Hey guys,

I'm running hot (almost overheating but not yet) unless I run my heater on at full blast. I've changed fan and fan clutch, thermostat, and flushed and refilled the coolant with the proper technique to drain any trapped air several times (each time, the coolant comes out sparkling clean.

Engine runs awesome otherwise and was rebuilt about 20,000 miles ago. Doesn't burn oil or lose coolant. Not a headgasket issue I'm sure. It only overheats on uphills or at idle after about 5 minutes. I'm going with a new radiator from radiator barn next.

A toyota tech told me that even after flushing the radiator and seeing really clean coolant, it could be clogged up pretty bad thus limiting flow. What else do you guys think it could be if its not the radiator.


thanks,

-shawn

 

Possibly bad new thermostat? Are you sure the fan is running/turning?

 

I had a bad thermostat, now I check every new one visually by boiling it on the stove. If it don't pop open when the water starts to boil, take it back.

 

Water boils at 212 F

Thermostat is supposed to open at 180 F IIRC.

 

If everything else checks out, suspect the radiator. Do driving conditions matter on the overheating? For example overheats on hot weather, but not cool, only at high speed/load but not at slow speed/load, etc.?

You can do a quick check by spraying it with cold water once the rad is hot and watch how the water evaporates, if there are spots that remain wet/cold, that area may be clogged. Or feel the face of the radiator for cooler areas. A shop could open up the rad for a look at the core, of you can get a pretty good idea looking in the openings yourself. Especially look inside the lower hose fitting, see if there are deposits along the bottom of the core. A new 3-row rad won't run much more than $100.

 

thanks for the reply guys,

to answer some questions:

I'm almost positive it's not the thermo cause it was overheating with the old thermo that was only a year old. After I replaced it, I tested it on the stove just for peace of mind and it popped open at the right temp.

Also, it's kinda weird but I can fire the car up when it's cold, and it won't overheat when it sits (longest I let it idle was for about 15 minutes) but when I drive, then let it idle, it overheats. doesn't overheat at high speeds (30-75+) but at slower speeds under load, like uphills. And as soon as I turn the heater on when I see it start to get hot, temp guage goes back down to normal, unless I'm griving up a hill and then the heater barely helps out.

By the way, all this started when I decided to change the fan clutch and flush the system. the old clutch was leaking fluid but worked. the new clutch also works good and draws plenty of air. The truck never overheated before.

I hope this anwers any questions. guess I just gotta change the rad even though it looks really clean inside and out and I can't really find any cold spots when I've checked it.

Any other ideas?

 

sounds like what my truck did a while ago i check every thing turns out the Radiator was pluged so i went to a junk yard and got one no problems now

 

Have you tried checking in between the condensor and radiator to see if you've got leaves and junk stuck in between them?

 

ironmike,

yeah, everything seems to look o.k. I've blasted both with a pressure washer and water flowed nicely in between the two.

 

took the radiator out today. looks like a 2 core. does a 3 core cool all that much better and possibly clog less?

btw, the inside and out of the old radiator look clean as heck. could there be a clog inside some of the cores that I could be causing this much overheating even if flushing it produces clean water?

 

The V6 radiator should be a 3-row, that is what comes from the factory. Likely your problem is just an undersized radiator. Water flushing clear through it really means little, if a passage is plugged, nothing will flow through it, so all you are seeing is the clear water running through the open passages. Blocked passages are usually clogged with hard deposits. I had similar overheating problems in my 22RE. It had a cheap aftermarket 2-row radiator installed by the PO after the original one was damaged in a fender bender. The core looked fairly clear but the passages were just tiny, like flattened soda straws. When I finally replaced it with a heavy duty 3-row unit, you could see down the passages, they were huge by comparison to the old one. Since replacing the radiator, I've not had a single overheating issue in 6+ years. Even had a fan clutch fail once (100F temps in stop and go traffic) and still did not overheat on me.

 

thanks roger,

yeah the PO did the same on mine. it's a 2 core radicon radiator. I saw in other posts that you run a godan radiator. where did you get it from and will it be an exact fit for my truck?

 

GoDan (now TransPro) radiator for a 22RE turbo is what I run on my 22RE:
- http://www.4crawler.com/4Runner.shtml#Engine

Picked it up at a local radiator shop of all places (http://www.radiatorland.com/). Other on-line radiator places carry them. Mine was an exact fit. One advantage of a local shop is you can take it back and exchange it if it doesn't fit. Had that issue with my VW, the replacement did not fit, took it back in and had the same shop rebuild the existing radiator with with a 3-row core.

 

just a side note,

I have driven the truck about 4-5 times since I saw it start to overheat. Each time was after I replaced something to see if that fixed the problem. On each of these times, the temp guage reached close to red but never hit red and the coolant never boiled over but was obviously much hotter than normal. Most I drove it during those times was about 20 miles.

Anybody think that with engine temps that high, I could have damaged anything or stressed the engine that much? Engine is strong and had a full long block rebuild about 20K ago.

-thanks

 

is the water pump going out i haveint see any one say anything about that

 

elton,

thanks for your replies in the past. I have come across some of your posts and they have been a great help.

as far as the water pump goes, there are no leaks, it was changed about a year ago, and both radiator hoses get hot when the truck runs. I would assume that this means it is moving water. also, when I drive above 25 mph (except uphills) the truck cools back down which I also assume means that coolant is flowing but not fast enough due to radiator blockages.

What do you think? did you have any water pump issues when your truck was overheating?

 

will my water pump was fine but u know those prestone radiator flush thing will they dont say it will clog radiator lol ya will now when i have to change my radiator fluid i take all the hose off and the Thermostat and run water thourgh the motor for awhile then the radiator so all the crap in the motor dont end up in radiator

 

bump..................