So,
On an 800 mile trip lately, weather varied from Rain/60s to Sun/90s, my truck coolant temperature would range from "O" to "AL" in NORMAL. Higher speeds usually -but not always- meant higher temperatures. Worst case had me pull over for 10 minutes to cool down (once it gets to "AL" it starts running rough, backfiring a bit, etc) for 10 minutes then not exceed 60mph for duration of trip.

Setup:
460 engine, performance cam/lifters. Holley 670 street avenger. Headers. Oversized air filter "mexican breather" style. New rad 2 yrs ago. Last rad flush one year ago. New thermostat 180 degree (validated working). Engine has <20,000 miles on it. Rad has fan shroud. New fan clutch 1 yr ago, recently tested good. Belts tightened properly. Load is about 300lbs less than GVWR as it has a camper and pulls a trailer about 2000lbs.

So, the question:
Is this NORMAL?

thanks,
...Vince

 

Did you notice of this happened in a change in altitude?

Maybe the timing off because, bad timing causes over-heating.

 

Radiator size will make a difference also. But your engine temp is load dependent so it is probably normal.

 

Dennis,
I live at 4000 feet, and on this trip went from 4000 to 3000 up to 7000 and ended up at 4400.
I wondered about the timing as it runs a teensy weensy bit rough, but the tuneup was last done at about 3000 miles ago. Does this vehicle need to be tuned up for smoooooooth running quite often?

thanks

 

What i was getting at is the fact when you operate the engine at Higher altitudes the air becomes thinner and as a result the mixture changes causing the timing to change.

When I drive from Calgary (3820') to the summit of Mt. Revelstoke BC (6300') to Osoyoos BC (1100').
I always have to adjust my timing (retard it) twice to prevent the pinging and less power plus some rise in coolant temp.

The coolant doesn't get hot enough to blow out or anything, it just slightly rises.

I also have a 7 blade / clutch fan.

 

So,
839 miles back and here's the results.

I can say now for certain that the timing is a wee bit out as it occasionally backfires when going downhill (coasting), however this was also related to a vacuum leak last month too... anyways the temperature depends on a couple of things:
-Load/Speed
-Ambient air temp
-Altitude

Day one: At 4400' I could not reasonably exceed 60mph for long periods when the ambient was 95F. HOWEVER once I hit >5500' at these temps two things happened: the oil pressure dropped (from 'AL' to 'R' (hi volume oil pump)) and when the pressure dropped so did the coolant temp (from 'AL' to 'RM').

Day two: Ambient air temp did not exceed 75F the whole trip, started at 5500', dropped to 3000', back to 4000' at home in Calgary. Coolant stayed consistently below 'M' even when I pressed the speed up to 70mph for long periods.

I think I'll check the timing and the cap/rotor/plugs to see how much "off" it was from being in-tune. I will also undo the "mexican style" air breather and put proper air snorkeling in place.

Clearly the higher temperatures were due to higher ambient air temps and I will most likely only have these troubles when I see this kind of weather again. For long stretches this isn't too bloody likely in Calgary!

Thanks for your help and tips folks.
..Vince

 

Where did you go, Revelstoke BC ?

 

Calgary > Twin Falls Idaho, via:
Lethbridge AB, Shelby MT, Butte MT, Idaho Falls ID, Pocatello ID, American Falls ID, Twin Falls ID.

Oh, and on the way down, my C6 tranny "lost" 2nd gear. Turns out the band adjuster screw lockdown nut wasn't tightened 2 years ago when it was rebuilt. $108USD later...

 

We have fellow FTE'rs down that way.

So you came back for the Stampede ? (Tongue in cheek)