beautiphu

Hi guys,

I've a new engine, and with the AST deleted. When the engine is cold, the coolant level sits about an inch below the top of the filler neck. Is this normal? Shouldn't the level go all the way to the top?

On shutdown, I hear a slight gargling noise, and I've been topping it with more coolant but it still drops to that level overnight. Any ideas?

Thanks.

CantGoStraight

My guess is your over flow tank is getting fuller and fuller, and soon you will be getting coolant on the ground. Sounds to me like your cooling system isn't drawing the fluid back in when it cools.

rotarypower101

iTrader: (1)

That looks like an old coolant cap with side grips “wings” replace it and see if the problem persists. They can leak air when the rubber gets old and hard

How is the overfill tank hooked up? Which nipple are you using?
Are you pressurizing the coolant system?

beautiphu

Actually for the AST elimination, there's an adaptor that sits where the cap is (not shown). The adaptor has a nipple that goes into the overflow tank, and the nipple on the filler neck is connected to the radiator.

The engine is in the car, and on shut down I hear gurgling noises. But not while running.

Axis8758

I have this problem as well. I have replaced my filler cap, the AST cap and the coolant line from the AST to the over flow tank. I did notice that I was leaking coolant from the overflow the last time I drove it.

RX7 RAGE

iTrader: (22)

So did replacing all 3 things fix the problem?

sferrett

The gurgling after you shut off is the coolant boiling, it's pretty normal.

Sled Driver

iTrader: (9)

The thermostat housing has a internal chamber connected via the nipple to the AST . This chamber only has a hole near the top of the thermostat neck (the nipple located near the bottom).

After I installed the AST elimination kit I also drilled a large 3/4" hole (down the thermostat neck) to allow this chamber to drain & coolant to flow freely through.

Without the hole the coolant is stagnant inside chamber & actually takes away capacity away from the thermostat housing.

After the mod there is still around 1/2" of air after you remove the radiator cap, but now the entire thermostat housing capacity is used.

4Fun

iTrader: (8)

Sled.
Do you have pics of what you did?

Sled Driver

iTrader: (9)

Basicly you can do this the next time you remove the thermostat housing to replace the thermostat.

Look straight down the filler neck & you will see seperate cavity with the drain hole at the top.

I used a drill press & clamped up the housing to hold it steady.

Starting with a small drill I worked my way up to a 3/4" bit.

Im sure you could use a smaller drill or drill more than one hole to achive the same result.

After you drill out the housing you need to clean out the metal shavings. That's why I removed the housing 1st.

I also removed the AST nipple from the housing & had the hole welded up while I had it off.

Axis8758

Nope.....Thinking that maybe the motor is on it's way out.

beautiphu

As it turns out after I replaced the radiator cap, the water level went to the top. So the old cap wasn't holding pressure and wouldnt draw back the coolant from the overflow bottle. Although I still hear a little of gurgling on shutdown. I guess that's normal (this is a new engine) and maybe I should put back the AST after all.

sferret, so do you have the AST or not? When I bought the car, the previous owner removed the AST, and my mechanic told me that there will always be a little bit of air in the system because of the removed AST, and so it might boil a little.

rotarypower101

iTrader: (1)

Good, I thought that might be it.

I was wondering how you were doing a AST elimination without a different setup than the pic!
As long as it is holding pressure and the coolant doesn’t need to be refilled after every drive it is probably operating correctly.