Truck Won't Warm Up

[fdbyrne]

Over the last few days I've noticed a change in my 4Runner (V6). It takes forever to get up to normal operating temperature. By forever I mean like half an hour. I just got to work. It was stop and go traffic all the way here and 13 degrees F. I'm not overstating it when I say it took half an hour to get to it's normal operating temperature.

I assumed that it was a stuck thermostat so I replaced that last night. My initial drive after replacing it seemed fine. No issues. Then, this morning it happened again.

I know it's cold out, but I don't think that's the cause. What am I missing? Maybe my fan is always running full speed?

 

[black4vcobra]

Are you full on coolant? If not, is there any leaking?

Next time you have a bit of time, remove the radiator cap and start the engine. There should be coolant within an inch or 2 of the top of the radiator, if not, add some coolant.

 

[fdbyrne]

There is plenty of coolant. Overflow tank is full and there is plenty in the radiator too.

 

[vincentcomcast]

Over the last few days I've noticed a change in my 4Runner (V6). It takes forever to get up to normal operating temperature. By forever I mean like half an hour. I just got to work. It was stop and go traffic all the way here and 13 degrees F. I'm not overstating it when I say it took half an hour to get to it's normal operating temperature.

I assumed that it was a stuck thermostat so I replaced that last night. My initial drive after replacing it seemed fine. No issues. Then, this morning it happened again.

I know it's cold out, but I don't think that's the cause. What am I missing? Maybe my fan is always running full speed?

Did you use the Toyota OEM thermostat or an aftermarket one? Does the ECU throw out an error code like P0126 or P0128?

Another possibility is that you might have a "defective" new thermostat even though this is odd. This happened to me before on another car.

 

[fdbyrne]

There are no codes and it runs fine. The thermostat that I used was aftermarket. I do still have the one that I pulled out. I guess that I can throw it in hot water and see if it opens up. If I can verify that the old one functions fine then that would point towards a different cause I guess.

The part that has me so perplexed is that after I swapped out the thermostat and took it for a drive last night it seemed to work just fine. This morning was a different story. That's just odd.

 

[chmura]

Buy a OEM Toyota Thermostat. This aftermarket one could be stuck open. This happened to me once before. Thermostats are cheap! No reason to go aftermarket for this part at all. If Toyota dealer is far from you. You can buy OEM online.

One site is Toyota Motor Parts - Genuine OEM Parts at Low Prices

I bet you are getting horrible horrible gas mileage. Better replace it soon to rule that out.

 

[fdbyrne]

Thanks for the advice. Before I go buy another thermostat is there anything else that might be causing this?

 

[Robs08Runner]

How about the temp gauge? Does it read normally? I would think if it warms up normally, but no heat, one of the hvac doors behind the dash is stuck.

 

[vincentcomcast]

An OEM part from the dealer solved my very similar issue in the past. I would try that first in your situation.

If problem persisted, maybe other folks would chime in with their opinions.

 

[fdbyrne]

How about the temp gauge? Does it read normally? I would think if it warms up normally, but no heat, one of the hvac doors behind the dash is stuck.

This issue isn't a HVAC problem. That works fine, relatively speaking. It's the engine itself that isn't warming up to normal operating temperature.

I think I'll test the function of the OEM thermostat that I pulled out when I get home. If it works fine then I guess that will tell me that I have a problem elsewhere. If it doesn't then it's probable that my issue is thermostat related and both the old OEM and new aftermarket units are bad.

 

[gm350reratliff]

You may want to hook it up to a scan tool that can display coolant temp any see what that says. I would also verfy with a temp gun or mechanical gauge as well. It could be a sending unit issue or an issue with the guage in the dash.

 

[fdbyrne]

Ok. I'm still stumped. The thermostat that I removed is fine so my problem is apparently not related to the thermostat.

A possible related issue is that I apparently have a large air bubble in my system from when the prior owner replaced the radiator. For a few seconds after a cold start I hear coolant running into the heater core. That may or may not be related. I've tried to burp it out without much luck.

I drove for half an hour this morning before my engine got up to temp. What else could it be?