Your feedback on temp while towing.

[ClicksCrazy]

We have a new 2,400lb Travel Trailer. Never towed much with our TB before.

In Prep for trailer I replaced the coolant, thermostat and coolant sensor. I also added a Hayden transcooler and did a trans service (Filter and fluid). All completed within the past 3 months. I also put in a new fan clutch within the past year.

The temp pegs at 210 all the time, and even while we were towing it home last week (In Florida).

HOWEVER: At one point, while in 3rd, the TB downshifted to maintain the 55 cruise. The rpm's went up to about 3,500 maybe a little more.

As soon as that happened, my temp went up about 15 degrees. When it did this, it had plenty of pull and got right back up to speed. It took about 5 minutes and the temp went back to 210.

Its my understanding, that should not happen. What if I was actually climbing a hill. I would certainly be at 3,500 rpm consistently.

Feedback?

 

[ClicksCrazy]

Thought I would add I that I am going to try replacing the cap and burping the system. But it will be hard to tell if it works since I am not towing all the time.

 

[djthumper]

Staying at 210 is a good thing. Did you put the new cooler before or after the built in one?

 

[Mooseman]

What he said. Mine kinda varies between just below 210 and just above without towing. And that's on the gauge, which is not that accurate.

Different things could affect the temp. Load, gear, incline, outside temp, A/C on. It's possible the sudden increase in RPM and load spiked the temp and the fan took a little time to catch up. Best thing for monitoring temps is to get a Bluetooth OBD adapter and the Android app Torque.

Out of curiosity, what brand fan clutch did you buy?

 

[NJTB]

I towed a 3500 lb. boat with mine from central jersey to PA, outside of Scranton, about 100 miles. On relatively flat ground, the temp stayed at 210 or so, but when I hit the big hills, went to 230. Struggled a bit on those hills.
I did drive in D3.

 

[littleblazer]

I've never towed mine on the highway but the combo weighs roughly 3500 lbs and the 12 mile drive in town yields a temp of 225, according to torque, just as I reach the ramp. But it's all stop and go. Both trucks too. One has a mechanical clutch and stays a little lower as a well as a trans cooler but at 90 degrees it's hard to keep both cool. Some where there is a list of commanded fan speed vs temp and I don't think the fan clutch really engages until you start going past 230. Either way since it came right down I think you're fine. I would burp the system like you said though.

 

[ClicksCrazy]

I installed the cooler before the factory one I believe. I followed this video:

Fan clutch, I actually paid a shop to do that, so I am not sure what brand. I know before I had it installed, it never ran on a cold start up...or ever I think. The new one runs on start up for a few mins, then goes off.

Based on these experiences, maybe its normal. I have a small local trip planned in Sept.. I will report after I burb the system and replace my cap.

My gut is telling me the impellers on the waterpump are just worn. Its original according to records and at 153k.

Forgot to mention. When the fan clutch was done, I made sure the shop put in the revised version.

However, the PCM was not re-flashed, which I believe increases response time. I think the local dealer wanted like $200 to reflash it though, so I didn't do it.

[Mod edit: Posts merged. Please use the edit button to add to your post. Thanks.]

 

[Mooseman]

Looked at the video and it is correct and is after the stock cooler.

Your `05 should be fine with the stock PCM programming. Only 02/03 had slight issues with fan engagement causing noise and shift issues.

Pump impellers don't wear. The pump only fails on either the seal (leaking) or the bearing (noise/wobble)

Here is the table for fan clutch engagement:

 

[Tiggerr]

If your going to 230 in big hills like that area I'd say your fine... sounds reasonably normal to me... don't forget gauge isn't real accurate either.. as long as temps come back down when your back on flat ground you should be fine...
Temp on my semi will climb too climbing hills like that...

Ok got confused as to who was where...

But in FL with the heat and a good grade...I still say you're fine

 

[ClicksCrazy]

Looked at that chart. Very interesting. The fan will only run at 29% at 225.

Am I reading that correctly?

I am not sure where I heard the blades on the impellers wear, maybe on the old Trailvoy site.

Thank you guys SO much for the feedback. Nice to have a community again.

 

[Mooseman]

We were always here. Just needed to find us!

 

[ClicksCrazy]

Here is a pick of my towing setup:

 

[Tiggerr]

Here is a pick of my towing setup:

That old school "tag-a-long" look camper has really made a comeback! I see tons of those everyday getting hauled out of northern Indiana....
Nice setup. I like those myself...especially the "retro" ones that look straight out of the 50's

 

[ClicksCrazy]

Update: A few interesting things on this.

1. Burping system. I am not sure if I did this correctly, but I took the radiator cap off (and reservoir cap) and let the truck idle until 210 temp was reached and let it sit there for a few minutes. As it was doing so, coolant would rise and overflow (I sucked it up with a baster). Eventually, it seemed to stop doing that or slowed down.

So I shut the truck off, and put on the new cap. When cold, I filled the reservoir tank as it had been depleted some.

2. New Cap. I got a new AC Delco cap. It was identical except the new cap had a thicker round rubber seal on it. The old cap had a different style rubber seal or it was worn because it was flat.

The old cap also had what I think is junk filling the slits around the top of the cap. I could dig it out with my finger. In the new cap, the slits around the top were clear and visible.

3. Performance. Before doing the above, I decided to run the trailblazer at about 2800 rpm in 3rd at 75mph for about 15 mins, just to see if I could get it hot. When I started this test, I took off fast and reved to 4000 to simulate what I experienced towing. I saw no temperature change.

Conclusion: I am not sure if burping or the cap will do anything, but it needed to be done anyway. Overall, it seems there is not a blaring issue with the cooling system, so maybe what I experienced was just a fluke, or poor gauge reporting.