TEDDER1

iTrader: (1)

get a 20oz bottle and cut it in half. then hold it tightly upside down and look in. it wont spill.

MILD7

Ok guys.... my worst fear has come true... started the engine with the filler cap off... and low and behold... bubbles. Here's the run down. When I first started the car (wasn't too cold... no 3,000 rpm warm up mode) and a steady flow of bubbles similar when you just open a soda. The stream of bubbles was constantly flowing for the first 30 seconds, and then began to slow. After about a minute, I counted about 5 bubbles per second. So it seems to me that my leak isn't too big.

So, now that I know that it's a water seal(s) how does this CRC stuff work? And where can I get it (autozone, etc?). Yes I do plan on replacing the motor soon, as soon as I can save up enough cash. I'm thinking the most cost effecient solution is a Mazda reman. Anyone know any qualified shops in the Socal area that could drop it in without too much down time and at a reasonable price (tri point is too pricey). Thinking about the rotary shop in Gardena. How much does labor usually cost. Not planning on doing anything else than a straight forward swap. Hoping not to spend more than 3 grand.

I really do appreciate all the help and support I 'm getting from you guys... it makes my situation easier to swallow knowing that I have fellow brothers who feel my pain.. and know what I'm gonig through. Thanks a million... you guys are the best!!!

Brian

jackc

Hey Brian...
I feel your pain... gone thru a engine/rear turbo/Diff as well all this year. Ouch!!! And my car is still not up to par and running
right.
However... I had leaks from the front overflow tanks area as well. It turned out to be a overfull overflow. Then bleeds out excess somewhere underneath.
If your car is not blowing white smoke in the mornings. This is a very good sign. You might have
air bubbles in your coolling system. When cold remove the rubber coolant hose on the throdle body and fill with distilled
water til you get some that flows from that disconnected hose.
Also squeeze the main rad-hose a few times to get the sir bubbles out.
Re-hook up hose to throdle body and make sure coolant is full.
I would check the AST for proper operation as well.

Best wishes.... jc.

bladeboy66

couldn't this problem be easily decided by bringing the car to someone who can run a compression test on the engine? correct me if I am worng but a compression test can tell you if your seal are bad- correct?
-Jon
94 base

95R2-89TII Ground Zero

I don't know if this is it, but my friend was having a similar problem. He would shut the car off and coolant would "spill". What it ended up being was that there was a clog in the system and the coolant was backed up. So I did a hella fluch on his car for him. I took the thermostat housing off after I cleaned the entire radiator. I sprayed water in the block and ran the motor with a hose attached to it to clean it out. The water would enter through where the thermostat was and exit through the bottom of the radiator. Then I put it all back together, and it worked great. The other thing that I have heard on forum is that the cap could be bad. I would try those two things first.

Yellow R1

I had the same problem - coolent leaking after shutdown in the same place.

I replaced the caps & it completely dissappeared. Pls do as the others on the Forum have suggested - replace the caps - its cheap & "may" fix your problem as it has with other owners.

The bubbles you refer too can be trapped air in your coolent system that gets in because there is not a strong seal - coolent leaks & air gets in.

Don't be ready to think its your seals - doubt it - do the cheap/logical fixes first & then worry about seals if its still present.

Good luck pal.

-Matt

Trout

When you use a pressure tester, how long should you leave it pressurized? Since changing to the SR Ultimate Rad last month, I have been pushing coolant out but not sucking it back in. But it is not always consistent - seems worse in stop and go driving than highway driving. It doesn't boil over either, just overflows the tank if you let it go on too long with out sucking some out of the tank & usually this is the same amount that I have to add back to the filler neck to top it off. No hard start or smoke or burning coolant smell and no overheating that ever saw on the guage.

I borrowed a pressure tester last week and put it on the filler cap first and pumped it up to about 16 psi, a second later the AST cap vented and let pressure down to 13 psi. So to do the 20 psi test per the FSM I put the tester on the AST and pumped it up to about 19 psi. Then left it for over 40 min. while looking around at every hose to see a leak - nothing. So I tried putting it back on the filler neck, pumped it to 16 then it vented to 13 psi and held for a while. When I started looking this time I could see coolant weeping not dripping from the lower radiator hose.

Alas, as suspected I should not have reused the Mazda spring clamps. No problem since I already had the worm clamps and new rad hoses in stock. So I replaced them and still have the same problem but now it will sometimes pull the coolant back in from the overflow tank. Last night I finally saw a coolant drip on the rad pan right below the water pump housing connections but couldn't feel around too good since it was so hot but I did feel a trace wet spot by the lower rad hose to water pump housing. Will try to tighten that clamp this evening. The only other place I suspect is the long hose than I have by-passed from the throttle body, it's been on and off a few times but I have reused the Mazda spring clamp - perhaps that one is weeping and not showing a leak.

I will try the running it with the cap off to check for bubbles just to be sure but since it sometimes pulls coolant back in now and doesn't consistently overflow I think/pray the motor is ok.

Do I need to leave the pressure tester on the system for an extended time like overnight to find these weeping type leaks since they don't spew coolant?
Help is appreciated,
Jack

BrianK

whoa whoa whoa whoa!! Hang on a cotton picking second.

Ok, depending on how hot your engine was, keep this in mind - water boils. What is your water/coolant ratio? When you take off the radiator cap, you've lowered the pressure in your cooling system, thus, lowering the boiling temperature of your water/coolant. It's possible that you're just seeing the result of boiling. Were the bubbles big or were they small and foamy? Mine was doing this too - big bubbles - result of boiling because the engine wasn't COMPLETELY COLD when I was checking.

Now, take a look at a much more common problem on the 7.... the radiator. Is yours still stock? When your engine bay gets hot, everything expands. Lots of stuff in there is made out of different materials and expands at different rates. One such thing is the radiator, being that it's made out of aluminim and plastic (what were they thinking??). If your radiator's plastic tanks get small cracks, they may not leak until the aluminum core expands and makes the cracks wider.

To see if it's your radiator - take off the mazda fresh air duct if you still have it on... remove the fuse panel just below that (just move it to the side). That should be enough to see the top of your radiator. Take a flashlight and shine it down on the radiator. See any sign of liquid on it? Take a paper towel and wipe it along the plastic tank where it meets the core... any sign of coolant or water? Do the same wipe on both sides of the top and bottom tanks - right where they meet the radiator. If you find any sign of coolant in these places, there's a VERY good chance that you just need to replace your radiator.

I had the SAME THING happen to me - leaking only after shutdown when hot. Everyone told me my seals were gone too, but before jumping on a rebuild, I had the radiator checked. low and behold, my problem was fix and the car was upgraded with a $412 Fluidyne radiator as opposed to a $3K rebuild. Let's hope this is your case too.

BrianK

Please check my above post before getting a rebuild started.

However, IF you end up needing a rebuild, I HIGHLY recommend Rotary Power in Gardena. The number is 310-516-9959. Don't get a reman, have them do a rebuild, especially if your housings aren't damaged from a blown out apex seal. I was asking him about his prices - he said that a straight rebuild with 2mm apex seals and no porting or performance mods will cost just over $2K.

Coincidently - it was Rotary Power that found my coolant leak and told me it was just the radiator, so at least you know they're honest about this sort of thing.

Good luck!

misdbman

I would also first lean to a coolant system leak. As the car gets hot it expells coolant into the overflow tank. If you have a pressure leak somewhere the coolant system will run at a lower pressure and the coolant will boil when the car is turned off. When the system cools off, it is supposed to suck the coolant back into the motor. With a coolant leak this does not happen and you need to constantly refill at the coolant neck. Also, over time this causes the overflow tank to have too much coolant in it, causing more on the ground. The rotary does expell some air into the coolant even with a good motor - that's why Mazda put in the plastic air-separator tank.

If you have a bad seal, the coolant will overflow with the motor running. This happened to my 2G for a couple of years prior to losing the motor.

Just never run the car hot...make sure you keep up with the coolant until you get it fixed.

MILD7

Again, thanks for all the help... I just got back from work and will be heading out to the autoparts store for a pressure tester thingy. One thing I noticed but failed to mention, was that everytime I pulled off the filler cap to add water (engine cold), there would be vaccum. It would take a little effort to pull it off and a suction sound could be heard... kinda like a cork popping sound. Does this have any significance in locating my prob? Just wondering.

Well post when I get the results of the coolant system pressure checker. Thanks again guys.

RonKMiller

Well......there's lots of interesting hypothesis here. But frankly there is no real investigation - just " this is what happened to me"
The whole coolant system is prone to failure as it ages at a number of points.

But like I said, let's look at this from a logical standpoint.

If it is a constant stream of small bubbles it's the seals. Period.
But before we make a conclusive diagnoses let's eliminate ANY other potential causes. And it's FREE. As in NOTHING, ZIP, ZILCH.
Sure beats the hell out of $100 an hour for a "rotary expert".

The next step is to pressurize the system with a dedicated radiator pressure tester which can be rented/borrowed/purchased if need be. AutoZone and probably a few other places will sell/rent you one with a major credit card expecting you to bring it back with no problem at all. They do it as a servce to their customers.

You cannot just take your car to a "radiator shop" expecting any conclusive results since it appears your leak is minor. You need to pressurize the system when it is stone cold for at least 24 hours, sometimes more. Sure, it's a pita to keep walking outside and pumping up the tester as it slowly drops - what you are trying to do is force water out of the system and find it. You may find only a drop or two on the ground, and you'll need to observe it constantly since these drops can evaporate quickly!

If it pisses on the ground you are lucky. The leak is not your O rings, but I doubt it - especially with the miles on your engine.
BUT - it could be your:

1) RADIATOR (BTW - lots of manufacturers use plastic in their radiators - including Mercedes) BrianK's method for detecting leaks is pretty clever but frankly you have to pull it and put it under water and pressure to find out for sure if it is leaking - remember, this is a small leak. The stock radiators are a very weak link on this car.

2) HOSES - God knows there are more than a few suspects here.

3) PRESSURE CAP(s) - We can only hope this is it. With your tester accessories you can check these out in a heartbeat. Test them - don't guess!

4) WATER PUMP - unlikely but still a potential culprit at 80K miles

5) LOW COOLANT SENSOR ON THE WATER PUMP HOUSING - it's on the front of the filler neck and of course is made from plastic!

6) AST - if equipped -what a piece of ****.

7) TURBO COOLANT HOSES - Oh yeah! Last but not least and a VERY likely suspect since they are buried down low. They turn into petrified rubber and leak around the clamps.

So - where is the leak? The only way to know for sure is to pump the sucker up and OBSERVE - Not guess. This is called the scientific method - and it works every time guys........

Once we've found it we can try to fix it.

So, until you "pump it up" for a while you'll never know.

Forget about the CRC until you find the leak - it's there hiding somewhere, and they are sneaky little bastards sometimes..

Brian, if you're not willing or able to do this then you are better off taking it to someone who knows what they are doing. They are few and far between when it comes to rotaries. They also like to sell rebuilds since it is good money. You may still need to go this route but you owe it to yourself to check it out thoroughly before you whip out the ol' checkbook!

Later,

Ron

MILD7

Thanks Ron,

I will attempt to pick up the pressure kit tomorrow... and might as well pick up a radiator cap/AST cap as well. I purchased a filler cap already. A little more history about my car... pretty much bone stock except intake/exhaust. When I bought the car 2 years and 2 months ago, the end tanks on the radiator cracked... as the AST leaked. Fortunately, when I bought the car, it still had a year left on the extended warantee, and the radiator has been replaced free of charge. The AST was replaced as well, but I had to fork out almost 2 bills for that since it wasn't covered. So basically, the radiator and AST are relatively new. I also replaced one of the hose going to the turbos (the small 6" hose underneath the airpump) about 6 months ago, because that develped a leak back then.

I crawled underneathe the car, removed the bottom cover... and no sign of leaks or coolant on the radiator (both on top and bottom). Also inspected the larger hoses to no avail.

I'm beginning to smell a slight hint of coolant under the hood right after I drive it. I'm not sure if it's from the overflow or not.

Like you suggested, the only way to know is to get down and do it right, step by step. My lack of patience at times gets the best of me. Will keep you posted! Thanks!

RonKMiller

Good - I forgot to mention you'll also need to buy a special plastic adaptor, about $20, to fit your AST tank top. You should replace the other turbo hose as well. I'll bet you replaced the uppermost one. The bottom one is harder to get to but you should do it as well. Once we locate the leak (hopefully not your seals) you should also consider replacing ALL your hoses and toss a new thermostat in as well for insurance. This is expensive stuff since it is all custom Mazda hose bends, but then again so are engines! Good luck!

Ron