Theory Re: Thermostat Jiggle Orientation
- Thread starter 1996_Valencia_Owen
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phattyduck
Elite Member
On a 5vz, 6 o'clock. On almost any other motor, 12 o'clock.
Refer to the FSM scan earlier in the thread.
-Charlie
octanejunkie
Elite Member
The jiggle valve is a safety feature in the event the thermostat fails, at least there is some coolant flow, the orientation of it has an impact which is documentable and somewhat marginal.
That being said, there are certain efficiencies in running an engine at 195-205 degrees vs 185 degrees, and that typically has to do with fuel atomization, BUT more specifically in when combined with longer intake runners and combustion chamber designs that promote quench and swirl while also curbing pre-ignition at a higher compression values, like 10:1 in a TBI setup. The chevy vortec head and the dodge magnum heads, for example, both run more efficiently when cammed and squeezed properly at higher temps, any so do many production vehicles since this design change in the early to mid 90s. Japanese and european manufacturers went the other way and shy away from higher temperatures for the reasons already stated here, but more specifically due to the alloys used in their design and manufacturing processes and productions.
There is no indication on the 3.4 toyota that I have read to indicate that performance, economy or longevity are benefited from a higher operating temperature.
Like has been said, it's your car and your money, spend it as you wish. I have no dog in this fight, but I did want to respond to the point of WHY a jiggle valve and why the higher temps in GM/Chevy motors, specifically.
That being said, there are certain efficiencies in running an engine at 195-205 degrees vs 185 degrees, and that typically has to do with fuel atomization, BUT more specifically in when combined with longer intake runners and combustion chamber designs that promote quench and swirl while also curbing pre-ignition at a higher compression values, like 10:1 in a TBI setup. The chevy vortec head and the dodge magnum heads, for example, both run more efficiently when cammed and squeezed properly at higher temps, any so do many production vehicles since this design change in the early to mid 90s. Japanese and european manufacturers went the other way and shy away from higher temperatures for the reasons already stated here, but more specifically due to the alloys used in their design and manufacturing processes and productions.
There is no indication on the 3.4 toyota that I have read to indicate that performance, economy or longevity are benefited from a higher operating temperature.
Like has been said, it's your car and your money, spend it as you wish. I have no dog in this fight, but I did want to respond to the point of WHY a jiggle valve and why the higher temps in GM/Chevy motors, specifically.
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19963.4lsr5
New member
I always was under the impression that the jiggle valve was to ensure any air trapped in the cooling system would be able to migrate to the rad. And really only in the picture when the engine off and the valve is dangling. Now saying that that was for engines with the t-stat on the top hose not at the lower hose like the 3.4. But once again if the ball is on the rad side of the T-stat than the coolant flow with the engine running should keep the ball against the hole sealing it off.
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Sent from my iPhone using Tapatalk
02gixxersix
New member
Haha touche! I don't have an FSM, though. I just trust the interwebs. :hurt:
02gixxersix
New member
I can't believe we are still talking about jiggle valves, but here is an exerpt from MotoRad:
"The purpose of the jiggle valve is to eliminate any air that may be trapped within the cooling system and allow it to pass by the thermostat. If an air pocket is trapped on the engine side of a thermostat that does not have a jiggle valve, then the engine could overheat before the thermostat gets warm enough to open. The jiggle valve eliminates this by allowing that air pocket to pass by the thermostat thus allowing direct coolant contact with the thermostat. You must be sure to replace a thermostat that has a jiggle valve with one that also has the jiggle valve. Careful attention needs to be paid when installing a thermostat with a jiggle valve to correctly position it into the housing to ensure it will function correctly."
12 o'clock makes more sense to me. Every single thermostat instruction I can find, including all generic installation instructions, says to make sure it's in the upward position. Everything except that blurp in the FSM lol. I bet it's a typo. You should see all the errors in aircraft maintenance manuals, and I'm sure those are much more highly scrutinized before they are sent out.
19963.4lsr5
New member
The jiggle valve has been around for a long time and I agree the 12 position is correct when the t-stat is in the top hose. The t-stat in the lower hose changes everything. Because there should not ever be any air trapped in the lower hose. But the valve in the lower hose will aid in filling the cooling system from empty. The stat opens from sensing the temp from the engine side (that's where the wax or plastic pill is) so any air in the lower hose will quickly go to the top hose as soon as engine is running and the t-stat opens no matter the position of the hole in the T-stat in the lower hose.
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mtbtim
Elite Member
If it's a typo, than can you explain why people have consistently recorded lower coolant temps when the jiggle valve is placed in the 6 o'clock position as compared to the 12 o'clock position?
I know it doesn't make sense why the 6 o'clock position lowers the temps if a jiggle valve is meant to allow air pockets to escape. The 12 o'clock position would make more sense if the jiggle valve is just allowing air to escape but it's doing something more on our engines that nobody seems to be able to explain. Once you see with your own eyes how it makes a difference, then you'll be a believer. The FSM has given us the correct information.
phattyduck
Elite Member
12 o'clock is correct for every other engine EXCEPT the 5VZ. All the other Toyota FSM's (I have a few) state to put the jiggle valve in the 12 o'clock position. Why would there be a typo that is opposite every other FSM that Toyota produces? Don't you think they would like to copy/paste where possible?
Here's the text of the 3RZ section:
INSTALLATION
1. PLACE THERMOSTAT IN WATER INLET HOUSING
(a) Install a new gasket to the thermostat.
(b) Align the jiggle valve of the thermostat with the protrusion of the water inlet housing, and insert the thermostat in the water inlet housing.
HINT:The jiggle valve may be set within 15° of either side of the prescribed position.
2. CONNECT WATER INLET WITH LOWER RADIATOR HOSE
Install the water inlet with the 2 nuts.
HINT: Facing the top mark (protrusion) upward.
Torque: 20 N·m (200 kgf·cm, 15 ft·lbf)
3. FILL WITH ENGINE COOLANT
4. START ENGINE AND CHECK FOR LEAKS
So, why would they get one right and one wrong with completely different text if they are supposed to be the same? (the protrusion on the 3RZ water pump housing is shown in the picture in the top position)
edit: There's also a drawing, pointing to the bottom location of the jiggle valve in the FSM for the 5VZ. I'm not sure how more clear this can be?
-Charlie
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I lol'ed
02gixxersix
New member
I haven't had my 4Runner during the summer or been in any slow or loaded down offroad situations yet, but it seems to run as cool as can be on the street. The only digital monitoring I have done is with Torque Pro, which isn't working too well for me yet, but shows me maintaining 180-190 degree temps around the base at 30 mph or less.
Additionally, I would think that if your jiggle valve position is dropping the temps of your coolant by 10+ degrees, you should probably burp your coolant system. However, just like with everything else, real world result mean more than a bunch of people arguing over logic or theoretical function. It seems like people see the temp drop, so have at it. If I end up with high temps I'll sping it around to see if it helps.
mtbtim
Elite Member
That's some solid advice for the inner retainer on our rear ABS axles and the sole retainer on the Non-ABS axles. The Dr Coffee method works great. I've used this method doing 4 axle seal jobs on 3rd Gen 4runners. I'm doing another rear axle seal job in a couple days and I'll be sure to flip the retainers on those axles as well.
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Running at 6 o'clock and no issues, heat is never a problem either.
LittleCaesar
New member
The original T-stat was sitting at 5 o'clock from the factory when I changed it out back in 09. Put in the new one at 6 and run now from 186-193F.
Heat usually gets to about 135F before the auto climate control kicks in. But it isn't as hot as my father's truck, which will put out heat at 170F when fully warmed up.
Heat usually gets to about 135F before the auto climate control kicks in. But it isn't as hot as my father's truck, which will put out heat at 170F when fully warmed up.
Tyler James Inc
Senior Member
Get jiggly with it!
My jiggle valve goes from 6 to 12 all the time- mostly when my wife touches it.
It's funny to see all these responses, yet no one REALLY addresses the question the OP had.
There may not be any way to prove it, but I am VERY confident there aren't pockets of air in the system, causing hot spots -and false-low readings. Like guys have said- the jiggle valve being for air-burping purposes wouldn't make sense at all, since the stat is at such a low position on the 5VZ.
I see the points on both sides, but I feel 100% confident following the FSM, and positioning it at 6 o'clock(which I did).
And I've never been in a '81-'01 Toyota that had a shortage of heat inside. I rarely go over halfway toward hot on the dial. Definitely wouldn't benefit from any "hotter heat" [emoji23]
My jiggle valve goes from 6 to 12 all the time- mostly when my wife touches it.
It's funny to see all these responses, yet no one REALLY addresses the question the OP had.
There may not be any way to prove it, but I am VERY confident there aren't pockets of air in the system, causing hot spots -and false-low readings. Like guys have said- the jiggle valve being for air-burping purposes wouldn't make sense at all, since the stat is at such a low position on the 5VZ.
I see the points on both sides, but I feel 100% confident following the FSM, and positioning it at 6 o'clock(which I did).
And I've never been in a '81-'01 Toyota that had a shortage of heat inside. I rarely go over halfway toward hot on the dial. Definitely wouldn't benefit from any "hotter heat" [emoji23]
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JayRolla
New member
I just replaced the seal on my rear axle. Almost 100k miles. Man the engineers really knew what they are doing right?
phattyduck
Elite Member
I kinda feel I did.
The OEM thermostat is set for 82*C, stamped right on the part (FSM states it should between 80*C and 84*C is acceptable). It also states that the valve should be at least 8.5mm open by 203*F, meaning that max cooling of the engine should be available before that point (and the thermostat should be working to cool the engine below this temp).
Normal operating temperature of the coolant (at the ECT sensor on the coolant outlet of the motor) needs to be above 80*C (176*F) for emissions monitors to run, also hinting that 80*C and above is normal operating range.
I have also read in multiple places that Toyota considers the normal operating temp of the 5VZ to be 80-95*C (176-203*F) - quoted as being 'from the FSM'. I haven't been able to find that myself yet though.
So, to the OP - 'cooler' running around the 190*F range is COMPLETELY NORMAL and how the engine was designed to run.
-Charlie
I actually think you did as well, tks!
