Tundra running warm

I have a 2008 tundra 5.7L with 190k miles and recently I've been noticing the truck runs warm at higher speeds on the highway (60 mph or higher). When on the highway I turned the heater to the max and the engine temps do lower a good amount making me think the radiator isn't preforming at its highest. I have also had issues with the coolant levels going down. My first thoughts to the coolant levels going down was the water pump was leaking so I went ahead and looked down at the pump with a camera but couldn't see much. I think I will have to remove the fan and shroud to get a better look. Keep in mind this is still the original water pump. I've checked the oil, looks fine with no signs of coolant in the oil and no smell or smoke of coolant being burned. If you have any ideas, suggestions or questions about this issue please let me know.

Thank you.

temps with the AC on.
temps with the heater on.

 

How much coolant have you added?Pressure test your cooling system before throwing parts at it. When my water pump started to leak, I didn’t notice until I was putting in the big Koyo radiator. It was leaking from the bottom, I never noticed it when swapping oil or even got a drip. Only thing I ever noticed was the expansion tank was a little low.

 

I am having the same issues


This recently started to happen. I have replaced the water pump, thermostat, radiator, radiator cap, with upper and lower radiator hoses. The fan clutch works fine, I did a pressure check and I am losing some pressure but I can not find the leak. The truck will run fine on short trips with no load.

 

Literally had this exact issue a week ago. For me it turned out to be a bad radiator, though the upper corner of the radiator was crusty for a few months and I was just lazy getting around to it. Replaced that and the thermostat to be safe and everything has been golden ever since.

 

If your water pump is leaking, change it...Now!

 

So i did a pressure test and turns out there is no pressure at all when hot or cold. As a matter of fact if I squeeze one of the hoses coming out from the radiator I can hear air traveling in and out of the expansion tank. My guess is the radiator cap is not sealing properly? But would that maybe be a cause to it running warm? Also for the amount of coolant I have put in it has been well over 3 gallons and the expansion tank still keeps draining into the system.

 

assuming you have no leaks and oil was good with no coolant as you are saying ... then the 3 gal of coolant must go somewhere else. Typically you don't add ANY coolant in years if everything is ok.
Are you sure the coolant is not draining out of the reservoir or the cap when the engine is hot?

Next time the engine is that hot, stop and check the ground or reservoir or the cap and see if coolant is leaking or draining ...

whatever you do, don't open the cap when the engine is warm and/or hot

 

I have checked the whole engine bay and no visible sign of coolant when the engine is hot.

 

did you check the hoses as well ?

 

Also check the heater core and hoses in that area. Not sure if there is a leak there if you can detect it quickly or goes unnoticed for a while. Do you smell any coolant when heater is on?

There must be a leak somewhere that is not detected. I am not familiar with water pump area or the engine block design and if it can cause some undetected leak (outside getting into oil). Maybe some more knowledgeable members can help in that area.

 

Unless I missed it....190,000 miles on the ORIGINAL radiator is about a full run. It's at the end of its useful life. I'd be replacing it regardless.

 

Yes I did, then all look fine. No cracks or any visible leaks.

 

All of the hoses going into the heater core look fine as well and there is no smell of coolant at all when the heater is on full blast.

 

Yes the radiator is the original radiator. I was going to first replace the radiator cap because it is not sealing properly and allowing the system to pressurize. Also replace the water pump because its past its life span and that is my only guess of where coolant could be leaking from at this point.

 

Ok, I’m lost. Do you have a cooling system pressure tester?

 

Sorry for the misunderstanding, no I do not have a pressure tester but I can sure tell you the system is not holding pressure when hot. I know you are NEVER supposed to take off the radiator cap when it's hot but I am able to with no burst of pressure when the system is hot. Also if I squeeze one of the hoses coming out from the radiator I can hear air traveling in and out of the system into the expansion tank telling me the radiator cap is not sealing.

 

I am still having this issue replaced radiator, temp sensor, upper and lower hoses, fan clutch works fine, water pump isn’t 6 months old but fixing to replace it. Also put a new thermostat in and new radiator cap cause If the system doesn’t build pressure it will not cool like it’s suppose to I will let you know if the water pump fixed my issue!

 

From my research others are having coolant leaks from under the intake manifold.

 

Now is the perfect time to buy a new tool that you'll get some use out of for all your vehicles or take it to a shop that can do it for you.

 

Ouch I'm really hoping that's not the case

 

So I followed your advice and went and rented a pressure tester to test the system. Turns out the system is not holding pressure and coolant is leaking through the weep hole in the pump and there is a small hole dripping coolant on the bottom corner of the radiator. I also picked up a new radiator cap because my original cap was missing one of the rubber seals inside. Also got a new pump and rad on the way, hopefully this will be the end of the issues and I will stay posted on how everything turns out afterwards and thank you all for the help, this sure would have been a process without it