Ok, so I've removed my A/C and all its components and figured I might as well get the Heater core the hell out of there too. But I have a couple questions.

Would I just need to cap the 2 circled items in the attached picture? Thats all I can see that would be affected by its removal.

And would I need to completely drain the coolant w/ the heater on high/max before plugging these 2 spots? What Im more wondering is since there wont be any kind of flow to this area ever again is it going to matter that there might be coolant sitting?

opinions, suggestions?

PS this is a 87 SE (if that matters)

 

You just plug them, Often spark plugs are used, and that it.

 

don't cap them with the crappy auto parts store bypass caps the water pump pressure at high RPM will blow those things up.

 

any suggestions on caps?

 

jb weld! haha j/k, but i would think even the bypass caps would hold if you clamped them down no?

 

thats what i was figuring, hose clamps should do the job.

 

no the end blows out of them, they don't actually come off.

Use a peice of actual NEW heater hose with a bolt that has a smooth shank area clamped into it, or a spark plug as suggested, but a bolt seems less ghetto.

Don't use bypass caps for coolant, they are not reinforced with fabric like normal heater hose is, they will always blow up at high RPM.

 

ooooh, good point slo, forgot about that

 

ah, that makes sence. thanks.

 

well i used the caps but tightened the hell out of them with clamps its been over 2 years no problems yet and i did the same by removing all ac equipment and heatercore in the front of the car. cools great now but sucks ***** during the summer, when your dieing for ac lol .

 

I blew out 2 caps on the left side of the engine in 2 weeks when I didn't have a heater core.

Also have the cold start assist system capped and blew out 2 of those, though they did last longer like 2 months.

 

run a bypass and connect them

 

LOL, yeah the rubber vacuum caps. I found that out the hard way That was a fun night.

 

maybe im the only one who actually thinks.

LLLLLLLLLLLLLOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOPP PPP

****, just run a loop from one side of the block to the other.
done

peace

 

follow magus2222 advice. bypass hose is the way to go!

 

the caps are alright but dont last long, but yes those are the 2 points to cap off

 

Some hoses with a section of 5/8" pipe (prefereably stainless,aluminum,etc..) hose clamped in will work just fine.

I had my heater bypassed with this setup for a couple years before I finally got around to fixing a leak. Just make sure you check on the connections every so often if you don't put a roll bead in the pipe.

 

Can anyone tell me what heater hoses do I need and how are they routed I'm trying to replace my heater core so I have heat this winter but I never had it hooked up when I bought the car so I don't know where the hoses go and someone please help me out I have an 88 fc. This is what fitting im looking at. To my understanding the one hose still hooked up to the metal tube is a heater core hose it goes from fire wall to radiator. Am I wrong?

 

Yes, the return line goes from the firewall, through the metal tube and into the lower radiator bung.
Yours- at least the part visible in the photo- appears intact.

The feed line comes from the other side of the block, snakes under the oil filter pedestal and into the firewall.
It is quite a convoluted shape and you pretty much have to spend the $60 on the OEM Mazda part.
It is commonly ignored and because it is prone to oil soak from filter changes, is the most likely to fail.

 

Okay so thank you for that wanted to be sure, so what is the one that is plugged coming off the rear of the back? The 2 other lines coming from the firewall I figure are the ac lines, bc the pump has been removed. So is that plugged line associated with the AC? . the reason I ask is I just got to the climax of my repair, heater core was removed. No visible breaks off the core, doesnt seem in bad shape at all. Everything was hooked up as it should be, coolant is clean, but never had heat. If the heater core doesn't appear to be bad could it still be? Or is there something else that would cause a lack of heat completely? Please help thank YOU.

The one that is plugged to be seen here.

Maybe be a little rusted color but no visable physical damage what so ever. And coolant was as green as st. Patrick himself.

Was not too difficult especially with the aid of the haynes manual.

The hoses seem to be in good shape.