Hey everyone, I just replaced my: Tstat, Timing belt, pulley, tensioner, water pump all my drive belts and new toyota red anti-freeze and now I can't stop my truck from running warm.

Past cooling performance (Per scan guage II) has always been: 190° max in the summer and 184-188° in the winter. After replacing all these parts I've been running 200-206°.

I just drove to Phoenix, AZ and back (300 mi. one way) and the temp always stayed right around 204° even if I held 3rd gear at 3500 rpms up long hills it would never get any hotter.

I tried burping it. I just parked my truck on the steepest hill i could find (my hitch was dragging in the rear) hot air/defroster on full blast reved the engine as I pinched the top and bottom radiator hose. When I initially jumped back in the truck the scanguage read 197° after driving a little it dropped to 193° but 3 minutes later it was back to 200°+.

Fan shows resistance when spun by hand. The thing is until I changed all these parts 190° was max and I don't think the fan spontaniously broke.

All parts are OEM from toyota. Outside temps has been from 50-70°

Pictures are of the water pump and the stalagmites I was growing.

 

I see you got a Toyota stat - a 180 deg one? T-stat jiggle valve installed in the down 6 o'clock position per FSM? You might want to pull the T-stat and slowly heat it in a pan of water with a thermometer to see what temp it opens.

Fan belt tension correct?

 

The Thermostat they gave me was 90916-03075. All the web sites I just checked link it to my truck. I couldn't find anywhere is shows the operating temp for the part number nor the truck's desired operating temp so maybe I could start with the pan trick.

I don't have one of those belt tension tools but I've been told if you can just get half a twist out of the belt you're in the correct range (I know thats pretty barbaric but it feels right).

The jiggle valve I placed at 12'oclock. The guide I was reading explained to put it there so air could escape the highest point.

Pot trick is a good place to start.

 

FSM reference for jiggle valve - down is specified:
http://www.ncttora.com/fsm/2003/Repa.../ther/inst.pdf

T-stat is stamped 82c which is 180 deg F.

Stat full open at 203F:
http://www.ncttora.com/fsm/2003/Repa...zfe/serdat.pdf

Engine operating temp 176-203 deg F, page DI-27:
http://www.ncttora.com/fsm/2003/Repa...zfe/preche.pdf

I'm not sure anybody has one of those fancy auxillary belt tensioning tools, but your method sounds good.

 

If you do heat the t-stat in a pan, suspend the t-stat with a wire/coat hanger so it's not touching any part of the pan and is fully submersed.

 

Thanks for the tip. I'm draining my antifreeze right now to check the thermostat and adjust the jiggle valve.

Also, thanks a lot for the info with the FSM. I wasn't able to open it in windows explorer, but I can see then just fine in firefox.

 

The way I do it:

 

I've always been told jiggle valve to the top to help with air bubbles

 

Ok the thermostat is correct. Now I'll go give the pot trick a shot. The jiggle valve being on top makes sense for the air to get out but the fact that the FSM says 6'oclock makes me a believer. I'll post the results of the tstat test. Thanks so far for the links and pictures guys.

 

Ok guys. Good news! The thermostat test ok, it was: 180° closed 190° closed 195° opening 200° open. I tried installing it in the truck (jiggle at 6'oclock), I filled the radiator and left the cap off as the truck ran. I made sure to really work the top hose and have a half full funnel in the fill neck at all times (I saw a lot of bubble come out). After a 20 mi. drive the truck never went over 190°. Thank you Thank you Thank you! I'm not sure if it was an air lock issue or the jiggle but its running great.

 

Wow, I wonder if it was the jiggle valve because I also have always installed them with it at the top.

 

Excellent! Bubble, jiggle valve, whatever......good you are back to normal! This is not the first time the changing the jiggle valve to the 6:00 position seemed to cure the issue. Crazy, huh?

James, do you normally run the higher temps as OP in the 12:00 position?

 

Jiggle valve at the 6 o'clock position is not a myth. A local here was telling me last week about his overheating problem after the dealership got done with his timing belt change. It was running hot at this point. Funny thing was his Toyota dash gauge was dead steady where they normally are in the halfway position but his scan gauge was saying about 205~210 all the time where it never did that before.
It was driving him nuts....finally, he noticed they put his new oem thermostat in at the 9 o'clock position. He checked the fsm and it said 6. He also did the boiling water check and he did note a few millimeters difference in the opening up as compared to another brand new oem thermostat so he put that brand new one in but clocked it at 6 and no more overheating....just like yours Joe.

I did find it interesting the the toyota dash gauge didn't show this...but his scan gauge did. SO, all you guys not at the 6 position might take a closer look at the real temperature readings.

Good call rworegon

 

Good stuff, Zuk!

More cases where 6 position makes a difference...starting page 3:
http://www.expeditionportal.com/foru...mal-water-temp

 

Good thread there

I noticed that 1st guy said his scan was reading 204 degrees but "The dash gauge is spot on the middle". Makes me think the factory gauge sucks...that it is not a real indicator of the true water temp...and when it does move it means you are overheating and melting solder.

 

Yeah the factory dash gauge in my experience will stay in the middle up to about 235*-240*F, at which point it will start moving to the right.

 

Not to be to repetitive but I second or third the notion about the stock temp gauge. Without my scangauge it would have looked like everything was at normal temp. One more way to justify my scangauge.

 

Next TB/WP replacement use my write-up (shameless plug).

http://www.skjos.net/toyota/timing/timing.html

I didn't know about the jiggle valve orientation until after I got it all put back together, but my SG temps are running 190-193, so I think I lucked out with its location. I did update my writeup with the 6 o'clock jiggle valve orientation.

 

I find it hard to believe that once the t-stat is open that little jiggle valve orientation is going to make any difference. But I'm open minded enough to consider something strange might be going on in there. Next time mine is out I'll try 6:00.

 

When I changed mine in 09, the jiggle valve was positioned closer to 5 o'clock than 6, and I had ever record from the previous owner since it rolled off the boat.

In the winter, mine runs from 188 to 195, but with the aid of the new fan clutch I am guessing, it runs only up to 191 in the summer.