Posts Tagged Engine

Signs That Engine Replacement Is Necessary

Posted on October 9, 2011 | Automotive Repair.

One of the first signs that a vehicle’s engine is worn and may need to be replaced is blue smoke from the tailpipe on start-up or when accelerating after coasting. Blue smoke is caused by oil leaking past worn cylinder bores and piston rings or through worn valve guides and into the combustion chamber where it is burned along with the air and fuel mixture. By the time the cylinder bore or valve guides are worn out on a modern engine, many other components are also likely to be worn out, so completely rebuilt engines are a good alternative to just performing a valve job or re-ring.

Unlike blue smoke indicating a worn out engine, a sudden plume of blue smoke from the exhaust pipe accompanied by significant loss of power is a sign that one or more pistons have developed holes or have broken into pieces, allowing oil to escape directly into the exhaust port. This sort of catastrophic engine damage typically results in the owner seeking engines for sale.

More serious signs that an engine needs to be replaced are unusual noises from within the block that increase with crankshaft speed rather than road speed. Most engines feature a crankshaft with plain journal main and rod bearings. Knocking is a sure sign that the connecting rod bearings are worn and in the process of failing, the noise itself being caused by excessive clearance between the crank journal and the bearing, or the wrist pin is failing. Rumbling noises from within the block are likewise caused by too much clearance on the main bearings. Operating under these conditions would also cause low oil pressure gauge readings or the oil pressure warning light illuminating while the motor is running above idle.

Repeated overheating can be both a cause and another sign of an engine needing replacement. Cracked castings and worn deck or cylinder head mating surfaces allow hot combustion gases to enter the coolant system, over-pressurizing it while displacing coolant from where it is needed. While a blown head gasket can cause a similar situation, the effect of overheating by any means potentially warps the cylinder heads, leading to the same problem happening repeatedly until the problem is remedied.

Coolant leaking from anywhere on the engine other than from the freeze plugs or hose connections strongly indicates a cracked block, and, whether it is cast iron or aluminum, this generally means replacement is in order, as remanufactured engines are usually less expensive than the labor and parts involved with welding up a cracked block.

Possible Reasons Why Your Car Refuses To Start

Posted on August 24, 2011 | Automotive Repair.

There is nothing more frustrating to a person in a hurry to hit the road than a vehicle that refuses to start. Engine troubles such as this are actually far more common than most vehicle owners imagine. Even if you follow a regular car maintenance schedule, you can still experience vehicle breakdown at any time.

While having your engine die on you is highly inconvenient, it is an issue that can easily be resolved. Just like any other problem, the first thing you must do to fix it is to determine its cause.

To be able to determine the exact reason why your car’s engine won’t start, it is important for you to understand how the assembly starts in the first place. When you turn your key in the ignition, voltage in your car’s battery travels to your ignition switch. The voltage then moves towards the starter relay and starter motor. When the starter motor receives the voltage, it spins to crank up the engine. If there is enough spark in the cylinders, compression, and of course, fuel, the engine will start.

You should know that there are many possible reasons why your car will die on you. To narrow them down, listen closely to what will happen after you turn the key in the ignition. If you do not hear a sound from your car, the problem lies with the battery. It could be dead or heavily corroded. If you will hear a ticking noise, then it’s one of two things. It could be your battery or your starter motor. If it’s not the battery, then there maybe an issue with the ignition system not receiving enough voltage.

When you hear your engine turn over but still refuses to start, these are the most probable reasons:

  • Wires connecting the battery to the starter motor may be frayed or loose, thereby preventing the motor from receiving voltage.
  • Not enough spark in the cyclinders.
  • Ideally, if your engine turns over but still won’t start, the first thing you check for is a spark. It’s always a good idea to have a spark tester stored in your trunk at all times. If there’s no spark, the problem lies with the ignition system.
  • Insufficient fuel.
  • However, if there’s a spark and the issue is still unresolved, check your fuel next. If the fuel meter shows there is still enough fuel but your car still won’t start. You can check the fuel pump, the pressure in the fuel line, the fuel filter, and the fuel injectors.
  • Insufficient compression.

If not enough fuel is the problem, then the problem can be attributed to lack of compression, which in turn can be caused by a timing belt gone loose. Once you have determined the reason why your car simply won’t start, you can go ahead and perform minor fixes. If you are clueless on how to go about fixing the problem, then it is time for you to seek the help of a trusted car repair service.