Drove the 10,000 lbs. travel trailer from South Padre Island to Brownsville today to get new trailer tires - about 40 miles. Everything was fine and temps for coolant and oil were normal (about 210F for oil and 197F for coolant). Ambient temperature is about 83F.

Coming back, I noticed the coolant temps creeping up to around 210F while driving about 35 MPH in Brownsville with a corresponding increase in the oil temperature. Got on the expressway, accelerated slowly to 55mph and the coolant temp climbed to 216+F with a corresponding increase in the oil temperature. Pulled over on the shoulder and after a few minutes at idle, the coolant temps went down to around 203F. Accelerated slowly to 55 mph and drove a few miles. The coolant temps climbed back to around 216F-219F. Stopped and idled and repeated the drill several times until I got the trailer back to the RV Park. I did check under the hood, and found no puking, the coolant level in the expansion tank was within 1/4 inch (low) of the min line and I saw no bubbles in the expansion tank. Both hoses looked good and there was no evidence of spray in the engine compartment.

I did notice while driving that there was a faint strange wrrrrrrr noise that I hadn't heard before when the temperature was climbing. There was no noise at idle.

After unhitching the trailer, I drove the truck without trailer at 30mph, 55mph and 65 mph. Engine oil temp/coolant temps were as follows: 55mph-201/190F; 65 mph 199/188F which are my normal ranges. Tonight the coolant level in the expansion tank is right on the min mark.

I need to take the trailer home to North Texas in two weeks. The truck just turned 90K miles and the coolant has been flushed and changed at the dealer as per schedule. Tomorrow morning I will sniff the coolant expansion tank for fuel smells and pull the inlet hose and see if there is decent flow.

Any thoughts would be appreciated.

 

With coolant temps at 219* your cooling fan should have been roaring. Did you hear it?
Deltas shouldn't be taken while pulling a trailer so the 15* rule will go away.

 

EGR valve connected?

Josh

 

Don't know if I heard the fan. Did hear a wrrrrrrr sound. The question is, why problems when towing, why no problems when not towing.

 

Truck is stock-egr works fine.

 

Your temps are a touch high unloaded too. Towing is amplifying the issue.

Josh

 

The fan would have been a unmistakable sound. It kinda sounds like a fighter jet. Set your Scangauge up to read FSS and see what it reads. I'm guessing you have a copy of the x-gauge codess since you have other PIDs set up.

 

I'll put in the codes tomorrow morning for the fan. What am I looking for and what is the unit of measure? Thanks.

 

Fan Speed Sensor read in RPM

Ford/Lincoln/Mercury Specific : Linear Logic : Home of the ScanGauge

 

Not necesarily. I run consistant 195 to 197 empty, even in 60 degree amb. in the rain. 202 to 204 towing. Has been this way since new and I still have the original t-stat. I actually think I have one of the better t-stats that isn't running on the cold side.

 

You're running the original t-stat because you're truck hardly has any miles on it.

And I was referring to his ECT/EOT temp spread and not the ECT temp by itself.

Josh

 

The outside temperature has dropped from 83F yesterday to 50F today. We had a cold front blow in last night.

Drove a few miles to breakfast today and got the ECT up to 190F. Drove back to the trailer and programmed the ScanGauge II to read fan rpm's. Here are the results:

Starting up at idle: 339
Driving out of the park at around 25mph: Near 400
Driving at 55mph and 190F ECT: 574-607
Idle at Traffic Light: 442
Driving back and over the causeway at 55mph and 188-190F ECT: 551

I'm letting the engine cool down now and I will check the wiring on the fan, the smell in the expansion tank and the flow into the expansion tank. This afternoon, I need to bring a friend's trailer on to the island. I'll see how the temperature behaves. It is less than 10 miles.

Anything else I should do? If I need a water pump, my choice out here will be between a Murray from O'Reilly or a mail order Gates. Does anyone have any experience with either of these pumps?

 

Looks like the fan is working. It would be interesting to see what the fan RPM is when the coolant temp raises.

 

At 210 my fan is unmistakably loud. Youll hear it for sure.

 

Just got back from towing a friend's 5th wheel from the main land on to the Island. The trailer probably weighed around 6000=7000 lbs. The trip was around 15 miles each way. Everything went smoothly going out with no trailer and also back with the trailer. The ECT ran from 188-192F both ways and the EOT temperature ran from 194-197. This delta is better than I usually get. The fan rpm's ran from 350-500 or so and the fan was on the whole time. I was surprised at this since I thought the whole idea about the newer fans was to cut off at higher speeds. The ambient temperature is 49F. The max speed was 55 mph.

So what were the differences between yesterday and today. Besides the ambient and running ECT temperatures and the lighter weight of today's trailer, I had the ScanGauge programmed for fan speed today and I could see that it was running all of the time. I also checked the wiring today and I jiggled the plug on the fan clutch and noticed it had broken off its pedestal. The fan ran prior to jiggling. All wires seemed to be intact on both sides of the plugs. I noticed that on the fan clutch side there seemed to be an extra light gauge blue wire not hooked to the plug but in the loom. There were five wires on both sides of the plug so perhaps this was just an extra wire? There was no diesel odor in the expansion tank.

When I get home and have a little time, I think I will replace the water pump as a preventative measure. I think 90+k miles out of pump is probably a reasonable life. I plan to use a Gates or Murray (O'Reilly). Does anyone have direct experience with either of these two pumps?

Thanks for everyone's thoughts. If anyone has additional thoughts, please add to this post. But at this point, I still don't know what happened yesterday and that bothers me a bit.