Leaking coolant under Carburetor
 

Hello there, this is my first time posting. I recently bought a 1979 SA RX-7, it runs great with one minor issue. It seems to be leaking coolant under the carb. I have no idea where the coolant is even coming from, to be honest. Any suggestions?

Also, the only work I have done on this car has been swapping the breaks out for new Brembo new old stock breaks as it runs like a charm, but it starts steaming after 20 mins of driving it due to the coolant.

Orings are leaking , you can do a search, more than one way to fix it

Welcome!

As noted ^, the stock intake manifold has a coolant passage that flows through it, in and out from the block. The passage is sealed by o-rings that position with the intake manifold, and sometimes they get old and hard and can leak.

Not a terribly difficult or expensive fix (changing the intake mani gasket and the o-rings), just takes attention to detail as you'll be disconnecting a lot of cables, hoses and wires, and they need to go back in the right places.

Hardest part is access to nuts and bolts that hold the carb on the manifold, and the manifold on the block; having the 79 with the thermal reactor, the manifold nuts can be a pain. It is possible to change the manifold gasket and o-rings without taking the carb off the manifold, but that makes putting the manifold on harder, so it's about a wash in difficulty either way.

Thank you, I started her up for the first time in a month and the battery was dead. Thank god it was, as the hood was open when I started the engine allowing my father to spot the huge gas leak. The fuel filter had burst and gas was pouring out. Off to the store to buy the O-rings and a new fule filter! :icon_tup: Sounds like a nightmare, but I can cope. I had to replace the spark plugs on my 2010 Sentra. Let's just say it involves removing the intake manifold, the ECU, and the throttle body off JUST to have access to the spark plugs. :lol:

Sorry to be a bother, but would I be replacing the seals that go between the intake /carb, or the sales between the intake/ engine. Yesterday i noticed an oil leak coming from up top( the carb) down to the little drip pan above the manifold. I took a video if you guys want to see what I'm talking about.

Intake and engine.

The carb spacer gaskets are not supposed to be replaced. Leave them alone or there's a good chance you'll ruin the spacer. You'll want to the get o-rings and gasket from Mazda, whether it be www.mazdatrix.com or www.onlinemazdaparts.com etc. Don't chance parts store o-rings. Getting the old intake gasket off of the engine will be a challenge. Be patient with it. I usually soak it with a spray type gasket remover. It will soften the gasket enough to scrape, however I always end up using a soft wire wheel with my rubber plugs set into the block to prevent debris from entering the engine.

I put a quarter and some red RTV on the engine side of the coolant ports. Never leaks and you don't get the hot coolant warming up the intake air anymore. You can use freeze plugs, but I can't recall the size.

20mm

Would O rings and intake gasket from Atkins Rotary be fine? I haven't ordered them yet but I could order them from Mazdatrix IF i could find them, I can't. Also, I LEAVE the carb on the intake manifold and remove both as one part after disconnecting all the tubes and wires? iv already removed the air filter and begun labeling all the wires with numbered pieces of tape. Also THANK YOU ALL I finally discovered my catalytic converter was burning all the coolant that fell down there along with the oil!

SA's (1979 and 80 models) did not come with CAT's. I think you may be referring to the thermal reactor.

That pic looks vaguely familiar... :)

I'm in California , Thermal reactors are not legal here for smog reasons . I'm pretty sure Cali 79-81 SA did have CC out of the dealer as the drivers manual has a California only subsection talking about it. It even has a breather pipe that runs out back .

No need to reinvent the wheel. ;)

Could be, I'm sure Glen would have the low down on what was standard on California smog cars. They were different to themselves.

I will leave the ultimate answer to Divin Driver but even in Kali I'm pretty sure it was still
the thermal reactor and no cat converters for 79-80. Now I'm sure some of the techs doing
inspection don't know the difference and may start an issue about it but the FSM should
put the issue to rest. I'm sure it details it in there.

The 79 or 80 model FSM makes no mention of a catalytic converter. The converter was not introduced until 1981 and was used in conjunction with Mazda's lean burn system. The California spec SA's came with an EGR valve on the center iron and the plumbing for that. Other than that, I don't believe there was any other differences other than the lack of the sub zero starting assist system.

In addition to the EGR valve and sub-zero delete, I know smog cars also have this valve up by the firewall and an emission sticker on the inside of the drivers rear quarter window.


https://cimg9.ibsrv.net/gimg/www.rx7...b784b25001.jpg

This is incorrect. The Cali version of the SA came factory equipped with a thermal reactor (and added an EGR that was not on the 49-state version).

I'm still passing smog with my Cali-spec 80, TR and all.

Yep. Vacuum delay switch.

Could it maybe be that the previous owner put a CC in it? Thermal reactors don't need a breather pipe .

Also. how the hell do I remove the intake manifold to pop the O rings in it. I started removing the carb, but it seems like I have to remove a lot of things to get to the Manifold and the O rings. Are there any diagrams?

Oh I think the reactor does have an extra tube for air. Divin can verify
I'm sure.

Its a messy process if you still have the rats nest. Take a look at the
manuals on Foxed.ca for the nitty gritty.

The manuals pretty darn vague, I do like the parts where it shows you how to test if sensors/parts are working properly. I'd greatly appreciate if some one had pictures, I know i sound like a bother, and there IS threads on this, but none have pictures .
https://cimg6.ibsrv.net/gimg/www.rx7...be474d144.jpeg