MadCityRich

I have a question about the proper operating temperature. When I'm driving, the idiot gauge on the dash shows needle at the half way point. Not a big deal. On my OBD-II scanner (DashDaq2), the coolant temperature reads between 199 and 212, depending on how hard it's being pushed, but mostly right around 203. 203 degrees seems a bit hot for operations. I would have expected about 180 degrees. Could this be due to the difference in where the gauge vs ECT are taking temperature readings? Could it be an error in my OBD-II reader? On my Subarus, the engine coolant temperature settles right in the 180 to 185 range, which seems about right. I'm at about 143,000 miles and replaced the radiator last spring with an aftermarket unit. I've also got an external transmission fluid cooler mounted in front of the radiator, though it's still plumbed through the cooler in the radiator. Maybe time to try a new thermostat? Any opinions/experience will be a help. Thanks, MadCityRich

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Alright, when I say your name, you say 'here.' And we will assume 'here' is short for 'here I am...rock you like a hurricane. -Ignignokt

1990yota-pickup

i dont think you have a problem at all...

1990yota-pickup

if u get over 220 then have a problem..

Ironmike4x4

I have an factory rated 180 thermostat and my scan gauge rarely even goes up to 200 unless it's summer time and I'm out 'wheeling. Have you done your timing belt yet? If not and you've already got 90k miles I'd go ahead and have the timing belt done along with the water pump and thermostat. 203 is an okay number but like yota-pickup said if you hit 220 you'd better start worrying.

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1998 4Runner SR5, Surco Safari rack, diff breather mod, Cobra WXST II CB radio, 31" General Grabber AT2 tires, clear corner/bumper lens, hitch mount backup lamps, KC hilites, PIAA fog lamps, PCV catch can.

1990yota-pickup

you maybe just need to put some coolant boaster stuff in the coolant..

1990yota-pickup

check this out i found this on 22r tech notes


FUEL SYSTEM: Twin side draft carburetors are a natural choice, but the EFI system will work excellent if the vehicle is originally equipped with one. (Some manifolds for the dual carbs have poorly designed water outlets that may cause overheating.) Long duration cams will seriously affect EFI engines, since combustion pressure drop dramatically even with high compression pistons. A fuel pressure adjuster may be needed. The Weber 32/36 or 38DPS are good upgrades for single carb set-ups. For carburetors, use a low pressure, high volume fuel pumps. Do not try to regulate lower fuel pressure with an adjuster because volume will also decrease. A fuel return line is mandatory to allow the fuel pump and carburetor to function properly. For any kind of performance do not rely on Toyota's mechanical or electric pump, they do not have enough volume. The 22RTE with any upgrade will need a higher output pump. The fuel pressure regulator should also be upgraded.

DailyDrive

Operating temperature is what your thermostat is set to. Factory should be 190F AFAIK.

If everything is working properly, and you are not in extreme ambient temperatures, it should not go more than a few degrees away from thermostat rating. And should always settle dead on the thermostat temperature when driving smoothly.

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'99 4WD 3.4L SR5 AT

1990yota-pickup

hey i just found this on 22r/re tech notes

you may already know this you may not


FUEL SYSTEM: Twin side draft carburetors are a natural choice, but the EFI system will work excellent if the vehicle is originally equipped with one. (Some manifolds for the dual carbs have poorly designed water outlets that may cause overheating.) Long duration cams will seriously affect EFI engines, since combustion pressure drop dramatically even with high compression pistons. A fuel pressure adjuster may be needed. The Weber 32/36 or 38DPS are good upgrades for single carb set-ups. For carburetors, use a low pressure, high volume fuel pumps. Do not try to regulate lower fuel pressure with an adjuster because volume will also decrease. A fuel return line is mandatory to allow the fuel pump and carburetor to function properly. For any kind of performance do not rely on Toyota's mechanical or electric pump, they do not have enough volume. The 22RTE with any upgrade will need a higher output pump. The fuel pressure regulator should also be upgraded.



check out this site http://www.toysport.com/technical%20...tech_notes.htm

FogRunner

There is nothing wrong with seeing the OBD-II report engine temp around 200-210F when running with a 190 degree thermostat.

To reason why the temp your seeing is about 10-15 degrees over the thermostat is because of the design of the cooling system and the placement of the coolant temp sensors.

The ECM and the engine temp gauge each have their own separate sensor. Because of the ECM coolant sensor is mounted on the front of the engine right in line with the coolant coming of the heads. The coolant here has fully cooled the engine and just came off the heads so it tends to be about 10-15 degrees hotter than the thermostat rating.

Now getting back to the gauge on the dash. Because of the design of the gauge you won't see any quick fluctions unless they are of a large amount.

The reason for this is the temp gauge is a "time/temperature" averaging type of gauge. For slight increases in temp it takes the gauge seeing that temp for 20-30 seconds before it changes to indicate that. But with changes of a large amount quickly it will reflect that.

The reason for this is prevent customers from seeing the gauge going up and down with hard acceleration or heavy loading up a hill and think there is a problem.

Also if you look at most other engine's cooling systems the thermostat is normally mounted on the top of the block by the heads. On the 3.4 its mounted on the bottom hose lower on the engine so it will see a better average temperature and keep the engine temp more stable despite intermittant hard loading.

So don't worry about seeing a touch over 200F its normal.


FOG

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2001 4runner SR5 - ARB Bull Bumper, Warn 9.5XP, GM CS-144 150 amp alternator, Tundra brakes, OME 883/891s, SS adjustable traction bar, B&M 70264, and too many ham radios and antennas.
2006 Jeep LJ - Stock down to the lug nuts

mt_goat

I concur with FOG

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~Dale~

93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift front, Alcan springs rear, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" Body Lift, 1.5" ball joint spacers, manual hubs, TJM T-17, Warn m8000.

1990yota-pickup

I TRIED to tell him from the start.. but you got all technical there fog runner...

MadCityRich

Thanks! I figured nothing was wrong and I'm pretty OCD about keeping up with maintenance, but had to be sure about the temps. 4Runner runs like a top and I want to keep it that way.

I had a suspicion it was just a sensor placement issue and I appreciate the confirmation.

MadCityRich

__________________
Alright, when I say your name, you say 'here.' And we will assume 'here' is short for 'here I am...rock you like a hurricane. -Ignignokt

FogRunner

I was re-reading the thread and saw the above. I have a transmission cooler also in front of the radiator but the transmission is piped to it ONLY and I kept the radiator out of the circuit.

With just the cooler in normal traffic on a hot day I never see above 175F and with it locked up on the highway it hangs around 125F. The only time I saw it get up to 200F was going up Pikes Peak with a car full of people.

Under hard acceleration the transmission does develop a good amount of fluid pressure which is the cause of the radiator transmission cooler tank failures that are commonly discussed around here.

Transmission fluid doesn't need to be warmer than 90-100 degrees to function properly. And it doesn't need to get hot to evaporate water like engine oil does because there is no combustion loading up the trans fluid with water.

If you do live in a northern area where you have allot of really cold weather you can get a by-pass thermostat that will keep it around 140F. The winters are mild down here and the cooler I have has two larger channels in it that act as a bypass at lower temps so even when its 40F outside it hangs around 100F when on the highway.

So I would seriously consider taking your radiator out of the transmission fluid circuit, because if the radiator tank ruptures you have a VERY VERY expensive problem when that coolant gets into your transmission.

But I'm like you in regards to maintaining your 4runner. I do all the work myself down to timing belts, waterpumps, valve covers, ETC.

And I'm pretty OCD also about that stuff also and it drives my wife nuts but I have never been broke down on the side of the road.


FOG

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2001 4runner SR5 - ARB Bull Bumper, Warn 9.5XP, GM CS-144 150 amp alternator, Tundra brakes, OME 883/891s, SS adjustable traction bar, B&M 70264, and too many ham radios and antennas.
2006 Jeep LJ - Stock down to the lug nuts

BigBallsMcFalls

188 normal road driving 60 deg out

212 normal sitting in traffic hot day

224 about the max it should ever go. fan should be able to take this down

eddieleephd

Really if you are really Ocd and can not handle the thought of yotas running hotter than most other vehicles then you can change the thermostat and anti-freeze and see what the obd says then.

However I concur that there is no issue at all and typical!!

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'99 3.4L 4x4 All Manual Taco
2.5" lift OME CO and Alcan Leafs
Deck Plate Mod.

DailyDrive

How many vehicles have you personally driven while monitoring the coolant temp coming in via ODBII?

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'99 4WD 3.4L SR5 AT

96743runner

My scangauge's coolant temp reading never went over 190 degrees. Most of the time it runs at 188 degrees. But that's probably because it doesn't get really hot where I live.

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1998 4Runner Limited Desert Dune 3.4 4x4 A340F (No. 439 off the assembly line on 11/97!) - Currently around 66k - with a few mods


2010 Tacoma Access Cab Black Sand Pearl 4.0 V6 4x4 TRD Off Road <1k miles

skjos

My ScanGauge reads coolant temp consistantly between 189 and 193.
Just more data to throw into the mix.

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2002 4runner SR5 4x4
1994 Ext Cab Truck 4x4 (22R-E)

eddieleephd

This is one question I should have asked first.

When was the last that you did a coolant flush and thermostat replacement??

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'99 3.4L 4x4 All Manual Taco
2.5" lift OME CO and Alcan Leafs
Deck Plate Mod.

DailyDrive

eddieleephd, so how about my question? How many vehicles have you personally driven while monitoring the coolant temp coming in via ODBII?

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'99 4WD 3.4L SR5 AT

BigBallsMcFalls

don't know about him, but I think zero peeps monitor ODBII

maybe they monitor OBDII ?

I know that I monitor all my vehicles with OBDII plugged in from the day
I get it from the dealer new, until I let it go or whatever. so it is not that rare, not in my neck of the woods. I always know rpm, tps, temp, injector duration, advance, all the time and every time on all my cars and trucks

DailyDrive

Good job Balls, but you are not the one saying that running 200+ on a 190F thermostat is perfectly fine

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'99 4WD 3.4L SR5 AT

mt_goat

Actually, these 5VZFEs came stock with a 180 F t-stat, but as Fog described so well in post #9, the t-stat on our trucks is in the return line side of the cooling system. It sees the coolant after it goes thought the radiator, unlike many vehicles that have the t-stat in the upper hose going to the radiator where the t-stat sees the hottest coolant. Also the temp sensor for the ECU is up in the hottest part of the system, naturally there is going to be a difference between the t-stat opening temp and the upper hose temp.

Also keep in mind that the t-stat opening temp is just the point which it starts to crack open, it doesn't open for complete flow until quite a bit hotter. For example here you can see a 180 F t-stat (right) next to a 160 F t-stat in 180+ water. The 180 F t-stat is just barely opened.

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~Dale~

93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift front, Alcan springs rear, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" Body Lift, 1.5" ball joint spacers, manual hubs, TJM T-17, Warn m8000.

camo31"10.50"

199yota-pickup...WTF does twin weber carb's have to do with a dang cooling issue.....lmao seriously!?!?

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FOR SALE 1986 Ext. Cab 4x4, rebuilt 22R, 5spd, 31x10.50 X-Terrains FOR SALE

1992 SR5 4runner V6, 5 speed, 4in. trail-master lift, 33x12.50 BFG muds, 4.56 gears!!! and an IMMACULATE interior..yes..you should be jealous

"Its still a toyota man.. Dont deprive it of its capabilities.."
"If you can read english, Thank a teacher...If you can speak it, Thank a soldier!!" Kelli Ruark-2009

BigBallsMcFalls

no I am the one saying if it gets to >220 that can still be normal


in other words, there is not a problem when the temp goes to 224. mine does
on hot days stuck on pavement

a thermostat doesn't really control the max water temp. it ensures the engine gets hot enough to run efficiently before dumping most of the coolant to the radiator. but it can break and cause overheating by blocking flow, but when that happens u really know it...temp will rocket past 224.

how hot your box gets ? if is never hits 224 then there is no problem AFAIK

it should run at 188-192 most days, 184 at zero deg F, 212-224 at 100 deg F outside