dutchboy

My temp guage is running higher than normal (halfway) and it does it with 4 minutes after a cold start up. The top radiator hose you cant touch,it's so hot. The bottom radiator is bone cold. All of this is within a 4 -10 minute cold start. Within the 4 minutes the guage is up to halfway. After 10 minutes,the guage stays at half way and the bottom hose is still cold.
Before I started it this afternoon(after sitting over night). I opened the radiator cap and the coolant was right their at the cap! Usually it is down about 1/2" from top. The over flow tank was a little low. I topped it to the full mark before starting.
This started early this morning when I was leaving New Jersey(2am) and drove 90 minutes,non stop to my home in Pa. The guaged stayed at halfway the whole trip.I had the heater blowin on high,for s n giggles. thinking "could help prevent it from overheating".

3VZ-E engine. 2 yrs ago I had a certified mechanic instal: New radiator,hoses,new water pump,thermostat,oil pump, and all new belts. Rig always ran great when it came to coolant temp. and havin a rockin heating system inside.
Had the headgaskets replaced (again by a certified mechanic)3yrs ago,heads were milled very little. Not enough to really even matter. Their are no coolant leaks anywhere.
Here's where the temp guage normally runs. (In heavy snow,in 4wd,it runs a tad higher,but nowhere close to half the guage).


Here it is only after 4 minutes of being started. After sitting over night.


Could this be a thermostat problem?
Cool it be the Coolant Temp. Sensor?

Sure could use some tips here as this is my daily rig and I cant afford any downtime. I can do the thermostat replacement,no problem.
Just wanna make sure that's the problem,before I go tearin everything down.
Thanx all.
Dutch

P.S. What is this? Just a turn in the plumbing I'm guessin.

91Toyota

Sounds like a thermostat isn't opening to me. Replace it

dutchboy

That's what Im thinkin too.
Thaknx :>)

91Toyota

Anytime...good luck!

abecedarian

If I had to rely on your gauges alone for information,
I'd say the first pic is one of an engine warming up and the second is normal...
... if only because of the fact the first pic has higher oil pressure and lower coolant temps and the second pic has lower oil pressure and higher coolant temp, indicative of an engine going through the normal warm-up cycle.

... and there is an obvious shift in camera position between the two photos.

... and the fact that the first was taken at Oct-7/4:18 pm and the 2nd at Oct-7/4:21 doesn't help you prove there is a problem.
3 minutes between photos, and the fact the coolant temp has moved higher and oil pressure moved lower only proves the photos were taken as the engine is warming up.

abecedarian

you ought to look closer at some photos.

dutchboy

ABE...
Hello?
You're right. The pics were taken during warm up. That's what I was trying to get across. The 1st pic is when it is warming up..BUT also,the same position it "normally" stops at when it is warmed up and running...for hours.
The 2nd picture is showing where the guage is NOW going AFTER 3 minutes have gone by.
Before yesterday...the guage looks as it does in the 1st pic...AT ALL TIMES AND CONDITIONS.
Maybe I should've posted a pic of the guage after 10 minutes and used a camera tripod to help you better understand.

You "ought" to read my entire post scenerio.
Like the part after 10 minutes,the lower rad. hose is still cold.
;>)

abecedarian

hmm... okay.
we can see what the gauge does after a few minutes, and then after a few minutes more...
but if you let the truck sit for say 15 minutes, what happens?

abecedarian

and if you have access to an external / infrared thermometer, that helps.

abecedarian

I'm just thinking about the things I'd use to troubleshoot a problem.

abecedarian

So maybe a pic taken hours after you've driven the truck showing what you claim to be the same as the first pic would prove what you're claiming.

abecedarian

On the other hand... I don't see anything even remotely showing an engine overheating.

dutchboy

Guage stays at the halfway mark. Like I said in my post. I drove it 90 minutes,non stop and the guage stayed at the halfway mark.
For my rig,this is unusual,as the guage always read about 1/4. Like the same position as the 1st pic.
I'm just trying to determine if this is (or could be),a thermostat situation vs an engine coolant sensor. Im def. thinking thermostat.
Not used to seeing my guage at the halfway mark after driving 90 minutes.

dutchboy

Before yesterday...after hours of driving the guage read 1/4,the same position as 1st pic. How could I get a pic of this "normal" position, if it's now staying at a different position? Now...no matter how much driving I do...it goes up to half. I could drive it for the next 4 days nonstop and it reads HALFWAY all the time now.

I never said it was overheating. I said that the temp guage is showing higher than normal. If it would have overheated,it would be more obvious to the situation.

abecedarian

<accent=manchester>yeah, I suppose a gauge reading one half scale could be problematic to some, yet for most people anything less than full scale is normal. So how about being more realistic and seeing how the thing works "normally".</accent>

so pardon my humour.

abecedarian

not sure about where you all are, but when it's colder out here, the gauge reads warmer than normal
is this somewhat consistant with your observations.

91Toyota

higher rpm = higher oil pressure

lower rpm = lower oil pressure

I looked at the pics...just didn't spend much time.

abecedarian

if you need some help convincing your gauge it's colder outside, spray the radiator with water.

abecedarian

as oil warms up, it gets thinner.
so
higher oil temp=lower oil pressure...
unless rpm goes up to make more pressure.

that's why some engines can make 30-50, maybe even 100 PSI oil pressure when cold, and ~10 PSI when warm.

91Toyota

Personally, if I saw my gauge into the red I would pull over to the side of the road...I wouldn't think "is it actually over-heating" and keep on driving. Sure, gauges break. They aren't that accurate. But really how often do they break like that? Not saying that your gauge is working properly...but I trust mine to an extent. It would help to know if it is "actually overheating"...but when you said the top rad hose was hot and the bottom was cold...I figured that was kinda a dead give-away.