RotaryEvolution

iTrader: (30)

i have an issue with coolant leaking internally into my engine so i am assuming i have a crack or a internal leak in one of the housings, i have done visual inspections and even tried sealing the sides of the coolant jackets and let water sit for about 10 minutes while watching for leaks but i found nothing.

the problem appears to only be with the rear rotor now so when i tear it down i want to have an idea of what to look for, i have checked for warpage but everything is within specs so what i really need to do is just try and pressure test the cooling system while torn down or a way to find the leak. any suggestions are welcome.

i want to fix this problem this time or i will likely just part out the car and give up on rotaries even though i love the concept, power range and sound. if i can't work on the internals then i won't own one.

the only thing i can think of is to seal the block and add coolant and try to see where the coolant is being drawn from but that isn't easy to do on an assembled engine..

WAYNE88N/A

After you tear her down, look at the "valley" on the housings that the o-rings sit in. Could have corrosion that resulted in pitting causing your problems, could have one of the "walls" that help support the rings broken off due to corrosion, or it could have been just an old, worn out seal/ring causing the problems. Only way to tell is to perform a close visual inspection with a flashlight (and maybe a magnifier) after all of the parts are cleaned...

aka_rocket

hey karack,
noticed you are in marysville. if you need a hand, just pm me. i am in chico at the moment but i usually come back to visit my parents. i'd be nice to meet some rotorhead in marysville, since their not so many. i'm getting ready to do a rebuild this winter, but its an oil leakage, not coolant.

by chance, you drive a silver 7? just curious because i've seen a silver one drive by my parent's place alot (maybe cuz i have a vert, a 1st gen, a turboII, and when my brother and i are home, a gxl, and a gtu parked there).

RotaryEvolution

iTrader: (30)

bump for other suggestions on how to approach this odd problem.



edit: lol wayne, you help so many people but forget when it counts. this is the second time ive inspected the parts. i guess im still not being thorough enough though or maybe i should just throw parts at it.

WAYNE88N/A

OK, lol, I missed the part where you said you inspected the housings. Gettin' old & senile, lol...

Mazdatrix had a writeup on pinhole leaks (in the rotor housing, IIRC) that are very difficult to see with just a visual examination, they even missed one and threw an engine together with it bad, maybe that's your prob...

RotaryEvolution

iTrader: (30)

could be, i found one with somewhat of major pinhole leaks but i still don't think that would explain why the coolant is pulsing like it is or do the o-ring seals have to be run in to seat properly? i am using hylomar on the housings, should i install them dry this time or use vaseline or a thin lubricant to install them?

RotaryEvolution

iTrader: (30)

no one here builds engines?

nuyz125

out of curiosity is the fluid leaking into your rear rotor housing, or into your oil? I just bought a supposed 20k rebuilt short block for my gxl and am having the same problem (fluid in oil) not to hijack your thread but I am interested in what to look for when I get it apart..
later

scathcart

No one here screws them up all the time (or admits they do)

I have had some issues diagnosing an engine before... if I wasn't so stubborn, I would have scrapped the entire engine and just grabbed a new core off the shelves, but hey... I'm like that.

Fill the engine with an alcohol-based dye and then used pressurized air to pressurize the cooling jacket to 20 psi for 1.5-2 mins. Drain the block at the drain plug, and immediately disassemble without rotating the engine.

The dye will seep into the engine and dry when it contacts air... and the run of dye will tell you exactly where the dye is entering your engine.

It takes a while to fab up... I have a set of plates I put in place of the water pump assembly to attach to an air compressor, but I am sure with a little enginuity, some spare rad hoses, and a tire valve you can redo this.

Not the easiest way, but it is sure fire at finding any cracks or pinhole testing, or a seal problem.

It might be noted that I now refuse to build any engine using anything but mazda inner coolant seals...

RotaryResurrection

iTrader: (8)

Also when using used housings with even minor pitting on the mating surfaces, always use some form of sealant on the rotorhousing-to-seal surface.

RotaryEvolution

iTrader: (30)

the coolant is leaking into the rear rotor housing but where from i don't know yet.


i am as stubborn as they come when building engines and i don't give up easily but this one is wearing me thin, if T2 parts were easier to come by i may have already started on a core engine... i will try your method, i already thought of something like that but i will have to see what i can come up with when i get the engine out of the car.


Kevin, what type of sealant works best? i have been using Hylomar but i have been thinking of experimenting but i figure why not ask. the rotor housings mating surfaces are almost perfectly flat with little pitting but there is some minor ones, the iron housings do have some also but all the housings i have seen have had some pitting on them in the iron housings.

RotaryResurrection

iTrader: (8)

Hylomar works well as an assembly aid, to hold stuff together. However, it sucks as a long term sealant. Over time, some or all of it gets washed away by the coolant supply. IT's okay to use it for the iron-side coolant groove, but use a hardening type sealer on the rotorhousing. I use permatex ultra black high temp rtv, personally. Back about 3 years ago I used to build engines without this sealer, and I did have a couple that wouldn't seal up...the rotorhousing surface is going to be dry, and the inner waterseal itself is dry and sort of stiff, so it may not seal up perfectly, and any little pit can let coolant leak by. The RTV just promotes better sealing, IMO. You could even go so far as to use it on both sides of the seal.

RotaryEvolution

iTrader: (30)

thanks for the suggestion, ever tried using a anaerobic sealant? i thought about this but i don't know if it could stand up to the heat for one and second it would be pretty tough to disassemble after being assembled as it basically turns rock hard after the parts are assembled and air is removed and it cures.

RotaryResurrection

iTrader: (8)

No, I wouldn't try that, you never know if something that hardens solid will crack away from the main body later on and cause problems. Just run a soft high temp sealant that stiffens when it is cured, unlike hylomar which never stiffens.

Aaron Cake

iTrader: (1)

If you have deep pits in the rotor housing, mix up some JB Weld (this is one of the few things I actually use it for) and spread it into the pit with a razor blade. Run over it a few times with the blade to get it as flat as possible. After a few days, when it is cured, sand with a high grit (400 or so) sandpaper. You should be going over the whole mating surface of the housing with sandpaper and a SANDING BLOCK anyway (sand it WET) to clean it up. The JB Weld perfectly patches any pits.

RotaryEvolution

iTrader: (30)

i will pull it this week and play with the mating surfaces more and try your suggestions. the surfaces were fairly clean and flat but could use some more attention and a stiffer sealant(high temp RTV) than the hylomar would likely do the trick but i think i am going to try some JB weld on questionable areas of the sealing surfaces on the rotor housings as well.

RotaryEvolution

iTrader: (30)

well here is what i found, easy to miss...


http://www.dealexpert.net/upload3/im...cture_045.jpg?


sorry for the indirect link, my usual hosting site seems to be down atm and this one doesn't allow image linking.

there is a pinhole in the housing right in front of the leading #2 spark plug, i assumed it was the coolant seals but they seem to be holding just fine. i guess on to the teardown again...

RotaryEvolution

iTrader: (30)

it's all back together and i did a final pressure check with the engine out and it is holding now, hopefully no more problems come up when it comes time to start.

aka_rocket

awesome!

RotaryEvolution

iTrader: (30)

i'm taking the JB weld mod out for a spin to the store right now, it withstood the 3/4 throttle spin around the block and i am letting it cool for a few mins to see how it is on a heat soak start. wish me luck.


edit: oh, and the JB weld mod helped a bit, it pulled harder at 3/4 than it ever did at full throttle.

RotaryEvolution

iTrader: (30)

it ran ok til i got about 5 miles away, started getting hot so i parked it then steam rolled out from under the hood on the driver's side of the engine bay. the heater hose had split and sprayed all over that side of the engine, so i got my pizza and then walked over to k-mart and got some cookies, distilled water and an 8mm wrench and walked back. i munched the cookies since i haven't eaten all day because i have been working like mad on this, i cut 1" off the end where it was deteriorated and clamped the new section down. it worked to get me home but i now noticed the thermostat has gotten itself stuck sideways so i will remove it and throw my extra one in it.

the idle is near perfect and it runs good, i just need to get all the kinks out now.


oh, it did flood out the first time i parked it after the first test drive, thereafter it started perfect but i also did not bleed the fuel pressure out after that point, odd that it starts ok with a primed fuel system and not a dry one, knowing how rotaries are....

RotaryEvolution

iTrader: (30)

35 miles, still has some air pockets i need to get out but it never got past 1/3 on the temp guage this time around.