Ok. My motor was just torn down by the builder. The engine had 800 miles on a rebuild when a radiator hose blew off when I got into boost. After I put it back on and filled the system, I kept having issues with the temps rising. When the hose blew off, the hottest the system got was 218* per the Haltech which was running any time I was driving the car for break in.

Fast forward to today when the builder called to tell me that it was not a blown out coolant wall as he suspected, it was that one of the OUTER seals on the front rotor was MELTED. These are the encapsulated seals that he uses in all of his builds. I have a couple of questions though.

First, the stock FD sensor doesn't even turn the fans on until (I believe) roughly 228*, so I was well within that. Second, wouldn't it take quite a bit higher of a temperature to cause that kind of deformation of those seals? Third, he said that the inner seals are perfectly fine. The outer seals see less heat due to their distance from the combustion chamber, so what are the odds of that?

To me, it sounds like one of two things. One: A seal that was not up to par from the beginning, or two: the seal was possibly pinched slightly during assembly, which led to the greater failure.

To the experienced builders here: What is your opinion of this? I'm not planning to broadcast the builder's name as I am not trying to attack anyone. I'm just trying to get a feel for whether a new O-ring set should come out of my pocket on a warranty engine for a failure like this. Is that reasonable, or does it seem that this is more of a "beyond the customer's control" situation?

I'm not really sure how that works, so I could use some input.

I decided to have the builder use factory coolant seals for this rebuild. I'm being charged a bit more for an all factory seal kit than for an O-ring kit and encapsulated seals, but I feel more comfortable with the factory stuff.

Thanks, guys!

 

I'm a big fan of factory coolant o-rings. They work, which is more than I can say for some of the alternatives out there.

When you said 'front rotor,' I'm assuming you meant 'front iron?'

Also, do you have any pictures?

 

The temp gauge won't work if there is no coolent in the motor.

The reading from your Haltech should be taken with a grain of salt.

How long was the engine run with no coolent in it?

 

You can buy a 12a gasket set from your local autoparts store for 130 bucks. I has the combution(factory style), coolant, dowel pin and oil control oring.Its cheaper than most "rotary shops" charge for similar seals. Though you do get a bunch og 12a crap you don't need.

List: Full Gasket Set - 1983 Mazda RX-7 | O'Reilly Auto Parts

 

Goodfella, yeah, I meant the front iron. Sorry! LOL. I'm still waiting on the pictures.

When the hose blew off initially, I heard it first and immediately saw water and steam shoot up from my vented hood. I pulled over within seconds. After I refilled everything, it seemed to be fine until I hit boost again, then it happened again. I pulled over, filled the system again, and headed home. Luckily, it was all interstate and it was about 31* outside, so temps never elevated more than a few degrees above my norm (about 190* at cruising speed). I understand that the gauge should be used as a tool, not an end-all answer. When I had an air pocket on my first start up, the gauge (factory) jumped WAY up for a moment. As soon as I clicked on the heater, the bubble started to move and the temps dropped immediately.

I'm anxious to see the pics because I want to see if this is a "total meltdown" or if it is in a small area where perhaps the seal was pinched and combustion gases were allowed to shoot by...

 

forgot to mention the 12a coolant seals can be used in a 13b and they are factory style. I am not a fan of the encapsulated orings. Stock works better and can be had for cheap.

 

The PM you sent me a few days ago asking for my input about this issue stated there was visible coolant in the combustion chamber. This is not possible if it is an outer coolant seal failure. This would only result in coolant leak externally, not internally.

The aftermarket outer coolant seals are not encapsulated.

Sounds like your builder is not giving you the entire story.

 

I just got off the phone with him. Looks like I won't be getting pictures of the coolant seals. He said he sent the irons to be cleaned up already, and everything is in the trash. Banzai, you're right. He did mention being confused due to the outer ring bring blown and still having the issue I had.

He said he's still looking in to it and he'll go measure ask the hard parts this weekend. I mentioned that I thought he had already done that yesterday. He said he did, but that he's going to go measure again to be sure he didn't make a mistake. Frustrated doesn't begin to describe how I'm feeling.

Depending on what transpires, does anyone want to buy a street ported 13B RE? I'm already having to pay $20 for a brand new seal kit. I'm not putting anything more in. :-(

 

That, and the coolant gauge measures the temperature of the COOLANT not the engine.

Some days I think I want spark plug temp gauges!

 

Ok. I heard back from the builder. He "checked, double and triple checked all clearances & housings- everything is well". He mentioned that the only seal issue he saw was a small area where the ring looked "shrunken". During my second conversation with him, he wasn't describing it as melted, just a bit smaller than it should have been.

Shrug. I really have no idea what the issue could have been if it WAS only the outer seal. I'll be paying him the $200 for the new seal kit and hopefully will have it back in the next day or two.

 

I always use OEM seals. They work the best