picazo505

My 87 T2 recently is showing me that i am low on coolant ,so i put some coolant and i drive around everything is fine,the car does'nt overheat, but then i park it later for a couple of hours or for next day in the morning and then when i start my car it tells me that is low on coolant ,this only happens when i park but when i drive off the beeps it shut off, i dont know what the hell is going on ,i check my hoses but they seem fine i dont see any leaks in the floor when i park ,can some one help?????????

rx_7_driver

did u check the one that goes to the overflow tank?? if that one leaks even a little it won't suck the coolant back into the rad

picazo505

there is another thing i was wondering, why when i was running low on coolant my reserve was it the same level i thought that if is running low it should pull coolant from the reserve and it didnt so i look to see if it was clog up with something but no it was clean so that is another thing

The Ace

As I have found (the hard way ) this could be caused by a number of things.

Starting from cheaper to most expensive:

- Air/Coolant leak in the little hoses or heater hoses
- Malfuctioning radiator cap
- Air leak from gaskets (two of them)
- Air/Coolant leak in the main coolant hoses
- Crack in thermostat housing
- Malfuctioning thermostat
- Cracked overflow tank
- Air/Coolant leak in Radiator, or clogged radiator
- Leaking/Malfunctioning Water Pump
- Internal damage (coolant passages -> corrosion, or water seals/o-rings)

Start from the begining and work yourself down




EDIT: Of course, you can start by telling us what happens to the coolant. If you constantly lose coolant (i.e you need to add every day), then you are either losing coolant or burning it. If you are losing it, it should be an obvious leak. If you are burning it....
If the coolant goes to the overflow and stays there (it does not get sucked back in the radiator), then search for a small air leak, check the rad cap, and perform the "bubbles tes".

picazo505

the coolant goes to the overflow and stays there (it does not get sucked back in the radiator this happens to my car?

picazo505

what is the bubble test????

The Ace

If the coolant does not get sucked back in the radiator, then one of the following applies:
1) Tiny leak(s) somewhere along the coolant hoses (start from the small ones in the overflow tank and continue replacing.
2) Malfunctioning rad cap. Get a new Mazda one
3) Leaky gasket. One in the filler neck, and one in water pump
4) Leaky thermostat housing. Check with a flashlight for cracks
5) Exhaust gases in coolant Worst case scenario (same as me)

The "bubbles test" is a cheap way to diagnose the last option. Let car cool down completely. Open radiator cap and fill with coolant. Start car (with rad cap off), and the coolant will drop. Fill in some more. Wait until car reaches operating temps, and thermostat starts to open/close (you will see the coolant going up and down. Dont worry). At this point, if everything is fine, you wont see anything. BUT, if you see tiny bubbles in the coolant emerging from within the radiator (and not the bubble that is produced when the coolant reaches the top of the filler neck and goes into the overflow), this means that exhaust gases are entering the coolant passages. This is bad news.

If you see a lot of bubbles, then this is pretty much far gone, and you need a way to seal the coolant passages (I'm searching for something like this right now), or you can have your engine rebuilt (mucho dinero, and for a not so good reason). Or you can live with it, and save up for a major rebuilt or new engine....

Just to let you know, I have the same issue right now (I think...) but I get veeeeeeeerrrrrrryyyyyyyy small and slow bubbles (like one every 10 minutes). Still I have the same problem....Just replace everything else to make sure, and if it still buzzes/overheats, then find a good radiator sealant and give it a try...

EDIT: Go check my own thread about overheating ("ARRRRRRGGGGGGGHHHHH Overheated again !!!" ), read it thoroughly, rate it 5 stars so it gets archived, and take notes of the various info bits there