And this is the cooling flush method that I used for my last two flushes. Yes, I overheated the coolant both times as prescribed in the write-up (although I chickened out each time before the needle could hit 'H'. Just above 3/4 was plenty hot enough for me.)

http://fc3s-pro.com/TECH/MODS/COOL/cooling.htm

There has been no evidence to suggest that my engine was harmed by it.

 

The car blew a hose and has been over heating ever since I fixed it. I know that I have a bubble(s) in the system and will flush it tomarow. When I start the car I will hear bubbles for a second. When the hose blew it over heated (3/4) and blistered the cap, so I put one on from a spare rad I had laying around. I don't know about the thermostat I'll to replace that also.

I ment to post that my car will only spirt coolent when I first crank it, and it will only come up for the first crank and then it stops spraying, even when the engine fires.

 

Found this - it's for motorbikes but most of the info, like how rad caps and "burp tanks" work, applies to cars, including our 7s.

http://faq.f650.com/FAQs/Coolant_Change_FAQ.htm

From what I'm reading in these pages (and in other hits) it seems that the reservoir tank won't function properly (ie get rid of air bubbles) unless the rad cap is 100%.

My own rad cap is moderately chewed.

And here's a quick checklist to go over...

http://faq.f650.com/FAQs/Overheating_FAQ.htm

It leads to the first link above.


And this from Aaron Cake in another thread:

That's it for me - time for bed!

 

I'll go over the car tomarow and let you know what I found. thanks

 

Well, I replaced the drivers side heater hose 'cause I saw a small hole in it. Hoping that was the problem, I started the car (no spirting with cap off) and saw a slight drip. So I reved it, nothing, so I reved her higher, nothing, so I mashed the gas and took 'er up to 7k and immediately let off do to the steam and stench. I guess I'll have to go through the rest of the hoses. I've got a lower rad hose under the hatch, but I couldn't find any sign of moisture there. Actually, I couldn't find any sign of where the water was escaping from ever, the block is wet, but nothing else seems to be. I guess I'm spending another Sunday in my parents garage turning wrenches. I hope this is the problem. At any rate, it'll give me more time to save up for the street ported S4 motor with S5 rotors. I'll keep everyone posted on what it actually turns out to be.

 

OK, I filled her up with coolant, made sure it had no bubles, let it run for a while, then took it for a spin. The car started out normally (1/4) then the light came on and the guage went to 1/2 then just a little over a half. I had put a pop bottle with a hole in it on the line that comes from the overflow tank to see if the coolant really was coming from there. When I poped the hood I saw that the over flow tank and the pop bottle were filled to the top with coolant I think it's a seal.

 

All right what are the tell tale signs of a bad seal? Later on when my car was cool it had sucked all the excess fluid out of the overflow tank. When I left for school I filled it up again, when I started it up, I left off the cap. When I rev the motor the coolent will spill over for a second then it will drop and I have to poor more in. When it spills over it only will gently over flow not shoot out.

 

Tell tale signs? Try this:

If it ISN'T a blown seal, then it's time to begin putting in new parts. Start with the cheapest.

- thermostat (Mazda)
- water pump (may not be doing its job well enough anymore - grab a reman and save $)
- electric fan (I have a 5-blade Fiero fan from a wreckers in my 7 now - https://www.rx7club.com/forum/showth...ight=fiero+fan )
- aluminum radiator (Fluidyne's has a great reputation on the Forum- your current rad may be partially/extensively clogged.)
- aftermarket temp gauge and a gauge pod to go with it - with an aftermarket you'll know exactly what temp your coolant's at. My new gauge can range across 25F while the factory gauge doesn't move at all - that freaks me out.

And when was the last time you got under the front of your car and checked the front of your rad? How much crap and road kill could be jammed in there now? Another thing I did during my July coolant flush was pull the rad and soak it Eagle1's Aluminum Rim Cleaner. Did it twice and it cleaned the rad right up. There was an awful of crap between the fins that came out.

 

I'll try to soaking the rad this weekend. When I left school to night I made sure that there wasn't a single bubble in the system, and it was full to the brim before I left. The drive from school to my house is 33 miles about 29 of them are freeway. Lately the gauge will be at 1/4 then the light comes on and the gauge goes to 1/2 and as long as I am moving at 50+mph it will stay there. If I slow down more than that the car will just over heat. So anyway tonight on my way home there was nothing, the gauge was at 1/4 the whole way, and no add coolant light. Is it fixed?? When I got off the freeway I tried driving slowly, about 40mph and nothing, then when I was close to my house I drove about 1/2mile at 6000rpm in second gear. I was trying to get it to over hea, and no surprise the add coolant light came on, and gauge went to 1/2. The surprise was when I stoped at home there was no steam, and the over flow was not full. I don't know if it was due to the cool weather, or very light traffc, mabey a combo, or mabey, just mabey my car is fixed.

 

Sounds like how my 7 was up until my latest flush. The temp would rise to 1/2 under regular to hard city driving. If I let her sit and idle for 5 to 10 minutes the temp would drop to about 1/3. Start driving and back up it would go.

All the time that this was happening, I believed/was certain that my coolant was 100% since it had been changed in July. Maybe I'd done something to mess up the previous change or maybe I had a bad batch or maybe the most recent flush got some blockage out of the sys. Dunno.

But you know where my vote goes.

 

Okay, everybody, it's been a week. Any progress out there?

 

mine is all fixed, i guess it wasnt a coolant seal, the caps were shot, not even for my car, it had a fuel leak, exhaust leak, and some other ****, cost me 500 bucks to fix the major stuff, still has an exhaust leak but its ok, cause ima get the dual N1's anyways so everything is good for now....

 

Awesome!

 

simple answer, pressure test your system. see where the leak is coming from.


-------------
Poor Flat Rate Mechanic

 

Concerning my post from 10/21 about a coolant leak. I finally got out my pressure tester (DUH!) and found that it was one of the pollution control water hoses. It turned out to be the one that is under the lower intake manifold. The leak was running down the back of the engine and onto the driver's side heater hose. I replaced both hoses for about $30.00. The intake gaskets cost another $11.00 and then I spent about another $11.00 for injector seals and boots. The whole job took about an hour with air tools. The car runs fine now.
On that air bubble issue that I have been reading about.... I used to work for Toyota when they had head-cracking problems. We used to loosen the temp sender on the top of the engine to let out the air as we filled it so that the head wouldn't crack when the thermostat opened. I pulled the driver's side heater hose off of the RX7 at the firewall and let the air out there as I filled the system. I only had on blink on the "Add Coolant" light when I took it for a drive.

 

Great tip! Thank you! I'll try to remember it for my next flush n' fill.