3.4 overheating HELP

So ive had tacomas since i could drive. Given im only 27... my father and both grandfathers were mechanics so this has me genuinely puzzled.

Has no common trend of when it overheats. Replaced thermostat, flushed coolant, no leaks.
doesnt get hot when sitting still.
sometimes at higher rpms but not always
Same as low rpms pulling a hill

Ill answer any questions. I guess i was in my early teens last time i was on here under a different name. Not sure what rules have changed but will do whatever needed to abide. Remember guys im a newb dont bash me too hard and hurt my little feelings lmfao!

 

Also this is my daily and i have to work tomorrow!
So any help would be greatly appreciated!
I know someone here has experienced this and knows exactly what it is!

 

Also when it does read hot, ive cut it off several times and popped the hood but never heard any boiling or seen any steam or evidence of it being hot but dont want to risk continue to drive because once again this is my daily

 

What does your oil look like?

When you say it starts reading hot where are you getting this info? The needle on the dash is moving up, or do you have a scangauge type device that's giving you the actual temp? Does your check engine light come on? Any error codes?

 

I have had this issue, but it was my radiator, same symptoms for what it's worth, and I didn't have a leak either. It was also the original radiator with 210k miles, I only replaced it because i started stockpiling parts due to its milage, and my check engine code has been a bad o2 sensor

 

Clogged Radiator

 

This. don’t rely on the dash gauge get a reader of some sort if you don’t already have one.

 

What temps have you been running?

 

Could be a clogged radiator, but I had some weird overheating issues on a 22re. It would be fine on the highway, but as soon as I got off and started driving 25 mph it would overheat.
Turned out to be a tiny head gasket leak. My oil was milky, but it didn't appear to be losing any coolant either.

 

Depending on where you are at in mileage, it may be worthwhile to replace the radiator, thermostat, water pump and while you are at it, change the timing belt. If you are replacing the radiator, you may as well knock out those routine maintenance tasks, as well.

Not that they all necessarily need to be replaced TODAY to solve the problem, but chances are, those changes will fix your issues and give you plenty more miles. The plastic in these radiators has a limited life span and the more the motor overheats, the weaker they get.

Over 200K, you are running on borrowed time with a stock radiator.

 

This is a double edged sword, though. I see a LOT of posts where people are freaking over their temps going up, when in reality the only thing that has changed is they are now seeing *actual* temps from their new scangauge, rather than the needle on the dash that only gives a "filtered" reading - the needle only moves when it gets higher than what the engineers determined is approaching the danger zone.

I had been tracking the trans temps of my new 4Runner when towing my 20' travel trailer up some pretty steep (1st gear) hills, and the temps were getting rather high, high enough I was certainly concerned. But they never got high enough the ECU decided to warn me about it with an idiot light or an error code. The temps were high enough I'm going to install an external trans cooler, but more because that's easy to do

 

Clutch Fan

 

Never noticed much change in engine temps 185-205 but never above 205 which is nothing to worry about. Transmission temps on the other hand climb up and down a lot when towing. So long as you know the ranges for each your fine. Knowledge is power right.

 

As long as you know what to do with that knowledge, sure.

But that's kinda why engineers "hide" certain things from us, like precise engine temps. Because we - the consumers - are stupid, lol

 

You have replaced the thermostat... is it a Toyota thermostat? if you have the 3.4, the bleed hole/jiggle valve installs at the 6 oclock position, not 12 oclock as on other engines. This is know to increase running temp by some 10 degrees.

Is it truly overheating? I ask because what some people claim to be overheating isnt, it is just running hotter than "normal". Is the radiator pressure cap holding pressure? Is the fan shround on the radiator and is the fan clutch functional. Hopefully it is as simple as the radiator. My buddy was telling me that he had an older ford truck in the shop for "overheating". It wasnt overheating, it was running hotter than normal due to AC condensor blockage due to the owner speeding up to hit as many of the Painted Lady butterflys that were migrating across the desert... doh!

 

Serves him right lol. Would've been even better if his truck did overheat and blew a gasket...Ford truck taken down by swarm of butterflies. Just has a nice ring to it...

Found one of those in my air filter the other day, snorkel got him. Was still alive too, took some encouragement to get him off.

 

^Check this^

 

Clutch Fan is only for a manual transmission.
You might want to check the Fan Clutch. (Is the radiator cooling fan spinning when the engine is up to temp?)

 

Mine recently popped above 205 so I've started to worry. I turn the heater on full blast and it cools rapidly. I plan on doing a cooling system flush soon.

 

Responding to most

Haven't checked actual temp.

Replaced fan clutch

Oil looks new

Hulled out a thermostat and it didnt overheat the only time I've driven it since but it just overheats sometimes anyways so I'm not sure if it was because of that or not.