No heat on passenger side, shop says blocked heater core

[CA-RJ]

Update:

Shop is still driving it with the fresh fluids in it. They are going to do a coolant test once they are done driving. I asked why they didn't test the old fluid and was told because there was so much stop leak in it they thought it would mess up the test (not sure about that?).

 

[CA-RJ]

And it looks like I am get the shaft all the way around. Shop says the compression numbers are good, coolant tested fine.

They flushed the heater core and said the heat is better but still about 10 degrees cooler on the passenger side. The only thing they are willing to do is replace the heater core at their cost, which leaves me paying $800.

Going full circle, I still can't understand how one side is cooler than the other if the blend door servos are good.

 

[Sungod]

It does sound odd that one side gets heat and the other doesn't, but could be the design of the heater core. Your radiator works with hot coolant enter the top and exiting the bottom, but heater cores sometimes flow left to right. You could play around with it and reverse the hoses to see what happens.

Thinking along those lines, I would ask how they flushed the core. They should have disconnected both hoses and ran water through in reverse. You get a good idea of the restriction doing that. It should flow right through without building any pressure.

If you have the skill and looking for options, you could try to flush the heater core with CLR. I have had success using it in the past with scale. You disconnect the hoses and fill the core with CLR solution (mix water and CLR). Let the CLR sit in the core for a few hours then back flush with a garden hose.

 

[CA-RJ]

I went down to the dealership and talked at length with the tech who was working on my truck. After speaking with him, I negotiated the pay for the heater core but the dealership to eat the labor. They agreed. So a new heater core goes in. The cooling system has been flushed several times, compression test was good (I saw the pictures of the gauge for each cylinder) so at this point I have the believe that there isn't currently a head gasket issue. I'm sure at some point the stop leak will stop working and I will develop a gasket leak and at that point I'll have to deal with that. I'm not sure there was anything more I could do on my end.

Thanks for the help. I appreciate all the comments and suggestions.

 

[YotaDriver]

I went down to the dealership and talked at length with the tech who was working on my truck. After speaking with him, I negotiated the pay for the heater core but the dealership to eat the labor. They agreed. So a new heater core goes in. The cooling system has been flushed several times, compression test was good (I saw the pictures of the gauge for each cylinder) so at this point I have the believe that there isn't currently a head gasket issue. I'm sure at some point the stop leak will stop working and I will develop a gasket leak and at that point I'll have to deal with that. I'm not sure there was anything more I could do on my end.

Thanks for the help. I appreciate all the comments and suggestions.

I wonder if the previous owner was/is a forum member...certainly wouldn't be surprised if they read up on the P0306 engine code they got using this forum either way.

The ease with which some people can pawn their problems off on unsuspecting others never ceases to amaze me. Sorry you got stung by someone else's selfishness, OP, but hopefully you get a lot of good use out of this engine before it croaks.

 

[Sungod]

Sounds like you got a decent deal paying for parts because labor on a heater core is big $$. Although I am sure parts are not cheap since you are probably getting stuck with $100 in coolant alone.

I would love to see a cut away of your old heater core to see what the stop leak did to it.

 

[sean-svm]

I was curious if you had any updates to your heat woes. I am experiencing the same symptoms, heat on drivers side, cool passenger side in my 2005 4Runner V6 Limited. I've verified that the actuators for both blend doors are functioning and have also disconnected the passenger blend door and operated it manually to make sure it was indeed moving. My next plan was to try to flush the core and cross my fingers. After a summer and fall that involved head gasket and radiator replacement among other repairs to now have heat on only half the truck is a real PIA.

 

[CA-RJ]

Update:

Some 5k miles later the truck is running great. The heater core was replaced, coolant flushed and the heat is amazing. Clearly the heater core being plugged was the issue. Drove to CA and back without any issues. Cross my fingers and hope that's the end of the issues.

 

[stackincheese]

Sorry guys I know old thread, but I recently joined because my 4th gen has been experiencing some common issues as well. I think my heater core is clogged and I read a lot of people did a back flush with great results, however nobody really detailed how they did it.

This video gave a great simple explanation: https://www.youtube.com/watch?v=M9SIafVsqyc. Will try this in a few weeks and let you guys know. Looking forward to getting heat back.

 

[fishin]

05 SR5 No heat

I have an 05 where the heat works fine, at times, but other times it doesn't. No change in settings. Where would I start to look for the problem? Thanks.