Losing coolant, bad ORings?
 

I'm losing coolant (a half pint in 25 miles) and getting white smoke and a stumbling engine when I start it. My conclusion is that the ORings between manifold and head are shot (120k on the car). But before I start taking all that stuff apart (looks pretty ponderous) I thought I'd check to see if someone had encountered some other cause. And I DID do a search already.

Any other possibilities, other than the ORings?

Should I put an RB header in at the same time?

I'm not gonna tackle this for a couple months (I'll just drive it around the block once a week to keep it alive - that makes 2 cars I'm driving around the block!), in the meantime i'll drive the 85GSL as DD, so I have time to gather info and ideas. Or maybe I can find someone to do it for me for mere money.

B

Hey, B, you've checked the simple stuff, like hoses?

I was leaking coolant, blew a heater hose. Fixed that, still was loosing coolant. Did a pressure test, found 3 leaks & a pin hole in the radiator.

Try pressure testing before assuming the worst, maybe?

You mentioned white smoke. Where are you seeing the white smoke? Out the tailpipe? Billowing out from under the hood? When my car's o-rings went, the thing I noticed was the smoke coming out from the hood not the tailpipe and no problems like stumbling. Has the car ever overheated?

If it was just hoses or a leaky radiator or cap, you would not be seeing the white smoke. Sounds like you have a water seal leak between the rotor housing and side or center housing. This usually happens as a result of overheating. The rotor housings and the side housings expand at different rates, so when the motor is overheated the rotor housings try to expand more than the tension bolts will allow, causing the rotor housings to crush themselves against the side and center housings, which are steel. When the motor cools, the now-deformed rotor housings do not seal properly.

wankelguy, that's a great, concise explanation of what happens to overheated rotaries. Thanks.

Well, about 2 years ago it overheated slightly when the cooling system went out (everything was shot, so I replaced everything: radiator, hoses horrible heater hoses, pump, thermo, etc.) and it's been good since.

I get white smoke out the tailpipe when I startup. I also get some smoke from underneath if I let it set to warmup, but I figured that was the shot ORings under the beehive (which I KNOW I've gotta replace soon).

I hope it's not the internal seals, and I don't think it is because it's so long since it overheated. And the motor runs SO smooth (as always: smoothest rotary I've ever known).

I've been unable to work on my 3 7s because of this dratted townhouse renovation I'm doing, but that should be sold in 2 months so I can get back to my cars. Unless I buy another townhouse to renovate.

B

Sounds like someone needs to get their priorities straight (j/k):D

Right now my priority is to augment the miserable SS and pension income (I'm 67) so I can die as I have lived: beyond my means.

B

You're 67? Wow, I thought I was an old-timer at 46!
Please stop talking about death...

After letting it sit overnight, pull the plugs. Bet they'll be wet with coolant, that's why it's hard to start in the mornings and white smoke. Internal coolant seals:(
Been there, experienced that. Sorry, rebuild is in your future, I fear.

I expect that the plugs will be wet in either case. I hope, of course, that it's the manifold ORings, but the large amount of lost coolant makes me worry that it's the internal seal. But I don't know any definitive test that will determine which it is.

A few months ago I read a long procedure for a temporary fix for the internal seal problem involving some patent leakstop stuff from PepBoys. Anyone have a convenient pointer to it?

Now I wish I'd bought that rebuilt 13b engine for $1000 that I had a shot at last year!

If the engine is shot, then I gotta decide whether to rebuild/replace the engine or sell the car. Hmmm. I've put $3700 into it the past 2 years (tires, rebuilt transmission, Tokico blues, cooling system,etc., etc.) so I'm reluctant to let it go. And it is a car that only I have driven.

B

Do a search for "block seal". I know its in the sa22 mailing list archives somewhere also. On a side note, my first engine lasted 5 or so years after overheating, and slowly lost compression over time till one day it just did not start. Pop the rad cap, start the car and look for bubbles in the coolant.

I had a friend who had an RX4 wagon with a bad water seal. The thing would puke out huge clouds of white smoke until it warmed up, then it would seal and run great. Finally, he just couldn't get it started. That's the way it usually happens with rotaries, they'll run with bad oil rings or water seals and make pretty decent power right up until the damn thing just won't start anymore.
Or is that just my RX4?

I got the block seal instructions on the second gen forum:

https://www.rx7club.com/showthread.p...nt+seal+repair

They're also on the web:

http://rotaryresurrection.com/coolantfix.html

I'm gonna start it with the rad cap off and see if it spews coolant, since that seems to be the best test for internal leak.

B

I started it with the cap off, the coolant was a little low, and after a couple minutes I got a small bubble and the level rose and dribbled over the neck. No gushing, even when it warmed up and when I raised the revs. The overflow tank was empty. The coolant seemed to overflow a while , then recede, then o'flow, etc.

I conclude that it's a smallish leak, and I still can't figure manifold or internal seal. Looks like a good try for the Block Seal treatment, but I won't be able to get at it for a couple weeks.

B

I'm thinking internal seal. But that's based on my experience with manifold o-ring failure. In that case, I had clouds of coolant vapor coming from the passenger side of the engine after it was warm. No leaks when cold, though. Anyway, good luck. :)

Let us know how it turned out. You may have a small leak not a big one--- yet.

Yeah, I'm not driving it until I get a chance too work on it.

B

Like Carl, my engine lasted numerous years and over 70K miles after the overheat before dying a horrible death. Like yours it too ran smoothly. We had gotten lots of bugs worked out, had DLIDFIS installed, ICAI, killed the nest... lots of love and that engine was kicking MAJOR ass... Then out of nowhere, it chucked an apex seal at 150K. Tearing down the engine showed an extreme amount of flaking on the rotor housings. I don't want to be the doomsayer, but start getting yourself used to the fact that any overheating - regardless of severity will absolutely shorten the life of your rotary.