Blown seals or bad water pump, please help.
 

Background story: My red rx7 finally got to where I was pushing starting it to drive it, so I bought a miata. Missed the rotors, traded for a supposedly good s4 rx7. Ran alright for about two days and then started overheating really bad.

The compression checks out good on the front and only one face on the rear is 90 something; the rest are good. When started up it revs itself to 2,500 or 2.600rpms, pulls good, and it hasn't flooded once on me. The oil is also good, just eye-balling it though. However, whenever I go to check if the water pump is working right. Just running it and filling it up with water while it runs to see if it keeps going down. I saw a few little bubbles and after a couple fills the water stayed topped off and started bubbling over. I had the smart idea of revving it and water exploded all over the place. I shut the car off, it was warmed up, and felt the bottom hose and top radiator hose and they were both still cold but the top of the engine was hot. After So, I'm starting to fear that I managed to buy another blown fc.

If anyone has an idea of if it might just be the water pump not working or maybe the cooling passages are clogged up (I was told that someone ran tons of stop leak through the radiator). Thanks for any help.

well there is a chance the stop leak is killing you. first thing i would do is swap the t-stat. you'd know if it was the pump cause water would drip outta the weep hole on the bottom of it. and if the seals were bad it would be like a gyser outta the hole.

and also it sounds like you have a bad motor as what your comp test says.

I replaced the thermostat with one that I bought/tested before putting in. There is no visible leaking externally. I figured that the motor did have bad seals but since the rear is still partially good I didn't figure that it would be overheating this bad because of the combustion gasses entering the cooling system. I'm going to try and flush out the engine cooling passages tmrw. However, I'm starting to think that this is all a waste because when I drove to the gas station and back today I was didn't go over 9/10ths hot (I know that is still bad) but when I shut it off I had steam rolling out of my coolant reservoir cap. I was going to smell it but I've already got third degree burns from my wrist to my shoulder because my other coolant res. cap exploded when I raised my hood a week ago. :nod:
Any idea how to go about flushing the actual engine coolant passages?

buy a flush kit from the auto store. but seriously it sounds like your about to open a bucket of worms. itss a bad motor is its getting as hot as you say it is.

Update: It is already getting dark and I burnt myself again so I'm calling it a day. Tmrw I'm going to pull the water pump off and see what it looks like.

So, I couldn't find anything wrong and accepted the fact that my coolant seals were fucked. (It was easier this time than last time :D).
Anyways I tried the block weld "fix" and I let it sit for 3hrs. I drove to the gas station, 3miles away, put ten dollars in my fc. (my other one finally stopped running with a full tank). I preceeded to drive down Highway 23 here in Kentucky. I drove 15 miles turned back around drove another 15 miles and went to town and parked; 34mile round trip. My temp gauge was between 1/4th and 1/2 the way up the whole trip and when I parked it I assumed my temp gauge just was stuck and it didn't do anything. Shut it off, no boiling (good because my left arm can only handle 3rd degree burns once for a car), and there was no bubbling or anything.
It might have fixed it, might not have; I'm putting my brakes on tmrw, filling it up, and driving as far as I can. If it doesn't overheat then it might be fixed.
I'll update. I know I'm always seeing posts about the block weld. I think I used
J & W not for sure though.... I'll check before I update again.
:icon_tup: Rotary endurance haha.

well your gunna really hate it if you ever have to tear down that motor. that shit is bad. the turbo motor i put in my car looked like it had that in it for some odd reason. but it had started to collect all the contaminents in the water and i had one housing that was packed from side to side with gunk. and it was really in there. im not even sure how the motor was able to move the water. and also it ended up ruining a iron from where all the junk sat o n it. jsut ate right thru it.

it has a very very noticeable smell if the seals are bad and the water and oil are mixing. its hard to miss

Well, I was 100 percent sure it was the water seals/coolant seals/w/e. I burnt my arm up because the coolant res. cap (the thing that isn't supposed to have pressure) exploded as I raised my hood one night I came home after the temp gauge was two inches past the big H on the temp gauge. I'll update tmrw after I go on a trip.

Be careful when you rebuild the motor. Check the front iron down near the eaxhaust port where it mates with the rotor housing. They have a tendency to crack there.

Thanks for all of the advice, I actually found rotor housings that aren't in that bad of shape for 60 dollars already. I just need this rx7 to last me until I get my red s5 fixed again. It got to where I had to roll start it to get it start up (I.E. If I put water in it, it would all disappear into the engine.) That was with a fuel-cut off switch too. So I figure it will need housings. I'm actually trying to find enough parts to make a budget, say junkyard if you want, 3 rotor 13b. haha....

$60 omgz you get what you pay for thats cheap you n00b.

No.. seriously. Theres nothing wrong with used parts if they spec out properly. That dude needs to go buff a knob somewheres.

It's getting kind of ridiculous with people telling everyone else that their way of doing something is wrong and mine is right, period.

Substituting used parts a reliable and commonly used practice in rebuilding, professionals as well as first timers. If the part is in good condition(it specs out, no warpage or hot spots), there is no reason why it can't or won't perform as well as it's new counterpart.

If you're happy plopping down $700 every time you need a new housing, then good for you. The rest of us will make do with our $20 housings and $500 "backyard" rebuilds.

Go back to your section.

That whole reply was full of win. As hilarious and entertaining as it will be, I'm not going to continue this argument because I see where it's going.

To the OP: You can build a reliable, replacement engine for less than 1k, just shop around the different vendors for good prices and build your own kit. Good luck with your car.