Omarrodriguez

Hello everybody
I would like to replace all the cooling system hoses, but the autoparts dont know /dont have/ including the mazda dealer/ not knowing what hoses I need.
I have the manual for my rx7 1985 gsl le 1.3 liter, but it does not list all the hoses.


1. My problem is as follows, I have 2 leaking small hoses coming out the last rear housing that is attached to the transmission, I would like to replace them but i dont know how to order them.

2. My problem started with the lower radiator hose which was leaking, and got replaced, then a small hose coming from the last housing attached to the transmission starting leaking, I replaced it with a hose of similar size ( not original). the car now started leaking from the water pump? what is the problem???? I replaced one hose and it starts leaking from another source? Need help !!!!!!!!!!!!!!!!!! and it happens after I run the car for a while without over overheating, but as soon I turn off the car it started leaking.

LongDuck

Welcome to the world of driving a 30 year old car! Seriously, though - the GSL-SE has a solid heater hose arrangement and the 2 hoses you're describing at the rear housing are: 1) the Thermowax Pellet return hose, and 2) the Heater Core return hose, both going back to the block from their respective locations.

The larger of the 2 goes back to the rear housing right below the oil filter and this hose is very typical to fail due to oil leakage from the O-rings on the pedestal dripping onto the heater hose and causing it to bulge and eventually burst. You can replace only the section with the 90deg bend just below the oil filter by splicing in a straight section - then, at least, you only have to find 90deg bend sections cut to fit instead of the factory hoses which run from the firewall all the way down to the bung. That slight restriction in the line may reduce interior heating effect if you live in a REALLY cold place, so keep that in mind.

For the other hose, it's just a straight section wound around the upper intake manifold to return the coolant from the Throttlebody to the top of the rear housing. This is simple to fix and would recommend replacing that whole section, plus the section which feeds into the Thermowax Pellet device coming from the back of the Waterpump. If one section is bad, you can expect that the other section is soon to fail.

Same goes for the heater core feed hose coming from the lower Radiator bung and snaking it's way up to the passenger side firewall - it's right next to the return which you mention is going bad on yours already.

Once you replace those few hoses, you should be good for awhile. Good luck,

Cameron38

iTrader: (2)

Mazdatrix lists all the various hoses and where they are located.. I recently replaced all the hoses on my SE. Some of the small ones are a royal pain to change.

Omarrodriguez

thank you so much for your input!, I will do that.

I will also look for the part in the website you recommended.

thanks.

t_g_farrell

iTrader: (1)

Heres the deal, you fixed a leaking hose, now the system pressure goes up a bit and the next
oldest/weakest hose starts leaking. Replace all the rubber stuff (coolant, oil, vacuum, brake
hoses, motor/tranny mounts, suspension bushings) or you will chasing the next weak rubber
part everyday.

As longduck said, welcome to living with a 30 year old car. By now anything rubber is dry rotted
and ready to fail.

LongDuck

^^^ true story (do them all while it's convenient) and you're welcome! Keep that car on the road,

Jeff20B

iTrader: (13)

Another cooling issue you might have to deal with is the oil cooler. The GSL-SE model has weak threaded bungs that tend to crack after 30 years. Mine went from a little wet but not dripping, to one drip every 30 seconds in only 100 miles. When I went to fix it, it made things worse. The coorect fix is to chop off the bungs and have new ones welded on, but being aluminum that's had oil in it and on it for 30 years, good luck.

So I swapped in a beehive. I'm not ashamed. It would have taken too much time to have my oil cooler fixed, and there are no guarantees it would even work, plus I needed it back on the road like yesterday.

I had to add two T fittings to mimic what the 12A beehive cars had and a couple short pieces of 5/8" heater hose and one longer piece.

Coolant temps were right where they usually are so I'd call it a success. I'd like to eventually get a short style radiator and 79-82 oil cooler under it, but for now, the beehive works.

Oh and I had to stretch the beehive hardline to fit a 13B. Don't forget that step. If you do it wrong, you'll have a leak. Alignment is hyper-critical. I guess this mod is not for the faint of heart.

j9fd3s

iTrader: (3)

for a GSL-SE the hose part numbers are as follows

upper radiator hose N304-15-511
lower radiator hose N304-15-521B

the 3 heater hoses are

by oil filter, 8871-61-230
from firewall to pipe 8871-61-212
and from pipe to radiator FA42-61-213A

the two small hoses under the intake are
N304-13-208A and N304-13-209

the Mazda dealers have just switched to a new parts catalog, and it is worse than the old microfishe readers we used to use, and it doesn't go older than 85...

elhartd

I have a 79 sa22c body with a 85 gsl motor in it and I have the beehive that I'm stuck at! I don't know how to replace radiator hoses cerrectly!? The beehive on top has the extra hose spot and IdK how or where it goes ! Pls help

mazdaverx713b

iTrader: (91)

Don't bother buying the hoses from the auto parts store. They won't have what you need anyways. Mike posted the list of the part numbers for the coolant hoses. Call the dealer and order them.

elhartd

So can I run coolent from motor to beehive then to heater core straight thro? I don't know how to run hoses right! On the 85 gsl motor I got a y-ed outlet metal hose thing that runs to the beehive oil cooler and one to heater core! So I'll probly switch out for the single out let of of my old 79 motor... Cus of the y-ed thing I have the hose I gotta find out where it goes if I don't switch it!? So help anyones!

j9fd3s

iTrader: (3)

the hose routing is in the manual which is here Foxed.ca - Mazda RX-7 Manuals

there is a T at the engine and a T at the heater pipe. one side of the T goes to the heater, and the other side of the T goes to the oil cooler.

the oil cooler and the heater are parallel