Jiggle Valve my fracking Theromostat!

cp99sr5

cp99sr5

New member
Last weekend I had the timing belt done, new water pump, Thermostat (part 90916-03075), Belts, Cam Seal, crank seal, etc., along with a brand new radiator, cap, upper and lower hoses and red coolant. Scanguage II temp now is at 205F on average versus the 190F it used to sit at before.

Read about the jiggle valve and the FSM saying install at 6 o'clock, can't determine if its reality/true fact or urban legend/voodoo! The 205F is when outside temps are in the 60's and doing a commute of 29 miles with speeds up to 70 MPH down to freeway, then about half the time in stop and go along with a few miles of street driving taking anywhere from 45 minutes to a hour and a half.

My concern is what happens when temps go into the 90's and 100's and I am running AC full blast or lugging the small boat and camping gear up into the mountains or running a trail? Will I overheat :flame:

Should I worry about this, make the dealership check to see if the thermo is in the correct orientation? I read a lot about optimum Oil Temps, Coolant temps and there is a lot of conflicting information (welcome to the WWW!) Will the 50/50 coolant mix boil at 220 under the 16PSI cap and ruin a trip? I am probably freaking out about nothing but its my runner and I want to take poper care of it. Input appreciated - Chris
 
Register to hide this ad
205 F is 96 Celsius and this is pretty high when outside is 60 F. THE OEM thermostat opens at 86 C.

Did you use an infrared thermometer to check the upper coolant temperature? Point it to the upper output line located on the top of the engine (not to the rubber hose, but to the metal).

The jiggle valve has no effect when all the air is removed from the radiator/coolant system.

Have you burp the system? If not, WHEN the engine is COOL, open the radiator cap and start the engine. Let it come to its operating temperature (still no cap on). Let it run and you may notice the coolant level is getting low. Now add more. Also keep the cabin heater on and fan is on. Continue filling until you see no drop in the coolant level.
 
Thank you Nissanh!

I do not have an infrared thermometer so I have not checked the temp that way, It was my understanding that the ECU sensor reads from the point you recommend to read from but it may be the off the hose.

I had hoped the stealership had burped it but not sure, Yesterday when I was driving I was running a temp of 207F water and 156F Transmission, I turned on the heater for the first time since the change along with the rear heater, blasted them both and the temps dropped to 193F Coolant and 140F Transmission in 6 minutes. I then turned the heaters off, turned the temp dial to the blue and in 20 minutes, the temps were back to 207F coolant and 140F Transmission. I will burp it myself per your procedure tonight and see how it goes, thanks again - Chris
 
Last edited:
Check my post. I almost guarantee they installed it at 12 o clock. Mine had the same exact issue and i removed the thermostat and placed it with the giggle valved in the 6oclock position and low and behold my temp went down at least 10 degrees. Fyi oem toyota fsm states 6oclock position. Hayens or chiltons, i dont remeber which one, states 12oclock which is totally wrong.
 
Last edited:
cp99sr5 said:
Last weekend I had the timing belt done, new water pump, Thermostat (part 90916-03075), Belts, Cam Seal, crank seal, etc., along with a brand new radiator, cap, upper and lower hoses and red coolant. Scanguage II temp now is at 205F on average versus the 190F it used to sit at before.

Read about the jiggle valve and the FSM saying install at 6 o'clock, can't determine if its reality/true fact or urban legend/voodoo! The 205F is when outside temps are in the 60's and doing a commute of 29 miles with speeds up to 70 MPH down to freeway, then about half the time in stop and go along with a few miles of street driving taking anywhere from 45 minutes to a hour and a half.

My concern is what happens when temps go into the 90's and 100's and I am running AC full blast or lugging the small boat and camping gear up into the mountains or running a trail? Will I overheat :flame:

Should I worry about this, make the dealership check to see if the thermo is in the correct orientation? I read a lot about optimum Oil Temps, Coolant temps and there is a lot of conflicting information (welcome to the WWW!) Will the 50/50 coolant mix boil at 220 under the 16PSI cap and ruin a trip? I am probably freaking out about nothing but its my runner and I want to take poper care of it. Input appreciated - Chris
Click to expand...

The coolant temp will likely stay right where it's at now even as the temperatures climb, assuming the thermostat is functioning properly. That's the whole purpose of the thermostat, to maintain constant engine temps regardless of ambient temps, and from my experience the cooling system on the 4Runner does this extremely well.

What's likely happening is the thermostat is just regulating at a higher temperature than your previous one.

All that said, there are a lot of people here who've experienced higher temps with the jiggle valve in positions other than 6 o' clock, and 205 is a lot higher than mine runs. I haven't seen a good explanation for why it matters, but the evidence seems to suggest that it does, and the Toyota manual says to put it in at 6 o' clock when you would normally install it at 12. The fact that it's unconventional suggest to me that there's a reason for it.

I just replaced mine (while doing timing belt and water pump) and my temps fluctuate between 184 and 188. I've never seen it one degree higher or lower than those values after it warms up, and in the past few weeks since it was done I've been in temps as high as 95 degrees and as low as 48.

It's not that hard to pull the thermostat and check it, so I'd probably do that for peace of mind.
 
nissanh said:
The jiggle valve has no effect when all the air is removed from the radiator/coolant system.

.
Click to expand...

That's the conventional logic, but there are a LOT of cases here where people have had higher temps with it installed at 12 O' clock instead of 6 as Toyota suggests. I can't come up with a logical explanation for it, but it's hard to argue with the data.
 
Thanks all, I was going to ask the dealership about checking it to see what they say. Either way, I thought the temps are high considering the thermostat opens at 186 supposedly.

The only other variable I can think of was that when I did the radiator bypass with the transmission oil cooler, I was unable to replace the entire length of hose from the tranny so when I had the new radiator put in I asked them to give me fresh hose there. Even though I did specifiy they leave my mod as it was, the tech ran all new hose from the Tranny to the Radiator then to the cooler and back to the tranny. I still doubt that could account for all the increase in heat though?
 
If I say thins once a day I say it at LEAST ten times a day.

"Just because a part is new doesn't mean it is good"

Blue
 
Do you know what temp thermostat u had installed? I was seeing temps in the 210s, course I have a SC, but when I did my TB and thermostat I went with a 170* stat, brought my temps to 183-188.
 
Gonna share my own experience; when I did the timing belt I installed the thermostat with a ex-Yota mechanic (a good buddy). He convinced me to install it at 12 o'clock. Was running low 199s-205s. After two weeks, I decided to flip it to 6 o'clock. Now, I run 188.6 most of the time and it will range 186 to 189. I have a second temp gauge on the upper rad hose that reads around 191-194. My Yota buddy refuses to acknowledge that there is a difference....I doubt you will over heat with the jiggle valve up and you may even get slightly better performance but just get them to flip it (and watch them do it) or flip it yourself. Simple job but follow the right steps.
 
Last edited:
I installed thermostats in many vehicles and never ever had an issue. Didn't even bothered to set a location. All runs with proper temperatures.

Hilux 3L (2.8 diesel, see below) got its thermostat horizontal and the joggle valve can be anywhere in this case.

Also 2nd gen 4runner got its thermostat horizontal.
 

Attachments

  • timingbelt1.jpg
    timingbelt1.jpg
    92.9 KB · Views: 4,370
Last edited:
GARunner, I do not have specs on the thermostat, the part number is in my original posting, it was OEM Toyota so I assumed it was the the right part in terms of opening temp. I did not see multiple listings/options in the parts diagram, maybe I overlooked something, I will research a bit more. I know that Stantz makes a couple for the runners, one said to open at 170F and the other 180F but I wanted to stick with OEM. And yes, the part could be bad even though its new.
 
as others (including mr durk) have indicated : AIR AIR AIR

This happened to me and it was air in the system.

DEMMAND a full reburp from the dealer!
 
OK, so this morning before work, I went out to burp! Started from a dead cold engine, slight incline on the drive way, cannot use the curb where I am at, busy street. Removed the cap and started the engine, turned on heater set to high, front and rear and fans to high. At first nothing, the fluid was up to the top of the neck and dripping out the top a little. Engine temp finally got to 190 and I could tell the thermostat opened because I saw a few bubbles coming out. Temp stayed at about 190 a bit so I pushed the RPM's a little to warm futher, got to about 197 and could not get any more bubbles out of it that I could tell. The level had dropped slightly from overflowing to the bottom of the neck where the cap would sit if on. Left it that way for awhile and then turned off the heaters to see if anything else would happen, Temps went to about 200 and stayed there, had to go to work so I put the cap back on and drove. Temp went to 204 and stayed there the whole time, outside temps were high 60's and it hugged 204 for the next hour to work.

The one thing I did notice was that though the heater was set to cold, the air set to flow through with the fan off, the air from the vents never got cold, I had to roll down the windows after a awhile due to the warmth. That went on until I parked and I still had much warmer than ambient temp air flowing through.

Thanks for the help everyone, I got an appointment with the dealer, I will discuss the issues with them and see what happens. Appreciate the help - Chris
 
I tried to do the "home burp" to fix my issue but it didn't work I ended up needing the mechanic to do a full burp. I did not pop the tires up as some have suggested. Perhaps that would have helped.
 
The only thing I would suggest is leaving the heater fans on the LOWest setting with the TEMP control on the highest and accelerate the engine while you do this. By blowing cold air on the heater coils you are fighting against your objective which is a fully open 'stat and good fluid flow through the system. With both heaters working with high fans and the engine at idle, you have a hard time achieving that. I usually have to keep the engine accelerated to like 1800 for a few minutes after an initial warm-up at idle to get a good burpworthy flow going through the rad. With the fluid-clutched rad fan, these engines don't heat up much at idle on a cool day with the heaters going. You want to see the coolant moving through the rad, not just a few bubbles.
 
Last edited:
kind of related, but i too replaced the stat when the radiator went out and i don't know if it's me, but now the upper hose stays hotter than the lower. i've always thought through the years of wrenching that both should be close to the same temp and that is a good indication of the system working properly. is that true? temp gauge reading has not changed. reaches less that half and that is where it was before the work.
 
I think the top hose should be warmer as the hot coolant from the engine comes through the top hose, is reduced in temp/cooled by dropping though the radiator and exits the radiator through the bottom hose to go back into and cool the engine. Touch is relative and affected by ambient conditions and other factors so the temp needs to be accuratly measured to make the correct determination.
 
You must log in or register to reply here.

Members online

Total: 843 (members: 4, guests: 839)

Forum statistics

Threads
278,312
Messages
3,554,085
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top