Engine Archives - Auto Repair Help

Cooling System Repairs

December 15, 2013 by Master Tech Lee Leave a Comment

Cooling System Repair can be your worst enemy if you don’t understand how your cooling system works.

Your cooling system performs a critical function. Simply put it maintains proper engine temperature by circulating coolant through the engine to pick up heat and passing it through a radiator to cool it with air. The coolant passes through a thermostat valve to control flow and possibly over a temperature sensor which controls external air cooling fans.

Automotive Cooling System

Cooling systems consist of three main parts:

Cooling System Part #1:

Your cooling systems pumping function is handled by its water pump, which keeps the coolant mixture moving.

The main water pump is gear- or belt-driven, but in many cars, a secondary electric water pump is used for improved flow and cooling.

Critical to the pumps operation is the drive belt that turns it On most newer cars this is the engine’s timing belt On older cars, the pump and belt are external and run off the main crankshaft pulley with a V or serpentine belt.

Maintenance of cooling system pumping is limited to scheduled coolant replacement and drive-belt replacement and tension adjustment (external type). Timing-belt-driven pumps should always be replaced at the same time as the timing belt and tensioner.

Cooling System Part#2: Piping

Your cooling systems piping consists of all hoses, any control valves, the heater core, the radiator and the expansion tank. Because of the materials used and the constant contact with coolant all parts in this system deteriorate more from time than use.

Maintenance of cooling system piping consists of scheduled coolant replacement of ail hoses on a regular basis and replacement of any plugged or leaking parts.

All hoses should be checked at least twice a year for abrasions, cracks, flexibility and evidence of leakage. Whenever the coolant is drained for replacement or during engine repairs, any suspect hoses should be replaced. All hoses should be replaced at least every few years.

Radiators, expansion tanks, heater cores and control valves are normally only replaced due to leakage or plugging. The condition of these parts should be assessed by a professional since proper functioning is critical to many other systems within your car.

Cooling System Part#3: Temperature Control

Your cooling systems temperature controls include all coolant temperature sensors, thermostat radiator or expansion tank cap, cooling fan(s) and fan clutch (if equipped). These cooling system parts function primarily independent of the engine but control the engine either through cooling or by sending control signals to your cars electronic systems.

The thermostat is a spring-loaded valve that opens and closes based on the temperature of the coolant flowing through it. A high temperature reading followed by a drop to normal temperature (or a continuously low temperature) is a common first sign of a sticking thermostat However; many other conditions may cause these symptoms, so you need to know how to eliminate each possibility.

The radiator or expansion tank cap is also a spring-loaded valve reading to system pressure. It serves to maintain proper system coolant level at predetermined pressures. It must always be replaced with an exact replacement cap with the same pressure setting. Never use other caps except for short-term emergencies!

A belt-driven fan blade for pulling air through the radiator is usually on the water pump pulley and should have a fan clutch to control it. The fan clutch allows the fan to turn with the belt at low engine speed and free-wheel at higher speeds. A bad fan clutch either doesn’t allow the fan to spin at low speed (overheating in traffic) or does allow it to free-wheel at high speed (potential overheating on highway or reduced gas mileage).

An electric fan can be either by itself (usually front-wheel drive) or auxiliary (used with a mechanical fan). Both types are controlled via a temperature sensor – in the radiator or upper radiator hose or on the thermostat or water pump housing. This sensor is usually an on/off type switch with a fixed temperature setting. (Some vehicles may have 2-3 settings for multi-speed fans.) This sensor is commonly called an auxiliary fan switch.

Other common temperature sensors are: 1) gauge sender (variable output): 2) warning light sender (on/off type): 3) lambda and/or fuel injection sensor(s) (variable to control fuel injection settings); 4) thermo-time switch (cold start valve control). Your car may have other sensors as well.

Temperature control is critical to both performance and emission control. Unfortunately, this system is the most difficult to troubleshoot without the proper equipment and diagrams, it’s even more difficult with computers that adjust timing, idle speed, and vacuum and fuel delivery automatically to make up for potentially faulty temperature sensor signals.

Maintenance of your cooling system sensors is virtually impossible since there’s nothing really to maintain. Keeping them clean both internally (coolant replacement) and externally (engine cleaning) is the best way to ensure trouble-free driving. Checking and replacing all parts at the factory-recommended time or mileage limits helps as well.

A Few Important Things to Remember

Heed these cooling system maintenance tips and you’re well on your way to ensuring your cooling system won’t let you down:

Tip #1: Keep your engine and engine compartment as well as your radiator fins and grill, as clean as possible. A clean engine runs much cooler – and it’s much easier to work on.

Tip #2: Replace coolant at or before factory recommended intervals with the proper type, mixture and volume of coolant always allow the coolant system to rid itself of air before installing the radiator cap.

Tip #3: Replace all cooling system hoses – upper and lower radiator hoses, bypass hoses, heater hoses, manifold coolant hoses and any other hoses on your vehicle-whenever you even suspect there may be a problem. All hoses should be replaced at least every two years.

Tip #4: Replace the thermostat with the original temperature setting equivalent the electronics in your vehicle may use that setting for other controls. Do not substitute under any circumstances.

Tip #5: Replace the radiator/expansion tank cap with the original pressure setting and 0E-type equivalent. Some aftermarket substitutions do not seal and hold pressure properly on foreign-manufactured cars. Again, don’t substitute under any circumstances.

Tip #6: Adjust or replace the water pump drive belt (external) at recommended intervals or more frequently, if required. Check belts whenever you’re working on any coolant system components.

Tip #7: Replace your water pump with an OEM/DES pump at the first signs of trouble or when your timing belt and tensioner are replaced. Watch for signs of overheating – you don’t want to break down in the hot sun when your water pump fails.

Tip #8: Replace the fan clutch and/or fan blade as needed (if applicable). Your cars temperature gauge is often your best guide as to when your fan clutch needs attention.

Tip #9: Replace temperature sensors as required by diagnosis. Leave troubleshooting of your sensors to experts who have the proper equipment and diagrams.

Tip #10: Keep your entire vehicle properly maintained because of the effect timing, idle speed, exhaust and other systems have on your engine’s temperature. Your cars cooling system is designed to function with all other systems operating properly. it cannot make up for a poorly operating or overheating engine condition.

Your Cooling System Parts Shopping List

Here’s a list of cooling system repair parts you should consider when repairing your cars cooling system:

– Coolant –

– Water Pump –

-Water Pump Drive Belt ( V-belt or serpentine belt)-

– Hoses (upper & lower radiator, bypass, heater, manifold coolant etc.) –

– Radiator-

– Expansion Tank-

– Heater Core –

– Control Valves –

– Temperature Sensors, as applicable-

– Radiator Cap and/or Expansion Tank Cap –

– Fan Clutch –

Auxiliary fan switch, gauge sender, warning light sender, lambda, fuel injection, thermo-time switch, etc.

Ask a technician for advice and/or help with your auto repair.

Cooling System Repairs

Do I Need Oil Change Every 3000 Miles

December 15, 2013 by Master Tech Lee Leave a Comment

With today’s oil technology, along with the new engine and fuel delivery technology, this is a question that gets asked more often than one thinks. Oil manufacturers have made huge breakthroughs in oil technology. This has allowed engine designers to make some very significant engine design breakthroughs. I personally use full synthetic oil in all my vehicles and a high quality oil filter and change my oil every 5,000 miles. I do not use the month’s method just miles traveled. Every vehicle in my fleet has over 200,000 miles on them and still performing at peak efficiency! Let’s face it, the cost of ownership for a vehicle plays a big role in the wallet.

The 3000 mile or 3 month oil change standard is a leftover from the days of sloppy fuel systems and old engine designs. Today’s engines are fitted with Sequential fuel injection systems and computer control timing. The amount of blow-by and fuel leaching into the crankcase, engine oil is virtually none existing. This alone was one of the major reasons for short oil changes. Engine sealing against moisture entering these new engine designs has been greatly improved. The Positive Crankcase Ventilation system (PCV) and increased engine operating temperatures have improved moisture control in the oil. This is all in place before the oil formula itself is managing all these engine and oil killing elements. A good oil filter will assist with keeping things clean and in order.

The benefit to using high quality synthetic oil is lower operating cost and longer engine life. If you operate your vehicle for the national average of 15,000 miles a year that’s three full synthetic oil changes a year. A full synthetic oil change average cost is $50.00. At only three a year that is $150.00 for maximum protection. Let’s look at the 3,000 miles or three months oil change we are being sold on. The average cost of none synthetic oil changes is about $30.00. You would need 5 oil changes a year if you operated your vehicle 15,000 miles. This would mean 5 trips to the service center. The cost would be $150.00 for the 5 oil changes at $30.00 per service. If you service the vehicles yourself like I do, you can get a full synthetic oil/filter change done for around $25.00. That would be $50.00 a year in oil changes. In my busy life, two less trips to the service center is time spent doing the thing I love to do. Time in my busy schedule is precious and in short amount. So the choice is yours, every 3,000 or 3 months with conventional oils or every 5,000 miles with full synthetic.

Do I Need Oil Change Every 3000 Miles

Your Engine Stalls

December 12, 2013 by Master Tech Lee Leave a Comment

Your engine stalls when cold immediately after starting and/or stumbles

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Problem: Your engine stalls when cold immediately after starting and/or stumbles.

A Stalling problem most of the time is the in adequate of fuel and/or too much air. A cold engine needs a rich mixture to start and run cold, and to idle. Any of the following can cause or contribute to a hard start and/or stalling problem:

Possible problems which might affect these conditions are:

Note: Do the basics first. Visual checks such as checking the air filter and perform a fuel pump pressure test. And checking all vacuum line connections.

•A vacuum leak from gaskets and/or vacuum hoses. Check for loose or broken vacuum hoses, leaks around the intake manifold gasket or throttle body, leaks around the PCV valve and EGR valve, and around the brake booster.

•A dirty or defective airflow (Mass Air Flow) sensor. Mass air flow sensor that has been contaminated by fuel varnish or dirt will under report airflow and be slow to react to changes in airflow. This can upset the air/fuel mixture causing idle, stalling and hesitation problems. Cleaning the airflow sensor wire with aerosol electronics cleaner can often restore normal operation and cure the problem.

•A coolant temperature sensor could be out of range. Computer needs in input from the (CTS) coolant temp sensor signal for (ECM) Electronic Control Module to effectively supply the correct amount of fuel to injectors. Take a scanner which can, which can read the Live data and verify the temperature reading of sensor compared to engine temp. If reading, let say, is 198 degrees and the engine is cold, say, 50 degrees, then you know the temp sensor is in accurate. Replace the temp sensor.

Note: Even though you do not have any codes does not mean one of the sensors is out of range. A code simply means you have an electrical problem with either a wire to sensor connector or a bad sensor.

•A defective idle speed control system. Idle speed on a fuel injected engine is controlled by allowing a small amount of air to bypass the throttle. If the idle air bypass circuit is plugged with dirt or fuel varnish or the solenoid valve is sticking or broken, the engine may not get enough air to idle normally causing it to stall. Cleaning the idle air bypass circuit in the throttle body with aerosol throttle cleaner will often remove the gunk and solve your stalling problem. If a good soaking with cleaner fails to fix the stalling problem, check the wiring connector. It might be loose or corroded. If no wiring faults are found, you may have to replace the idle speed control solenoid.

•A bad Manifold Absolute Pressure (MAP) sensor. This sensor monitors intake vacuum, which the PCM uses to determine the engine load. If the MAP sensor is not reading accurately, the PCM may add too much fuel or not enough, causing the engine to stall. See the article on MAP sensors for how to diagnose this sensor.

•Low engine compression. If your engine has a lot of miles on it, and compression is low because the piston rings and/or cylinders are worn out it has one or more leaky valves, it may not have enough oomph to keep idling. A compression check will tell you if this is a problem or not, and if it is there is no easy fix other than to overhaul or replace the engine.

•Worn or fouled spark plugs. Ignition misfire can make any engine stall at idle. When the engine is running slowly, there is less momentum to keep it going, so a bad misfire may cause it to stall if the spark plugs have not been changed in a long time, a new set of plugs and/or plug wires can restore a good hot spark and eliminate the misfire. A weak ignition coil or a faulty crankshaft position sensor may also cause a stalling problem.

•Bad Gas. Gasoline that contains too much alcohol (more than 10%), Alternatively, gasoline that has been contaminated with water or some other substance may not burn well and cause your engine to stall. If the stalling started to occur shortly after your last fill-up, suspect bad gas. The cure is to drain the tank and refill it with fresh gas from another filling station, or add some isopropyl to gas and just use up the bad fuel (if the engine runs okay at highway speeds), then refill at another station when the tank is near empty.

Problem: Your engine stalls when you stop for a traffic light or when idling.

A stop light or idle stall often means the engine is not idling fast enough (idle speed too low), or the engine is being pulled down by a load on it created by the air-conditioning compressor and/or alternator- it could also mean the fuel mixture is too rich or too lean, causing the engine to run poorly, or a bad or clogged Exhausts Gas Recirculation (EGR) valve.

Possible causes that may contribute to this kind of stalling include:

•Exhaust Gas Recirculation. This part known as EGR for short is a well known problem. When coming to a stop, the egr hangs open, due to carbon deposits or clogged ports or tube. This part will cause vacuum leaks as well, so check the EGR first.

•A Bad A/C compressor. If the compressor is binding up, possibly due to a lack of lubrication, internal wear or an over-charged system (too much refrigerant), it may be lugging down the engine when it is engaged. If the problem only occurs when the NC is on, there is an issue with the air-conditioning compressor.

•Unusually high electrical load on the charging system. If the battery is run down and the alternator is working hard to recharge it, the increases load on the engine may pull down the idle rpm to the point where it causes the engine to stall. Check the battery state of charge to see if the battery is run down or failing. Alternator average should charge at a rate of 13.3 to 14.8 volts at idle. If the battery is low, use a battery charger to recharge it. If the battery is failing and is not holding a charge, time to buy a new battery.

NOTE: Using a volt meter, while the engine is running, at idle you can test the alternator output. – Red lead of meter to the positive and Black lead of meter to negative side of battery. A reading between 13.3 to 14.8 volts is a good range for charging. Make sure all accessories are off. In addition, to Load test the battery you will need a load tester or go to your local parts store. They should be able to perform the load test for free. Remember testing the battery engine off with a volt meter is not a true way to load test. With that said, any battery, you test with a meter, dead or charged will read the batteries voltage until a load is applied. A battery is only as good as its weakest one.

Problem: Your engine just stalls unexpectedly while driving.

Stalls like this are often ignition-related and happen when the engine loses spark. The underlying cause is often a bad crankshaft position sensor, or sometimes a failing ignition coil (if the engine has only one coil). A faulty ignition switch that loses contact intermittently may also cause the engine to suddenly die for no reason.

•When this happens, open the hood and check for spark. This can be done by pulling off a plug wire (if the engine has plug wires), and placing the end near the block while a helper cranks the engine. DO NOT hold the wire as it may shock you if the ignition system is working. If you do not see a spark or hear the plug wire snapping when the engine is cranking, the fault is in the ignition system.

•If the engine has spark, it may have died due to a loss of fuel pressure. When fuel pumps fail, they usually just quit with little or no warning. The engine usually won’t restart, and the vehicle has to be towed in for repairs. Listen for a buzz from the vicinity of the fuel tank when the ignition is turned on. No buzz means the fuel pump isn’t running. It might just be a blown fuse or a bad relay, but on a high-mileage, vehicle is often a bad fuel pump.

•Another possibility is a bad ECM (engine computer) relay. The power supply to the PCM is often routed through one or two main power relays. If one of these relays loses contact momentarily, it’s like pulling the plug on the PCM. The ECM shuts down and turns off the ignition and fuel injectors, causing the engine to stall. One way to see if this is a possibility is to switch or replace the ECM power relay(s). If the problem goes away, the cause was a bad relay. If it continues, the fault is something else (possible a wiring fault in the ECM relay or ECM power circuit).

•Yet another possibility is low system voltage, loss of voltage, or overcharging. The PCM and other control modules require a steady 12 volts to operate correctly. If the supply voltage suddenly drops below 9 volts, or surges about 14 volts, or cuts out, the Electronic Control Module may temporarily kill the injectors or ignition circuit. The underlying cause may be an intermittent short somewhere in the electrical system or charging system that causes a momentary drop or surge in voltage. These can be very difficult to find, and often require hooking up a scan tool that can capture snapshot data when the stall occurs. By looking over the data, a technician can see the chain of events that caused the stall, and hopefully identify, isolate, and repair the fault. Check out one or the other.

Car Repair | Auto Repair | Truck Repair

Preventive Maintenance Goes A Long Way

December 12, 2013 by Master Tech Lee Leave a Comment

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Automotive Maintenance is something most of us ignore, until our vehicle stops functioning, that is. And then we wonder what went wrong, where. Auto Maintenance is one of the most serious aspects of ownership. It determines the longevity, performance, and reliability of whichever vehicle you drive. Therefore regular maintenance is crucial. (Follow your car or truck Owner’s Manual)

Owner checks and service

When you fill up the gas tank you should check

ENGINE OIL LEVEL

Inspect the engine oil level and add the proper oil when necessary. Note: Remember most cars should burn oil every 2000 miles or more. If you never had to add oil, it means the top half of your engine is not getting proper lubrication. That would indicate an engine problem. Reason is, the upper half of your engine “Valves” needs oil to lube all the moving parts in the engine head area.

NOTICE: It is important to check your oil regularly and keep it at the proper level. Failure to keep your engine oil at the proper level can cause damage to your engine not covered by your warranty.

ENGINE COOLANT LEVEL

Inspect the engine coolant level and coolant mixture when necessary.

WINDSHIELD WASHER FLUID LEVEL

Inspect the fluid level in the windshield washer tank and add the proper fluid when necessary.

The following information covers the tests, inspections, and services required to maintain the safety, dependability, and emission control performance of the vehicle. Complete the necessary repairs and procedures on time. Use only the recommended fluids and lubricants.

At least once per month

Tire Inflation

Visually inspect tires including the spare tire. Verify that the tires are inflated to the pressures specified on the Certification/Tire label located on the driver door lock pillar.

Tire wear inspection and rotation every 6000 miles

Tire rotation may be required for high mileage highway drivers prior to the Engine Oil Life System service notification. Check the tires for wear and, if necessary, rotate the tires.

At least once per month

Starter switch check

CAUTION: When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured

Ensure that you have enough room around the vehicle, which should be parked on a level surface.
Firmly apply both the park brake and the regular brake.
Start the engine:

On automatic transmission vehicles, try to start the engine in each gear. The starter should work only in PARK (P) or NEUTRAL (N). If the starter works in any other position, the vehicle needs service.

On manual transmission vehicles, put the shift lever in NEUTRAL (N), push the clutch down halfway and try to start the engine. The starter should work only when the clutch is pushed down all the way to the floor. If the starter works when the clutch is not pushed all the way down, the vehicle needs service.

Automatic transmission shut lock control check

CAUTION: When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured. Personal injury or property damage may result. Make sure there is enough room around the vehicle, in case the vehicle does move. Do not use the accelerator pedal, and be ready to turn OF1 the engine immediately if it starts.

Ensure that you have enough room around the vehicle, which should be parked on a level surface.
Firmly apply the parking brake. Be ready to apply the regular brake immediately if the vehicle begins to move.
With the engine off, turn the key to the RUN position, but do not start the engine.
Without applying the regular brake, try to move the shift lever out of PARK (P) with normal effort.
If the shift lever moves out of PARK (P), the vehicle needs service.

Ignition transmission lock check

With the vehicle parked, set the parking brake.
Try to turn the ignition key to LOCK in each shift lever position:
With an automatic transmission, the key should turn to LOCK only when the shift lever is in PARK (P).
With a manual transmission, the key should turn to LOCK only when you press the key release button.
On all vehicles, the key should come out only in LOCK.

Park brake and automatic transmission park (p) Mechanism Check

CAUTION: When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured.

CAUTION: When performing this check, the vehicle could move suddenly. Personal injury or property damage may result. Make sure there is enough room around the vehicle, in case the vehicle does move. Do not use the accelerator pedal, and be ready to turn OFF the engine immediately if it starts. You or others could be injured, and property could be damaged. Make sure there is room in front of your vehicle in case it begins to roll. Be ready to apply the regular brake at once should the vehicle begin to move.

Follow this procedure to test the parking brake and an automatic transmission PARK mechanism:

Park on a fairly steep hill, with the vehicle facing downhill.
Keep your foot on the hydraulic brake pedal.
With the parking brake set, perform the following test:
Start the engine.
Place the transmission in NEUTRAL.
Slowly remove foot pressure from the regular brake pedal. If the vehicle moves adjust Park Brake. In order to check the PARK (P) mechanism of an automatic transmission, additionally perform the following test:
SHIFT TO PARK (P).
Release all brakes. If the vehicle moves adjust Park Brake.

Under body flushing service

Every spring uses plain water to flush any corrosive materials from the underbody. Clean any areas where mud and another debris can collect thoroughly. And also, go to the nearest car wash and high-pressure spray engine with soap and rinse. All the above will keep oil and debris from softening hoses and corroding electrical components. Especially cars in colder climates, due to the salt trucks spreading the roads, can do a lot of damage to electrical components in the engine bay, anti-lock wheel sensors, and ride controls.

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