From a PM earlier, Got referred to post here on it.

I thought I fixed all of the coolant leaks earlier, and if I just start the car and let it idle, it will not overheat or have any coolant leaks.

I will test in about an hour whether or not I can trigger this via normal/low rpm driving or not, however, redlining it and generally making a nuisance of myself on the roads where I live (60+ before redlining it in 2nd? WTF? But 5k+ rpm is held no longer than about 5 seconds, 10 at max.), I found out that the car overheats as mentioned prior.

However, my hunch is that the leak is only triggered via higher RPM driving.

As per Aaron Cake's FAQ:

The underbelly shroud is on
Coolant was recently changed
Never was taken past about 65mph
OEM Mazda Thermostat replaced, and properly installed, as well as a new filler neck
(Edit)
Passes champagne test
Only smoke that comes from the exhaust is upon warmup

 

Special note: past 5k RPM, the water pump has a tendancy to cavitate. That's why it isn't recommended to stay at high revs all day long without an underdrive pulley.

You should be fine if you don't stay there all day though.

 

5k+ rpms were only held for a matter of seconds.

Additionally, it only overheats AFTER I park and go into idle currently. I haven't managed to actually overheat it during driving, just after I park and go to check the goddamn radiator for any leaks

 

How long do you let it idle before the coolant starts boiling?

If the car is fine when you're traveling at high speeds it indicates some sort of issue with your fan (from what I recall).

If you start the car bone cold, can you overheat it without driving it?

 

1 minute or so, and no I can't overheat it without driving it if I start it bone cold. Only after I drive it. It's also only started as of today, as you drove it around yourself IIRC and it had zero issues with overheating.

Although it is getting air in the coolant somehow. Which is driving me batty to figure out.

 

Yeah, we had it idling for about 10 minutes.

It sat comfortably low on temp guage. Then I drove it REALLY hard all the way through 3rd gear I believe and back to his house. It felt fine, I was watching the temp guage like a hawk. I heard a *slight* bit of bubbling from the overflow. Not much, but I still heard it then. I imagine it's gotten worse.

Like I said earlier, bone cold, make sure your care is uber full, cap it, and start it. Try to find drips anywhere.

 

Yep. Heading out right now to get back on the bolts from hell on the underbelly shroud.

I never knew stuff could get THAT rusty.

 

Oh man, you should have seen my stock seat mounting brackets. The bolts on it were solid rust.

 

There was one or two like that on the blue RX-7 as well. I used tons of anti-seize on them to not go through THAT hell again.

 

er. I probably will when i get seats mounted back in there..

I haven't had seats mounted since I took the stock ones out.

 

Update: Found a hiss in the engine compartment.

Overheats even when idling now.

Can't be a blown coolant seal, or else I'd be getting half of the incoming "compression" and whatnot.

Think we can pinpoint it from here, Jm? It gives a VERY audible hiss when on.

 

Is the cap on your overflow tank backwards?

Maybe a small pinhead leak when vehicle is underload. (small rad hose)

Defective thermostat.

Do you have to keep adding coolant?

 

All the coolant goes straight to the coolant resevoir.

I.e., if I have the coolant reservoir get near full, then take a siphon and fill up the radiator properly, then the reservoir is properly full while the filler neck is at proper "filling" as well.

 

The resevoir shouldn't be filling up at all

Did you get a new rad cap? Some cars have 2. Here is pic that may help.

 

It has 2, both are new.

Replacing the whole system to a 1-cap system also results in the same condition.

It's the same problem I had when I first got the car, just amplified.

 

All I can say is pinpoint that hissing sound bro.

 

So, more updates.

http://s381.photobucket.com/albums/o...t=MVI_0715.flv - this is it idling.

Note how it pushes out a steady stream of coolant.

However, it is NOT burning any coolant. At all. If I take the coolant out of the reservoir bottle, and put it into the filler cap, it'll end up with the same exact amount I originally put in.


The temperature gauge does NOT budge from there UNTILL, and ONLY untill it gets so low on coolant, it has to overheat period. It does not matter how hard it is driven - however, driving it harder accelerates the coolant loss. Having the heater on accelerates the coolant loss. Driving it hard + the heater on means spectacular bursting action.


The hissing came from here yesterday.


Is the best course of action replacing coolant hoses? Clamps? I know of at least two places that have given evidence of leaking -after- I fixed the two major leaks up front, should I just replace all of the radiator hoses that have not been tested?

 

I'm having basically the same problem.

Mine over pressurizes then dumps a bunch of coolant into the reservoir, leaving the engine without anything until it over heats.

Recently, though, I went through and replaced everything in the system and took out the thermostat which REALLY seemed to help.

Basically, with the thermostat out, the coolant flows better and it doesn't over heat.

Unfortunately, mine still leaks periodically after it's been underload and after it's parked-much like what you're describing.

 

Do *not* run without a thermostat.

 

99 Are any of the hoses leaking? If so replace otherwise leave em alone. Maybe you got a bad/faulty thermostat? IF you can't figure out the problem it might be wise to take it to someone who knows rotaries before you hurt something else.

 

The thermostat is a brand new one from Mazdatrix. There is NO LEAKING, as established earlier in the thread - air is getting into the system, that is it.

Verified working in boiling water before install.

I've gone out and done a bunch more testing.

It does NOT overheat if I remove the filler neck cap, and put in a funnel to do the champagne test. At all. I'm uploading a video of that test. I'll post it shortly (It's 1:30 about, so it takes awhile.)


This is after 15+ minutes of idling with the champagne test going. It does NOT budge from there, period.

 

http://s381.photobucket.com/albums/o...t=MVI_0720.flv

Champagne test, part 2 - I don't understand, other than a huge leak?

 

After spending several hours -

I can get about 1 minute worth of heat from the heater, then the heat stops. The whole filler neck+upper radiator hose is just air.

 

i suggest getting this to help bleed your coolant system. that little funnel is not working. http://www.matcotools.com/ProductImages/SFF2A.jpg
http://www.matcotools.com/Catalog/to...2125&page=18&#

basically it is a much bigger funnel, with attachments so you can screw it onto the radiator neck. the way this thing works is it has more capacity so when air is bleeding out the fluid goes in and the weight of the coolant also helps get the air out. this tool also won't make a mess like in your video so you can see any leaks.

the way i bleed is i jack up the nose of the car and leave it on an incline while it is running and just let it bleed for as long as it needs, maybe a half hour or more. you said you recently changed thermostat and coolant so i would think that it has tons of air in the system. when i changed radiators it took me about a half hour of bleeding to get all of it out. also turn your heat on about ten minutes into bleeding to make sure you have heat. there could be air trapped in the heater core as well, thats why i bleed on an incline.

so if you can go to a pep boys or something try and get this tool. i start by attaching this tool, then i fill it up. after i have filled it, i squeeze the upper and lower hoses to get some air out. then i bleed the radiator screw, that should get the air out of the front of the system. then it it a waiting game, just let it run until there are NO bubbles. you could also raise the idle to 2k rpm to speed things up.

try this out and let me know if it helps.

 

One problem was a pinhole leak in a brand new radiator cap.

Swapped it to the old POS, it has solved one issue.