A 1987 Mazda RX-7 turbo it is not overheating but after you get done driving for about 10 to 20 minutes the overflow tank is almost or it is overflowing what would be the problem?

Thank you,
-Jason

 

did it just start doing this? or did you do/change anything on the car?

 

Sounds like a coolant seal might be going... >_>

 

check your pressure cap first and see if its in good condition

 

could be a small pin leak in the coolant overflow line and that causes a pressure drop

 

The radiator cap looks new and I didn't see any coolant leaks from under the car, but this was the 1st real time I got into any boost.

I let the TII warm up in the driveway. I went on a 6 mile drive and was into the turbo a little bit, came back home, checked everything out, ran the same road again, but this time I took it to redline in 1st, 2nd and 3rd, put it in the garage, shut it off and then I notice coolant running out from under the hood. It was coming out the overflow tank.

The TII starts right up hot or cold, I never see smoke, it idles nicely, and pulls hard to redline.

I do notice my temperature gauge never climbs out of the very lower range.

I'm heading into town, (not in the TII) to get a radiator cap and thermostat.

Again it's a 87 TII and it is stock:




Your help is appreciated.

Thank you,
-Jason

 

replace the rad cap and the line that goes from the waterpump elbow to the overflow tank. Make sure you go to mazda to buy the cap aftermarket ones suck and rarely work. the thermostat should be fine

 

It has a new hose to the overflow tank and it's on it's 2nd new radiator cap...do I really need to spend $30 for a Mazda Radiator Cap?

I popped the pressure cap, started the TII to look for the "champagne bubbles." I saw plenty of large bubble and a lot of "gurgling". The coolant smells like coolant and not fuel.

What's going on here??

-Jason

 

You do not need to spend $30 on a mazda cap...

Drive the car a bit, then pop the hood and listen near the radiator cap for any noise. If there is an air leak, you may hear it while the car cools down. Put a zip tie on the overflow hoses and make sure they are tight for good measure. I had put on a brand new mazda cap after my rebuild (amongst other things) and my overflow kept filling and my light kept coming on. I finally took the cap off after 3 years and put my old unknown "calsonic" cap back on. NO MORE overflowing! My old non-mazda cap WORKS and the brand new mazda cap never worked. I am no longer worried to drive the car and I am not having any problems.

PS
NICE car. Clean and stock is a dream of mine...

 

The system seems to be pressuring. The large coolant hose from the top of the radiator does feel pressurized and if I pop the cap I hear pressure being released and the overflow tank gurgles.

Also, the TII is very easy to cold start with no issues at all and I never see any smoke.

To summarize:
- Very easy to cold start with no issues at all and I never see any smoke.
- Temperature gauge never climbs out of the very lower range.
- New hose to the overflow tank and it's on it's 2nd new radiator cap
- I pop the pressure cap, start the TII and look for the "champagne bubbles." I see plenty of large bubble and a lot of "gurgling". The coolant smells like coolant and not fuel.
- The system seems to be pressuring. The large coolant hose from the top of the radiator does feel pressurized and if I pop the cap, (carefully) I hear pressure being released and the overflow tank gurgles.

-Jason

 

It's at Mazda for a pressure check of the cooling system. We'll see what the outcome is...

-Jason

 

Where's my LS6 when I need reliability?!

Rats!!! I just called Mazda and they, "recommend a new motor". The mechanic bled the cooling system and pressure checked it. He said the pressure hit 18 and was still climbing therefore coolant is leaking into the combustion chamber.

Why does my car start right up with no issues?
Why doesn't it smoke, (at all)?
Why do I have lots of power with seemingly no driveability issues?
Why doesn't the exhaust smell sweet, like coolant?
Why doesn't the coolant smell like gas fumes?
Why isn't the oil milky?
Why doesn't the oil smell odd?

Oh yeah...and why did I just buy a complete RevII RB Exhaust?

Someone who knows what they're talking about please answer these questions for me.

 

 

^ quiter!

 

It quit me first.

I built that LS6 Rx-7 a few years back and it was so nice. I enjoyed ripping on it and then parking it in the garage with no worries, knowing full well it was ready for more punishment.

I'm not sure what I'll do with this TII...

-Jason

 

Wait a sec... the pressure hit 18 and was still climbing? That means pressure was BUILDING and NOT going anywhere. How could pressure increase if was leaking?

 

I'm just trying to get a response...I won't V8 swap this TII...yet.

Thank you for the suggestion about pressure...I'll talk to Mazda tomorrow when I pick it up.

-Jason

 

Radiator cap off with funnel inserted into coolant neck
Started car and idled
Funnel filled up with coolant
Emptied funnel
Funnel filled up again
Emptied funnel
Funnel filled again
Thermostat opened drawing the coolant back in
Added coolant until full
Turned car off.
Installed cooling system pressure tester
Started car and idled
Cooling system built pressure to 18psi
Turned car off
Combustion chamber leaking into coolant system
New engine recommended: $5378

I spoke with the mechanic and he said he tested the coolant for combustion gases and didn't detect any.

I drove the TII to Mazda the other day, (about 25 miles) and no coolant ever escaped the over flow tank. I took it easy and never got into boost.

I drove it home from Mazda today and when I got near the house I went full boost through 4th gear from a stop. I pulled into the shop and it's hissing and leaking out the overflow tank. The over flow tank is also gurgling like crazy, (car is off). I can also hear the radiator cap hissing. I put a little pressure on the top if the cap and that made the over flow tank gurgle differently...

Another weird thing. The temperature gauge needle would never climb more than 1/4 way through the operating rage of the gauge. When I got the TII back from Mazda within 6-7minute of driving it was on the top line of the operating range just before the "H". It came back down on it's own, but I thought that was weird...

-Jason

 

All sounds... odd.
You have to actually coolant pressure test for a few hours... See if it looses any over a long period.

You hit near H (overheated!) but it came down immediately... Sounds like the t'stat is stuck, never opened fully and the coolant never made it's way to the radiator, until finally at the end it kicked open. Did you buy a NEW mazda t'stat? That's the piece you will need the genuine mazda part from. Any other t'stats don't have that handy jiggle pin in them.

 

A few hours? Thankfully they didn't do that...it was $93 for a single hour! Surely the car isn't going to be running this long?

The cooling system gurggled and hissed for about 40 minutes after shutting it off last evening.

Mazda thermostat or pressure cap...I'm hearing different things here...??

-Jason

 

Mazda T'stat... the cap, based on my experience doesn't need to be mazda. My brand new mazda cap was bad and caused problems for me! Also a new overflow hose and clamps will help. Worst case, check the plastic piece the cap and line connect to. It could be cracked and causing air to leak. Coolant may not leak, but you may hear air leak.

 

Stupid dealership! $27 radiator cap, $28 thermostat and $7 thermostat gasket.

I ordered all 3 online, (supposedly made by Mazda OEM) for $49 and that included an insane $13 shipping charge. Can you tell I hate spending money paying absurd prices?!

The hose from the coolant neck to the overflow tank is new and clamped.

I'll do what Kevin suggests on his Rotary Ressurection site and check for coolant seal failure myself, (probably should have done this before ordering parts, but whatever. I guess I'd need them in I have to put a different motor in the car.

-Jason

 

its pushing coolant out when hot, but when it cools down, is it sucking the coolant back in? like normal

 

Nope, it pushes coolant out when I get into boost. If I drive it easy and don't spool the turbo it seems to do fine.

-Jason

 

At work, skimming thread...

Doesn't sound blown to me.

Did you replace the thermostat and cap already?

Don't trust the dealer's diagnosis yet.

Take video of filler neck, car warm, rad cap off (warm up with the cap off), for us to see how much bubbles.