Need to replace Heater Core. How?? What am I getting into? 1990 240sx

[RamonetB]

Hey guys!

I did some searches as was surprised to see that there is very little info on it here.

I need to replace my heater core. There are no leaks, but I know it's partially clogged. I don't get good (or consistent) heat in cold temps. Considering I had to have my radiator also replaced because the PO got it clogged up, and also taking into account I had the core flushed and was told there was a ton of gunk in it... well... I don't want to be cold this winter.

So, I've got a new heater core.

I know I need to remove the dash and drain the coolant. Disconnect the heater core hoses from the engine as well. Stuff like that. BUT, can anyone here give me a better insight on how to perform this operation?

This thread: zerothread?id=5808 talks about woes in trying to remove it from the driver's side vs the passenger side. Any thoughts or suggestions on this?

I've never done a heater core replacement and have no doubt I can do it. But the more I know the less I have to discover and curse about later.

Help me out, guys.

[tiger]

Ok, all I can offer is... the heater core is going to be a PAIN in the butt to get to.. you have to take off just about everything. Do it right, take the dash out and it won't be that hard after that..

[MasterOfAngle]

Heater cores are such a PITA to replace that id rather not have heat than replace one of those things. My 95' 240sx needs a new heater core but I refuse to replace it, I just put a jacket on. You have to take the entire dashboard out and its in the center towards the passenger side of the car. I'm an Audi mechanic and Ive had heater cores that sucked so bad to replace that I was almost about to quit my job on the spot...but good luck.

[NM50]

The forces of darkness engineered Nissans heater control system.You need to evacuate the A/C,pull the dash pad,remove the center support beam and support to the floor.Remove the A/C evaporator,and then the heater box.Disassemble the box to get to the core.The best tips are to take pictures as you go along so you can see how it goes back together and use tampons in the core nipples to keep from spilling coolant on your carpet.No joke they work.

[RamonetB]

Actually, removing it and replacing it wasn't as hard as I thought it was going to be. But then again, without ever having replaced another heater core, I have no point of reference to judge it by.

I drained the coolant.Removed the cluster.Removed the dash.Disconnect wire harnesses to remove the center support railRemove the center support rail.Remove the inlet and outlet houses from the heater core inside the engine compartment.Then removed the heater control box.

I didn't have to evacuate the AC. There's enough flex and play in the hose lines to allow it to be moved enough to pull the heater box out. Just make sure your firewall insulation rubber gaskets are put back when it's all screwed back together. They'll pop out when moving the heater core out (obviously) and the AC unit around.

The heater core itself actually just slides into the heater box. Pretty simple there.

Then put it all back together. Took about 5 hours with 2 people who hadn't done this sort of thing before. I wouldn't want to do it again, but I already feel the heat coming and going. There must still be some crap left in the system from the old heater core (which was insanely clogged).

I'm taking her next week to be professionally flushed. It sure is nice to have heat again.

-kirk

[LOVEMY240]

HAVE FUN!!! IT TOOK ME ABOUT 6 HOURS I RECOMMEND REMOVING THE PASSENGER SEAT. REMOVING THE EVAPORATOR IS NOT NECESSARY BUT IT MAKES REMOVING THE HEATER UNIT A WHOLE LOT EASIER. THE DASH COMES OFF PRETTY EASY BUT THERE ARE SOME BOLTS THAT ARE NOT ON THE DIAGRAMS I FOUND ON THE WEB. GET A LOT OF BAGGIES AND BE READY TO LABEL ALL THE SCREWS AND BOLTS THAT YOU TAKE OUT--THERES A LOT OF THEM. THIS JOB IS NOT IMPOSSIBLE BUT ITS A COMMITMENT ONCE YOU START YOU KIND OF HAVE TO FINISH

[300 z man]

I see you already got the job done. But check this site out they have some great "How to sections'.

http://www.xenonz31.com/issues.html