So I’ve bled the coolant system after replacing the water pump/thermostat etc.

but seems like the heater is not getting as hot as it should be... during the bleeding process, the heater air gets sub hot maybe warm. But now seems like it doesn’t get even that hot.

is it another sign of coolant seal failure?

I seem to need to fill up with water/coolant every other time I drive.

used to have some hot start issues, until I got the hks twin power band now the car starts up almost every time fine...

I know it’s unlikely but Couldn’t be evaporating through the radiator cap?

 

First, define "fill up with coolant" - like a splash? Or a good amount?

The cooling system is sealed. Once full you are good. It can't evaporate out or disappear - it's in there in a sealed, closed system. This should be a top priority to figure out. The coolant is either leaking out of the system, going into the overflow tank and not getting sucked back in, or going into the engine and burned.

All that said, the FD's heater for whatever reason isn't great. You do have to have it set on "floor" vent, not "face" - that's in the owner's manual. It's designed to just blow hot air at your feet or defrost.

Sometimes the heater core can get plugged up and flushing it can help. I've done it to mine and it really didn't make much of a difference, though.

Dale

 

Heater not blowing hot and frequent need to fill up with water/coolant could both be due to coolant loss or leaks such that the system never reaches normal operating pressure and temperature. First, you need to identify the location of the leak(s) or loss. White, sweet-smelling exhaust? Puddles under the car? Are you checking the coolant level in the overflow tank? Is it overfilled or low? Where are you adding the additional coolant?

 

check your mix actuator. its just under the glove box to the left. see if it moves with hot/cold ****. i had to take mine apart and clean it, good as new

 

No puddles or anything... I think at least some of it going in the reservoir tank... I’m not sure how much.. but I drove two days and I had to refill maybe 1/2 gallon.

the car gets up to 85-95 c. Sometime around 100 c..

I don’t see any visible leaks...

do I need to take the dash out to get to that temp controller?

 

Half a gallon? Something is going on here. Do the champagne test and get a solid idea where that coolant is going.

The air mix motor is accessible without removing the dash. With the key to On, car not running, move the temp dial on the dash from cold to hot. You should hear that motor move the door in the heater duct. Should be the same thing when it moves back.

Dale

 

So when I turn the temperature dials, with the key on position. I can actually hear something, the temp motor moving. So that should be ok right?

a bad sign today though. Randomly the car had a hard time starting. Like it was totally flooded or something. But it caught on and when it did a bunch of white smoke puffed out. Then went away.

then the water level warning light came on... when I look for bubbles in the coolant, there were a lot of champagne like bubbles...

the car once fired up and cleared, it drives really good..

 

Sounds like coolant seals are toast, unfortunately, you've got pretty much every symptom of this issue.

 

Yep, that does sound like it. When you shut the car down, as the coolant system cools and depressurizes coolant leaks into the combustion chamber. This makes for a hard cold start and smoke on cold start.

There are testers you can get at the parts store that will tell you if you have exhaust/combustion in coolant so you can have a 100% answer.

The good thing is many engines with bad water seals end up being decent rebuild candidates. The bad thing is you have to rebuild the engine. You definitely want to do it sooner than later, if you let a motor that's drinking water sit the water can sit in the combustion chamber and rust the seals into the rotors, many times you end up with junk rotors if they sit too long. If you do need to wait a bit, drive the car once a week or so, that will keep things happy.

Dale

 

Argh...

would bad coolant seals read bad compression?

I did a coolant test for exhaust gasses and it was with a blue liquid in a blastocyst syringe that put on top of the radiator cap at idle would change colors if there was exhaust mixed.. it changed colors slightly but not to the obvious..

How much would a rebuild be roughly? Maybe street port it?

 

You can have great compression and a bad coolant seal.

Rebuild costs vary WIDELY. A lot of it depends on how much you do yourself, what parts are good and bad on the engine, etc. Also there's no end of stuff you can buy to upgrade "while you're in there".

Kevin Landers at Rotary Resurrection does a good budget rebuild. You can also look at buying a new Mazda short block, IRP is selling them around $5000 or so. There are options in SoCal, like Mazdatrix, that may be worthwhile. I don't know if there's other shops near you that I would trust.

Dale

 

Ah ok.. bummer because when I had my compression tested a little while back, it read really well. And the guy who checked it said if it is good then the coolant seal should be good too.
but ya seems like all the symptoms are pointing to a coolant seal. Hot start issues, champagne bubbles, heater not getting hot, having to refill coolant constantly.

also does it really matter which type of coolant/water you use??? I had some extra Toyota red coolant and I used it in the 7. Maybe coincidence but that day is when it smoked white smoke..

but today it started back up and not smoking a ton like that one start up yesterday

 

You only want to use plain green Prestone coolant, 50/50 with distilled water. Some of the other coolants out there don't have the right additive mix. I don't know if they will cause long term damage but they typically are more expensive anyhow.

Used to be all cars used plain green coolant and life was good. Now it's a pain in the ***.

That said, any time I fill up coolant I get 1 jug of full strength Prestone and 1 gallon of distilled water from the grocery store. You can buy the 50/50 but you are paying extra for water - distilled water is like 90 cents at the grocery store.

Dale

 

So the car is starting and driving fine again.. It is smoking white smoke a little bit but not all tan. Maybe I’m just starting to notice it…

But as far as the coolant seal failing goes. Kennett completely fail any time? Randomly? Where it completely doesn’t start?
or is it more of a gradual failure ?

 

It doesn't get better, that's for sure. With a bad coolant seal, once the weather warms up the car will most likely overheat often. Overheat events cause more stress on the seals and can also warp rotor housings, which means it's going to cost more to rebuild.

At this point I'm 90% sure you have a bad seal. You can do some further tests to cement that to 100% but everything points that way.

It sucks, but you just have to start doing research and figure out what option is best for you and your budget.

Dale

 

So it’s gotten harder to start the car again when it’s warm... similar to before I added the hks twin power. After I added that and put new plugs and wires, the hot/warm start issue went away... but now I think the coolant seals are wearing out even more probably causing it to not start again....?

 

It'll be pretty consistent, it wont get any better. Mine was very drivable when mine went and acted very similarly to yours. I'd recommend rebuilding it sooner rather than later to save the plates from any corrosion.

 

ah bummer then... I just picked up some of my favorite wheels for the rx7. Fikse fm5

Im going to the local rx7 rebuilder soon and try to get some quotes and options. But what’s the rough estimate to rebuild? Maybe street port while at it?

while at it might as well do an upgrade in the fuel rail injectors and single turbo it...
So it’ll be a totally different car... but while the motor i out is probably the best time to work on it right 😅

 

Rebuilds can vary greatly in price, depends on who you know and where you go. Assuming you reuse your housings / rotors and take the car to someone you don't personally know (but is recommended in your area) I would expect around $3500 all said and done. Just for a rebuilt engine, no upgrades, only direct replacements.

Gotta think labor to both take the engine out and put it back in, porting work adds another ~$200, rebuild kits alone go for $600 to upwards of $1500 just for seals and what not.

Adding a single turbo conversion on top of that...it gets expensive real quick. Especially if you pay someone to do the conversion for you. Get the engine rebuilt and ported and put back in with the twins would be my advice. Once it's back together and you know its running correctly then pursue the single turbo conversion as you see fit.