Engine Operating Temps while Towing - conundrum (1 Viewer)

[MXB]

I really appreciate the knowledge gained from this forum. We have a 2006 LC with 185k and love it!

While towing appx. 4000lb trailer to Disney World Fort Wilderness with the fam, noticed that my normal operating temps were 196F. Driving in 4th, ambient temps 93F, trans temps 145F, speed 58-60mph, 2600 rpm....but whenever I would exceed 3500 rpm to go up a grade or pass someone- temps rose to 205-208 and stayed there even after settling back to normal speed.

They never return to sub 200 until we stop for gas or rest. I then maintained sub 200 temps for 4 hours by consciously not going over 3000 rpm.

At idle, or in the city temps are sub 200- hit 201 once.

Under load I expect it to be higher, but surprised it won’t recalibrate back down. Coolant is full to the neck, fins are clear- sticky thermostat? Thoughts?
Thanks.

 

[baggar11]

Luckily my LX doesn't exhibit issues while towing. But if it's anything like the 80 series, I'd look at the radiator and fan clutch.

 

[erse]

From the details you list. Sticky thermostat might be a reasonable suspicion. Change it out and see where it gets you. 205 under stress doesn'tt
sound terrible but it should fall back to baseline after the stress is reduced I would think.
Thermostat change is a quick and cheap place to start

 

[geanes]

I tow a small trailer (Morris Mule knock-off). Weighs about 1100lbs total. Driving to Dallas this weekend (4 hr trip), I'd see 195 on engine temp under hard acceleration, but it would settle at 190 very quickly. 93 degree ambient. Without the trailer, my 98 LX (4-speed) runs 188 on the engine temp without any variation. Trans temps would settle around 145-150 cruising at 75mph when overdrive was on. It would climb quickly to 178 when accelerating or decelerating, but return to the 145-150 range within a minute or two. I recently replaced my fan clutch and did a thorough cleaning of the radiator and trans cooler using a coil cleaning spray.