I have an 02 Tundra, 4.7 4x4 that will redline 15-20 minutes after starting it. So far I've replaced the radiator and t-stat, the hoses are still good and the water pump is less than 2 years old. No sign of blown headgaskets either. Any thoughts on this?

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What is the ambient temperature and how is it being driven at that 15-20 minute mark?
Fan clutch working properly?

 

Check the fan clutch.

 

Fan clutch seems ok, proper resistance when you spin it. After replacing everything I just sat it at idle in the garage, once it reaches operating temperature it steadily and relatively climbs toward the red line after.

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Any other way to determine if fan clutch is bad?

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Just throwing this out there.... The sending unit or -something- on my '00 4.7 is broken. As soon as the t-stat opens, the needle jumps to "OVERHEAT"/redline. I know it is NOT overheating as I have been driving it like this for almost 2 years now .

Possibly your sending unit or sensor or something is problematic and once it detects a slight increase in temp, it just goes.

What signs have you looked at for the possibility of a bad head gasket?

Have you replaced the radiator cap?

 

I didn't replace the cap (for some reason). As far as the head gasket I haven't seen any oil and coolant mixing anywhere and no white smoke blowing out. I didn't put a test on it but that's just my guess.
The CTS and/or sending unit crossed my mind. I bought the truck from my dad, he took meticulous care of it over the years (has 230k miles) but I wouldn't be shocked if the newer pump is a reman, which some can have issues

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A couple years ago when the HG on my 22re went kaput, the only symptom I got was coolant being pushed out of the overflow reservoir once you shut it off. No mixing of the fluids, MAYBE white smoke, but it was still decently cold here, so I was getting condensation plumes anyhow.

Why not buy a fan clutch, then return it if its not the problem. Or keep it just to replace it since it probably has 230K miles on it.

But all this happened after you replaced all those parts? Have you tried driving it? Once you get up to speed the fan isnt doing much work.

 

It overheated before replacing the parts, the radiator definitely needed replacing, it was seeping out in different places, just strange with all the new parts that it's still doing it. I could try a fan clutch I guess....I'm curious about those sensors, think that's a realistic possibility?

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I would try the fan clutch and rad cap since it was doing it before the new parts.

 

Thanks much! I'll give that a shot!

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Also noteworthy, even as the guage approaches the redline, the air coming out of the vents isn't hot. I already bypassed the heater core once and that it still overheated

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Hmm no hot air from the vents, maybe you have an air bubble stuck in the cooling system somewhere. Have you tried "burping" the system?

 

It had appeared as though we got all the air out but I can't say 100% that I did

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