Operating Temperature??

I have a 2006 w/ the factory tow package. On a recent trip towing my boat home from the lake I noticed my temp. on the scangauge going up/down as I went up/down hills. The highest I saw it go to was 204degrees. I was towing my boat which is about 6k plus a bed full of gear and 3 people. The motor was working hard pulling up hills which I expected w/ that much weight. I had the A/C running and it was about 95 outside. This is my boat/truck loaded.

My question is what is the highest temperature I should let it go to before I start to be concerned?? When I was at 204 degrees I was going up a long steep hill running in 3rd at about 60mph. On the way down the hill it would go down to about 190 degrees. Looking at my temp. gauge on the truck it didn't seem to go up when my temp was at 204, and still appeared to be in the center between Cold/Hot. So what is the normal operating temperature range?

 

sounds normal for towing that much weight.

 

According to my spec sheet the thermostat on the 4.0's doesn't open fully till 203 degrees, so I'd say 204 is nothing to worry about.

My empty 06 Prerunner hits 198 with the A/C on while climbing 2000' in 13 miles to get home every night when it's over 90.

 

186-190 is normal for me.

 

Thats what I'm at normally when I'm not towing 186-190.

So what would be the temp that I should start to worry?

 

i've hit 198 with my bed full of stuff while moving

 

She was working really hard during the 3 hour trip. A/C on full blast, towing 6k plus atleast 500lbs in the bed, plus three people in the truck. Along with the weight I had the hills of KY to contend with. She did good, pulled strong in third. I was surprised at how much power she had when in 3rd.

 

To the OP, I would begin to get concerned at the temp where the thermostat is fully open, I would begin to get very concerned a few degrees past that temp and would start to do things to lessen the temp load, as in AC off, slow down some, heat fully on with HVAC fan on high, etc.

 

If it would have gotten any hotter I probably would have. I'm wondering if there is anything I can do to make it cool easier. Such as a bigger radiator or something along those lines.

 

Stay right and go slower. Obviously it did fine going 60 uphill, but it probably isn't necessary to maintain that speed. Yeah, people behind you may get pissed, but as long as your in the right lane, it's hard for them to bitch.

 

Having synthethic in engine, transfer, front/rear diffs will help.
If you tow a lot maybe going to heavier oil in the fan clutch or even puting electric one in addition would do the trick.
Installing small water spray in front of radiators for the times when is really hot hot

 

Yes it did great at 60, and honestly I could have gone faster but with such a heavy load I was taking it easy. I wasn't in a rush, but in the future I'm wondering if there is anything I can do to keep it cooler.

Blue T- I'm already running synthetics all around b/c this boat gets towed 5-10 miles every weekend, and about 1000+ miles down to the lake a few times a year. I just dont want this to become a problem and have to turn the A/C off and slow down. It pulled the boat great and I was really surprised and how strong th 4.0 was. I was impressed. It wasn't a light load by any means. I just hope that getting a bigger truck isn't my only other option.

 

I'm looking for a bigger boat and your looks pretty nice, about what I'm in the market for.. what size is it and are you sure its 6k lbs? A single axle trailer usually has a 3500 lbs axle and 1700lbs max tires - does it have trailer brakes? I wouldn't want to tow something that heavy with my taco on a regular basis or any distance to be honest with you. I have 19fter now an it can struggle at times.

 

That sounds about normal for a more than average payload.

Here in Texas with the AC running and city driving I can see 186-190. If I'm idling a long time with the AC on it goes up to 194+.

This is just with myself in the truck.

Does anyone think that the Scangauge's temp reading is going to be a little low compared to the true temp in the engine? It does say *wT which I take to mean the water/coolant temp, and not the oil temp, etc.

 

Its a 1997 20.5 ft Four Winns Cuddy Cab, w/ a 5.7 liter Volvo Penta Duo-Outdrive(2 props) Yeah the about it around 5200 lbs w/ the trailer about 800lbs. So i'm guessing I'm right around 6k w/ just the boat. It has a Four Winns matching trailer and I was surprised that it only had a single axel. On the Four Winns forum that seems to be a common complaint for the brand. The newer ones seem to have the tandom axels and I really wish mine did. It does have trailer brakes, I'm not sure if there are working very well, as it seems to struggle to stop sometimes. It does struggle a bit, but w/ 6k behind you unless you have a huge v8 or diesel I'm sure you are going to feel it regardless.

 

I figure out I should ask just in case.
How about the clutch? Look at ih8mud there is a writeup there to replace clutch fan fluid with different grades that should make it spin more at lower rpms and sooner

 

Would this help on the interstate?

 

+1
I have a 2006 prerunner access cab. Ive pulled a 1983 jeep CJ7 lifted with big tires and all that offroading crap on a flatbed trailer, dual axel w/ trailer brakes and all that. with a Polaris predator on the trailer as well and a honda 300ex in the bed, along with 1 person besides myself and gear like ice chest and gas, water and stuff. Anyways, with all that stuff its pushing around 4500-5000lbs. Nearly touching the bumb stops. And i was having a little trouble climbing over steep hills. Temperature wasnt a real problem i dont think, meaning the guage didnt move, but the gas guage wasnt my friend.

Youre saying you had around 7000lbs total and room to spare....doesnt add up.

 

I would be concerned if it went above 220 degrees and looked like it was still rising. I would begin to slow down and look for a place to let it cool down if it approached 240.

At 204 degrees your thermostat is probably not even all the way open yet.

 

Room to spare??? I'm not really sure what you are refering to. But yes right around 7k of weight in the truck, including all the gear/coolers/and 3 people. I could def. feel the weight of all that, but didn't really struggle on the hills when it was in 3rd. It was never floored, and probably could have gone a little faster going up hills but never tried it.