Cooling question 2011 5.7l

My truck does not run hot at all, but after driving it, I can put my hand on the lower radiator hose and it is like room temperature. I wouldn't think it's possible for the radiator to cool the coolant that much before it goes back to the motor.
Has anybody else had this?
I guess as long as it's not overheating it's ok, but it just seems very odd to me.

 

Hmmm.... does seem a little odd.

Only thing I can think.... are you sure it's circulating and the gauges are working?

I've never had occasion to check the hose, but I guess now I'll check it next time my engine is hot, just out of curiosity.

 

Gauges must be working because I watch it warm up, reach a temperature and stay pretty much there. It varies a little, but not much.
I put a new thermostat on it a few months ago because it was getting warm when I towed. That solved the problem.
Never checked it until after I did that and I only did it out of curiosity one day.

 

That’s completely normal. The only time the lower rad hose will get hot is when the thermostat is fully open. For that to happen on a heathy cooling system, you’d have to be working it fairly hard in warm weather.

 

That's good to know. All the other vehicles I have owned, this is the first one I have seen that happen. But if it's normal on these, good deal.

 

Just got home from driving about 30-45 minutes at highway speeds.
Got my temperature gun out and shot the top part of the radiator. ~199.
Shot the area right before the thermostat on the engine. ~199 as well.
Shot the thermostat housing. ~80!!!!!!!
Shot the lower radiator hose. ~80 as well.
WOW

 

Well I got another thermostat and did an old school mod to make sure I was getting flow through the whole system.
I drilled a few small holes in the thermostat to make sure coolant was flowing even when the thermostat hadn't opened yet.
Went for a drive yesterday. Shot the same spots as before.
Upper and lower radiator hoses were ~114.
Area on engine right before thermostat was ~146.
It wasn't a long drive, but this at least tells me I am getting flow. The gauge read a good bit lower than normal, so at least I know it works.
Today I will be pulling an enclosed trailer for about 1.25 hours on the interstate. We'll see how it does.

 

Well, I pulled my 14' tandem axle enclosed trailer on the interstate today after the thermostat mod.
Went 1.5 hours each way.
Traveled at between 75-80 with the trailer full. RPM's stayed between 3300-3500 all the way there. No difference if Tow Haul was on or off.
Temp gauge stayed just a coochie hair below where it ran not towing. Good news.
Went 80 with the trailer empty. RPM's stayed right at 3500 all the way back. Temp gauge stayed the same.

BAD NEWS, the gas mileage doing this SUCKED bad!!!!!
I filled up before I left, reset my Trip Meter.
At 157 miles I ran COMPLETELY out of gas.
(Yes, my fuel gauge is one of the ones that never reads right. I will change this ASAP.)
This worked out to right about 7 miles per gallon!!!!! FRIGGIN HORRIBLE!!

 

My engine never goes above 194 - no matter how hot it is outside or stop-go towing But the transmission sure does heat up. At idle it will be 183 but stop-go gets it to over 230 for a few seconds here and there.

If I were towing I'd watch the trans temps too maybe even use something like Torque Pro ($5 for android-apple + and a bluetooth odb2 connector) adding the custom Toyota PID so you'll know Real time trans temps and can then use that information to select the correct gear - maybe not sucking al the gas in 157 miles of towing - just a thought - Luck.

https://play.google.com/store/apps/details?id=org.prowl.torque&hl=en_US&gl=US

 

I did keep an eye on the trans and oil temps as well. They never varied off of normal.
I may look into that app. But I don't tow very often at all.

So are you basically saying that I should have gone to 'S' mode on the shifter and played with it to maybe get the rpms to drop?
The only time they really dropped, momentarily, was going downhill.

Thanks for the help.

 

I have the

$27 Ancel AD310 Classic Enhanced Universal OBD II Scanner Car Engine Fault Code Reader CAN Diagnostic Scan Tool, Read and Clear Error Codes for 1996 or Newer OBD2 Protocol Vehicle (Black)

Ancel AD310 OBDII scan tool that shows live data, but just looking at it a minute ago, looks like it doesn't show engine or trans temps. Shows almost 50 other items though. LOL

 

Exactly - I usually can use 5 which is still an OD with some slip occurring but watching the trans temps I can see (in my case) it can make it drop from about 230 to 205 just by bringing it down from 6 to 5. I only bring it down to 4 when going thru mountain passes or other steep inclines lasting a while. Luck.

 

I will definitely have to do this next time.
I guess just leaving it in Drive causes the motor to work to hard, therefore sucking the gas.

 

I pull a 9000lbs RV twice a year. I'm always in 4th. Trans temps stay close to engine temps, even in the mountains.

My average is 9.2 mpg dragging the camper. I don't go much above 65 mph.

The engine loves 2900 rpm.

 

Well it now throws a code about the thermostat and the temperature.
I think I will get another thermostat and only drill 1 hole this time. I drilled 4 on the current one. At least I now know that it worked.
1 hole will still give the thermostat a chance to open on it's own as well.

 

Its really just creating a "jiggle" valve (with no jiggle) - Odd how some thermostats come that way to begin with. (My 01 4Runner does from factory).

 

If you keep the truck cooler than it wants to be you’ll continue to get terrible fuel economy. So confused on why you’re drilling holes in thermostats.

 

Ditto. Drilling holes in a thermostat defeats the whole purpose of having a thermostat, and keeps the ECM operating in open loop. Running an engine too cold is almost as bad for it as overheating.

 

Kind of like leaving the fridge door cracked open to make sure it’s working…

 

LOL, it was basically to make sure I was getting good flow out of the water pump. NOT a permanent fix.
However if you look at PLENTY of thermostats out there, they do have 'weep' holes in them from the factory.
That is what I will do with the next one. 1 very small hole to let coolant flow all the time at a very small rate. It won't affect the thermostat doing it's normal thing.