HELP no idea why my poor truck is overheating :(

Hello everyone, I have a 2003 Tacoma 3.4l that has been running hot/overheating for a while now, but I can’t figure out what it is and I’ve taken it to several shops and no fix.
I’ll do a quick list of what I’ve done, and then further down a more detailed explanation:

Truck heats up, but after performing pressure test, I replaced thermostat twice, upper radiator hose, coolant flush, fan clutch, and still overheating.

The first time that i noticed it running hot, I saw that the coolant reservoir was empty, so I filled it with coolant and it was okay. A few days later it was still heating up so I took it to get a cooling system evaluation at pep boys. They told me the heat was coming from the upper hose, and they wanted to replace my upper hose, thermostat, coolant sensor, and do a coolant flush. I was worried about my head gaskets (since I’ve read too many horror stories) so I asked them and they said they had done a pressure test, and that the gaskets were okay. (To this day I am worried that was a lie, they never did the pressure test, and my gaskets are about to blow). Anyway they wanted to charge an extra $650.00 to replace all of that so I ended up just replacing it all except the sensor. I also went ahead and replaced the fan clutch because it wouldn’t hold. After all of that, for a few days the engine was running fine, but now it’s beginning to do the same thing, and heat up about 30 minutes into driving. I’ll notice it’ll heat up if I drive the truck like 40+ mph and it only heats up after I slow down and air stops flowing. At very low speeds or idle it won’t heat up.

Please help im thinking either pep boys lied and my gaskets are about to pop, or maybe the sensor is bad? They never told me it was bad they just recommended I change it too.

 

Have you replaced your water pump recently? What about a new radiator cap?

 

I replaced the water pump during the same job when the timing belt was replaced, and yes I got a new cap. Once again like with pep boys, I’m a little paranoid that the shop DIDNT replace the water pump like they said, cause the original job was supposed to be just the timing belt.

Edit: I guess I can’t say “i” replaced it, the shop was supposed to replace it,
About a year and a half ago

 

I fought overheating issues for about 8 months until I figured out what was up.

1st...you can also rent an exhaust gas detector at your nearby chain autoparts store to double check that exhaust gasses are not bypassing your head gasket and going into the coolant.
It looks like this. If there exhaust gasses it'll turn yellow.


2nd...how clean is your radiator? I did all kinds of stuff to my truck. I pulled the radiator and it was absulutely plugged with dirt. I cleaned it out and put it back in. Now my truck doesn't go over 195 degrees.
Clogged...

 

I’ll probably try that actually...I hadn’t really thought about it because also a few months before the water pump replacement, I forgot to mention my radiator cracked as well lol...so that was replaced about 2 years ago. But the coolant reservoir tank was extremely dirty recently too, whenever I did the flush.

Worst case scenario, is it really that hard to replace a water pump yourself?

 

It's not all that hard.

You gotta remove the fan, fan clutch a bunch of pulleys, timing belt cover and lower radiator hose, and maybe some more to get to it. While your in there if your timing belt is getting older you might as well replace that as well.

The red arrows point to the water pump. This is mine either putting it back together or taking it apart.


When I replaced mine last spring I also replaced all my AC components. My compressor grenaded. It's a lot easier when the bumper, grill, condensor are all off the truck. Also letting all the air our helped.

 

should be able to tell if the water pump looks "newer" than the rest of the engine.

 

This^...I think you can see a little bit of the end of the pump if you follow the lower radiator hose to where it connects to the thermostat. If it's much cleaner than the rest it's probably newer.

it's pretty standard to replace the pump when replacing the timing belt. The water pump is like $30 or something.

 

Do yourself a favor and take it to a reputable mechanic, not pep boys...they screwed me over big time and don't know what the hell they are doing. They also managed to lose my damn keys.

Are you losing coolant? If so, and you can't find the leak i'd consider a pressure / leak down test - - and NOT by pep boys.

 

I generally would stay as far away from Pep Boys, Express Oil, Pennzoil, etc. etc. etc. as possible, when it comes to having someone do work on my truck. Either take it to a Toyota specialist, a dealer, or learn to do the work yourself. For jobs like this that are either too time consuming or too easy to screw up, I'll suck it up and take it to the dealer or a Toyota specialist.

Oil changes, brakes, tire rotations, other lubing and drains/fills and pittly one/two hour stuff like cleaning the intake, sensors/switches, brake fluid changing/bleeding are jobs I will do myself. Which is about 99% of the maintenance needed on the truck. I have likely saved thousands of dollars by doing these (very simple/not time consuming jobs) myself, instead of what I consider wasting $2-300 a pop on a labor for a $50 parts/fluids swap.

My truck sees a real mechanic maybe once or twice every 5 years. And when I hand my truck over to someone else, I want to be damn sure they know what the hell they're doing or have some type of labor warranty.

IF you are continuing to lose coolant, the water pump would be the first place to diagnose. Removing the timing belt cover should reveal any leaks in/around the water pump area. If that is the case, I would very reluctantly go back to Pep Boys and tell them to fix their F-up. And keep a watchful eye on it afterwards to make sure it's not going to have any problems in the short term.

To add, if it is indeed the water pump and they are at fault, if they do fix it, go somewhere else and get a compression test done. If there are problems, go back to Pep Boys with said printout of compression test, and say "look, your shitty waterpump install made my truck overheat, and now we have bigger problems"... obviously don't word it that way, but in a nutshell, that's what I'd do.

 

on the 3.4 V6, if the thermostat is installed incorrectly with the "jiggle valve" at the 12 o-clock it will run a little hotter, 5 to 10 degrees. many, many posts regarding this. Put the jiggle valve at the bottom.

 

Awesome advice

 

Quicker, simpler and cheaper to just look in the radiator with the engine warm and running. If it looks like the fluid is boiling/really turbulent, you've got an exhaust leak. It's not as precise and won't catching a tiny leak but no gear needed. Generally if you're not blowing fluid out of the overflow you don't have a leak on that side of the gasket. And if you're not blowing white smoke, none on that side either. But if you're regularly running dry, that fluid has to be going SOMEWHERE.

 

what is "hot"? you never mentioned a temperature. is it +5, +10 , +20, redline?

are you seeing any fluid drips or spots where you park?

the upper radiator hose SHOULD be hot as it flows through it and and then down through the radiator to cool.

if there is a faulty sensor they could (and probably) have used a cheapo part that reads wrong

You may want to get yourself a bluetooth OBDII plug-in module to monitor temps (or a more expensive device with more bells & whistles)

If you don't notice any leaks up around the heads then your gaskets should be OK, replace only if you really want.

 

My old 98 4Runner with a 3.4L had overheating or running very hot issues. When I took it to a Toyota Specialist, they took one look at it and said, "Clogged radiator." I didn't believe it. One day later, $200 later and they flushed and cleaned the radiator inside and out. Never ran warm after that.

 

You can always put a brand new shiny aluminum one in!
http://www.championradiators.com/Toyota-Tacoma-Radiator-1995-2004

 

Mine has been slowly creeping up in temp. It use to be 199-203 and now it’s reaching 208. It’s original from the factory so it’s time for a new one. I ordered an all aluminum one from Champion Radiator. Should get it tomorrow but can’t install for a couple more weeks.

 

I'd say the radiator is old and inefficient from buildup inside and out (especially if it's the original). Flushing won't do much to clean it out.

And "the heat is coming from the upper hose" is bogus, as if the hose itself is generating the heat. It's supposed to be hot because that's the outlet from the engine, so that mechanic is an idiot (like most mechanics).

 

“Can’t” because I’m currently on ship and won’t be off for two more weeks. Luckily we’re in port and I can order shtuff to the boat but upper management won’t approve of me fixing my radiator on company property. She’ll be fine till I get home.

 

Where you live? If in TX, or near ATX, bring it to me, I'll shoot ya strait.