In case anyone cares, or happens to need this info, I found this site that documents the heater core replacement:

http://www.btinternet.com/~d.brooks1...lownecufix.htm

Yes, it's about replacing an ECU, but it mentions the entire process of replacing the heater core as well. The dude's in the UK, so grain of salt - right hand drive Maxima.

I just did the job following the instructions and ended up with perfect results. Here's the pain:

After the complete demolition:
http://www.mindspring.com/~gruven/maxima/before.jpg

Post ressurection:
http://www.mindspring.com/~gruven/maxima/after.jpg

And if someone had only stolen the car when it was:
http://www.mindspring.com/~gruven/maxima/detail.jpg

For anyone doing this task, it sucked. Took me about 14 hours. The ac didn't need to be discharged (despite other opinions). And the dealer technician that I spoke with that quoted me 4.5 hours, I should've taken him up on that because he had NO IDEA what he was talking about. He told me the ac needed to be discharged and the dash didn't need to come out...Both of which are completely wrong. Anyway, I'm so glad it's over and everything still works.

Been there and done that. Only thing is Courtesy gave me a VG core for my VE. GRRRRR But I made it work with some hose adaptors. I only found out that the core's in/outlet diameters were different AFTER putting the thing in. Courtesy said, "no problem, just return it and we will switch it". Oh hell no!

My dealer quoted like $900+ because of the extensive labor.

I was the same as you. I didn't have to detach any ac hoses either.

Ya, almost a grand sounds more realistic to me. And when I finally got that original core out, I was hoping and praying with my fingers crossed that they had got me the right replacement. Been there done that not having the right part when you need it because someone somewhere made a typo...Ya, sure, I'll just rent another hoist, pull the motor, take off the head, bla bla bla...Pacino's got the right quote for that one:

"Don't waste my muthafuc/<in time!"

I am taking my dash apart right now to replace the heater core. How did you get the dash past the tilt steering ****? No matter how i look at it i cant get it past that stupid ****. Itherwise i could pull the dash out.

I don't quite remember off cuff, but if it memory serves me right, you have to drop the steering column first, before the dash comes out. There's two screws that hold the column up to the metal bracing.

Before taking out the dash, the steering wheel, ignition, etc (the whole column) will be sitting about 5 inches from the drivers side floorpan.

If you look at:

http://www.mindspring.com/~gruven/maxima/detail.jpg

You'll see what I'm talking about.

I finally got it done. It took me about 9 hours including a lunch break. Would have been done sooner but had to find clamps for my radiator hoses since i had bypassed the heater core for a while. All in all it was a bigger job then i thought. I know why my father, who is a mechanic by trade, comes home everyday and says hes tired. Its a pain in the butt to be slumping in a car and over a hood all day. ANd thanks for the pics they came in handy.

Ive gone through the same grief, replaced the core. Now i must have forgotten something cuz for the life of it i cant get any heat out of it. I know the core is getting coolant and there are no clogs, Is there a sensore or switch,harness,assembly i may have forgotten?

oh my gawd - i just went thru this a few weeks ago. make sure to get a new heater core - my uncle said that with all the disassembly you have to do, better get a new one than patch up an old core.

as for not getting any heat? did you put the 2 cables back in the right way?(fresh air vent, heater core vent). how about which vents were open/closed when you dissasembled it? there's also the motor switch that opens and closes the vents - must be put back the right way. I broke one of these vent covers after forcing out the duct, good thing i put together models and used the plastic cement to glue it back together.

anyways, good luck finding the source of your problem. hope this gives you something to start with

This thread reminds me why I havn't done this yet. If I imagine myself on the beach while I'm driving in the miserable south Jersey winter, I can sort of feel heat coming out the vents instead of semi warm/cool air. And yesterday on the highway, I actually got warm! If I keep the revs at 3K I get some heat, too bad that's a little high for the 35 mph speed limit the whole way to work every freezing morning! My parents live in Florida..they have an extra bedroom. Mom, Dad, I'm on my way!

For those of you that have done the heater core, can anyone tell me what kind of temperature they are getting out of it with the settings being full hot and full blower?

Well after my car has warmed up sufficiently it works great. And you shouldnt use full blower on heat settings because the air moves so fast across the heater core that it doesnt get heated good enough. When using heat i always go one setting below max for the best heat. believe me on this one.

nah man, i cant even get enough heat to defrost the windows. I cant possibly imagine why mine doesnt have any heat.

Damn man, I feel for you. All that work and you are still cold! YOu sure the valve is working/hooked up properly?

Ditto. Check the temp gauge on the cluster and make sure the coolant system is working correctly. May want to check the thermostat -- that was the first of my Maxima's issues. It would take a LONG time before heat ever came up - thermostat was staying closed and never opening. Fixed that and the next winter the heater core leaked. Car must want to go back to Florida or something...

The thermostat is a long shot, but drive around for like 30-40 minutes. If still no heat, and coolant system is up to temp (and not overheating), I'd say you have to go back to the dash mess and make sure you have the vent flap re-installed correctly. Make sure it works too...

If someone could do me this favour I would greatly appreciate it. With a hot engine and the heater on full and the blower on full could someone give me the temperature of the air that comes out of their heating. Please use the front panel ducts for this test. If possible need actual temperature of air.

I would think that it would be in the mid to upper 80's. Although I'd be curious to know why you would need that specific kind of info. Not trying to be a smart@$$, but if it's hot enuff to defrost the windshield, it **SHOULD** be hot enuff to warm a human being...

The reason that I am asking is that when the weather is from 32F to about 40F the heater is fine. As soon as my the outside temperature drops below freezing my heater has a hard time getting the car warm. Yes I have changed the thermostat and checked all the valves and checked the operation of all the stepper motors for the heating system. My only recourse is the heating core itself. I dont know if its just the heating systems on these cars that stink or do I have a problem?

I think from all these threads and all the strange problems these cars have, it must be that the heaters stink. I have never seen a car where the two left vents blow warm and the right vents blow cold. Is the duct work separate in these cars?

I think these cars are simply known for many different bugs...heat...Bose stereos...faulty radio antennas...etc. Of course, mine is 14 years old and you can expect it. But I have to admit, the heater issues are illogical sometimes.

RickC

Well i have had my maxima 4 years and its 13 years old. The heat was messed up till i replaced the core. Now if you dont make very sure you put it together right you will probably get the problems you stated. I myself had forgotten to plug in the connector for the controls that change the airflow from top to bottom to vent, on my 89 GXE. So i was getting wierd airflow problems. but i fixed that real quick. cant be having air flow problems in the car when you got friends with you.

any tips tricks or where to start in completing this project?

where can I get a good price for a new heater core?

how much and where to buy heater core?

How to start on this project? tips tricks? problems to avoid?

Yes, take your time doing it, take pictures if you have to during the process and make sure that everything is plugged back in as you took it out. For me it took 2 people 11 hours to do but luckily I had no problems afterwards.

Ok great, I have digital camera!

where can i buy and how much for the heater core??

The place that I got my heater core was out of a dealer in Phoenix, I cant remember the name of the dealer, I do remember the price being about 135 bucks. Have fun

The dealership in question is Scottsdale (AZ) Infiniti. Sorry I don't have a number for them, but they do have a website and a toll free number. They quoted me $131.89 for the core, special order only, and they're charging $10.30 to ship to Albuquerque. Darn good deal.

airlock in heater core... u might have to bleed it to get all the air out.

Anyone that is having to replace the heater core is in for a big surprise when you think it doesn't take that long. Took some guys and I ten hours to get it all done...... if you don't believe me, check out this pic and the link to more pix underneath it



Some more heater core pix

Aaron, I also have an 89, but mine's a GXE. I've got the dash totally stripped down, crash bar removed, but now I'm nervous about removing the heater core assembly. With all the cables and doors, etc, I'm convinced I'm going to screw up. Any tips on getting that big black box out?
A friend of mine (Nissan dealership mechanic) says the Freon needs to be drained before I can proceed, but nobody else mentions that. So, how do I get the core out without draining Freon?

I emailed ya Ross

I finally finished my heater core replacement last weekend (I was working alone). Thanks everybody for your help and suggestions. As soon as they fix the site, I'm definitely becoming a paying participant. This thread alone saved me $700.

The '89 and '90's had a design flaw in that the heater core was the highest point of the heating system. This causes an air lock in the heater core. I think it was solved for the '91' and definitely for the '92-'94 model years. The TSB from Nissan recommends jacking the front of the car 39 inches up, then removing the rad cap and run the car for up to 1/2 an hour with the climate control (or temp lever) at full hot. Grab a beer and watch the air farting out of the filler neck. If anyone REALLY REALLY wants, I can post the TSB here. (I joined the nissan.com tech site for 24 hours and downloaded all the 3rd gen TSB's)