found many have failed to check the basics cause many want to believe the issue couldn't be that simple. Lastly can you read your EGT's its a long shot however restricted exhaust can cause higher engine temps, (the 7.3 power stroke uses a program to restrict exhaust when cold to keep more heat in the engine to warm up faster) Diagnosise is about eliminating possibility's. Lastly is the software upgrade, what was the intent? usually lets say if the engine is perhaps not "clean" at the tailpipe due to incomplete combustion temps its not beneath the engineers to increase engine temps to help scavenge better. With Ford after a reprogram if we developed issues we could call engineering for a definition as to what they were trying to achieve. Though I haven't tried it before what if you enter the software vs to the internet and see if anything pops up... 

[JDCrow]

43 minutes ago, Rikadoo said:

Ok so my question is when you took it in for "service" what all did they do? Things I know of cooling systems is, coolant less than 50/50 can create issue (example is less coolant more water cooling increases cavitation) so start with checking the concentration of coolant, another is a pressure cap failure or wrong pressure cap, did they replace the cap, when the engine is cold remove the cap and look at the rubber seal, is it cracked or distorted, (if a pressure cap cannot maintain pressure the boiling point drops more boiling less cooling) Use a tester and see just what the pressure is "holding" at. Next you said they steam cleaned the radiator, is it a rear mount radiator ? if so was the radiator restricted from the slobber tube and when they steam cleaned it did grease get on the belt? Being a cummins is the tensioner takin a dump? the ones I worked on as it starts to fail they will start to not run true in line with the belt, in a short while the belt shreds loosing tension just before the belt rips off. and lastly MANY a technician has been lured into a overheating problem only to discover that the sender has become biased, Is the engine really overheating? I know this sounds like im not possibly understanding the situation, but these are all the basics, and in my time as a mechanic I found many have failed to check the basics cause many want to believe the issue couldn't be that simple. Lastly can you read your EGT's its a long shot however restricted exhaust can cause higher engine temps, (the 7.3 power stroke uses a program to restrict exhaust when cold to keep more heat in the engine to warm up faster) Diagnosise is about eliminating possibility's. Lastly is the software upgrade, what was the intent? usually lets say if the engine is perhaps not "clean" at the tailpipe due to incomplete combustion temps its not beneath the engineers to increase engine temps to help scavenge better. With Ford after a reprogram if we developed issues we could call engineering for a definition as to what they were trying to achieve. Though I haven't tried it before what if you enter the software vs to the internet and see if anything pops up... 

Exactly, tons of variables. We just did a complete flush on pops 6.4 Because he took it in for a wrench light. I told him to do thermostats with it, he didn’t want to go through the trouble. So he replaced oil temp sensor, coolant temp sensor and was about ready to tackle an oil cooler. I asked him one last time, did you replace the thermostats? He said no only has 130k. Needless to say he took off for hunting, got 30 miles, came back in limp mode. Took thermostats out, one was completely broke and blocking the hose.

So agree, pressure test and diagnostics while running to see what’s in/out of spec. 

[Rikadoo]

Hey JD so i read your story on pops 6.4, good find…BUT! If he still has that truck and you havnt done what im about to tell you your going to want to get it back.

So the upper radiator hose where it conneted to the t stat housing, the big plastic part was it black or white? If its black dont pass go go directly to FORD and get this new hose AC3Z-8260-A (or quick # KM-5058) or if it has the white plastic on the end of the hose then go to Ford an buy 3 of these O-rings BC3Z-8590-PA  (or RTS-1077 quick #) 

If you have the black hose then remove both ends (tstat end an radiator) then throw that as far as you can, what i used to do prior to installing the new one is to use a piece of scotchbrite an lightly clean both hose nipples, i would then put a slight amount of dielectric on them, install the hose an refill.

if you have the white end on the hose then remove both ends of the radiator hose an use a pic and replace the o rings two on one end an one one the other, then prep both nipples like you did above reinstall an refill.

If you already did either or then kindly disregaurd this text😎

Those black hoses only used one o ring an would leak an most people wouldnt catch it till the coolant got so low by then it was too late.

Another huge issue was the lower radiator hose wher it connected to the water pump. It too should be white at the WP end, if not its a 8C3Z-8075-C the reason that one is so important is the black ends only use 1 o ring and once they were no longer soft an supple they would allow air to get past it then cause cavitation and it rots out the timing cover plate, an while your rollin down the road all the coolant gets pumped directly into the lubrication system, thats when it really gets ugly!!! Dont get me wrong they can be PITA to get to but its worth the trouble. As a Ford tech i made more hours repairing those damm engines than you can shake two sticks at.

Lookin forward to hearing more about your remodel upgrade👍

[JDCrow]

15 minutes ago, Rikadoo said:

Hey JD so i read your story on pops 6.4, good find…BUT! If he still has that truck and you havnt done what im about to tell you your going to want to get it back.

So the upper radiator hose where it conneted to the t stat housing, the big plastic part was it black or white? If its black dont pass go go directly to FORD and get this new hose AC3Z-8260-A (or quick # KM-5058) or if it has the white plastic on the end of the hose then go to Ford an buy 3 of these O-rings BC3Z-8590-PA  (or RTS-1077 quick #) 

If you have the black hose then remove both ends (tstat end an radiator) then throw that as far as you can, what i used to do prior to installing the new one is to use a piece of scotchbrite an lightly clean both hose nipples, i would then put a slight amount of dielectric on them, install the hose an refill.

if you have the white end on the hose then remove both ends of the radiator hose an use a pic and replace the o rings two on one end an one one the other, then prep both nipples like you did above reinstall an refill.

If you already did either or then kindly disregaurd this text😎

Those black hoses only used one o ring an would leak an most people wouldnt catch it till the coolant got so low by then it was too late.

Another huge issue was the lower radiator hose wher it connected to the water pump. It too should be white at the WP end, if not its a 8C3Z-8075-C the reason that one is so important is the black ends only use 1 o ring and once they were no longer soft an supple they would allow air to get past it then cause cavitation and it rots out the timing cover plate, an while your rollin down the road all the coolant gets pumped directly into the lubrication system, thats when it really gets ugly!!! Dont get me wrong they can be PITA to get to but its worth the trouble. As a Ford tech i made more hours repairing those damm engines than you can shake two sticks at.

Lookin forward to hearing more about your remodel upgrade👍

Thanks for heads up. We did both hoses when I did a Mishimoto Rad and new intercooler with boots a few years back. It lost weight from some coolers and exhaust right after he bought it new. Right now he went to get the trans Serviced and the shop claims the case is cracked. Never heard of the 5sp ever cracking. I understand it’s a very good trans. 

Edited September 30, 2021 by JDCrow

[Gary M]

6 hours ago, Rikadoo said:

Ok so my question is when you took it in for "service" what all did they do? Things I know of cooling systems is, coolant less than 50/50 can create issue (example is less coolant more water cooling increases cavitation) so start with checking the concentration of coolant, another is a pressure cap failure or wrong pressure cap, did they replace the cap, when the engine is cold remove the cap and look at the rubber seal, is it cracked or distorted, (if a pressure cap cannot maintain pressure the boiling point drops more boiling less cooling) Use a tester and see just what the pressure is "holding" at. Next you said they steam cleaned the radiator, is it a rear mount radiator ? if so was the radiator restricted from the slobber tube and when they steam cleaned it did grease get on the belt? Being a cummins is the tensioner takin a dump? the ones I worked on as it starts to fail they will start to not run true in line with the belt, in a short while the belt shreds loosing tension just before the belt rips off. and lastly MANY a technician has been lured into a overheating problem only to discover that the sender has become biased, Is the engine really overheating? I know this sounds like im not possibly understanding the situation, but these are all the basics, and in my time as a mechanic I found many have failed to check the basics cause many want to believe the issue couldn't be that simple. Lastly can you read your EGT's its a long shot however restricted exhaust can cause higher engine temps, (the 7.3 power stroke uses a program to restrict exhaust when cold to keep more heat in the engine to warm up faster) Diagnosise is about eliminating possibility's. Lastly is the software upgrade, what was the intent? usually lets say if the engine is perhaps not "clean" at the tailpipe due to incomplete combustion temps its not beneath the engineers to increase engine temps to help scavenge better. With Ford after a reprogram if we developed issues we could call engineering for a definition as to what they were trying to achieve. Though I haven't tried it before what if you enter the software vs to the internet and see if anything pops up... 

1. Engine service

2. Genny service

3. ECM printout ( because Ive had regen issues) Frank and Tom suggested it. DPF plugged once on the road. October 2019.

4. Rear Radiator steam cleaned as I lost diesel fuel which coated underneath and Im sure the radiator. 1year ago. Its a habit now to clean. SCA’s good.

5. ECM software update of which I was not told till I picked it up. My VGT Actuator  died last November and it got a software update then also. Different shop. I’m saving responses as should I make it home(so to speak), Ill dump all this on my mechanic since I have no convenient place and tools to take care of myself.

I am assuming your response was for me!!

If not, let me know. 

[Rikadoo]

Hey gary so overheating is always such a challange, plus to throw a wrench into the mix a recient software upgrade!!! I have reading how the “cummins overheat” is showing up all over these sites, please let us know when the culpret is found, good luck

[Gary M]

47 minutes ago, Rikadoo said:

Hey gary so overheating is always such a challange, plus to throw a wrench into the mix a recient software upgrade!!! I have reading how the “cummins overheat” is showing up all over these sites, please let us know when the culpret is found, good luck

Oh I will. Hopefully I get a food answer.

[Gary M]

On 9/29/2021 at 6:46 AM, Ivylog said:

While 200+ degrees on level ground seems high, we’re you in a high headwind situation? Would explain the poorer mpg.

On my second leg of trip I was getting a head wind. But first leg no wind, temps a little above normal and still 6.5 mpg. I went from 6.5 to 7.5 a year ago when my VGT actuator was replaced and my first software upgrade.