borincano

It will start warming up but slowly, very slow. it would take like another 10 minutes to get to operating temp if I stop on the side of the road and let it idle. The fan clutch could be stuck I guess. is the fan suposed to run right of the bat when the truck is started? I think mine does.

toyota4x4907

Yes. with these Yota engines the fan will turn at full speed for a few seconds after sart-up for whatever reason, then should slowly settle to just moving.

If it doesnt take very far for it to cool off, I would try just taking the fan off and seeing if the temp changes while driving.

My99

Can you describe the symptoms in terms of how your gauge behaves vs. how your heater feels? Do you notice for instance when the temp is registered fully warm that you heater is nice and toasty and then when you start driving and the temp gauge goes down that it feels that heat dissipates accordingly?

Even with a foul fan clutch, if your thermostat is acting correctly the truck should stay warm.

You say you checked your thermostat (and assuming you have a 22re), and I'm also assuming that you replaced the gasket at the same time. It's really hard to screw it up, as the t-stat drops into the housing and the upper pipe just slips down on top of it. I really do suspect your thermostat, although odds of it happening twice are extremely slim. Did you ensure that your topped off on coolant? Sometimes air bubbles can cause a little havoc. You say when you start driving that the engine cools down. How cool does it get? Does it go all the way down to full cold, or does it drop only a little? After driving for 15-20 min does it come back to operating temp or does it stay cold the entire time? And again, when I say cold, are you judging from the temp gauge alone, or do you find the heater becomes less effective as well?

borincano

I have the same symptoms as SWMItoyota did. Thats why I posted on this thead. I have been searching for this for about a month. Not sure though if my seal is damaged some how

My99

You'd know if your fan was on. All these 22REs roar first thing in the morning (through first and second gear usually - ~15-20 seconds). Surely you've heard this. It then quiets down. The only other time mine ever runs are on the hottest summer days in stop and go traffic or if I'm pushing it on the highway (100+ degrees). Then you will hear it spool up making a whirring noise for a few seconds until the temp cools down enough to kick it off.

Don't focus on the fan however, this may be broken, but isn't the cause. The only thing the fan can do is cool the coolant in the radiator. The coolant in your radiator should not be flowing into the engine unless the thermostat opens to allow it to happen... which shouldn't occur until the engine reaches operating temp.

Dumb question, but just to make sure - you have checked your coolant lately, correct? You're not noticing your low on coolant have you? Check your radiator when the truck's cold, don't go off of the reservoir level alone.

Again, can you confirm that your heat output corresponds directly with what you temp gauge is telling you... this will help us narrow down the fact that your truck is actually getting cold when driving, not the gauge flaking out for some reason.

borincano

I have a 95 4runner with the 3.0. The engine would take 10 minutes to warm up and I leave in P.R. which never drops from 80F. once I start driving for about 15-20 minutes, the temp starts droping until it hits about 1/4 of the way up and thats when the transmision would stop shifting past 3rd. When I changed the t-stat both times what I did was remove the housing from the engine and let the coolant drain from there. Then I installed the T-stat with a new seal and some of the "permatex ultra rubber gasket sealant and dressing" stuff. Then I re-installed the housing and filled up th radiator with coolant all the way up. with the rad cap off, I started the engine and waited for the t-atat to open and suck up the coolant to the engine , and then toped it of again.

borincano

The first time I test drove it on the second T-stat, the temp gauge started climbing to red about 5 min into the test drive and then all of a sudden it went back to the center mark and I drove it for about 20 min mantaining operating temps.
After the engine cooled down, I re-checked the coolant level and the radiator was fine but the external resivoir was empty. so I filed the resivoir up and eversince I did that, the temp wont hold at operating temp when driven.???

My99

I'm going to bow out of this one, because I'm far from an expert on the V6 3.0. I do know they are prone to head-gasket issues, which depending on how hot (and why) your truck got, is an issue you could have. Faulty headgaskets will cause erratic issues with your coolant temps for sure.

There is a thread regarding thermostats, but I believe it pertains to the 22RE's only. http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

borincano

No problem. Thanks for your replys!

borincano

Ok, I just ran the truck up at idle and the engine reached operating temp within 10 minutes (gauge needle at center mark). Turned on the heater for about 5 minute and it was blowing outside air temp the whole time, though I looked by the radiator and I could not see a heater core. Could this truck not have heater at all?
Also noticed that the radiator has a small leak on the bottom cap of the radiator (no drops while running for about 15-20 mins, just coolant on the seam). Dont know whats going on since the gauge reads good eng temp, but heater blows outside air temp???

SWMItoyota

Can't hurt to check the seal... might save you a lot of headache...

You looked by the radiator and did not see a heater core???

skypilot

iTrader: (1)

There is a valve on the firewall that may be closed, has three hoses on it and a cable from inside on the underside. Cable may be broken or the valve is stuck shut.
I know mine is broken and does not give me full flow to the heater coil. But he cold kit console is burning hot!

Squeeze all you hoses in case one is blocked.

Maybe the water pump is shot from corrosion and is not putting out enough force?
I was reading about Toyota anti-freeze requirements and their corrosion properties. one picture showed a pump with truly excessive clearance due to the housing being eaten away.

borincano

Well I looked by my radiator and all I saw was the radiator alone no other core loking like the heater core, so I guess since I live in Puerto Rico, the previous owners thought there was no need for it. But also, Im not sure, Is the heater core a seperate radiator type thing?

Not sure on the valve at the firewall. Is it in the engine compartment firewall side or the interior side? And , would it alow airflow if it's closed? mine blows good, it just doesn't heat.

About the water pump: would'nt my engine over heat with low water pressure runing through it?

When the engine at idle indicates operating temp on the gauge, the top hose feels hot to touch, but I can touch it for a few seconds beforeI have to let go. not sure if it' hot enough.

borincano

I have a couple of thoughts here. Let me know if they make sence.

-My engine reaches operating temp at idle, then once I start driving and the t-stat opens to prevent overheating the ram air will also cool the engine temp, wouldn't the t-stat close back up if the engine starts cooling execively?
-The t-stat for what I know, will open at the rated temp (195F) but at what temp is it desinged to close back up to mantain operating temp?

lekiboy

mine has a somewhat similar story with the threadstarter but still has not solved it..

heater runs fine
just replaced my thermostat with an original toyota t-stat with oring properly placed...
replaced my temp sender
drained replaced fully my coolant and water mix
i can feel the upper hose gets hot after the t-stat opens...


but still, my temp gauge is just milimeters above from the lowest line...it just flickers for a while but the range is just from 0mm to 10mm...


any ideas on this? thanks!

skypilot

iTrader: (1)

Sounds just like mine. Get a meat thermo and if it reads 180 you are fine, just make a mental note about its position. the gauge was never calibrated at the factory.
If you want get an autometer temp gauge and hang it to the right of the radio in one of those "pod" mounts.

lekiboy

i really want to solve this...is there a way to fix this gauge?

skypilot

iTrader: (1)

I doubt it, you might chase a high resistance ground on the dash panel or the engine block to get a little more voltage to the gauge. You could try reseating the large blue connector behind that area of the dash and using an electronic circuit board cleaning solvent. Considering how old some of these trucks are they are really holding up quite well.

Buck87

Swim,
Thanks for letting us know what the resolution to your problem was. I learned something.

lekiboy

Finally solved my "constant cold temp gauge"....After weeks of trying to find the culprit and hours of surfing the web, I brought my truck to one of the shops near to my house. It turned out that the mechanioc supervisor used to be an Ex- Toyota electrical specialist. He told me that there is a temp sending uniot at the back of the throttle body just on top of the engine block. It cannot be seen superficially because it is being covered by ruber tubes and pipes..We replaced it and voila, the temp reached to normal. The new sending unit cost was just 3 USD...tsk tsk tsk...



THE USUAL CULPRIT FOR COLD TEMP GAUGES


It was difficult to reach and you have to use a deep 12mm socket with a 6inch extender....hew!

I thought I can move on to the repaint but the mechanic saw some drops of coolant on the ground. He removed the engine protector shield below and saw the leak coming from the lower part of the radiator. The plastic part holding the lower part of the radiator has some cracks. He recommended me to a radiator shop who will remove the lower plastic part and replace / seal it with a brass body...cost = 100USD...I will probably bring it there next weekend.