240 No Heat

[240nessx]

Hey, so winter is coming and I'm starting to now want to use my heat. My problem is the heat wont come in, it stays cold the entire time. I changed my thermostat and radiator cap cause they were bad recently and i hoped that would possibly fix it, but it didn't. I also disconnected the upper and lower hoses going to the heater core and blew it out with compressed air and also let drain-o sit in it to hopefully unclog it. I washed the drain-o out, and the pipes are clear and clean now but the hoses going to and from the heater core are still not getting hot.

My question is, do 240s have a valve for the heater core? Where would it be? or could my heater core just have gone bad? I bought the car during the summer and just got it on the road this month so, i don't know if i did something to it, or i bought it with no heat. thanks

[breadbox]

well if you replaced everything else, then I have to say heater core.

[sandcrabsailor]

Post pics of your hose set-up. My ex-wife sabotaged the heat before I got my s13 back in the divorce. She re-routed some of the hoses and ended up completely bypassing the heater core. Perhaps it's a lineup issue. Replacing a heater core is a pain in the butt, so do the idiot check first, or better yet, have someone else idiot check you.
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[truepinoy]

You can use drain-o in your heater core?!?

[240nessx]

sry i havent replied...been busy, and yea u can put drain-o in u disconnect the 2 hoses that go into the heater core plug one side pour drain o in let it sit blow it out and it should get rid of clogs u have, ill get pics tomorrow, and do 240s have a heater valve? if so mine might be stuck if its not rerouted.... thanks

[OutToWinPAHC]

When you flushed it, and you got water out of the other end then I would assume it a valve problems / or selector problem. Draino.... no just no.

Best bet is to check the selector cables, check to see if the heater core is getting hot.

[240nessx]

How is drain-o so bad for the system compared to blowing it out with compressed air? a tech where I work told me to do that, but neways with the heater core, the top hose going into the firewall gets hot but the lower one coming out is always cold. How can I check if the heater core is getting hot? And this valve ur talking about, where is it located?

[OutToWinPAHC]

It's located in the factory service manual (not to be a d!ck but there are detailed photos and diagrams as well as testing proceedures in there)

And why is drain cleaner bad... because if you poured it into a clog and it coul eat through the core or hose then now you have a leak. Which lets air in the system that can lead to engine failure. Also I don't know how the gaskets, and o rings will like that.

[alms24sebring]

If your getting a clean strong flow of water from the outlet, it sounds like the valve or selector is stuck or broken. Sorry, I'm not sure where it is. On some cars it is right before the hose enters the firewall. Others, its behind the firewall. Factory Service Manual time. click SEARCH. I think someone had posted a link to a FSM recently.

[240nessx]

where in the fsm does it show how to test components and component location? ive looked through it but cant find any info on it...thats y im asking here

[OutToWinPAHC]

Sorry it was in 89-90, same stuff though, when it comes to heat.

http://www.nicoclub.com/FSM/240sx/1989-90/HEATER_S.pdf

[alms24sebring]

Oh gatcha, well here you go^

[240nessx]

wow that fsm article is perfect...ill read that and look into the valve operation and the blend-air door. thanks didnt think to look into the 89-90 fsm cause i thought itd be different but thanks so much.

[240nessx]

ive read through that manual, and still cant find the location of the blend-air door and the control valve. I took apart the center console and found the cable that connects to a rod. when you move from cold to hot the cable moves that rod forward and backward. should that be opening the control valve? how do i check it.