02 DC Taco running hot on highway

Brand new HD fan clutch installed last week before we headed for the beach. Still ran into the same issues, though did notice an increase in air flow.

 

Stopped up heater core?

 

Is the lower shroud at the bottom of the radiator shroud installed? It looks like a long strip.

 

Negative on the lower shroud. It did not come with the truck when purchased. Seems someone else either broke it or forgot to reinstall.

 

that's a huge step in the right direction and when you put the lower shroud back on the radiator it will help it pull air and increase airflow even more

 

To be clear, When you say lower shroud, you mean the one inch or so strip that attaches to the main shroud.

 

yes, that thing completes the enclosure that allows the fan to pull good suction through the radiator instead of spinning air around behind the radiator. if the fan isn't surrounded by a complete ring then it just grabs air from the open space rather then pull it through the radiator because it will always grab air from the least resistance it can find.

it doesn't make a huge dramatic shocking change but it can cause several degrees of difference in temps to occur most notably in traffic or when not traveling at highway speeds which will force air through the radiator.

 

I replaced my thermostat today with the OEM toyota 82C and there was a noticeable difference on the drive home. Typically I was seeing highway temps in the 200-202 range on my UG. Temp seemed to hold steady/plateau at 188.6 in subdued highway driving (<2100rpm). I got after a bit on an uphill grade (3000) and it touched 195 but then cooled off.

The two thermos were night and day different. Whatever the PO had put in there was obviously some chinsy aftermarket. Tiny spring and no jiggle valve. I'm thinking the spring just didn't have enough travel to open the thermo enough for proper flow.

I'm also missing the bottom radiator shroud so I'll get that on order and replace.

 

Where did you get that HD clutch? I've been looking for one but all I can find is aftermarket with no designation of standard/HD. I believe the OEM was Aisin for these?

 

I got this from Napa. They had two options, and this one seems to move a significant amount more air than the original.

 

Does anyone have a final ruling on this? Based on experience towing a U-Haul through desert grades I can confirm that temp gauge starts moving around 235 and hits bottom of red at 250. I was doing 25 up these grades with heater on full blast watching my temp gauge creep up to 240. Needless to say it was a hot trip buying never hit the red. I have since changed oil and multiple ATF drain + refill.

Now running around south Texas my scan gauge routinely gets to 208-217 fairly easily. I've done everything I can think of, I'm pretty much just taking solice in the fact that Taco temp gauge stays at exact middle. I'm about ready to take engine temp off my scan gauge. It seems a lot of people have an idea of what temp it should run but no definitive range other than 235+ is when Toyota is telling you something's up.

I have a 6 month old radiator, OEM thermo, new and clean coolant, new fan clutch, full rad shroud, new rad hoses, 6 month old water pump, new rad cap. I give up.

 

I never got a real resolution to this. I towed a reasonably heavy trailer from Virginia to where we are living now in Colorado and according to my ultra guage i was running around 215 the whole way. On some hills it would go as high as 228 and on downhills would run back down in the high 190's. I only once pulled over because I was concerned about the temp, and that was driving through the texas panhandle where it was 103 out and I was pulling a long continuous grade. According to the ulta guage temp got to 230. That is the only time I noticed a real increase in the location of the factory temp guage and it started pushing the threshold of the red mark on the factory temp guage. Since we have been in Colorado I've driven around the state a fair bit and without a trailer, driving over some passes in pretty warm temps, I've gotten up to 222.

This is with an entirely new cooling system. New radiator in Feb, new hoses, thermostat, water pump. The only thing not replaced is the heater core.

What I have noticed is it doesnt matter how hot it is outside or how fast or slow I'm driving, the temp will start to creep up once I downshift. Rpm above 3k driving uphill will move the ultra guage readout up.

 

fan clutch, its the only thing left

 

I forgot to list that. It was done the same time the hoses, thermostat and water pump.

 

were all parts genuine oem parts or oem parts brands? aftermarket parts never seam to work correctly on these trucks, especially thermostats.

is it a 4 cylinder or v6?

 

All parts were OEM parts except the fan clutch. I went to the dealer to get an oem heavy duty fan clutch and they didnt have one. Napa had a larger heavier duty one that I ended up getting and it definitely moves more air. My taco is a V6.

 

195-200 is normal temps.. when you hit 215+ you have an issue. carry on.

 

Thats what I thought. The question is what is the issue? Driving normally on the highway or around town, or idling, the truck stays between 194 and 203 regardless of the temp outside, but long uphill grades, especially pulling a trailer or heavily laden make the temp creep up. I do not believe that I drive in a manner that should lead to huge heat generation.

 

change your coolant to the proper stuff Toyota calls for, the red stuff from the dealer or equivalent and while you're in there swap both hoses and replace the thermostat.

I had all that dont 3 years ago at 160k cause my cats weren't getting hot enough for emissions standards to pass smog.

I run 195-200 at all times unless I have a loaded bed then I have been up to 210 in 5th gear, when I drop to 4th it cools down again.

 

As per my previous, I have new hoses and T-stat, and did a thorough flush and am running Toyota red coolant. When I had the timing belt and water pump done they did the head gasket check and said no problem.