I am a newbie and have a 93 RX-7. There is a major coolant leak under the car in the middle. I was going to try to pressurize the system to determine where the system is leaking. What other advice would any one have and can this be done by a novice? Any input would be greatly appreciated.

 

That's the best route, make sure you don't go over 20psi, you'll blow other components.

 

access to a lift would be the best if possible. after pressurizing the system, the coolent will leak but depending on where its located, it usualy dumps on top of the underpan and streams somewhere not where its leaking from.

 

very likely to be your lower turbo coolant hose chief.
turbo coolant hoses frequently split because of the heat of the turbos... not uncommon to leak down as you're describing. under normal operating circumstances, this'd be the first culprit. run a search on the turbo coolant hoses and you'll find info and pics.

oh, and let me know if i was right

 

I had a coolant leak two months ago and it came from a hose right behind the airpump. I thought I was a goner but after a call to Ray Crowe, he was able to send me a coolant hose kit and it was back to normal. I was able to determine where it was coming from by filling the radiator coolant and finding where the smoke was coming from.Good luck on your quest on whre your leak is coming from.

 

dont go over 20psi?!?!?! Its 30 psi man!

 

Yes, 20.6 psi to be exact. Please look at page E4 of service manual, before you give that kind of advice. Doesn't look like you own an FD, so it may be true in a FB, but this is third gen section.

 

i had the same problem. Turned out to be the coolant hose under my UIM, near the TB.

 

Actually he just bought and FD for a price I could cry about.

As for the topic, notice how everyone is mentioning different hoses. That's because most of them are prone to leaking or busting - I suggest buying all of them and replacing all of them - especially the hard-to-access ones that are close to the engine block and have been roasted for 13 years.

Dave

 

Go under the car, take the underbelly off, and locate the leak. Just saying its in the middle of the car, its hard to tell where it might actually be leaking. I've seen all the hoses above, ast, waterpump, and even the rad. If its leaking to the point you could see it under your car when the car is not running, no need to pressure test it. Just follow the trail from the bottom or top of the car.

 

I have done further research and here is where I am at. I looked at Rob Robinette's site and this appears to be pretty scary. The turbo coolant hoses are under the air pump. His comments were to remove the air box, air pump, loosen the A/C unit and alternator. So I checked with the local Mazda dealer and all they needed was a mask and a gun. They wanted as an estimate $400 labor. I may have to press forward myself and see what I can do.

 

dont be scare on the car, labor is expensive, and like us we do it all, save on labor and learn your car, is the best way to learn yourself is reading, start with easy jobs and move on with major jobs, it will pay in the long run

 

The turbo coolant hoses can be replaced in no time once the airbox, airpump, and cross-over pipe are out of the way. All you need is a skinny arm and a pair of pliers. You don't have to mess with the A/C. Just loosen the alternator to release the tension on the belt.

 

Ditto. Mine's leaked twice.

 

i had a coolant leak about a month ago..o no wait...it was an internal leak from a blown seal ..just got the car back today with a new motor, and it already has 146 miles on it...only 850 more till its broken in!

 

I don't mean to sound dumb, but.. what does UIM and TB stand for? I did try the glossary at Rob Robinette's site but they were not listed. Thanks again.

 

UIM = Upper Intake Manifold
TB = Throttle Body

Don't be scared to do the work yourself. Just follow the FSM (Factory Service Manual which can be downloaded for free) and double check your work and you'll be ok. It may seem intimidating at first but after you've done the work you'll look back and say "Damn...that was easy! Glad I didn't pay somebody $400 to THAT!" If you run into problems, feel free to come back and ask as we're all here to help.

Best of luck man!

 

I appreciate all of the encouragement and assistance. I appear to be striking out though. Our 1 and only Autozone store did not have the right adapter for the cooling system pressure tester. I have taken out the air box and I can see the turbo hoses and they "appear" to be OK. I did also take the belly pan off to help determine where the leak is coming from. I found the FSM's yesterday and downloaded them. I will see if I can determine and check the hoses located under the UIM and TB. Thanks again.

 

I am really not having any luck here. I think that I am going to fill it up with water and start it with the belly pan off and maybe I can see where it is leaking. I was looking at the radiator drain plug. Is the a secret to getting it out without breaking it? It appears to take a special tool but not sure. Thanks.

 

special tool called a screwdriver.

 

Would there be any way that coolant could come from the plate on the bottom of the bell housing? When I took the plate of there was "some" water on it. Not sure if it is leaking somewhere else and running down or what. Thanks in advance.

 

There is a coolant line running along the back of the engine near the firewall. It connects to the throttle body, and is used to increase the idle RPMs during cold starts.


Check the diagram here:
http://www.autosportracetech.com/RX-7/coolingsystem.htm

There are two soft lines near the firewall, one going into the upper part of the throttle body, and one coming out of it. The one coming out of the TB is closer to the driver's side, and will connect to a hard line after a short distance.

The last photo on this site shows the upper hose removed:
http://www.face2faces.co.uk/RX7/howto/coolflush.htm

Good luck,
-s-

 

After I did the last post I filled the system with water only and started the car. What I found was that the overflow tank was overflowing at the little hole on top of the tank. Was this caused by "air" in the system?

 

Well I thought that things were looking up. The leak seemed to have went away. NOT! I checked the coolant level after driving for a short period and it was low, I added some distilled water and noticed under the car it was running out as fast as I could pour it in. The engine was cool and had not been started for a couple days. It appears to be leaking somewhere around the cover for the torque converter. Not exactly sure but I plan to look at it further this weekend. Any ideas? Thanks in advance.

 

I took off the small plate at the bottom of the bell housing. When the coolant system is slightly pressurized at the hose that connects to the throttle body, coolant flows down around the torque converter within the bell housing and out the hole where the small plate at the bell housing normally sits. When I took off the small plate, a small beat up bolt had been sitting on the small plate. I am not sure where this came from. Also, the bell housing is not mounted flush on the passenger side but the drivers side seems to be flush. Do you guys have any idea where this coolant is leaking from? I want to check the lower end of the hose that connects to the throttle body but I cannot seem to figure out how to get to it. I cannot find any leaks looking from the top of the engine bay.

Thanks!