Rawze.com: Rawze's ISX Technical Discussion and more

I have a 2011 PETERBILT 387 with a Cummins ISX that is randomly overheating and or running warm.

I took it to the shop, they tested and let idle for 8 hours and it did not run warm or overheat. They gave truck back to me. I let truck idle for 1 and half hour before leaving...Truck started to heat up past 220 and climbing. I turned the keys back over to shop to recheck.

They replaced fan clutch, pressure tested system and changed thermostat. I picked it up and prepped to go back on the road.

I idled truck that evening while sleeping...just to see. I woke up after 6 hours of idling because AC stop blowing cold...Truck was starting to overheat. It overheated until it did an emergency shutdown due to being to hot. Shutdown at 235. I took pics to prove to shop.

They recommended dealer...so truck now goes to Peterbilt. After 24hours and several hours of idling, test for cracked sleeve, head and or gaskets, Peterbilt states, "unable to duplicate complaint".

At this point, no one has a resolve. Peterbilt has recommended allowing Cummins to put it on the Dyno for stress test, etc. in an attempt to duplicate?

Any suggestions...I am baffled.[attachment=2131]

Oh man if I understood it well from ur post that truck is overheating just and only when u are in or @ it.....keep a bit of a distance ....maybe

seriously what u have there is weird....hope that somebody here will give u an idea were to look now that the shops cannot find it....

Have you used an infrared thermometer and checked the thermostat when it's overheating. Have actually seen the fan working and have u changed the temp sensor it's like $20 buck and it's the cheapest thing to do first

Rereading your post if a/c stop blowing cold air you engine fan stopped working. Check the air line going to fan clutch and fan solenoid.

(I have had a fer extra beers tonite lol)...

I have had 2 that no one could fix that were overheating. -- That being said,.. most of the time is is something obvious but there are too many morons at the stealerships with their head up their arsse any more to find the actual problem(s).

Of the 2 that werer NOt ovbious, (clogged raditor, annodized radiator, bad thermostat, or brass ring on bottom of housing,.. etc.etc.etc.. -- They were...

* One of them had the fan solenoid plumbed backwards from the factory. It would work but made the clutch slip and would not cool the truck properly in a hard pull. -- it also caused the truck to eat fan clutches once in a while too.

* th eOther one, the damn engine fan was installed backwards,.. and it was PUSHING air forward into the radiator instead of pulling it through like it should. At idle it was had=rd to see the problem,.. but going down the road,.. no air was getting through the radiator because it was pushing against the incoming air to the front of it. -- The irony of that truck, is that it was at about 8 or 9 places and EVERY MECHANIC said they could not find anything wrong... -- I saw it as soon as the hood went up,.. and sad part is,.. i don't own a pete.

(10-25-2016 )gatow900 Wrote: [ -> ]Rereading your post if a/c stop blowing cold air you engine fan stopped working. Check the air line going to fan clutch and fan solenoid.

The fan should default to always on if the solenoid loses power, I had that problem yesterday.,dirty connection.

Overheating while idling has to be something stopping the coolant flow ,like a bad tstat not opening or a slipping belt maybe not driving the water pump. Check belt tensioner and pump . I never had a truck overheat idling. Just because a part is new doesn't mean it's good, especially tstats.

With a new fan clutch and tstat,you would think they checked to make sure it was cycling properly.
You say the a/c went hot, check that compressor didn't seize and high pressure cutoff switch, can't see that causing it to overheat.

I'm with Rawze on checking fan direction.
Some of the people fixing trucks have trouble pumping gas.

you can add a slipping water pump impeller to the list of possibles as well.

You didn't state in your post whether or not you've had to add any coolant before or after the issue arose. It sounds like your running in a warm region if your running the A/C so maybe you didn't check to see if the heat was blowing hot when it was overheating. If it doesn't I'd have the system pressurized again and watch the tech. do it and see the results first hand.

I have taken all suggestions and will let you know how this turns out. Thank you all for responding