2008 Toyota RAV4 Heating Problem

Hello! I have a 2008 Toyota Rav4 all wheel drive that has 80,000 miles on it. It’s been having a lot of problems lately, namely the water pump. I got it replaced at our local mechanic’s about 3 weeks ago and all was fine until I tried to turn on the heat last night. Only cold air blew out and then came on intermittently and then just stopped again. The fan works fine, it’s just not blowing hot air. Not sure if this is related to the water pump being replaced? Do I need to flush the heater core? There is no leakage. I am really getting annoyed with all the issues the car has been having lately and don’t want to spend a lot more money to fix it at this point. How much would it be to replace the heater core?

Before you do anything else, check the fluid level in the radiator, if it is low that could cause warm antifreeze from reaching the heater core. You could have an air bubble that could also stop the flow of antifreeze. Take it back to your mechanic if you do not know what fluid to put in, and you could ask him to ‘burp’ the system.

Sounds like there was an air pocket left in the cooling system. Check the coolant in the radiator with the engine completely cold, and then check and top off the resiviour. You should also inspect the radiator cap.

I am going to guess on it being a v6 if that is the case using a vacuum bleeder is quickest and eliminates air pockets on the first try.

Yes it’s a V6, should’ve mentioned that. I hope that’s all it needs! Thanks!

Just checked the radiator fluid and there’s none in the reservoir. Is it possible that this is related to the water pump being replaced recently? I have not seen any leakage, but it’s obviously going somewhere, or maybe it just wasn’t replaced when they worked on the water pump?

The v6 is prone to trapping air if it is not filled properly when cooling system work is done. Most years have a air bleed screw on the engine to help with filling. The cooling system was not filled properly when replacing the water pump. If the engine is cold remove the radiator cap and fill the radiator then fill the resiviour. Drive it and check the resiviour only, never remove a radiator cap once the engine is warm.

More than likely he did not get the system bled properly. It sucked all the fluid out of the reservoir. Fill the reservoir with the “red” 50/50 mix anti-freeze to the hot line. Drive it around and check it again. Had the same thing happen with after they replaced my radiator after a front end collision.