bad coolant seal


no real reason why the cooling system should be boiling in such a short period of time, even with an air pocket.

 

Don't think that would cause his symptoms.
Thought experiment:
Delete the heater core entirely...would the car overheat?

I've never had trouble bleeding my FC as so many others have but even after a rad swap (presumably with lots of air in the loop), the car would sit idling in the driveway for a good 10-15 minutes before the thermostat even opened up, so I agree that something else is going on.

Looking at your pic of the two thermostats, the new one appears to have a much larger bottom plug than the old one.
Possibly not relevant, but it does look different.

 

the t-stat on the right is not correct due to that bottom bypass port cover being too large and why that thermostat wouldn't fit properly.

but the claim of the engine running warm initially is what leads me to believe the engine was already compromised. coolant seals still age, regardless how many miles you have on the engine.

 

Yeah but I haven't had big coolant loss, or any coolant smell from exhaust. And any coolant loss I've experienced can be explained by a small leak towards bottom of radiator.

The heater works fine again, but drove it and when the heater was on so was the "cooling fan" light. Plus my temp started to go above half. Turned off immediately.

My coolant level might have gotten low after spilling some during the initial t stat swap so I am gonna top off and turn on with the filler cap off, to see if any bubbles coming up.

 

I was saying clogged core to his no heat issue.

 

There's really nothing special about bleeding fc cooling systems if it doesn't want to bleed and is boiling over then you have an issue somewhere.

 

Do you mean "burping?" I thought that's how you can tell if a coolant seal is bad?

 

I'm refering to bleeding air from the system after any cooling system repairs.

 

Screw this I'm going to a dealership. Tried "burping" it from the filler-cap area and it "vomitted" coolant all over everything, smoke flying everywhere. I have no idea what im doing and I'm probably making everything worse.

 

the dealership probably knows even less than you do, just because mazda is on the sign out front doesn't mean the techs know anything about a 30 year old car.


but all this air in your system gives me a strong hint what your problem is.

 

What Do you suggest, then?

 

He told you already...

 

save your coins for a rebuild.

 

Don't waste your time with the dealer, they have ZERO clue. Find a local rotary shop if you insist on taking it somewhere.

 

Dealers are only as good as the techs working in them. Broadly saying they all suck isn't always true.

 

I didn't see anyone say they all suck.

Please list all the dealerships you are familiar with that have certified rotary techs from back in the day. I'm willing to bet there's less in the the entire country than you can count on both hands, if even that many.

 

you could ask at the dealer if they have anyone experienced on older rotaries, the RX8 doesn't count.

i also used to work for dealerships, most likely they're going to tell you it needs an engine even without opening the hood.

 

I don't want to pay for an engine rebuild until I know that's what it needs. And I can't diagnose it myself, so what am i supposed to do?

At this point, the Mazdatrix rebuild has 6k miles on it. After putting the old thermostat back on the situation is totally new. I drove it for 5 minutes and my temp gauge is already over 50% but the top hose is cold.

Before, it would only raise temp to half if I was going over 75 mph. Is it possible that the coolant pressure sensor is bad, or I bent the wire (its brittle) and effected the signal?

I am still not buying the coolant seal thing. No smoke on startup, recent rebuild. And there has been a leak under the hood for a while now. What am I missing?

 

you could put a pressure tester on it and see how much pressure it is building up, but i'm still not seeing how the coolant could be boiling in 12 minutes unless air is being pushed into the system. a bad coolant seal doesn't always allow coolant into the engine.

how long ago was this engine built? not counting miles.

 

If the top hose is staying cold than the thermostat isn't working right. But, as been mentioned, if you got the volcano you say you did, theres a very good chance coolant seal is bad

Hell, it may not even be a coolant seal, it could be a hairline crack in an iron or coolant passageway, both of which may NOT have been visible during the rebuild, and has all of a sudden decided to show its ugly, blowing face. Just cause it was rebuilt XXX # of miles ago doesn't mean that something engine wise hasn't gone bad, it is VERY possible

 

If the gauge reads hot but the upper hose is cold, the thermostat is not opening.
What happens if you remove the thermostat entirely?

 

I meant to say coolant temp sensor earlier, is that a variable?

It was rebuilt probably 4 years ago. I just bought it in June and drove it from So Cal to OK.

So I should uninstall the thermostat, reattach the t stat housing, and run it that way? What do I look for, exactly?

 

Yes.

At the very least the upper rad hose should get hot.
Then feel the lower hose, it too should get hot and you've confirmed flow through the radiator (which leaks, right?).

As long as you have a cool engine and are cracking the loop to remove the thermostat, at the same time you could flush the block through the main drain (located at the driver side engine mount). You would expect to see clear strong flow.

Remove the drive belts so you can spin the waterpump by hand. You can generally feel bad bearings and see weeping seals, so unless the impeller is completely eaten away, you've checked the pump off the list.

After these simple tests, all the external suspects will have been ruled out and RE's dire predictions are pretty much all that's left to guess, given the info we have.

 

You shouldn't be driving it until it's been bled its not uncommon for coolant to erupt and make a mess when initially bleeding air. It likes to push up into the funnel or if you don't use a funnel all over the ground if the stat hasn't opened in a system full of air.

The engine needs nothing more then idle to bleed the air out after coolant work while light free reving can help speed it up its not needed. The special funnel makes it vastly easier and less messy.

You likely just aren't properly getting it bled. If both hoses get warm and your heat is hot then it's likely bled.

Last but not least if your confidence in your abilities is gone then get the car to a shop capable enough and let them do it. Otherwise the coolant seals will be screwed if they aren't all ready.

 

Musker I just noticed your profile says arizona. Where in Arizona are you located?

Also I don't recommend running no thermostat and the oem thermostat is what you should use.