ukheman

Hi, I need some help with this plz, I have a 2006 Mazda RX8 192PS. It was involved in a flash food.
I have removed the spark plugs and cracked over the engine.
The engine is turning over freely….
Oil came out of the holes in a mixture of the fuel. Dropped the oil from the sump and noticed water there. Checked my coolant level saw it was empty so i topped up. Hey presto the water was being drained out from the sump.
I’ve got an engine lined up for around $2000 or is it worth trying to repair the engine that’s in…

Thanks…..

rotarygod

If you have replaced all the fluids and are absolutely sure that all of the flood waters are drained out, the news probably isn't good. If you drive the car, does coolant slowly leak into the oil pan? If so you've got a water seal leak on the bottom of the engine between a housing somewhere. The only way to fix this is to rebuild the engine. It's probably not a serious rebuild requiring all new metal seals since your car is fairly new. You never know until you see inside. It still requires a tear down to fix it though if this is what it is.

ukheman

i havent tried to start the engine with an new set of plugs. incase its not fisable in cost. i have compression tested the 4 plugs and all 4 give over 100 PSI. the water isnt only leaking from into the sump but also from under the car nr the gearbox. which indicates ive got 2 leaks. i have to pull the engine out for the replacement so i thought id try and see if its worth while to replace any seals.. but dont know which ones at this stage..

should i try replacing the spark plugs and see if i can get the engine to start. ? then try and replace the seals... any idea where i can get info for the coolant system and the seals i need to replace. thanks

nycgps

iTrader: (1)

Well ur engine might still start with new plugs, but if its really leaking coolant, how far can you drive before ur engine is toasted ?

Just double check and see if its coolant leak first, dont worry about driving it for now.

ukheman

its definately a coolant leak as when you top up the coolant it simply drains straight back out at the bottom. no matter how much you pure in at the top it empties the reservoir. this is with the sump plug closed (in).i was thinking of replacing the plugs and simply trying to start the engine for a few seconds. then replace the seals. if it doesnt even start then that idea can go by the way side.. any ideals where i could find a schemetic on the cooling system or have anyone else had any experience in a rebuild and which seals i may need to replace. thanks....

nycgps

iTrader: (1)

have u check the lower Radiator hose ?

It sounds stupid but sometimes that could be the problem.

ukheman

yes its not from there. as the 1st leak is nr gearbox clutch side. when i open the sump plug it then drains from there aswell. been looking on the net with regards the coolant seal .. need more research at the moment..

nycgps

iTrader: (1)

Unplug ur spark plugs, and just keep pouring distilled water into the coolant bottle until u see something comes back out.

So u can have a better idea where its *coming* from.

if it comes out from ur spark plugs then ...

it does sound like it is going to be a costly fix

ukheman

thats what i did, my plugs are all off. sump plug on. i kept pouring water down and it drains from the bel housing nr the gearbox.
its not coming out of the spark plugs

any ideas ??

nycgps

iTrader: (1)

it does sound like some seals has gone to the Rotary heaven.

*Sigh*

ukheman

whats the rotary heaven ... i thought the coolant went thru the back housing and the rotary housing..

nycgps

iTrader: (1)

thats why I Said some *seals*, not the whole thing.

ukheman

sorry, i didnt know what you mean by the word "rotary heaven"

nycgps

iTrader: (1)

hmm ...

Heaven means its *dead*

Seals are *dead*, not the whole motor tho

Just replace the seals I guess

but you still have to take the motor out to replace them *just like what RG said*

rotarygod

It does sound like a leak from between the housings somewhere. You won't necessarily get low compression depending on where it is. The leak could and probably is only going to the outside of the engine and is not internal.

rotorocks

Not the seals, seals are there to isolate the combustion chambers and provide compression. Seals have noting to do with coolant. O-rings do. Ukheman you sound like there is a damaged outer o-ring between one of the housings which leaks coolant to the outside.

If you can actually do it yourself, it will not be a costly rebuild.
Just get a complete gasket and O rings kit from mazdartrix, and make sure you order front and rear oil seals for the crank shaft (they are not included in the kit, but kost like $12 each from the dealer) And you should be good. you have good compresstion so no need to replace any of the seals or anything else. Overall, this whole thing (parts wise) will cost you around three hundred bucks.

When you open that motor, make sure to keep track of your side seals and which goes where, because they are all different length, and if you get them confused, you are somewhat screwed.

Good luck

ukheman

whats really confusing me though is why is water coming from the bottom of the transmission. as soon as i pour water into the coolant it comes directly out from there, that make me think ive got a cracked back housing. if water was filling in the rotary chambers then surely it would pour out of the spark holes as i turn over the engine.. any thoughts..

rotorocks

There is a million and one way water can sneak out of the motor once the o-ring broke. it all depends on the location of where it ruptured. i would say it is very unlikely that you will have a cracked housing.

having a broken o-ring does not necessarily mean that you will have any water in your chambers at all.
there are 2 orings internal (prevents from water getting from the water jackets into the combustion part of the motor0 and external (prevents from water escaping outside)
in your case it is most likely that you have a ruptured external o-ring.
Water could come through the crack in the oring get into the hole of one of the dowel pins, and through there find it's way to the back of the motor. Who knows? Like i said, there are a bunch of ways for it to get out once it finds it's way past that external o-ring.

Look at this image: see the inner and outer groove for the o-rings? could be cracked anywhere. there is also a bunch of silicone added here and there for additional sealing, which could direct the water one way or the other.



You will not know for sure unless you open the motor up.

rotarygod

It could be a cracked housing. It could also be leaking out a tension bolt hole and into the bellhousing of the transmission. If this is the case then you only need to remove the transmission to fix it.

If a water o-ring between the housings is leaking, you won't only need a new seal. You might but another possibility is that it's leaking not because the seal failed but because your rotor housing got warped a small amount. If this is the case you'll need a new rotor housing as well. They are aluminum. The other housings are cast iron. If you drive the engine hard before it's fully warmed up, this will cause uneven heating of these housings. That's potentially bad news and a big reason why the '09 RX-8 has a variable redline that limits max revs based on how warm the engine is.

ukheman

ro to rocks thanks for that info.... whats bafferling me is why is water draining into the sump ??.. draining outside i can live with the outer ring being broken and also the explanation about combustion and seals

i thought the inner 0 ring would need to break to allow the mix of oil and water...

or does the sump... cover the area of the back housing and or rotary housin at the botton aswell allowing the water to drip down...

i am going to take the engine out but down have time until next week so im trying to think methodlogically at the moment... true until the engine is opened up i cant be 100%...at the same time im trying to hedge by bets it doesnt cost me a fortune...

rotorocks

A little off topic, but has anyone ever thought as to why the connecting holes inside the water jacket are so small? Wouldn't it improve the cooling if the holes were actually larger, thus improving the coolant flow through the engine?

I spoke about it with ray as we were working on my motor, but never came to any conclusions.
i could assume that Mazda left the holes as they are in order to actually slow the speed of flow, and induce more turbulence, so that all of the coolant's capacity to absorb heat is utilized, but could it be that it actually may be the reason why the housing developed the tiny cracks around the spark plugs? because of the insufficient coolant flow?

When i saw that my first thought was to take the dremel tool and hack those holes to a double of the size, but decided to ask around first


EDIT:
To answer your question ukheman, look at the picture. See those legs on the housings? That's where the oilpan is bolted onto.

Brettus

iTrader: (2)

This sounds very strange to me .
some questions
I take it the engine was submersed in water for some time ?
Before it was submersed it was running OK?
Since being submersed you have not had the engine running- correct?

If the engine was running before the flood and has not run since - there is no reason why there would be any blown seals or gaskets !

ukheman

i am a salvage dealer hence dont know what exactly happened after the flood. by the looks of it . someone has tried to turn the engine with the spark plugs in. hence there was compression of water thru the air intake in the combustion chambers. we took the plugs out and drained any water out and compression tested each chamber. also can see fuel shooting out of the spark holes. i initially thought the water compression would had lead to a cracked or warped iron housing and or rotary housing. the amount of water that is coming out from the tranny is quite alot. and doesnt seem like a seal broken .. and it tends to come out from 1 place and the pressure is similar to that if you opened and drained the rad.. but then when you open the sump plug. after abit you get water from there aswell... looking form under the car. there is definately no water leaks from the outside between all chambers. from top to bottom.. but between the last iron housing and bell housing of the transmission there is water. and not from the last iron housing and the rotory housing. so i can only think that the bell housing is filling up with water and pouring along the crank then back down in to the sump... as we poured some red dye and there was a definate delay in colour from the tranny leak ... 2 mins and a further delay until the sump colour changed... this is turning out to be more of a high school experiment rather than a money spinning idea.....

RX8-Frontier

Smaller holes INCREASE the velocity, not decrease. So evidently, Mazda wants the water to circulate FASTER. Opening up the holes will cause the water to slow down, and yeah, would allow more heat to transfer to the water, but it *might* be too much and cause cracking. Typically, you want the water to move as fast as possible, because you get more cooling effect by running more water through which allows more cool water to run through in a given time.

edit: BUT, I just realized, we may be talking about different holes; if it's larger on either side, but just necks down to a smaller diameter for a short period, then that's being used to either increase the pressure of the fluid, and increase the velocity for a short burst.

rotorocks

I actually wanna take it to its own tread. This is interesting.