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diy auto service: cooling system repair and diagnosis by symptom

by:DMS Seals     2020-08-05
The biggest key to cooling system service with no problem is to maintain the quality of coolant.
Due to corrosion caused by acidic coolant, it can cause many cooling system problems.
It corrupts the gasket, the pump impeller, the lining, the block, the radiator, the hose, the oil cooler, the exhaust gas recycling cooler and the heater core material, resulting in a leak.
Replacement of cooling system components usually requires drainage of cooling system.
Since the coolant may be hot, please check the temperature of the upper radiator hose before opening the lid.
Components can be replaced once the system is drained.
There may still be some coolant loss on the part, so the drain tank should be used to reduce cleaning.
Service Tip: Always follow the appropriate service procedure guidelines developed by the engine manufacturer to get the best results.
An overheated coolant can cause severe burns.
Always check the coolant temperature by touching the radiator hose before turning on the system.
The release of pressure will cause the water in the coolant to boil and become a hot fountain.
Discharge and refilling the discharge plug of the discharge cooling system of the cooling system (petcock)
Usually located at the bottom of the radiator.
Before opening the drain plug, check what the coolant capacity is and whether the drain tray has enough capacity.
To drain the coolant: Open the radiator cover if the coolant is not hot.
Open the drain valve (petcock)
At the bottom of the radiator.
If the lower radiator hose extends below the radiator, there may also be a drain plug on that hose.
Service tip: If the upper part of the engine is working, it may not be necessary to exhaust the volume of the entire cooling system.
Just drain until the coolant level is lower than the Assembly.
If the engine is removed, a coolant plug on the side of the block can be used to drain the block.
Replenishment of cooling systems;
Ethylene glycol to be recommended (EG)
Or extend the life of coolant (ELC)
And the water of the recommended mixture (50/50)
Than or using pre-mixed coolant.
Make sure to close all drains and reinstall the plug.
Fill de with funnel-aeration tank.
When the coolant enters the block and the radiator, it may be filled with drainage several times.
If the system does not use de-
Ventilation tank, deflator plug may need to be removed from around the thermostat housing at the top of the cooling system.
Some engines use a special program, such as a quick acceleration of the throttle several times.
This makes the air fresher.
Follow the procedures of the vehicle you are working on.
Once the system is full, start the engine and run it in a short time.
Refill the system to the full \"cold\" mark.
Start and run the engine until it heats up to the operating temperature.
In order for the engine to reach the operating temperature, road testing of the vehicle may be required.
Observe the coolant level.
It should be close to the full \"hot\" mark.
Service tip: de-
The aeration tank has an exhaust hose attached to the thermostat housing and the top of the radiator.
This should drain the air from the cooling system so that the block and radiator will be filled with coolant.
Thermostat replacement thermostat (s)
Located in the thermostat housing where the upper radiator hose is connected to the engine, or reverse cooling at the lower radiator hose and pump.
The cooling system may only need to remove it in a partial drain.
Open the thermostat shell to remove the thermostat (s).
Most gas engines use one and the other (diesel)
Use two thermostats.
Compare the old and new thermostat.
The opening temperature is usually marked on the thermostat.
Replace the old thermostat with a new thermostat of the same temperature level.
Some thermostats use o-
Ring seal when others sit in the cut
Take out a gasket.
Make sure the thermostat is in the right direction and in the cutting positionout properly.
When tightening the case, make sure the case is tilted, indicating that the thermostat has moved.
Check whether the hose has a soft point and the condition inside the hose.
Now is a good time to install the new hose if needed.
Large quantities of plastic/aluminum radiators are used for cars and light trucks.
Breaking the plastic label or line connection on the radiator is a concern.
The radiator installation usually also supports fan cover and charging air cooler (
CAC with turbochargers)
And the AC condenser.
The electric fan can also be installed on the radiator.
To remove the radiator, the cooling system must be discharged all the way.
Grill, fan cover and fan according to vehicle model (
Electric or mechanical)
Radiator may need to be removed.
Remove the upper hose, lower hose and any vent hose carefully without damaging the hose connection fittings.
Some radiator tanks are equipped with transmission and oil cooler.
The oil circuit needs to be removed from the radiator fitting.
The radiator is usually installed on the rubber bracket, or the radiator bracket is bolted to the vehicle core bracket.
Disconnect or remove fan cover, CAC, and AC condenser if necessary.
Support the radiator and remove the bracket.
Remove the radiator carefully to avoid damage.
Reinstall the radiator on the bracket and make sure there are no contacts that can rub the radiator.
Reconnect the bracket, fan cover, CAC, ac condenser and coolant hose.
Refill the cooling system as mentioned earlier.
The most common reason for replacing the pump is that the coolant leaks from the crying hole.
Because there are different types of pumps (
Belt Drive and timing belt drive)
, There are different types of removal programs.
Full drainage of the cooling system is required for all types.
After replacing the pump, refill the cooling system.
The mechanical fan also uses a water pump shaft driven by a snake belt.
Used to fix the fan with four bolts.
Today, many mechanical fans are screwed on the pump shaft with reverse threads, especially on General Motors and Dodge pickup trucks.
This means that you loosen it in a clockwise direction and tighten it in a counter-clockwise direction.
Loosen the fan before removing the belt.
Since these pumps are driven by belts, the fan belt needs to be removed.
Most vehicles today use snake-like drive accessories, including water pumps.
If there is no snake band diagram on the vehicle, make one.
Use the circuit breaker lever on the automatic tension, remove the tension from the belt and remove the belt from one of the pulleys (alternator).
The pump has a pulley that can be bolted or pressed on the pulley.
Check the new pump to see if it is with the pulley.
Re-use of pulleys on new pumps may be necessary.
Some pulleys require special tools to remove and install the pulleys without damaging them.
Once the belt is removed, the pump is secured inside by many bolts.
Track the position of the bolts as some applications use several lengths of bolts in special positions. An o-
Ring or gasket used to seal the water pump to a block or gearbox.
Remove the pump and clean the face of the block or gear box.
Remove all the old gasket material, however, be careful not to scratch the surface as this can cause a leak.
Install the pump with a new washer or o-ring.
Install the bolts in the appropriate position and torque according to specifications.
Use the circuit breaker lever in the tensioning device and reinstall the belt with the correct wiring. If V-
Use the belt, adjust the belt tension, and check with the tension meter.
The pump driven by the timing belt some overhead cam engines use the pump shaft as the idler wheel of the timing belt.
This means that the timing belt must be removed to replace the pump.
If there is no service information about changing the timing belt, please do not start this project.
If you are doing a timing belt, it makes sense to replace the pump and vice versa.
After replacing the timing belt many times, the water pump began to leak after a short period of time.
Before dismantling, take the engine to the timing position according to the factory procedure.
Remove the front of the engine and remove the timing belt.
Depending on the engine installation design, the engine may need to be supported.
After removing the timing belt, loosen the bolt and replace the water pump.
Install a new pump with a new washer or O-ring.
Install the timing belt on the water pump pulley.
Timing cam using factory program (s)
When installing the timing belt.
Once installed and adjusted, rotate the engine in two turns in the normal direction of rotation and re-check the timing mark.
Don\'t turn the engine back.
Complete the front of the engine and replenish the cooling system.
Service tip: do not rotate the engine when the timing belt is off, as this may bend the valve on the overfit engine.
Common cooling system problems engine overheating or overheating engine temperature is controlled by the coolant flow through the engine to the radiator.
Heat is released (radiated)to the air.
Anything that affects either of them will cause the temperature to rise.
Be sure to check the coolant level first.
Low coolant levels usually mean a coolant leak.
Pressure Test for cooling system.
The thermostat turns off or limits the flow of the radiator.
Is the heat of the upper radiator hose indicating the flow to the radiator?
If the cooling system is not drained and the thermostat is replaced.
Limited airflow through the radiator.
Is the radiator core blocked by dirt or is the fins bent?
Is the fin missing?
Clean the radiator, straighten the fins with a fin comb, or repair the radiator.
Service tip: Due to AC condenser and air charging cooler (CAC)
They may also cause blockage in front of the radiator.
Make sure they are clean too.
The coolant flow through the radiator is limited.
The tube at the core may be blocked.
This usually occurs when the coolant is not maintained or the coolant is wrong (EG and ELC)
Mix together.
Use an infrared thermometer to measure the temperature of the tube from the hot side to the cold side when the engine is running.
There should be a consistent temperature drop on all tubes.
The cooler tube indicates less flow (restricted).
Send the radiator out for inspection or not welded and send it out.
The pump impeller may be eroded and cannot be pumped into the coolant.
When the coolant is circulating, the silicate level in the coolant may cause the impeller to be sandblasted.
Incorrect SCA levels on diesel engines and acidic coolant containing high levels of silicate may be the reason.
Replace the pump and rinse the cooling system.
The non-joining of the coolant fan will cause insufficient airflow of the radiator.
This is especially noteworthy in the case of lower vehicle speeds and parking and driving.
Check the fan clutch for leakage.
Fan relays for most electric fans are controlled by the engine ECM.
Use the scanning tool or OEM software to check the on or off status of the fan in the software.
You can also check the coolant temperature, AC pressure, and intake temperature to see if the sensor reports the correct information.
Scanning tools or software can also allow you to turn the fan on and off.
Service tip: the problem of coolant fan may also affect the AC operation (
High side pressure)
And reduce engine power due to the lack of airflow of the turbocharged CAC (
High intake temperature)at low speeds.
The engine runs cold or without heat. The engine temperature is controlled by the opening and closing of the thermostat.
If the thermostat is stuck on, the coolant is sent to the radiator all the time.
This may cause the engine to take longer to warm up, or it is not allowed to warm up at all to provide heat.
Be sure to check the coolant level first.
Because the heater core is often very high in the cooling system, there will be a lack of coolant flow.
Low coolant levels usually mean a coolant leak.
Pressure Test for cooling system.
Check the upper hose when the engine starts to warm up.
If the hose is warm before the engine reaches the opening temperature of the thermostat, it will not turn off as it should.
Change the thermostat.
When the coolant leaks a lot, the leaking coolant is visible and usually leaves a white track to the source.
The pressure test of the cooling system usually helps to find a leak.
Sometimes, it\'s better to check if the cooling system is cold before it gets warm.
A leak in the pump\'s weep hole may occur in one leak and then in another.
Look for the white path from the crying hole.
Replace the pump if found.
It is difficult to find internal coolant leaks that either appear in the oil analysis or have turned the oil into cream coffee.
The reasons may be four main candidates;
Diesel liner seals, oil coolers, exhaust gas recycling coolers, and head washers.
The diesel wet liner uses a liner seal.
They sealed the removable liner on the block.
If it leaks, the lower seal usually leaks into the Quaker.
The lining seal also does not push the oil into the cooling system.
To find this leak, remove the oil bottom shell and perform a pressure test on the cooling system.
When the cooling system coolant is under pressure, it should be dropped from the bottom of the liner to the block.
The engine needs to be removed and the lining seal replaced.
The typical reason is acidic coolant.
Oil cooler heat exchanger or o-
The ring failure pushes the coolant into the oil and pushes the oil into the coolant.
If the coolant is found in the oil, check if there is a sticky slip coating on the top of the cooling system.
When the engine is turned off, the cooling system maintains the pressure and pushes the coolant into the lubrication system.
When the engine is running, a higher oil pressure pushes the oil into the cooling system.
The failure of the exhaust gas recycling cooler on the diesel engine will allow the coolant to enter the air inlet of the engine.
When the cylinder burns the coolant, this usually also results in white smoke discharged.
Because of the white smoke, this may be confused with the head gasket problem.
The coolant will be in all cylinders.
In the pressure test of the cooling system, remove the exhaust and air intake pipe from the cooler.
If there is evidence of coolant, please replace the cooler.
A head gasket leak will leak the coolant into the cylinder.
The coolant will be discharged from the ring and into the Quaker.
A fragrant white smoke discharged will also accompany the coolant in the oil.
The source of the coolant can be a blow head gasket, a broken head, or a twisted head.
This leakage usually occurs in one or two cylinders.
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