Intermittent Overheating?
 

Im a bit stumped. The 4Runner is having random overheating phase in & outs.

Driving around town. It doesn't overheat unless i've been driving for awhile, I turn the heater on, it goes for a bit longer but then the temp gauge starts to rise again. Once im at idle, it cools back down.

On the freeway, Same symptom. but happens a bit quicker since at 65 im reving at 2800. but like i said, if i clutch on the downhills it keeps cool.

Now, I have a rebuilt fan clutch, a brand new radiator, a brand new thermostat, and a brand new waterpump. ( all AISIN/Toyota used, including the fluids. Davez offroad radiator. )

Here's my idea regarding the overheating:

Clogged radiator? - never used a Davez radiator before and i've heard good things. but it didnt' start overheating like this until this radiator was installed.

No fan shroud? - My bumper & winch really block the front. So im assuming its not getting the right amount of air flow, therefore needs the shroud?

Defective waterpump and/or Thermostat? - Toyota parts.. i wouldnt' expect them to fail so easily since my last set waterpump went 165k miles and the thermostat went 150k?

94-95 fan on a 92 model? - i did the 94-95 bladed fan conversion and got rid of the circular fan. The 94-95 fan is noticably smaller than my factory fan. Could this be the issue?

Anyone got any ideas?

Had a similar happening on my Frontier, the water pump was cavitating at higher rpm, drove me nuts!!! Great flow at idle to 1500, but would cavitate above that.

Yeah. Im HOPING the water pump isn't the problem. Granted my timing belt & water pump are under warranty from when I had the top end done.

Im gonna try and pop the fan shroud and my 92 fan back on and see if that helps the air flow.

The rebuilt fan clutch had the incorrect weight of silicone(sp) fluid put in?

Fan I do not think would be an issue.

I put 7000 CST in it.

Have you thermoscanned the radiator for hot/cold spots?

negative. lol

put the fan shroud back on. it's there for a reason - to direct airflow. without the shroud, your fan is just moving air around in the engine compartment and not pulling through the radiator to it's potential because it's not being forced to draw through the radiator. try a house box fan or computer axial fan w/o a shroud and you'll see what i'm talking about. also, having your bumper, lights, and winch blocking the path isn't helping either - so at least put the shroud back on, THEN start looking at other issues.

x2 on the shroud and put the oem fan blade back on, also like above, blocking the the radiator with winch bumper and lights ect does not help, but perhaps with out the shroud your just pushing the limit enough to make the temp rise.

Keep your fan blade without the ring on it. Worst idea ever (fan wise).

Sounds like an air flow problem, either your fan clutch is not working right or the winch and lights are not letting air through.

I'll try the fan shroud tonight. Might help things a little bit.

Be a good idea to scan when you do, eliminate the wonder what, and did that fix its...

I honestly dont see why its having issues. I've never had a problem with air flow before with the bumper, winch and lights. The bumper has been there since 2009-10? the lights & winch were added in december? I understand summer has rolled around here in California, but its only been getting in the high 80s, low 90s ( which is ridiculously low for our summers ) The only thing i've done different is added a 3 core STEEL radiator and got rid of the aluminum radiator that cracked, got rid of the shroud and added a 94-95 fan.

Early stages of the HG giving out....again?

Dont say that. I wont be a 4Runner owner for much longer, if thats the case :)

That's cold man... Don't jinx him..:hillbill::oops:

really though. Im not even 10k miles on my new top end :P you've no idea how fast i'd drive this 4Runner into the ground if the headgasket pops again. :)

I tried not too......... :)
Good luck.



Maybe your cousin would sell you hers......lol.

pfft... i'd get a 22re ext cab 89-95 or a 98+ 3rz ext cab tacoma :P

Might even go for an FZJ80

Seriously, give it a try with the shroud and test the fan clutch to be sure it's working properly.