revenge240

Hi all, hope everyone had a good new year! This question might've been covered but not sure if anyone has a solution of some sort.
The inlet nipple on my heater core (the nipple with the blend door valve) busted a while back when reattaching the heater hose to it. It's not completely broken, as you'll see in the pic below. My only options are:
1. Buy a used heater core, and hope the plastic nipples don't shatter when installing.(new heater cores are long discontinued for the 91 240)
2. Find some kind of twist in nipple that won't destroy the remaining plastic nipple.
3. Just go without heat (but I'd rather not).

Buying a used heater core may be a good option, but I'm worried about the plastic breaking once I try to clamp a hose onto it.
Alternatively, is there some kind of "twist-in" aluminum nipple that can bite into plastic without leaking or destroying it?
Appreciate any help in advance!

Pics below show broken inlet nipple and length that broke off.

afishysilvia

Maybe try and remove the nipple, tap it aluminum core (or weld if you have access) some AN fitting or another form of fitting so you can thread a nipple or use NPT fittings.

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Agamemnon

RockAuto.com has them for $25.

Also the Nissan Stanza used the same core. You might be able to find some in a junk yard.

burnsauto

Exactly, don't waste your time putting in a used one that's 30 years old. Just make sure that the gaskets for those plastic fittings are in right, and that the screws are tightened down. A lot of aftermarket coolers with fittings on them won't have them as tight as they should be, some even go so far as to include instructions reminding you to double check the tightness of the fittings (like a radiator that has an oil cooler built in, etc.)

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revenge240

Thanks for the suggestions so far.
I actually did order a replacement heater core from Amazon, which looks like a good fit, however on the inlet side, there is a control valve that opens the core and blend door when you slide the controls to heat. The valve doesn?t appear to be transferable as it?s built into the nipple on the inlet side.
Can I just disregard this valve and not connect it to the new heater core?

burnsauto

you will lose some functionality of it as it'll have coolant constantly flowing through it, so some temperature control will be lost in the process. Good news is you'll have a working defroster (not sure if it's even a thing to need one living in vegas..) but when it cools down at night you won't freeze.

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revenge240

Thanks again for all the help, everyone!
Here are pics of my fix and the solution for any future reference:
First, a close up picture of the inlet side of the heater core. There is a valve there and you'll have hot coolant flowing through the heater core all the time, which will add some heat to your cabin when you don't necessarily want it. Thus, I was prompted to find a way to keep that inlet nipple, if I could.

Below, I used some painter's tape and oscillating tool to cut off the damaged part of the old nipple.

Lastly, cut off the end of the new nipple and spliced to the old inlet nipple using a 1/2" plastic barb fitting from Home Depot.

I added J.B. Weld around the splice to prevent any leaks from occurring. The nipple is now a bit longer than stock, but that's okay with me
I haven't hooked my heater core back up yet, but I got the dash put back together and will report back once I get it all hooked up to let everyone know if it worked or not. I'm pretty confident this will work though..

tuzzio

There was a dude on facebook (I think) recently who was inquiring about making aluminum ones. I shouldve hit the save button.

Either way, good fix!

Super_OK_S13

Check these out... little pricey but i think the heater cores are all the same 4 screw pattern/size outlet flange, just different core sizes/outlet shape tubes.

https://boostdoc.com.au/collections/...r-core-outlets

Edit: tuzzio, was it the same guy that i bought the pcv/water bypass stuff from on the ka24 page? (Not nicetime racing) I mentioned it to him in DMs that making them in aluminum would be a good idea seeing he did a good job on the other parts.

burnsauto

Good God!

$25 Heater Core - Check
$225 A/N Fittings - Check

Lets Get to work.

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tuzzio

Honestly, I cant remember. I spend too much time online. I should research this later.

Even with the exchange rate, they're about $175 (and shipping To / From AUS is EXPENSIVE)

I have a friend who could likely accomplish this. It has been discussed and he thought there would be little to no money in it. Sheesh.

afishysilvia

Shit I wish I would have seen those before I made my setup. Would have been way cleaner. Welp....if my dash has to come back out definitely going with those.

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afishysilvia

$175 is not bad for something machined specifically. It could be less if more made/desired.

The machine does most the work but machining items takes time. Anyways OP, how’s your fix? working?

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burnsauto

175 bucks seems steep, especially thinking that the only benefit would be switching to an A/N fitting, which unless your going real racecar, the benefits are negligible. If it also solved the issues that aftermarket fittings present (no control valve), I could maybe understand the appeal for a part like that at such a cost. Lipstick on a pig is the common M/O for the S Chassis...but I guess to each his own.

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afishysilvia

Maybe your way of building, not here though. Quality comes at a cost, the over engineering is a matter of perspective. If you?re doing things half ass or worried somethings too nice for the 240 cause if it?s age or general perception you should move on from the chassis. This is getting far off topic, in only interested in the OP and if his fix.

Primary concern, the JB weld and coolant. Would attached the with a hose and clamps have been better? I just know coolant is a slippery devil.

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revenge240

Update: Fix is working good so far! Drove around for about 20 minutes and it was definitely nice to feel heat in the 240 for the first time in 9 years.. The JB Weld combined with the inner plastic barb connector is very strong. As a note: the JB Weld was more to create a seal around the splice, not to hold the pieces together. The plastic barb is holding the 2 pieces together very well. I did have to drill out the inside diameter of the new nipple just a bit as it was a little too narrow, but the barb fit perfect into the original nipple.
Those aluminum heater core nipples look great, but not so sure it's worth that much when you can buy an entire heater core with new nipples for $30, but to each their own..
I'll update again if there are any issues, but I think this will hold up for a long time.
Below are some pics of how it looks now. I'll also include a photo of the plastic barb I got to splice the new and old nipples together(only came in a 5 pack at my closest Home Depot):

Kingtal0n

some race cars need heat

jedi03

https://www.restomodair.com/ to easy!

knate

I just ordered the OSC 98819 heater core from Amazon, and it comes with the plastic fittings (unlike many others), $25 with free shipping.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

revenge240

That heater core works fine(I bought and used the same one), but like I said in one of my previous posts, the inlet nipple doesn?t have a control valve on it like the original factory heater core does, and no aftermarket heater core out there, does either.. As some have noted, it?ll still work, but you?ll have hot coolant always flowing through your heater core, so it?ll add radiant heat to your cabin when you might not want it. That said, adding an inline control valve on the inlet hose would be an ingenious fix, but you?d have to remember to activate it, or somehow wire it in to the mechanical pull wire, but that?s beyond my scope.

As an update: after a couple more test drives, the JB weld ended up cracking and it leaked a bit. Thankfully, it was all from the outside of the car so dash removal wasn?t necessary(but I?m actually confident I could pull the dash in less than 2 hours now haha). This time, I pulled the plastic barb and nipple end out, applied some JB Weld Plastic Bonder around the barb itself, and put it back in. That should create a much better positive seal than the barb alone.
I?ve already test driven it twice with heater on and so far so good, but I?ll obviously update again if I experience any issues.

Thanks everyone!

ixfxi

a heater core should not be hot 100% of the time, this is why cars that are well-designed have coolant shutoff control valves / bypass valves. the 240 is one of the few that i know that has the valve integrated into the core and is controlled via cable. other cars have an actual valve that can be actuated electronically (solenoid) or manually (knob). some allow bypass so that the coolant flow is not blocked.

my first experience with this was the shitty miata which not only has bad coolant flow design, but also keeps the core hot 100% of the time resulting in hot cabin. the miata forums are full of some of the dumbest people on the planet, and they advise things like sealing up the HVAC ducting - not realizing that the heater core is hot, so ducting is a moot point. the solution to eliminating hot air from the cabin is removing heat from the heat source (ie: the core).

if you're cheap/lazy grab the manual heater shutoff valve and plumb it. if your feeling fancy you can use an electronic one with solenoid, even go as far as to mount a switch in the HVAC controls so that you can ditch the cable going to the flap.

the billet outlet with an fittings is totally pointless. most of the time i see absolutely no merit in going with AN fittings, unless you just like to tell people about how much time and money you've spent on them. they are expensive and a pain in the ass to work on. absolutely nothing wrong with rubber hose (not silicone) + quality stainless clamp. silicone hoses suck as well, only limited uses for those.

burnsauto

That's what I was getting at. I can understand the point of them on critical areas, but a heater core seems a bit silly. Again, unless it's a car that needs that level of reliability, like a race platform, it seems a little silly to spend 200 bucks on fittings to fix a problem that doesn't exist. Now, with the replacement cores not coming with an adjustable valve, that's an issue..do these expensive fittings give a solution? No. They replace a plastic piece for the sake of looking tough. I'm not saying that they aren't nice parts, they are, but unless you're going for that "look" or being used on a race application where every line sees increased coolant pressure and temperature, you'll never notice any difference once your hood is closed and you're driving down the road.

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afishysilvia

Why do you guys care? OP fixed it....

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jedi03

Good News! Also my STI doesn't have flow regulator, just nice blockoff to keep the heat from the heater off me...

ixfxi

to me, JB weld has always been junk fix. it doesnt hold up at higher temperatures. most guys dont know or care about that.

its fix a flat in a bottle
its radiator stop leak
its straight junk

kyral

seems like kind of a huge time sink to do a ghetto repair which is like an oxymoron
especially when those water necks are replaceable and readily available as well as heater cores with and without removable water necks
you also wont notice the valve being open all the time. maybe if you had AC you might, but i have had no problems with that on my car

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ixfxi

in colder climates i would agree and say you probably wouldnt notice

in hotter climates, you'll be pissed wondering why the air when set on VENT/COLD feels warmer than the outside air. And I am talking about having the AC off, just vent. the minute you turn the AC on, this is all moot