Whats wrong with my heater??

[COAKScottishrunner]

Getting to it and the help

Thank you guys for the help,
I did take a look under the dash and everything seems to be moving alright. The two oddities I want to mention first are I did have heat for like two weeks or a week before it went back to lukewarm, also, the rear back seat floor heaters work well. But I am thinking it is the core cloged with gunk after looking through the thred. How do I get to said heater core though?

 

[djaye.]

Thank you guys for the help,
I did take a look under the dash and everything seems to be moving alright. The two oddities I want to mention first are I did have heat for like two weeks or a week before it went back to lukewarm, also, the rear back seat floor heaters work well. But I am thinking it is the core cloged with gunk after looking through the thred. How do I get to said heater core though?

You can access both heater core connections for flushing right in the engine bay at the firewall. As far as changing said heater core, well that's another story...

 

[MattFromPA]

Hey guys, new to the forum, I'm having nearly this exact issue with my 2003 4runner SR5.

Just bought it and only noticed the issue this morning.

Air is warm when accelerating but cools down very quickly as the engine winds down. Almost cold coming out when I'm sitting at a light.

I've read so many posts that say so many things(heating core flush, water pump, low coolant, aftermarket stereo), I just don't know where to start.

I've got coolant full in the reservoir, first thing I checked.

In one post I read something about the radiator hoses being different temps.

My in and out tubes in the radiator are not the same temp. One hot one not.

I am not a car genius, any help would be appreciated.

 

[jbtvt]

Hey guys, new to the forum, I'm having nearly this exact issue with my 2003 4runner SR5.

Just bought it and only noticed the issue this morning.

Air is warm when accelerating but cools down very quickly as the engine winds down. Almost cold coming out when I'm sitting at a light.

I've read so many posts that say so many things(heating core flush, water pump, low coolant, aftermarket stereo), I just don't know where to start.

I've got coolant full in the reservoir, first thing I checked.

In one post I read something about the radiator hoses being different temps.

My in and out tubes in the radiator are not the same temp. One hot one not.

I am not a car genius, any help would be appreciated.

You can get a bottle of coolant flush at your local parts store or online, very easy to use, just follow directions on it. It's important to use distilled water to prevent deposits, and the right Toyota coolant to prevent corrosion. At dealer or online, aftermarket brands make some that are supposedly compatible but boy worth the few bucks saved imo. If someone removed the thermostat that would also keep car running cooler but shouldn't affect it as quickly as to be noticeable at a stop light so clogged core would be my first guess also. And easiest to fix

 

[MattFromPA]

Just had the heater core flushed today and the guy said stuff came out and he declared it fixed.

After driving for a few minutes to warm it up it was pretty clear the problem hasn't been fixed. It's still inconsistent.

Sometimes warm, sometimes not. High fan speed and foot well seems to not work at all. More warm sure while foot is on the gas.

Is this thermostat, radiator, water pump, or something else?

 

[YotaKid87]

just had this issue, first we found the thermostat was stuck open. got better but still not hot. then found core was plugged. you could also have a heater box door issue