2008 Express 3500 6.0L 2WD

Admin: I didn't put it in the Express thread because I think it's a generic problem. Move if you wish.

The engine is running at about 209 -210 Deg F. Not boiling over.

Coolant level (Anti freeze) is correct and stays at correct level during a 1 hour highway trip averaging 75-80 Mph.. Coolant is not "disappearing" as it would with a blown head gasket and there is no white smoke at the tailpipe.

Oil level is correct..

I can't tell if the cooling fan is running. The shroud is too deep and I'm too short. (i have a ladder and will break it out if necessary tomorrow.) (It's been a long day and its getting dark.)
How can I check for proper coolant flow? Its low milage (165K) so I don't suspect there is coolant flow blockage.

I hope there is good news because I'm hoping to drive about 100 miles Sunday.

Thanks for any and all help, Jim

 

I assume this is a change from how it has been in the past? Are you reporting the dash gauge or have you checked it by another method? Last coolant system maintenance?

 

Thanks Rednucleus, yes, it's a new behavior. Started today. Nothing unusual has changed. Yes, I'm referring to the cluster gauge reading. I have a new diagnostic tool but I don't know how to use it yet. (see my other recent thread) And lastly, it's a recent purchase and I didn't get any maintenance docs so I would assume that no cooling system maintenance has been done.

Edit: when this overheating is happening, the cabin AC is overwhelmed with heat. Had to roll down the windows to let excess heat escape. That gave some credibility to the cluster gauge.

 

I guess I would start with a system flush/fluid change and a new thermostat; hoses if needed based on that history.

 

Thanks Rednucleus, sounds good. What temperature thermostat should I get? Or do I have to open it up to find out what the OEM is?

 

I would go with the oem temp; parts store should be easy find. Looks like 190 is standard equipment

 

We have an excellent garage nearby that specializes in this vintage Suburban's, Tahoe's and Express's and he only charges $60 for a diagnosis. I think I'll let him do that on Monday. After watching a few YouTubes on replacing that thermostat, I don't want to go through that much effort and be wrong. If his estimate is reasonable I might even have him do it. That replacement process looks like a real PIA. I'll be 83 in a few weeks and I must admit just watching those videos made me tired.

Edit: Don't be misled by my avatar, it's just a bit out of date.

 

I'm 66 and right there with you! I encourage a complete cooling service (flush/coolant/hoses/thermostat) if you have no vehicle history. Let us know what they find

 

Took it to the garage I mentioned for the $60. diagnosis and he said thermostat, so I replaced the thermostat and the symptom didn't change. I then took it to a radiator shop for a flush. The radiator guy discovered a bad fan clutch, so I replaced the fan clutch.

After all that, the cooling liquid temp was still running around 210° F. I took it back to the radiator guy and he said that 210° F was about the correct temperature for that truck. After more checking around, the consensus of my locals was that it was running at the correct temperature.

So there you have it my friends. I do feel better having a new thermostat, cooling system flush and fan clutch.

Sorry for the delay getting back. I have been busy. Regards, Jim