I have a slow coolant leak, gallon every two weeks. at first it was the radiator - had it replaced, then hose connectors on top of engine - had them replaced, then bad connection on radiator hose - had it replaced. Still losing coolant. I am looking for a diagram of the cooling system so that I can try and trace where the leak might be.

Half a gallon a week? Bad for the car, bad for the pocketbook.
Have a shop do a pressure test of your coolant system to check for leaks. You might also want a block test where they check for exhaust gases getting into the coolant system-maybe your coolant is getting into a cylinder and burning off. How does the car run? any white smoke out the exhaust? Or signs of overheating?
That's kind of a worst-case scenario (head gasket problem, or cylinder head problem), but that's an awful lot of coolant loss, and it's got to be going somewhere.
Good luck.

CAR OVERHEATING FIRST CHECK FOR LOW COOLANT IN THE RADIATOR COOLANT OVERFLOW JUG.IF COOLANT LEVEL IN OVERFLOW JUG LOW REFILL ADD COOLANT BACK TO THE FULL COLD MARK.PUT RADAITOR CAP ON COOLANT OVERFLOW JUG START ENGINE LET IT IDLE UNTIL IT OPERATING TEMPERATURE.MAKE SURE TOP RADIATOR HOSE GETTING HOT WHILE ENGINE WARM UP.IF TOP RADIATOR HOSE DONT GET HOT WHILE ENGINE IDLING YOUR THERMOSTAT COULD BE STUCK CLOSE CAUSING CAR TO OVERHEAT.IF TOP HOSE IS GETTING HOT.CHECK FOR COOLANT LEAKS CHECK TOP RADIATOR HOSE AND BOTTOM RADIATOR HOSE FOR LEAKS.CHECK FOR LEAKS AT THE RADIATOR CORES AND PLASTIC SIDE CONTAINERS.IF ALL IS GOOD ENGINE OVERHEATING WHILE IN A LONG TRAFFIC LINE, COOLANT FANS NOT COMING ON.COULD HAVE FAULTY ENGINE COOLANT TEMPERATURE SENSOR OR BLOWN COOLING FAN FUSE OR RELAY.COULD HAVE PCM FAULT.MAKE COOLING FAN ELECTRICAL CONNECTORS AND WIRING NOT DAMAGE OR BROKEN.

WELL YOU NEED TO DRAIN COOLANT LEVEL BELOW THERMOSTAT LEVEL.YOU HAVE TO DISCONNECT MAF SENSOR LOOSEN AIRDUCT 2 LARGE CLAMPS LOOSEN REMOVE 4 SCREWS TO AIR FILTER COVER LIFT UP REMOVE COVER. THEN REMOVE AIR FILTER AND HOUSING, FIRST DISCONNECT MAF SENSOR.YOU HAVE TO DISCONNECT THROTTLE CABLE AND SHIFT CABLE.YOU HAVE TO DISCONNECT REMOVE THROTTLE BODY COOLANT HOSES DISCONNECT IDLE SPEED CONTROL VALVE CONNECTOR AND DISCONNECT TPS SENSOR CONNECTOR. THEN REMOVE THROTTLE BODY ASSEMBLY. YOU NEED TO BUY NEW THROTTLE BODY COOLANT HOSES AND NEW THROTTLE BODY GASKET FOLLOW TOP COOLANT HOSE TO ENGINE BLOCK.NOW YOU SEE CAN AND REMOVE THE THERMOSTAT HOUSING REPLACE THE THERMOSTAT.BESURE TO HAVE EXTRA COOLANT ON HAND.BLEED COOLANT SYSTEM WHEN DONE.TO BLEED COOLANT SYSTEM REMOVE RADIATOR CAP ON OVERFLOW JUG.THEN OPEN BLEED SCREW ON THE WATER PUMP BYPASS HOSE PIPE JUST A LITTLE.POUR COOLANT IN THE OVERFLOW JUG UNTIL LEVEL STOP DROPPING.STOP AT COLD MARK ON JUG.CLOSE BLEEDER SCREW ON WATER PUMP BYPASS HOSE PIPE.CRANK VECHICLE CHECK FOR LEAKS. START UP ENGINE LET IDLE FEW MINUTES THEN CHECK COOLANT LEVEL ADD MORE UNTIL UNTIL LEVEL STOP DROPPING.PUT RADIATOR CAP BACK ON OVERFLOW RESERVOIR. LET ENGINE IDLE WATCH COOLANT TEMPERATURE GAUGE.WHEN GAUGE START CLIMBING. TURN OFF ENGINE WAIT FEW MINUTES TAKE A LARGE RAG OPEN RADIATOR JUST A LITTLE YOU HEAR HISS NOISE.WHEN PRESSURE STABILIZE DONT GET SCALDED BECAREFUL.OPEN CAP LITTLE MORE.IF COOLANT PRESSURE STILL BOILS OUT WAIT 20 MINUTES ADD MORE COOLANT TO RADIATOR OVER FLOW WHEN COOLANT LEVEL STOP DROPPING.PUT RADIATOR CAP BACK ON START VECHICLE UP LET IDLE UNTIL THERMOSTAT OPEN. THEN FEEL TOP RADIATOR HOSE FEELS HOT THERMOSTAT OPEN WATCH TEMPERATURE GAUGE.IF GAUGE TEMP START CLIMBING TURN OFF ENGINE WAIT A WHILE.CHECK AND ADD MORE COOLANT.WHEN THE ENGINE CAN IDLE TEMP GAUGE STOP CLIMBING YOU HAVE BLEED COOLANT SYSTEM.KEEP CHECK ON COOLANT LEVEL.

Turn off the engine as soon as you suspect a leak, to prevent the engine from overheating.

2 Determine which radiator hose is leaking and exactly where the leak is coming from by looking for wetness.

3 Purchase 1 gallon of antifreeze and the correct replacement radiator hose from your local auto-parts store or dealer. (Radiator hoses are not interchangeable. They come in specific sizes and shapes for your particular car model.)

4 Wait for the engine to cool down for at least 20 minutes, before beginning any work on the cooling system.

5 Place a large pan or wide bucket on the ground under the hose to catch the coolant.

6 Use a screwdriver to loosen the hose clamps at both ends of the hose you are replacing.

7 Remove the radiator hose by twisting and pulling where it connects to the radiator and engine. If the hose won't budge, use a utility knife to cut it off the fittings.

8 Remove the hose clamps from the old radiator hose and slide them onto the new hose.

9 Put the new radiator hose on. Spray the inside of the hose ends with WD-40 if the hose is hard to get on. Tighten the hose clamps.

10 Refill the radiator and the coolant reservoir with a 50-50 mixture of water and antifreeze.

11 "Burp the cooling system" by running the engine with the radiator cap off until the engine warms up. Keep the engine running until both the upper and lower radiator hoses feel warm (this indicates that the thermostat is open and the coolant is flowing through the entire system). Burping the cooling system allows any air bubbles to escape. Add coolant to the radiator as needed.

12 Look for leaks. Inspect around the hose clamps for dampness. Tighten the hose clamps if there is any wetness.

13 Put the radiator cap back on.

14 Check the coolant level after driving, to ensure there are no leaks

ENGINE NOT GOING TO START IF GET TOO HOT FIRST THING I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP THEN ADD COOLANT UNTIL COOLANT LEVEL CORRECT THATS WHEN THERMOSTAT OPEN UP AND TOP HOSE HOT.CHECK FOR LEAKING RADIATOR HOSES CHECK TOP RADIATOR HOSE CHECK BOTTOM RADIATOR HOSE.CHECK FOR LEAKS AROUND THE RADIATOR LOOK DOWN BELOW COOLANTS FANS CHECK FOR LEAKS AT RADIATOR CORES OR LEAKS AT THE RADIATOR PLASTIC SIDE CONTAINERS. CHECK FOR LEAKS AT WATER PUMP WEEP HOLE AND CHECK FOR LEAKS AT THE HEATER HOSES AROUND ENGINE BLOCK TO THE HEATER CORE HOSES. THERE IS A REASON CAR OVERHEAT.IF CAR OVERHEAT WHILE DRIVING YOU HAVE FAULTY THERMOSTAT OR LEAKING OUT COOLANT OR BLOWN HEAD GASKET.IF ENGINE OVER HEAT WHILE SITTING DURING A LONG IDLING PERIOD.YOU COULD HAVE FAULTY COOLANT TEMPERATURE SENSOR OR FAULTY COOLING FAN FUSE OR RELAY.HOT WIRE COOLANT TO SEE IF IT RUNS IF NO REPLACE FAN MOTOR. IF YES FAN MOTOR COULD HAVE FAULTY WIRE OR PCM FAILURE. CHECK ENGINE CRANKCASE IF OIL LOOKS LIKE MILK SHAKE ENGINE HEAD GASKET LEAKING.

TO CHANGE RADIATOR FIRST YOU TURN OFF RADIO FIRST TO KEEP FROM LOSING RADIO CODE.DISCONNECT NEGATIVE BATTERY CABLE.RAISE FRONT OF VECHICLE SUPPORT ON JACK STANDS.REMOVE THE LOWER SPLASH SHIELDS.NOW YOU NEED TO DRAIN THE COOLING SYSTEM.CATCH COOLANT IN A LARGE DRAIN PAN.REUSE COOLANT IF ITS FAIRLY NEW.IF COOLANT VERY OLD CHANGE IT.PUT OLD COOLANT IN SOME EMPTY CONTAINER TAKE TO A GARAGE OR WHOEVER DISPOSE IT.DONT POUR ON GROUND.HARMFUL TO THE ENVIRONMENT.MOVE THE AIR INTAKE DUCT PASSES OVER THE TOP RADIATOR HOSE.NOW WHEN ALL COOLANT DRAIN OUT.LOOSEN UPPER AND LOWER RADIATOR HOSE CLAMPS.THEN DETACH THE RADIATOR HOSES FROM THE FITTINGS.IF THEY ARE STUCK GRASP EACH HOSE NEAR THE END WITH A PAIR OF ADJUSTABLE PLIERS AND TWIST IT TO BREAK THE SEAL THEN PULL IT OFF REMOVE SMALL COOLANT SURGE LINES FROM TOP OF RADIATOR THAT GOES TO THE OVER FLOW RESERVOIR..DISCONNECT COOLING FAN ELECTRICAL CONNECTOR.THEN REMOVE THE COOLING FAN.REMOVE DISCONNECT AUTOMATIC TRANSMISSION COOLER LINES GET READY TO CATCH TRANSMISSION FLUID THEN PLUG LINES. NOW UNSCREW THE FOUR BOLTS TWO ON EACH SIDE OF THE RADIATOR THAT ATTACH RADIATOR TO THE AIR CONDITIONER CONDENSOR CAREFULLY TIP TOP OF THE RADIATOR SLIGHTLY TOWARDS THE ENGINE.REMOVE THE UPPER RADIATOR SEAL AND LIFT RADIATOR FROM THE ENGINE.NOW IS THE TIME TO REPLACE THE UPPER AND LOWER RADIATOR HOSES WITH NEW ONES SINCE ALL COOLANT REMOVE I WOULD REPLACE THERMOSTAT AND RADIATOR PRESSURE CAP.NOW WHEN YOU GET READY TO INSTALL NEW RADIATOR USE SHEETS OF CARD BOARD PROTECT RADIATOR FINS AND CORES FROM DAMAGE WHILE SITTING RADIATOR BACK IN PLACE.ONCE YOU GET UPPER AND LOWER HOSES IN PLACE ALSO PLACE SMALL SURGE HOSES FROM THE OVER FLOW RESERVOIR TO RADIATOR NEW THERMOSTAT AND TRANSMISSION COOLER LINES ALL HOOK UP. START POURING ANTIFREEZE IN THE RADIATOR OR OVERFLOW RESERVOIR IF RADIATOR DONT HAVE RADIATOR CAP ON IT.POUR A FULL GALLON ANTIFREEZE AND A HALF MORE IF LONG AS THE COOLANT STAYS ON THE COLD LEVEL MARK ON OVERFLOW RESERVOIR DONT OVER FILL.IF YOU POUR ANTIFREEZE IN RADIATOR KEEP POURING ANTIFREEZE UNTIL LEVEL STOP DROPPING AND LEVEL OFF AT RADIATOR TOP.START ENGINE CHECK FOR LEAKS. LET ENGINE RUN UNTIL IT WARM UP TOP RADIATOR HOSE GET HOT.WATCH COOLANT LEVEL IN RADIATOR OR COOLANT OVERFLOW RESERVOIR WHEN THERMOSTAT OPENS COOLANT LEVEL WILL DROP.ONCE YOU HAVE ENOUGH COOLANT IN THE SYSTEM COOLANT LEVEL WILL STOP DROPPING.THEN YOU READY TO GO.LET ENGINE SIT A LITTLE WHILE CHECK COOLANT LEVEL AGAIN.COOLANT LEVEL IN THE OVER FLOW RESERVOIR SHOULD BE AT HOT MARK FOR HOT ENGINE AND WHEN ENGINE COLD COOLANT LEVEL SHOULD BE AT THE COLD MARK.IF POUR ANTIFREEZE IN THE RADIATOR COOLANT LEVEL SHOULD BE AT TOP OF RADIATOR BELOW PRESSURE CAP.

BUY YOUR RADIATOR HOSES FIRST MAKE SURE NEW HOSES MATCH THE OLD HOSES. BUY NEW RADIATOR CLAMPS AND HAVE EXTRA GALLON OF ANTIFREEZE. MAKE SURE ENGINE IS COOL IF YOU GOING TO CHANGE TOP RADIATOR HOSE REMOVE RADIATOR CAP OR OVER FLOW JUG CAP IF YOUR RADIATOR DONT HAVE RADIATOR CAP FIND RADIATOR DRAIN PLUG.PLACE A CATCH PAN.OPEN RADIATOR DRAIN PLUG CATCH ANTIFREEZE. DRAIN HALF ANTIFEEZE IF YOU GOING TO REPLACE TOP HOSE AND DRAIN OUT ALL ANTIFREEZE IF YOU GOING TO CHANGE LOWER COOLANT HOSE TO WATER PUMP.WHEN DONE CLOSE DRAIN PLUG.PUT ANTIFREEZE IN A SAFE PLACE FROM PETS AND KIDS UNTIL JOB DONE. WHEN YOU REMOVE COOLANT REMOVE WATER HOSE CLAMPS THEN REMOVE RADIATOR HOSES PUT NEW RADIATOR HOSES AND CLAMPS ON HOSES TIGHTEN HOSE CLAMPS DONT OVER TIGHTEN. POUR ANTIFREEZE IN RADIATOR.CRANK ENGINE UP CHECK FOR LEAKS.CHECK COOLANT LEVEL WHEN THERMOSTAT OPENS ADD MORE COOLANT AS NEEDED.

Follow the top radiator hose UNTIL it reach a metal neck-like- thing.Disconnect to hose Follow the neck to where it connects to the thermostat casing. Un screw the two bolts and and remove the thermostat from the casing.. You'll have to remove the air intake

Drain about 1 gallon of coolant from radiator Follow upper radiator hose to engine housing Remove 2 bolts on housing--make note how thermostat is installed Clean both surfaces completely Install new gasket and thermostat Tighten both bolts evenly and securely Re-fill radiator slowly to prevent "airlock" Check for leaks Start engine with heater on Run to normal operating temp Check coolant level

Was the cap on correctly when you opened up to refill it? To verify a leak clean up any residue that is on the engine etc and let it sit...then check for anything on the ground, chassis and at any hose connections. Check for leaks cold and hot. When hot there is pressure in the system and may reveal leak, however, many water pumps leak better cold with the cap removed (pressure actually will push the seal against the shaft and stop it from leaking) " It's leaking and I don't know where" isn't a statement I'd ever permit to pass me by...My next question would be, show me where. That does nothing to instill confidence in that shop.
One note: if it does turn out to be a pinhole in the radiator, believe it or not, a tablespoon of black pepper actually works. Just don't use more than two.

i think its going to be the head gasket duto the way its leaking coolant. one of the water jackets maybe i would have it checked to be sure but it sounds like head gasket