Question about 5vzfe

N

nissanh

Senior Member
My neighbor bought a 03 tacoma v6 5vzfe with 89K miles. When we bought it we notice the temperature needle comes slightly below 3/4 in the gauge (usually it should be below 1/2). Radiator is still factory. After running about 15-20 minutes, I noticed the lower radiator hose is still cool. Can this be due to a clogged radiator?

We cleaned the MAF sensor, intake hose, throttle body and air filter box (had a K&N filter and oil over the intake system!)

Idle RPM stays about 1200 when the engine is hot, and when the AC is turned on, the RPM drops to about 1000.

Any idea what's wrong?
 
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At 89k miles, if it hasn't had the timing belt done, then it is time to have it done. Just replace all of it and see if it still happens and go from there.
 
What makes you think something is wrong? It might be just an out of calibration gauge. What happens when he drives it under a load. Does the temp gauge stay the same. If it does, then nothing is wrong. Stop being a hypochondriac.


FWIW- My volt gauge reads almost at top but my multimeter says 13.8 volts...
 
Curtperry, I suspect thermostat too. No T-belt replacement sticker anywhere in the engine bay so sometime soon I am going to replace the T-belt and the other components.


Since it is an automatic, isn't it better to replace the radiator like in every 10 years?

Singtore, I did use a digital IR thermometer to check the temperature at the output hose at the metal pipe and was 82 Celsius (179.6 F). I forgot the lower radiator hose temp. Yes, after driving 60 miles at 60 MPH, the gauge stays the same.

What do you think about the high RPM? IS this normal after cleaning a dirty MAF sensor?

Thanks
 
nissanh said:
Curtperry, I suspect thermostat too. No T-belt replacement sticker anywhere in the engine bay so sometime soon I am going to replace the T-belt and the other components.


Since it is an automatic, isn't it better to replace the radiator like in every 10 years?

Singtore, I did use a digital IR thermometer to check the temperature at the output hose at the metal pipe and was 82 Celsius (179.6 F). I forgot the lower radiator hose temp. Yes, after driving 60 miles at 60 MPH, the gauge stays the same.

What do you think about the high RPM? IS this normal after cleaning a dirty MAF sensor?

Thanks
Click to expand...

I don't get it.

The temperature was reading below normal and you still want to fix it.


As for the high idle. Check all the vacuum hoses for leaks.
 
nissanh said:
After running about 15-20 minutes, I noticed the lower radiator hose is still cool. Can this be due to a clogged radiator?
Click to expand...

Sing, this is why he's questioning it.

How's the heat in the cab?

That's the #1 sign of a bad thermostat.

It should be hot, not warm. I it's not hot, then change the stat. If its fine, leave it be. Probably a bad gauge.
 
Singtore, it is 3/4 from the bottom or 1/4 from the top.

DOC2012, you mean the heat in the cabin? Heater works fine.

OK, I'll try the thermostat.

Back to RPM.... There are only 2 vacuum hoses connected, one to the air filter box and one to the box attached right in the middle of the main intake hose. All in place. I just sprayed the throttle body cleaner and wiped the gunk off the throttle body with a paper towel (didn't use a tooth brush).
 
Idle RPM is 1200??? And when AC is on its 1000? That seems very high! My idle RPM after the engine has warmed up is around 650-700. Plus, I NEVER run my AC, even if its 103 out! hahaha. I would check all vacuum hoses and the intake.
 
The RPM is crazy high. There's got to be more than 2 vacuum lines. There has to be.

Check the throttle linkage as well. See if it was adjusted at all.


What I mean by the heat in the cabin is just what I said. Lol.

With the heater ON, is the heat HOT, or just warm? If its just warm, it's probably the thermostat.
 
Remove your throttle body and clean it very thoroughly including the sensors and that should fix your high idle. Check voltage at your battery with it on/off and make sure it is in spec 13.8+ on, 12.8~ off. Clean any dirty grounds, and check/clean the connection for your coolant temp sensor. If your thermostat was stuck shut the truck would constantly go up in temperature, unless your coolant looks very dirty I wouldn't bother opening up the system.
 
I must be a complete idiot. if the top hose is hot and the bottom hose is cooler, then what is the radiator doing?


Singtore, I did use a digital IR thermometer to check the temperature at the output hose at the metal pipe and was 82 Celsius (179.6 F). I forgot the lower radiator hose temp. Yes, after driving 60 miles at 60 MPH, the gauge stays the same.
Click to expand...

So again. What is the problem? You even said the temperature was 179.6 F. What do you want it to read?
 
Last edited:
Could also be the sensor that the gauge gets its reading from. I had an older Camry that had a bad sensor that pegged the temp gauge at max until I fixed it.
 
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