Engine Stalls While Driving

If the engine stalls while driving, one cause of stalling is something called vapor lock. Vapor lock can occur if the engine gets abnormally hot. So, then maybe vapor lock is causing this vehicle to stall.

If the stalling only occur if the engine is abnormally hot, then the possible cause is a vapor lock, vapor lock is probably occurring. At this point, you're probably wondering what exactly is vapor lock? And... how does it cause stalling? Well, vapor lock is when gas boils before it gets into the engine. It is triggered by an extremely hot engine. When the gas boils, air bubbles will form (in the gas), causing the air/fuel mixture to be too lean. By "too lean", it means that there's too much air and not enough gasoline. Consequently, the engine stalls since it can't stay running on such a weak (i.e. lean) air/fuel mixture.

What to do?

When vapor lock strikes, the only thing you can do is wait for the engine to cool down. Incidentally, why is the engine got so hot? Was there a good reason for this? If not, more than likely this vehicle has a cooling system problem - please look into this.

If the stalling occur at engine normal temperature, the possible cause is a faulty fuel pressure regulator.

First off, an engine that stalls while driving is generally having a fuel problem... specifically, a lack of fuel. The car that is equipped with fuel injection engines has something called a "fuel pressure regulator". Its purpose is to maintain fuel pressure to each of the fuel injectors. Any problem with this device will result in a fuel-starved engine and, of course, a fuel-starved engine will stall.

What to do?

You will need to have a mechanic verify that the fuel pressure regulator is faulty. If this is indeed the case, have it replaced. In a situation like this, some mechanics may offer to replace several other items related to the above. For now, just stick with the replacement of the fuel pressure regulator. This should correct the problem. You can always return at another time for the other items the mechanic suggested.

Clutch Vibration When Depressed

Without opening up the clutch/transmission assembly it's hard to determine the exact cause of this problem. However, based on the experience of many mechanics.autotech will offer the following likely possibilities.

The possible reason why there is clutch vibration when depressed

(1) Loose clutch disc.
(2) Loose pressure plate.
(3) Loose flywheel.

As mentioned, it's difficult if not impossible to determine the exact cause of this problem without opening up the clutch and transmission assembly. However, the diagnosis provided is a very good guess. Why? Well, the reason goes something like this. The flywheel is a round metal plate connected to the engine crankshaft. Therefore, as the engine runs, the flywheel turns.

When the vehicle is in gear and you're driving along, the pressure plate (another round metal plate) is pressing the clutch disc against the flywheel and thus allowing the transfer of engine power to the transmission. So essentially, all three parts are "connected". Now, as the clutch is released (by depressing the clutch pedal), any looseness in any one of these parts will cause that part to wobble and this wobbling will consequently be felt in the clutch pedal.

What to do?

In this situation, let's hope that your car is under warranty, extended warranty, or a service contract. Why? Because a transmission teardown probably cannot be avoided and such work is always expensive. 

However, if the vehicle isn't under any kind of warranty/service contract, try to find a reputable car repair shop since they are extremely reputable and are known for their quality level of work. By the way, if you decide to ignore the problem, it will only get worse and result in an even more expensive repair bill.

Coolant Boiling Over After Engine Start

If the radiator boil over after engine start, it indicates a leaking radiator cap or a wrong anti-freeze / water ratio.

Leaking Radiator Cap

The purpose of the radiator cap is to keep the entire engine cooling system under pressure. This has the effect of raising the boiling point of the coolant. If the radiator cap is leaking (i.e. not sealing well), the boiling point of the coolant will be considerably less than normal. As a result, the engine (and therefore the coolant) will only have to be semi-hot for the radiator to boil over.

Wrong Anti-freeze/Water Ratio

As you probably know, anti-freeze is added to water (in the radiator) to keep the water from freezing when the outside temperature is very cold. In addition to this, anti-freeze also raises the boiling point of water. In most cases, a 50/50 mix of anti-freeze and water is adequate to provide both freeze and boil-over protection. However, if the anti-freeze/water ratio is wrong (e.g. not enough anti-freeze and too much water), it'll boil at a lower temperature... specifically, when the engine is only semi-hot.

What to do?

First, when the engine is cold, remove the radiator cap and closely examine it. Look for cracks in the rubber part of the cap's underside. Screw the cap back on, making sure it solidly attaches to the radiator fill hole (i.e. no looseness). 

If anything seems odd about the radiator cap, replace it and see if this corrects the boil-over problem. Otherwise, replace the coolant with a 50/50 mixture of water and anti-freeze. You'll want to first get the entire cooling system backflushed in order to remove all of the old coolants. Why? Because simply opening up the valve at the bottom of the radiator won't completely drain the cooling system.

Battery Light Keeps Coming On

If battery warning light keeps coming on while driving, it indicates a slipping alternator belt or failing alternator.

The reason why battery light keeps coming on

(1) Slipping alternator belt
(2) Failing alternator

First, let's get some background information. An alternator is a belt-driven device that does two things,

1) it recharges the battery and,
2) it provides electricity to accessories while the engine is running.

So, if the battery light is on, it means the alternator isn't generating any electricity to,
1) charge the battery or,
2) power the accessories.

With that said, we have the following two possibilities...

Slipping Alternator Belt - If the belt occasionally slips, the alternator won't generate any electricity during the slippage. This will trigger the battery light to flicker.

Failing Alternator - If the alternator occasionally fails/dies, it won't (of course) generate any electricity during the failure. This will trigger the battery light to flicker. Although rare, it's possible that wire coming off the alternator may have become loose. If this is the case, each time the loose wire breaks contact with the alternator, the battery light will come on.

What to do?

Please take the car to a reputable car repair shop and ask the mechanic to inspect the alternator and its belt. Hopefully, all you'll need is to have the belt adjusted or replaced.

Have this problem taken care of soon. If you don't, you can be sure that one day the battery light won't just flicker but rather it'll come on steady. When that happens, you will have roughly 20 minutes of driving left before the engine conks out.

If the mechanic says you need a new alternator, don't be surprised if tells you that he'll have to replace something called the "voltage regulator" as well. Why? Because, on many vehicles, its necessary to replace both the alternator and voltage regulator at the same time.