Repair And Fix it

Park the vehicle on a flat surface and apply the parking brake. Open the hood (even if the vehicle is being lifted to test the manifold, the open hood will offer more lighting to see better underneath the vehicle). If there is no need to lift the vehicle to test the manifold to block connection, proceed to Step 4.

Place a wheel chock against the outer tread of one of the rear tires for extra protection (if lifting the vehicle).

Hoist the front of the vehicle up with a jack and place it onto jack stands (one side at a time).

Put on the safety glasses and gloves and then start the engine.

Put the stethoscope on (and crawl under the hoisted vehicle, if applicable) and run the tip of the stethoscope along the manifold to engine block connection. Be aware of moving engine parts and loose fitting clothes; especially if testing from the engine compartment area. Also be aware that it will not take long for the front exhaust system to get extremely hot. Be sure arms and hands are well covered and protected.

Check the manifold to engine block connection thoroughly. The moment the tip of the stethoscope gets near a leak, the sound will intensify greatly. Check for leaks in other locations along the manifold to block connection and even check the front exhaust pipe to manifold connection.

Turn on your Toyota Corolla and wait three to four minutes for the engine to warm up.

Push the "A/C" button, then adjust the fan strength as desired with the dial.

Determine whether the A/C is working by feeling the air coming out of the vents. If the air isnt cold within a minute or two, the A/C system in your Corolla needs repairing.

Locate the tailpipe section of your emissions test results.

Find "HC PPM" within the tailpipe section. You read this as hydrocarbon parts per million, and it means the number of hydrocarbon molecules for every million molecules emitted through the exhaust.

Determine whether you pass or fail the HC PPM part of the test. The number of hydrocarbons allowed varies from state to state, but generally for vehicles made after 1994, your vehicle will need an HC PPM reading of below 50.

Interpret the HC PPM reading. If you fail the HC PPM part of the test, it could mean that there is a problem with the carburetor, fuel injection system or oxygen sensor, or that the engine oil is diluted or the air cleaner is dirty.

Disconnect the hydraulic hoses at the cylinder. Cap the cylinder and hoses with the correct size JIC caps and plugs. Remove the hydraulic cylinder from the equipment and place it on a work bench with the service ports facing up.

Remove the JIC caps from the cylinder service ports and fill both sides of the cylinder with clean hydraulic fluid. Connect one of the hydraulic pressure gauges to the service port of the blind side of the cylinder using a T-fitting. Connect the T-fitting to one of the outlet ports of the directional valve.

Connect a T-fitting to the service port of the piston side of the cylinder. Connect the other side of the T-fitting to the other ball valve and then to the other outlet port of the directional valve. Connect the third side of the T-connector with a short piece of hose to another T-connector. Install the hydraulic pressure gauge to one port of the last T-fitting and the other port to the pressure relief valve.

Connect a hydraulic hand pump to the inlet port of the directional valve following the manufacturers instructions. Open both ball valves and stroke the cylinder in each direction to remove all air from both sides of the cylinder. Position the piston rod mid-way and close the ball valve on the blind end of the cylinder.

Back out the adjustment on the pressure relief valve all the way. Set the directional valve to divert flow to the rod side of the cylinder. Activate the hydraulic pump and slowly turn in the pressure relief adjustment until the gauge pressure on the rod side of the cylinder equals the rated pressure of the cylinder.

Close the ball valve on the rod side of the cylinder and stop the hydraulic pump. Record the readings on both hydraulic gauges over time and observe any changes. Depending on the design of the cylinder, the rod side of the cylinder can be as much as twice the pressure of the blind side of the cylinder. If there are any differential pressure changes over time, then there is a problem with the piston or cylinder tube. Repair or replace the cylinder as required.

Open your hood and check the oil dipstick. See if there are remnants of coolant on the dipstick. Once a head gasket breaks, it usually causes coolant to filter into the oil, giving it a milky appearance. To be certain, drain some oil into a pan, place under light and see if there are spots.

Turn on the engine, leave it in park and walk to the back of your car to check the exhaust pipe. When head gaskets fail, the exhaust has a white color. Sometimes, there is a sweet smell coming out of the pipe.

Open your hood and use a flashlight to inspect the area around the engine block and compression cylinder. See if there are obvious cracks or coolant leaks that may indicate a bad head gasket.

Gently rev the engine while the car is in park. If your car feels like it may stall going back to an idle position, you may have a faulty head gasket. Once the head gasket fails, the compression may not be sufficient to keep the engine running. Try this method multiple times to get a better idea if you have a bad head gasket.

Find the oil pressure specification for your model vehicle and engine size in your owners manual or a vehicle service manual for your car. Find the voltage and resistance parameters for the oil pressure sensing unit in your vehicles service manual.

Disconnect the wires that attach to the oil pressure sensing unit. Its usually located on the bottom of the engine near the oil filter. Attach the multimeter that leads to the sensor and then start the vehicle. Check the multimeter and note the voltage and resistance reported by the multimeter.

Turn off the vehicle and disconnect the multimeter. Connect the potentiometer to the oil pressure sensing unit by connecting one lead to the blue and white wire on the sensor and the other potentiometer connection to the ground connection on the frame.

Set the potentiometer to the resistance (in ohms) as specified by your owners or service manual. Start the vehicle. Check the reading on the potentiometer and note the resistance. Turn off the vehicle, disconnect the potentiometer and reconnect the leads to the oil pressure sensor.

Replace an oil pressure sending unit that returns values outside the acceptable range for your model vehicle. Replace the electronic oil pressure gauge if the sending unit tested within acceptable ranges.