Heater core removal

[nissanh]

I removed the heater core in a 4runner without removing the AC. Some claim it is easy to remove the heater core unit without removing the dash by removing the AC evaporator and the blower motor. Well.. my experience is, it is impossible to remove the heater control unit without removing the dash. It is not hard. Best thing is you can do it if you have time and patience.

The tools I used are 10, 12 and 14 mm and Philips screwdriver.
You can see the step by step pictures towards the end of this thread.

Before doing anything, remove the ground terminal from your battery and wait about a minute.

Remember, the dash will come off with a very light pull. if it is not coming off, you might have a nut/bot some where.

You then can remove the cross metal bar holding the steering column.

Disconnect the heater/cooler selector cable and air flow direction cable. Make a note (sharpie) where the metal clip holds the outer housing of the cable.

Remove all the 10 mm nuts/bolts holding the Heater/AC control unit, AC evaporator and blower. This will give some extra space to giggle around the pull the heater core unit out.

This is also good time to check any leaks in the Heater control valve in the engine bay. IF you get hot water in the heater core when you are running the AC, it will kill the cold air as about 20% cold air is directed through the heater core.

 

[Royisme]

Thanks for the write up! I haven't had a car it wasn't a pita in, so here's hoping mine last many more years!

 

[Singtoe]

For all that work required to replace the heater core, why didn't you buy a new one. It will only be a matter of time before that used one craps the bucket.

 

[nissanh]

Complete removal pictures listed below.


I recently did my car's (Geo prizm = Toyota sprinter) heater core. Tried online forums and no luck. Talked to a mechanic and that is about $700 - 1000 job. No way! I am a mechanically inclined person. So I tried it on my own and I was successful! Unfortunately I did not take pictures to make a thread to help out others.

(It is impossible to access the heater core simply by removing the AC evaporator as some claim. You got to remove the dash to install the heater core)

I then made this thread on how to replace the heater core.

It is easy. You need time. If you have good 6-8 hours, you can do it.




Another discovery during this removal. If your car is old (about 15 or more), check the proper operation of the hot water valve sending coolant to the heater core. It should NOT pass water when it is closed (While in AC mode). You can use some pressured air to check it. If it leaks, you are sending hot water into the heater core and this WILL warm up the cold air!

You can also check the leak this way. Keep the heat/cold selector on cold side. After about 20 or so mile drive check the hose AFTER the hot coolant valve. If it is hot, your valve is leaking and sending hot water to the heater core (which you don't want)

You can buy this valve for about $30 New. Now you can enjoy ice cold AC in summer!

 

[nissanh]

More pictures

 

[nissanh]

More Pictures-2

 

[nissanh]

Pictures-3

 

[nissanh]

Pictures-4

 

[nissanh]

Pictures-5

 

[Singtoe]

Complete removal pictures listed below.


Well.. My 4runner has no problem with the heater core. Heater core is made out of Either fully Aluminum or Copper + Aluminum and all soldered, it cannot get bad.

The only way to kill the heater core is by clogging it or sending very hot coolant through it after over heating the car (This is what happened to my car!)

Anyway, I recently did my car's (Geo prizm = Toyota sprinter) heater core, after no help from online forums. Mechanic will ask somewhere around $700 - 1000.
Some says remove the AC evaporator without removing dash.

So I wanted to see how to do it. I replaced my car's heater core and realized damn, why I did not made a thread on this!!!

I then made this thread on how to replace it without removing the AC as well as saving couple of hundred $$$$$! May be a lift? Winch? bull bar?

It is easy. You need time. If you have good 6-8 hours, you can do it.




Another discovery during this removal. If your car is old (about 15 or more), check the proper operation of the hot water valve sending coolant to the heater core. It should NOT pass water when it is closed (While in AC mode). You can use some pressured air to check it. If it leaks, you are sending hot water and this WILL warm up the cold air! You can also check the leak this way. Keep the heat/cold selector on cold side. After about 20 or so mile drive check the hose after the hot coolant valve. If it is hot, your valve is leaking and sending hot water to the heater core (which you don't want)

Remedy: Use two 1/2 inch hot water ball valve (ebay $5 each) to shut down the water flow to the heater core on both hoses! So during the summer months I am going to shut the two 1/2 inch ball valves so I get no hot water in the heater core and will only receive cold cold air.

This is wrong in so many ways.

 

[nissanh]

Which part of the thread is incorrect? Please I like to know.

I did the exact procedure to replace my car's heater core and it is working fine as well.

 

[Singtoe]

Complete removal pictures listed below.


Well.. My 4runner has no problem with the heater core. Heater core is made out of Either fully Aluminum or Copper + Aluminum and all soldered, it cannot get bad.

The only way to kill the heater core is by clogging it or sending very hot coolant through it after over heating the car (This is what happened to my car!)

Anyway, I recently did my car's (Geo prizm = Toyota sprinter) heater core, after no help from online forums. Mechanic will ask somewhere around $700 - 1000.
Some says remove the AC evaporator without removing dash.

So I wanted to see how to do it. I replaced my car's heater core and realized damn, why I did not made a thread on this!!!

I then made this thread on how to replace it without removing the AC as well as saving couple of hundred $$$$$! May be a lift? Winch? bull bar?

It is easy. You need time. If you have good 6-8 hours, you can do it.




Another discovery during this removal. If your car is old (about 15 or more), check the proper operation of the hot water valve sending coolant to the heater core. It should NOT pass water when it is closed (While in AC mode). You can use some pressured air to check it. If it leaks, you are sending hot water and this WILL warm up the cold air! You can also check the leak this way. Keep the heat/cold selector on cold side. After about 20 or so mile drive check the hose after the hot coolant valve. If it is hot, your valve is leaking and sending hot water to the heater core (which you don't want)

Remedy: Use two 1/2 inch hot water ball valve (ebay $5 each) to shut down the water flow to the heater core on both hoses! So during the summer months I am going to shut the two 1/2 inch ball valves so I get no hot water in the heater core and will only receive cold cold air.

Which part of the thread is incorrect? Please I like to know.

I did the exact procedure to replace my car's heater core and it is working fine as well.

Well.. My 4runner has no problem with the heater core.

But you are still replacing yours?


Heater cores will corrode and leak.

I understand saving some money but hot damn. The heater valve is $32 on ebay. You spent $10 on two ball valves. Spend $20 more and replace it with the correct part. Plus, on the limited models, the controller needs to be able to regulate the heater valve to provide auto climate control.

I am not going to do 6-8 hours worth of work just to stick a used core in. How much was really saved buying the used core verse buying a $80 new one off ebay.

 

[KidVermicious]

I understand saving some money but hot damn. The heater valve is $32 on ebay. You spent $10 on two ball valves. Spend $20 more and replace it with the correct part.

This. For all the effort you put into that, spend a couple more bucks and do it right.

 

[thor999]

Thanks for all the pics! Have a feeling I will be facing issues this winter, had some last winter.

 

[nissanh]

Correction.

I address TWO things in this thread.

First : Heater Core removal
I installed a NEW HEATER CORE into my car "sprinter" made by Toyota, but wanted to show the world how to do it. I chose a 4runner for that purpose.

Second: For older cars (except Limited models, thanks for pointing this out)

IF your AC is low or having hot air when you select outside air (cold mode), try this:

The hot coolant shut off valve will leak. Even a 97 4runner with 180 K miles will leak (I checked 2 trucks and they both leaked).
I pulled mine out and washed and blow in it while the valve is closed. It is leaking.

If you see the inside of the heater/AC control box, you will see the door DOES NOT close the heater core 100%. So about 20% AC air will pass through the heater core when you have AC or simple outside air on. If hot water comes to the heater core this 20% opening will warm the cold air generated by the AC lowering your AC efficiency.

I practically saw this in my 92 car. I isolated the heater core due to the leak. During hot summer days I simply used speed of 2 or 3 max to cool my car. This is what lead me to this conclusion.

Try it your self, When you are running AC, check the water hose AFTER the valve and the return hose from the heater core, if the hoses are hot like the lower radiator hose, you are sending hot coolant in to kill the cooler air generated by the AC.


I hope this clarify.

 

[c1alex]

thank you for your time.

You made me do it with this great post.
Thanks a lot!:bluejump:

 

[nissanh]

You made me do it with this great post.
Thanks a lot!:bluejump:

You are welcome!!!!

 

[MattinLA]

WHEW Labors of HERCULES here.

Yowza, I cannot believe the huge amount of CRAP that has to be moved out of the way to access the heater box and contents. OK, SO I REPLACED the heater core myself on a Camry once, that was annoying but pretty straightforward with lots of trim removal, but THAT doesn't hold a candle compared to THIS massive job. Stuff, stuff and MORE stuff to be removed! Your pictures are terrific, really shows what's involved. Whew. SHOULD I ATTEMPT THIS. How do you keep track of SCREWS? How many harness leads MUST be disconnected? Realistically, is it like 3 hours to open it up and another 3 to close it up? How liable are you to BREAK brittle plastic tabs off? Is it easier to REMOVE THE FRONT SEATS? Whew. What is the standard price of a Pep Boys sized repair place to DO this job?

 

[nissanh]

Yes you should attempt this.

I kept the screws came from the left side on the drivers side and screws from the right on the right side. Alternatively, as you remove the nut/bolt, attach it to the removed part so you can keep a track of it. Take a picture or two before you remove it.

I don't remember how many wire plugs I removed, but good thing is there is no two identical plugs. opening takes about 3 hours, and closing must be done slowly and carefully, so like.... 5 hours.

Pulling the dash etc, is fairly simple and needs less force. You might want to buy few plastic clips that hold the dash to the front firewall right below the windshield (there are 5 of these clips, and 1 or 2 can be off or broken)). See attached

No need to remove the front seats.

I heard the heater core replacement is very expensive.

 

[BOSSIND]

I had to do this the other week, the heater box dampers were not working, one was frozen open and there for the 4runner generated no heat. I bought a good heater box used, Took me about 5 hours, really wasn't a bad job at all. I left the support bar in, I just loosen it from the body and this gave me room to pull the old heater box out and install the new.

I also removed the seats, though not necessary it gave me plenty of room for myself to move around and made sure nothing happen to the seats.

She is blowing hot air now.