I'm about to take my ambulance on its first road trip but I'm skeered because the OBDII connector is dead so my ScanGauge doesn't work. The temp gauge always says normal, but several times I have heard the fan kick on for a few seconds when driving in routine conditions. Is that normal with these big vans? Is the weight of the ambulance box so much that the fan has to kick in more often?


Again, when I've heard the fan, it only came on a few seconds. My only experience is with the Fseries 6.0s I've had - when those fans came on, the temp would be at least 205, usually more than 210, and it would run longer. However, those were always pulling a trailer, which I guess is about the same as the heavy ambulance box.

Is there any way to tell whether the engine is running hot besides the truck's idiot gauge?

 

Check the fuse for the obd connector and the cigarette lighter that is normally why the obd connector won't work a new fuse is usually all it takes. Then you should be able to use the scangauge.

 

It's not solely temperature that will engage the fan. During summer when coming off the highway say, slowing from 110KPH (70 MPH) to 50 KPH (30 MPH) i am coasting, and when i go to give it throttle, the fan clutch is almost always engaged for a good 5-10 seconds and then goes away. Also sometimes just from a dead stop, my temperature in the truck has never been over 207 this spring in 70F (20C) weather and the fan still does this, in the colder parts of the year it doesn't happen. The truck just likes cold air

 

Yeah, my fan will roar for maybe a second or so when starting from a stop when the a/c is on and engine is fully warmed up.
I just figure the sudden change in engine rpm brings the fan rpm up too before the pcm re-adjusts the duty cycle.

 

You could use one of those handheld laser pointer thermometers. There not 100% accurate but the nicer ones are pretty decent. Once you get the OBD port sorted, you'll have a new cool tool in the box. Aim it at the engine valley somewhere near where the sender is in the F series. Not sure what you can get a reading on in the vans.

Maybe temp rig an oldskool temp gauge somewhere? You may have one laying around or they only cost a few bucks at the parts store.

Either of these options would be ok for monitoring for temp spikes or odd behavior but you'd have to take the actual number with a grain of salt.

 

really, just get a temp gauge. They're easy to install anywhere in the cab.

 

Use the gauge in the dash.

 

That's like checking water with your finger to see when it's close to boiling.

 

So all of these trucks out there should have a separate water temp gauge plumbed in?

 

Should have. The factory gauge is nothing more than a stepper type switch feeding the gauge. My 2005 would move in app. 4 increments. Scan gauge gives you actual temps.