1985 E250 6.9 running warm

[teletech]

I have a recently purchased van I'm working to bring up to par, largely as a way to mount the goodies off my old van.

The issue that has me concerned at present is it's running on the hot side, once it reaches operating temperature it settles either near the "A" or "L" in the NORMAL on the gauge. I've replaced the thermostat (a correct Motorcraft unit came out and a brand new one went in). I thought perhaps compromised cooling system but once it picks a temperature, it moves very little during that trip... Uphill, downhill, idle, heater blasting, or heater off, it stays pretty much the same. Next trip it chooses a slightly different place on the gauge to settle.
The coolant was pretty funky, but not unusually so. The fan clutch feels OK. The cooling system builds what seems to be a normal amount of pressure and has no leaks.
I'm almost wondering if it could be something in the gauge system. I'll dig out a mechanical thermometer but I thought I'd ask if anyone else has had this experience.

 

[79jasper]

Just go get a mechanical temp gauge and mount it up.
I've seen these stock "gauges" all over the place.

Sent from my SM-G892A using Tapatalk

 

[BR3]

Agreed.

I found out first hand that changes in the total electrical system will adversly affect the reading. I made several upgrades to my grounding, and all of a sudden when my mechanical gauge reads 190 my stock gauge reads between a and l.

The stocker uses a thermistor that reduces resistance with temp, then that's read by the psom, so any little change in there could be your issue

 

[Alberta_Mud]

I had a 84 and when the voltage regulator was going the gauges would set randomly.

A side note worth mentioning on my 92 is that it would run hot especially with a light load - would overheat with anything heavy. Had the injection pump rebuilt and new injectors and the temps went way down back to the N. Leads me to think as the injection pump wears it changes the timing.

Just throwing it out as a FYI

 

[Macrobb]

Leads me to think as the injection pump wears it changes the timing

Uh... Yeah....
I've been saying this for years...
Actually, a worn out pump/injector setup will get so retarded that you get blue smoke at idle. That's usually when people start noticing that something is actually wrong, despite it slowly losing power over time.

While the *correct* thing to do is replace the IP, you can usually keep it running well enough in the short term by drastically advancing the timing(I've had to actually skip the IP gear a tooth ahead, due to a lack of adjustment room in rotating the IP). It won't be as good as a new IP, but you'll gain some mileage, power, lower water temps and lower egt temps.

 

[chris142]

My stock gauge is junk too. It shows "M" when its only 200f. Turning the AC blower up makes it go even higher.