So I was at work and when I had to go get drug tested, I started the car and it was hard to start and shuttered. I had to gas it to keep it going. After 30 seconds or so it was good. After my test it wouldn't start, so I changed the plugs and it started right up. It was flooded. But, I noticed my coolant overflow bottle was 3/4 full, way above the 1/2 way mark. ?????? Even after cool, it remained above 3/4. What caused that? It has a new rad cap about 2 months old.

90' Vert mtx

 

overflow bottle getting full and not going back in is a sign of bad coolant seals alot of the time. hows your temps?

 

Most likely a leak in the cooling system. Pressure test it at 15+'psi and you should find the leak. If you don't find a leak, replace the hose from the rad to the overflow tank.

 

I was afraid to hear this--Coolant seals. First, I'll buy a pressure tester like suggested to check it first.

Would the car still run good if the seals were bad though? Once struggling through starting, it runs fine.

Temps are midrange on the gauge like normal, but unfortunately I took the Buzzer out so I get no warning of low coolant. I have an infrared temp tool that shows around 190-199F water temps ay the top hose

Thanks for the inputs!

 

NO..Don't Scare the guy off EFF!...haha!
The overflow bottle Getting full and Coolant not going back in,could be a sign of the Hose from the Rad to the Bottle,or the hose from on the inside if the jug having a small leak in it,or being disconnected inside the Jug.
The Rad cap opens a bit once the coolant has expanded in the cooling system and makes it's way to the Overflow jug.IF the hose in between the Jug and the Rad are not adequate.,the Cooling system can't Take the Coolant Back into the System.
So it will stay in the Jug.

 

I'll check things out this weekend. Up until the other day, the coolant overfill bottle has been at the right levels (I changed the w/p a few months ago and routinely check it (overflow bottle)). So, I think the hose is good and no leak in the bottle. But I'll check this weekend. OBE right now.

 

I personally would get a Temp gauge in that car if you have no Sensors to tell you what is going on.
25 Bucks will save you 2k.
You "could have" also had a Little air in the system that pushed some coolant out.Then again it should have sucked coolant back in,and your overflow bottle would have been lower than before.
.Just keep checking the level On the rad,and at the water thermo neck for Inconsistencies. If you are Really Freaking out,try doing a compression check or a Cooling system Pressure test to see if the Engine is OK.That will tell you all you need to know,and either put you at ease or Break the bank!
By the way.What BRAND of Rad cap did you replace the old one with?
STANT is crap for these cars..( crazy but the OEM stuff is Recommended for the Cap and the Thermostat).

 

I have a factory OEM cap. I agree, I need to get a temp gauge. Any recommendations on brand, part number?

I might throwout I replaced the w/p, radiator and cap all within this year. All mazda parts.

 

best way is to pressure check for leaks. its very easy, and then you can actually replace the part that is bad, instead of just buying stuff and hoping...

for gauges i like the greddy ones, but its up to you really. i also like to buy the little pipe HKS and greddy sell to mount the sender, it makes the install much simpler.

 

Autozone and Oriellies loan pressure testers. I borrowed one last week to find a leak in my kid's '87 gxl

 

about the starting and running issue, change your coolant temp sensor in the back of the water pump. this is what tells the computer to mix the air/fuel ratio properly at certain operable temps. when it fails, you either get too much fuel or not enough and the air flow meter cant keep up with it.
our air flow meters are a bad design. flap is not very accurate, so we have to rely on other parts of the system to correct our problems.
wish there was a mod that wasnt so expensive so we could have a wire resistor sensor instead. this would make our fc problems alot easier to diagnose properly.

 

Well, it started right up and ran until operating temp. Coolant bottle didn't fill up this time like it did before?? You may be right about the coolant sensor. The connector was broke when I changed the w/p awhile back so I had to tape it. It may be loose. Maybe it give intermitant contact?

Time to go online to research water temp gauges.

 

Weird, this morning it started but it was right up. I smell gas in the vents. No sign of fuel leakage. Do you think it might be the ECU dumping too much fuel intermitently?? I would say leaking injector, but it didn't happen last night?

 

If you smell gas get to the engine bay and start inspecting right away, dont procrastinate on that one or it can bite you in the *** quick.

 

+1

You need to figure out 2 things...

1) Where the gas smell is coming from

2) repair


Yes, they start up rich and gassy smelling, but you shouldn't be smelling fuel from your vents!

If you can't figure it out, take it to a rotary shop. I can promise that if you don't, your RX7 will burn to the ground.

 

that's a bit drastic to say, since we don't have that much info about the car.

my car smells like a gas station when i start it but then again, that's normal for it.

even with cats installed it will smell a bit like raw fuel on first startup, sometimes people just don't notice it until they're looking for problems.

 

I know it is a bit drastic, but it can sometimes be better to fear the worst than hope the best and have an engine bay fire.