Another overheating issue but a little different

Rig is a 98 with a 4.0 and a auto with Overdrive, I have 4:56’s on 33’s

OK here is the symptom. Rig runs around 210 220 while pulling my Pop-up, the trip I take has a lot of big hills on the highway. I can pull three or four big hills everything still cool then almost to the top of a big hill and BAM check gages light pops on the temp is pegged. Followed all the things I searched here for, changed thermostat, hoses, water pump, and radiator. I think the fan works both of them seem to spin when at idle.
Now what do I try, kind of sick of throwing money at it.

Transmission also uses the radiator to cool. Do you have a transmission cooler? If not, the extra heat generated by the transmission working so hard can put the cooling system over the top.

I have one that will be installed this weekend, but I'm not sure that will make that big a differance, I'm careful to not let the tranny shift much while on the hills, I'll run in third If I need to. But I will be installing one next, not much cost for something that can't hurt.

Try to look at the parts as maintenance/wear items. Some of them were probably about due to be replaced anyway. Still cheaper than a car payment .

Weird how you can climb some hills, then have the sudden spike. But it does sound like a cumulative thing in which the system eventually becomes overwhelmed (or takes enough time heated up to cause problem). Temp sender bad?????

I wonder about air flow through your radiator - look for bugs and rocks and crap in the a/c condensor and clean those out as best you can if you haven't. It's free. The grill (at least on my '95) comes out easily and you can pick alot of the crap out. Air or water pressure from the engine side out will push some of it out also.

If your temp sender is good, overheat at speed is usually a radiator issue - either air flow or water flow or combination thereof. Running 210 on flat land seems a bit high at highway speed to me unless outside temp is 100+. Mine pulls the boat (2000 pounds) more like 195 - thermostat opening temp. Does go up some up hills, but I usually baby it some too. Hate to overheat.

Possible the lower radiator hose is collapsing when it heats up? Seems like it would earlier, but...

some have a spring inside. Mine doesn't but I got around it by just putting several hose clamps on the outside of the hose at intervals in the places most likely to collapse. Keeps the hose round.

Are you running your a/c up the steep hills? Adds load on the system, and preheats the air going through the radiator. If so, try turning off the a/c and see if that makes any difference.

Hope you solve your problem.

Haha, I am just about to leave on a long trip up high mountains with 1200lbs of cargo....

I am wondering the same thing, mine gets super hot!

I really think the whole motor gets heatsoaked. I think I am going to pop the hood up hills so it can suck in some cool air. (the secondary latch will keep it down....hopefully!)

Is the tranny locking up? If the t/c isn't locking, that will generate extra heat.

When I lived in the Desert and had a motor I liked, I'd most always install a high volume oil pump, a pancake filter adapter and an engine oil cooler. Bathing the inside of the motor with 160 F oil, really works wonders on keeping the temperature down.
There is more than one way to cool a motor.
The only real shortcoming to an engine oil cooler is when it gets cold out. And adapters with a thermostatic bypass are pricey.

lawsoncl said:

Is the tranny locking up? If the t/c isn't locking, that will generate extra heat.

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This is somethig I have thought about, but everything seems to go along fine, doesn't feel like it's sliping. In fact on the trip home I would just keep the rpms around 2 and just let it pull in 4th (overdrive) and in t never down shifted by the time I got to the top of the hills I'd be running about 20MPH but I didn't over heat.