I have a coolant leak in my 1995 sonata and was told it was coming from the pipe that is attached to the lower radiator hose at one end and runs under air intake and goes to the water pump. my problem is that i can't find the technical name for it anywhere to be able to nuy a replacement pipe. if you can help me with this matter i would greatly appreciate it.

I ASSUME you are leaking from the engine, not the radiator? These engines have a tube running from a radiator hose to the back of the water pump. The pipe is 2 pieces. if thats what is leaking buy new pipes from the dealer with all o rings (2) . Theres also a BY PASS hose on the end of the pipe, replace that also. You should be able to replace them without taking off the intake manifold. They usually last forever unless you have not been keeping good coolant/ anti freeze.

2.2L Engine

1. Disconnect the negative battery cable.
   
2. Properly drain and recover the coolant until the level is below the thermostat.
   
3. Unfasten the coolant outlet-to-inlet manifold attaching bolt and nut, then remove the outlet.
   
4. Remove the thermostat. Clean the inlet manifold and outlet mating surfaces.

To install:

1. Install a new O-ring onto the thermostat
   
2. Place the thermostat in the inlet manifold.
   
3. Attach the coolant outlet to the inlet manifold, using the bolt and nut. Tighten to 89 inch lbs. (10 Nm).
   
4. Refill the engine cooling system.
   
5. Connect the negative battery cable, then start the engine and check for coolant leaks.
   

Fig. 1: The thermostat is located in the lower radiator hose on the 2.2L engine (click image for zoom)



2.3L and 2.4L Engines
(see Figure 7)

When adding coolant, it is important that you use GM Goodwrench DEX-COOL® (orange colored, silicate free) coolant meeting GM specifications. On these vehicles, if silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner; at 30,000 milee or 24 months.

1. Disconnect the negative battery cable.
   
2. Properly drain and recover the coolant to a level below the thermostat.
   
3. Unfasten the cover-to-outlet pipe bolt, which is accessible through the exhaust manifold runners.
   
4. Raise and safely support the vehicle.
   
5. Disconnect the radiator and heater hoses from the outlet pipe.
   
6. Unfasten the outlet pipe-to-oil pan bolt and the cover-to-outlet pipe bolts.
   
7. Remove the thermostat, then clean the old gasket material from the mating surfaces.

Fig. 7: Thermostat removal and installation-2.3L and 2.4L engines

To install:

1. Position the thermostat in ite correct location, then install the cover-to-outlet pipe bolt. Tighten the bolt to 10 ft. lbs. (14 Nm).
2. Install the outlet pipe-to-oil pan bolt. Tighten the pipe-to-oil pan bolt to 19 ft. lbs. (26 Nm) and the pipe-to-transaxle bolt to 40 ft. lbs. (54 Nm).
   
3. Connect the radiator and heater hoses to the outlet pipe.
   
4. Carefully lower the vehicle.
   
5. Install the cover-to-outlet pipe bolt through the exhaust manifold runner.
   
6. Properly fill the cooling system, then connect the negative battery cable.

Hope helps (remember to rate and comment this answer).

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

Please see my tip at http://www.fixya.com/cars/r5973094-starter_replace . These are generic instructions. Specific instructions from autozone.com are pasted below. Let me know if you have questions.

1995-96 VEHICLES

See Figure 13

1. Disconnect the negative battery cable.
2. Remove the upper mounting bracket above the radiator.
3. Detach the electrical connections at the coolant fan, then remove the fan.
4. Disconnect the upper and lower oil cooler pipes from the radiator.
5. Raise and safely support the vehicle.
6. Unfasten the retainers from the engine harness and position them away from the starter.
7. Disconnect both lower oil cooler hoses from the radiator.
8. Detach the starter electrical connections.
9. Remove the upper flywheel inspection cover.
10. Unfasten the mounting bolts/screws, then remove the starter and shims (if used) from the engine.

Fig. Fig. 13: Starter motor mounting-1996 3.8L engine shown

To install:

1. Position the starter and shims (if used) to the engine, then secure with the mounting bolts/screws. Tighten to 32 ft. lbs. (43 Nm).
2. Attach the electrical connections to the starter. Tighten the solenoid battery terminal outside nut to 12 ft. lbs. (16 Nm). and the solenoid "S'' terminal inside nut to 22 inch lbs. (2.5 Nm).
3. Position the upper inspection cover, then secure with the retainers to 89 inch lbs. (10 Nm).
4. Attach both lower oil cooler hoses to the radiator.
5. Fasten the engine wire harness and retainers.
6. Carefully lower the vehicle.
7. Attach the oil cooler pipes to the radiator.
8. Install the coolant fan and attach the electrical connectors.
9. Install the upper engine mounting bracket and tighten the bolt/screws to 32 ft. lbs. (43 Nm).
10. Connect the negative battery cable, then check the engine oil level and add as necessary.

1988–91 Models

1. Disconnect the negative battery cable.
2. Properly drain the cooling system into a suitable container.
3. Disconnect the fan motor and motor connector.
4. Disconnect the upper and lower radiator hoses.
5. Disconnect and plug the automatic transaxle cooling lines at the radiator, if equipped.
6. Disconnect the coolant reservoir overflow hose.
7. Remove the radiator attaching bolts and brackets.
8. Remove the radiator with the cooling fan attached.
9. Remove the cooling fan and shroud from the radiator. NOTE: Check all cooling system hoses for any signs of damage, leaks or deterioration and replace if necessary. To install:
   
10. Attach the cooling fan and shroud to the radiator and install the assembly.
11. Attach the radiator bolts and brackets. Tighten the radiator bracket bolts to 7 ft. lbs. (10 Nm).
12. Connect the coolant reservoir overflow hose.
13. Connect the automatic transaxle cooling lines to the radiator, if equipped.
14. Connect the upper and lower radiator hoses.
15. Connect the fan motor and thermo-switch wire connector.
16. Refill the system with the proper type and quantity of coolant, check for leaks and bleed the cooling system.
17. Reconnect the negative battery cable. Fig. 7: Cooling system components — 1988–91 engines
    

1992–95 Models

1. Disconnect the negative battery cable.
2. Properly drain the cooling system into a suitable container.
3. Disconnect the fan motor and motor connector.
4. Disconnect the upper and lower radiator hoses.
5. Disconnect and plug the automatic transaxle cooling lines at the radiator, if equipped.
6. Disconnect the coolant reservoir overflow hose.
7. Remove the radiator attaching bolts and brackets.
8. Remove the radiator with the cooling fan attached.
9. Remove the cooling fan and shroud from the radiator. NOTE: Check all cooling system hoses for any signs of damage, leaks or deterioration and replace if necessary. To install:
   
10. Attach the cooling fan and shroud to the radiator and install the assembly.
11. Attach the radiator bolts and brackets. Tighten the radiator bracket bolts to 7 ft. lbs. (10 Nm).
12. Connect the coolant reservoir overflow hose.
13. Connect the automatic transaxle cooling lines to the radiator, if equipped.
14. Connect the upper and lower radiator hoses.
15. Connect the fan motor and thermo-switch wire connector.
16. Refill the system with the proper type and quantity of coolant, check for leaks and bleed the cooling system.
17. Reconnect the negative battery cable. Fig. 8: Cooling system components — 1992–95 engines
    

The coolant light is warning low coolant level. If left unchecked then overheating will follow. Find out where the coolant is leaking from. Look around the engine bay for a brown stain in a arc perpendicular to the water pump pulley. Water pumps as they age often leak through the water seal at the centre and as the engine runs this water spins off the pulley around the engine bay. Check all pipe unions and the radiator core for leaks. Then check the interior heater unit supply and return pipes and unions - check the foot well carpets fro tell tale dampness. Check the filler cap rubber seal is good - enough to hold the coolant pressure. Check the inside of the oil filler cap for white mayonnaise build up - if there is it could be head gasket leak. Lastly check the exhaust for white gases (steam) and remove the plugs one at a time to check them. If water leaks into a cylinder(s) the plug(s) will look clean

If you're running it without a thermostat it's clear there isn't enough/any coolant circulating through the block. When the motor is running are the hoses off the radiator soft and flexible or stiff. If they're soft there's no coolant flowing through them. Chances are the radiator core is bad or there is a crack in it somewhere. Have it removed and tested.

Work on the vehicle cold!! Top radiator hose on this connects to the coolant filler cap gooseneck(no thermostat in here as this is an outlet). The thermostat housing is on the RH side of the engine above the transmission which is the inlet. You will see the LOWER radiator hose running to a pipe and at the end the pipe its connected to the gooseneck (thermostat housing). This is the thermostat location. Be careful with the connectors to the sensors, they may be brittle and will break easily. Hopefully this helps

First, plastic tube may be the overflow vent from the coolant bottle.Check to see where the attached end goes. You are going to have to check engine for coolant leaks (carefully refill system without spilling anything, then look for dripping anywhere. Look for leaks from all hoses, fittings radiator, water pump etc) After checking for leaks, start it up and check again (watch where you put your hands though) While running, check that the fan comes on when the vehicle reaches operating temp.(no fan, check fan motor, sensor & relay) Turn the heat on (does it have heat?) Check temp of lower hose and upper hose. If overheat happens, is lower hose still cold? (likely bad thermostat). If you found a leak, replace whatever is leaking...best insurance is to change thermostat after any overheat. Last, is there any white smoke from tailpipe, does engine run rough? If so, could be a failed head gasket or crack in cylinder head. (at this point last thing to worry about unless there is excessive smoke or rough run or oil in radiator or coolant in oil).

Hello **** B. First double check the hose connection for the leak, it can drain to another connection & appear to leak there. Second, yes there is a gasket on the pipe connection to the block. To replace the gasket, park the car in a location for least 5 to 6 hours to cool down mabe longer. Have the gasket replacement, a tube of gasket sealant, 2 gallons of antifreeze, a drain bucket, and a very large rag or rags. Remove the hose, catch the fluid in bucket, remove the pipe, clean the old gasket area, apply gasket sealent, attache gasket, mount the pipe, tighten all mounting bolts a 1/2 to 3/4 turn each until torqued downed evenly, and attache hose. Fill reservoir, with radiator cap off, start engine and add coolant to radiator until full and you see fluid flowing. Apply cap & check for leaks. Easy???????? Good Luck.