TwinCharged RX7

iTrader: (14)

Thats a good idea, but how do i do this? I don't want to cut the nipple and tap the block, that could leave metal pieces in the coolant passage right? I guess instead of using a bolt as a block off I could use the sensor as a block off. I don't want to do too much of a cob job haha. Where is the frost plug on the rear iron? please tell me its not covered by the bell housing. i really don't want to take the engine out again.

DaveW

Well, that explains air getting in. It's getting sucked in through the same leak when the system goes into vacuum as it cools.

Dave

Sgtblue

iTrader: (16)

Establishing exactly where your leaking coolant is priority one. Be it from where the rear nipple was blocked-off for the TB coolant line (best scenario and most likely) to a rear frost plug (less likely, but alot more work to access...the motor doesn't have to come out, but the transmission, clutch and flywheel would).

Either way since you've got everything removed to make it easy, you could just loop a NEW section of hose with NEW hose clamps from the rear nipple to the front nipple just behind the filler neck. Anywhere along that loop you could then place a 'T' fitting and your coolant temp sensor as set out in DaleClark's instructions that I mentioned earlier. Below is a picture of where I placed mine. It has an old piece of hose over the fittings to keep it from rubbing on anything important. Buy a male 1/8" AN plug at the local hardware store for where the current sensor is located now.

mono4lamar

iTrader: (32)

I could take you in but I wont have access to my lift as I have a car on it right now. I'll see if I can open a bay up. I didn't think you would be free this weekend . I'll let you know if we can work something out this weekend.

TwinCharged RX7

iTrader: (14)

If i can get the piece for the pressure tester from autozone tonight i'll pressure check it and see if replacing the block off last night did the trick.

I think it's unluckly that the blockoff was the problem, it had no signs of a leak, so unless it was spraying out and then managing not to drip anywhere close to its base its unlikely.

The most disturbing thing is the flywheel view plate on the top of the engine, the underside was coated in coolant. and the view plate on the passenger side also shows signs of coolant next to it. I have access to a lift but only at night time for only one night at a time, so it would be difficult to remove the tranny.

Mono, if the above doesn't work, if you happen to be on my side of the river at all this weekend i could put it on a lift over here for you to take a peek. If not we can arange a different time for me to come over.

Sgt Blue - I think i'll try that over the winter, but for now i'm just going to try to solve the problem. its def a better spot than where i have it now. Except on mine i have 2 nipples on the back of the Tstat housing which are already looped together, so maybe i'll just cut that hose and put the sensor in there.

TwinCharged RX7

iTrader: (14)

With the pressure tester, will i be able to hear the leak if it looses pressure?

DaveW

Unless there is a pressure differential between the two nipples, no flow will occur and the reading will still be screwed up and not read engine temperature.

Dave

crcleofdst

Agreed. It's best to stick with the tried and true method described by Sgtblue above.

DaveW

Maybe, if it is a big one. But most likely, you will see the pressure begin to drop, and see coolant accumulating somewhere.

Dave

TwinCharged RX7

iTrader: (14)

I got the pressure tester attachment, it doesn't hold 13psi, the blocked off nipple is not leaking, i removed the bottom view plate on the bell housing and more coolant is leaking out. any info on changing the frost plugs? i've searched but can't find much on how to actually do it.

and is there any reason why a freshly rebuilt engine would have this problem, other than the builder's error?

TwinCharged RX7

iTrader: (14)

I ordered 4 plugs from Ray at Malloy, only like 2.95 a piece haha, sure is a lot of labor for such a cheap piece.

They will be in next thursday, so I plan on tackling the project the weekend following. Anyone know of a DIY on this? It doesn't even mention them in the FSM and I don't see any threads on how to do it.

I ordered 4, but I'm guessing only 1 is leaking, so i'm going to practice with 1 on my old engine. ahead of time.

Do I poke a hole in the center of one, stick something in the hole to grab it, and then pop it out? Then do i just hammer the new one in? Any kind of sealant needed?

Sgtblue

iTrader: (16)

They don't go bad very often. My guess is that the previous owner didn't change coolant very often.
I've only messed with them once long ago on an old truck. IIRC, after draining coolant I punched a hole in it and pried it out. Just be careful not to nick the wall where it has to seal. Having some emery cloth might be a good thing to clean up the sealing surface. I also remember borrowing a tool from a mechanic friend to re-install. It was like a big punch, but with a round head sized to fit the frost plug and I tapped it into place. I don't recall using any sealant, it was just a press fit. I do remember a couple of them on the truck being in an awkward place behind the motor mounts. At least you shouldn't have that trouble.

DaveW

http://www.hotrodders.com/forum/what...ugs-99101.html

Dave

TwinCharged RX7

iTrader: (14)

Thanks Dave,

since I already have some "right stuff" left over, i'll use that as the sealant. But first i will clean the holes really well.

I'll probly be doing it overnight friday and it may spill into saturday. I'll post results.

TwinCharged RX7

iTrader: (14)

so i took the tranny out today and put the pressure tester on, a lot of the tension bolts are actually leaking. And the upper left tension bolts have allen wrench fitting in the middle of the head and are not normal bolts, they seem to be torqued correctly though. How do I fix this? i dont even know how the allen wrench bolts work.

DaveW

I don't know what is supposed to be there, but what you describe sound like they may be "Allen nuts," which could have been used to replace stripped threads?

Dave

TwinCharged RX7

iTrader: (14)

I'm not sure, i took off the nuts on the four that were allen drives, untorqued every bolt in the correct order, then torqued everything back down in order. I've read threads where race engines were torqued down more and some people go a little more than the 30lbs recommended by the mannual, so I did 40 all around.

tranny is back in, now i have to button everything up tomorrow, if this didnt fix it i have no idea how to stop the leaks.

DaveW

IIRC, there are also outer coolant o-rings. Maybe one of these is bad or its seating area is corroded, causing the coolant to come out thru the bolt holes.

Dave

TwinCharged RX7

iTrader: (14)

I'm not familiar with how the coolant system works around the tension bolts. I see that the rear iron has passages in it, where all the freeze plugs are. I've seen threads recommending that tension bolts should be re-torqued every time the clutch is change to prolong the life of the coolant seals. People have warned that during this process coolant will come out, which mine definitely is, so after torquing it back down you would think that it would fix the problem. I'm not sure how else you can seal it, its just a washer on the end of the bolts.

Has anyone else had leaking tension bolts before?

TwinCharged RX7

iTrader: (14)

bump?

DaveW

I have no direct experience here, but...

In the parts diagrams/catalog, there are o-rings around the tension bolts. That, as you have surmised, indicates that the tension bolts need to be isolated from coolant to keep them from leaking.

Any time there is an o-ring present between (similar or dissimilar) metal components in contact with water (coolant) there are several possibilities of leakage:
1. o-ring seating surfaces are OK but o-ring takes a set/hardens and no longer seals
2. o-ring is OK, but joint loosens and leaks (this would be the retightening scenario)
3. corrosion occurs and pushes the o-ring away from solid metal, creating a leak path.

Since I have no direct experience with this on a rotary engine, I can't with any certainty pick which one is occuring, but just knowing the nature of the rotary, I'd guess #3.

Dave

TwinCharged RX7

iTrader: (14)

I am really hoping for #2.

1 & 3 mean the engine comes out. I just put it in and it only has 350 miles on the rebuild, but it has leaked since i put it in. I would hope they are new o rings, it was built by Pineapple, and it did sit for a while, but never had coolant in it while sitting to cause corrosion.

If it is 1 or 3, can i remove the engine, pull the tension bolts, remove the rear iron, put new o rings in, and put it back together? or does removing the rear iron and bolts really make it so the whole engine needs to be pulled apart and resealed?

DaveW

a) This may indicate a problem with either the assembly process or a pre-existing corrosion problem that was not taken into account.
b) I have no idea. I've never had a rotary apart.

Dave

Sgtblue

iTrader: (16)

Never dealt with the problem... but thinking I'd order a set of sealing washers from Malloy. Loosen tension bolts in order according to FSM, but leaving some tension...maybe 5 to 10 ft/lbs. Remove them ONE at a time, Clean them carefully, replace the "sealing washer" and re-insall w/a little oil, initially tightening only to the 5 ft/lbs or so. When all are replaced, torque to specs and in the order according to FSM. Page C-71.

TwinCharged RX7

iTrader: (14)

Thanks sgt blue, i may try this if the retorque didn't fix the problem. I filled the radiator back up with coolant and pumped the tester up to 13psi, now i'm going to wait a bit and go check it. hopefully its where its supposed to be.