the coolant warning buzzer comes on after about minute of running but the goes off about 5 minutes later. Both the tank and filler necks were full. When I recheck them they need about 2 cups of water to refill. The water is going into the over flow bottle and not returning( getting over full). Both caps seem good including the return flap.
Any idea's

 

Replace the AST (radiator) cap, it is bad.

 

Yeah, it is probably a bad cap. I'd replace both the AST cap and the one on the filler neck. Replacing the one on the radiator may not be a bad idea either. If it is going to the overflow tank and not getting sucked back, that means you have a leak somewhere (usually a cap).

-Charlie

 

The hose that runs from the AST to the reservoir tank sometimes develops a small air leak, usually at the AST nipple, since there is no factory hose clamp on it. An air leak in the hose will prevent the coolant from being drawn back into the system from the reservoir tank when the engine cools down. Check the hose and install a clamp on the AST nipple. It only needs to be snug, since this hose is not pressurized.

 

Is there any way to tell if the AST cap is bad and where can I get another on just like the one that came on the AST? I have only had mine for about a year and I don't want to believe that it's bad already.

 

a good auto parts store should be able to pressure test the cap for you if you have doubts. or a repair shop

 

I have replaced both caps and still no luck?. The tube to the over flow tank seems ok.

 

I have replaced both caps and the hose to the over flow tank seems ok

 

What you are describing is also one of the early symptoms of your coolant o-rings failing. Compression leaks out of the combustion chamber into the coolant and constantly adds bubbles of gas, pressurizing the system, which forces the coolant past the rad cap into the coolant reservoir. When you turn the engine off and the engine cools, some of the vacuum required to draw the coolant from the coolant reservoir tank back into the engine is lost thru the leaking o-rings, so the coolant tank slowly fills up with each warm-up cool-down cycle. You can pay to check for exhaust gas in coolant test or do a simple test yourself. With the engine cold, run a tight-fitting hose from the fitting on the top of the filler neck (not AST) to a bottle of water. Clamp off or plug the other line to the AST so you will not have coolant backing up into the AST and running on the ground. Place the end of the hose below the surface of the water. Start the engine and observe the water bottle for bubbles coming out of the hose. As the engine initially warms up, there should be periodic streams of bubbles, as the thermostat opens, coolant expands and circulates and forces any residual air from the system. After the engine is at operating temperature, there should not be any more bubbles coming out of the hose. If there is a steady stream of bubbles coming out of the warm engine, it is from leaking exhaust gas. Only real fix is to re-build the engine. Have done so twice myself. Start with the easy fixes first (rad cap and leaky hoses), but you should also consider the worst case.

 

Agree completely, this is what happened to my engine. I had 95k miles on it so i expected something to happen soon. I could see the bubbles when i took the cap off and let the car warm up, and i had white smoke. If the crack is not big i know that on the robrobinette or sudsuneri(sp) site they had someone run sealant through the system to seal the crack, but its only a temporary fix for the rebuild.

 

word....^ what these 2 said....

i was at 132k when it happend to me.

that stuff only works for like 5-10k miles. Better start saving from now til then =/

 

39,000 miles and it happened to me.

The cool part is I had a major failure, so when I turned the engine over, it would pumb out coolant at the pressure of the engine. I was like Old Faithful going off.

 

You could do the bubble test and see (take off the cap when the engine is cold and start the motor, watch for bubbles). Replacing hoses and caps is much cheaper than replacing an engine - so don't jump to conclusions until you've looked over the system for leaks. When my cap was bad it wouldn't leak out, but it was letting air in as the system cooled.

 

Unfortunatly, you might have just joined the ranks of a lot of us here. I see the number of posts you have and assume you recently bought the car. When I bought mine, I did'nt know much about the 3rd gens other than I had owned a brand new first gen, loved it, had no problems, and this must be a newer, kickass, fast version of that. While I was looking at mine before buying, I noticed a bit of what I thought was steam rising in the engine bay. The prior owner and I dismissed it as condensation "on" the engine, from not being driven very often. Mileage.............94,700. I bought it, drove the heck out of it for 2500 or so miles, and then had a problem. One day, I left the house and the coolant buzzer was going off. Not knowing what I know now, I add some water and figure this is normal maintenance. The next 3 times I drive it, same thing, buzzer, add water. The LAST time, start it and the garage is instantly filled with so much smoke, I could'nt see my windshield wipers. I am afraid that you have learned as I have, caveat emptor. Good news is, $20,000 later in engine and mods, I still have it, love it, and would'nt consider another toy car.

 

Sooo your saying there's three caps on an FD ? ? ? Lets see one on the ast, one on the filler neck by the air pump, and one on the radiator ? ? ? ? Must be one of those aftermarket radiators.

 

The stock setup has only 2 metal pressure caps -- one on the AST and the other on the filler neck on top of the engine. Only the AST cap is a pressure-relief cap. When it relieves pressure, the surplus coolant flows from the nipple on the neck of the AST to the overflow tank. As the engine cools, vacuum draws that coolant back into the engine from the overflow tank through a return valve in the AST cap.

The overflow tank also has a cap, but it is just a plastic snap-on thing like the windshield washer fluid tanks have.

If the coolant level is rising in the overflow tank and dropping at the filler neck over time, and the hose from the AST to the overflow tank is air leak-free, the best thing is to replace the AST cap. If that doesn't solve it, you need to do the tests described earlier in this thread to see if the engine o-ring seals are failing. But first check the return hose, and then replace the AST pressure cap.

 

Iceman has detailed the proper test, which I also used to confirm seal failure. I used a clear 2L bottle with some coolant in it, bottle on top of IC duct. You want engine to heat up and get upper rad hose hot, with t-stat open. You can't just do a cold start with cap off and find small leaks.

To check for leaks in the hose to the exp tank:

There is some standard clear pvc tubing that fits just right into this hose. Check size and get about 3 ft of it at hardware store. I pull off the hose near the relief cap, stick this tubing in making sure it's a tight fit, then suck coolant up hose so it's about a foot above the engine, then, uh, seal hose with tongue tip. If return line it good, level in clear hose will not drop in a minute or three. I use a red pinch clamp (pep boys) when reconnecting this important hose to filler neck or AST.

 

I'm going through this same sort of issue right now. I am hoping that air is being sucked into the engine from a leak in the coolant system. My car has been down for a many weeks now. In my sitation, I had the coolant light/buzzer go off and all the coolant was in the reservoir tank. I had been smelling a faint smell of coolant in the engine bayFor a long time(months), but never saw a visible leak.

This last time the coolant/buzzer light went off three days in a row and on the third day on the way to work the car over heated. I was only two miles from home, so I had it towed home. I now started seeing coolant leak underneath the car on the driver's side, but I couln't find the source of the leak. I also bought new caps for the filler neck and the AST. I even rented a coolant pressure tester and dye/black light/goggles kit to find the leak with no luck. Still leaking.

I also had to change out the AST, because it wasn't holding a tight seal anymore, after I messed up the lip that held the cap on. DamonB, suggested that I just go change out ALL the coolant hoses. I changed out about 9 of the 14-15 hoses that Ray at Malloy sent me and pressure tested the system. Now, I had an even faster leak. Pouring actually down the front of the block. So, this weekend I am going to install a new waterpump and gaskets.

I hope that this is the solution to my nightmare.

Goog luck to you.

 

your TONGUE TIP? i can't be hearing this. getting coolant on your tongue/ingesting coolant is not good, it can make you sick + it can be fatal. i hope that was a joke.

edit:

isn't a radiator/coolant system pressure test a easier way to check the coolant seal/ring integrity.

 

japndes - have you you figured out the problem with your car?

 

i had a similar problem.. was the radiator or ast cap... replaced both

 

Coolant seals for me... but I've been running like that for ~15K miles