Ford Focus 3 jerks. The car twitches! Why are valves knocking on a hot engine?

Ford Focus 3. There is steam coming out from under the cap of the expansion tank (white smoke)

Breakdown cylinder head gaskets

The most common answer to such a problem is the burning out of the cylinder head gasket (cylinder head), if it is not difficult for you to disassemble the engine, your first thought will probably be to change this gasket. But imagine that there are two more reasons that antifreeze squeezes out of the system.

1- This airlock in the coolant system, because of it, not only the stove in the cabin may not work, and this is already a sign of a plug in the coolant - coolant, provided that the fluid level is normal, but the thermostat may not work correctly. Which can lead to an increase in pressure in the cooling system. Well, squeezing out antifreeze.

2- This is a problem associated with the expansion tank, well, and the smart cap of this tank.

To improve the circulation of coolant through the engine system, when the engine is started, a small pressure is created by the pump, which increases the efficiency of the cooling system. If there is not enough pressure in the coolant system, the engine will heat up faster. Which can lead to boiling or decomposition of the antifreeze. When the decomposition of antifreeze boils, vapors are looking for weak spots... Such as wooden rubber o-rings of the cooling system, bad pipes, not tightly tightened the cap of the expansion tank or radiator.

The cylinder head is, of course, also not a minor problem, but it is also quite possible to diagnose it and, as it turned out, it was very simple.

We start the engine, open the cover of the expansion tank, if on idle you can see bubbles that come from the main hose, this is one of two things, either the air lock breaks, or there is a problem with the cylinder head gasket.

If this is an airlock, then after gasping and waiting for a while, you can get rid of it, the most effective procedure is very difficult in the description, since you need to carry out a series of sequential actions and it is better to show them on the camera.

If there is no plug and there is a problem with the cylinder head, then you will have constant or weak bubbling in the expansion barrel or the level of antifreeze will gradually go away.
If your coolant goes somewhere and there are no traces on the engine, then there may be coolant either in the cylinder or in the muffler, which also often happens. This indicates a problem with the cylinder head.

Expansion tank malfunctions

First, be sure to look at the drips of antifreeze along the barrel, there are three problems with it:

1- the cover of the expansion tank (the cover gasket is hardened) allows air to pass through, there is also a deformation of the cover of the RB - an expansion tank - only replacement with the original.

2- the thread of the expansion tank cap is torn off, in which case a new cap will not help for a long time!

3- the expansion barrel is leaking or bursting along the seam, which manifests itself from an increase in pressure in the engine coolant system, there are cases that as engine cooling the slot joins and the coolant stops squeezing out.

4- air leaks (happens, but rarely)

The most important thing is visual inspection for leaks, and check for damaged hoses.

Pay attention to the thread on which the tank cap was screwed.

It so happens that if you tighten the lid, it rises crookedly and the liquid easily comes out of the tank. If you look at the carving of the tank, it is not really clear whether it is intact or not, but if it turns out to be highlighted on one side, it is all ripped off.

Other reasons

1. White emulsion (foam) on the oil dipstick or on the oil filler cap indicates that coolant has entered the lubrication system, most likely through a hole in the cylinder head gasket. Sometimes, though rarely, the gasket is safe and sound, and the leakage occurs due to a crack in the block itself. But in any case, if there is a white emulsion in the lubrication system, you need to sound the alarm, or even better, pick up a tool and fix the malfunction.

2. White smoke from exhaust pipe when the engine is running, indicates the penetration of coolant into the cylinder (s) of the engine. At the same time, its level decreases, since it partially "flies into the pipe". Car exhaust can be white when the engine warms up, a large amount of condensate and high air humidity - this is not a malfunction, but if there is always a lot of smoke, it is worth considering.

3. Oil spots on the surface of the coolant in the expansion tank or in the radiator indicate the penetration of oil where it should not be.

The reason is most likely a malfunction of the cylinder head gasket. At least it's worth checking it out.

4. Bubbles leaving through expansion tank or radiator indicate coolant penetration exhaust gases... There is a hole somewhere, and most likely it is in the gasket of the block head. A certain number of bubbles may appear when replacing the coolant - this is normal, but if the antifreeze is constantly "bubbling" - then something is wrong.

5 . Clogged oil filler neck

6. Antifreeze leaves under the exhaust manifold mounting stud

8. Water from the radiator enters the cylinder block - it is necessary to replace the radiator

Ford Focus 3. The noise of the engine valve train

Knocking valves in the engine: causes and elimination of the problem

No matter how reliable the car is, the time comes and you are forced to go to the service station to diagnose and repair faults. At the same time, most of the breakdowns can be corrected with your own hands, but there are some that only professionals can help in eliminating. Valve knocking is a common problem, which is somewhere in the middle in terms of the difficulty of fixing. In some cases, it is possible to identify the malfunction and make repairs on its own, while in others, you have to turn to the master for help.

How to diagnose knocking

Without sufficient experience, it is sometimes difficult for car owners to identify the problem by ear. This is not surprising, because the source of extraneous noise can be anything - the crankshaft, bearings, a faulty belt and valves. But unlike other sounds, the knock of the valves betrays itself with a characteristic resonance, with a certain metallic tapping, near the gas distribution mechanism. In addition, unusual noise appears regardless of the engine speed.

In practice, it is not difficult to recognize that the valves are knocking, but sometimes even experienced car owners cannot diagnose their malfunction. But to confirm or refute suspicions, you can make a diagnosis with your own hands. For this:

Raise the hood, then unscrew the cover from the engine filler hole (through which oil flows).
-Listen to the motor operation. If the volume rises, the valves are the cause of the problem.
-Place a stethoscope next to the part you suspect is malfunctioning. With this device, you can accurately determine the cause extraneous noise.

Reasons for knocking

Valve knocking can be caused by many reasons, each of which deserves special attention. Please note that all machines are equipped with camshaft(in the upper part of the engine), and the operation of the valves is provided by the elements of this unit - rods or, in other words, pushers.

So why are the valves knocking? Let's highlight the main reasons:

Changing the clearance between valves and tappets. At car release, the distance between the rods and the valves is fine-tuned. In case of deviation of the parameter from the norm (decrease or increase), a “metallic” tapping appears.
-Fueling the car with low-quality fuel. In the case of using bad fuel, engine detonation appears, due to which the valves also suffer.
-Lack of oil pressure during acceleration. There are situations when the knock of valves appears only when driving at high speed or at the moment of acceleration. The reason is insufficient pressure in the engine lubrication system to increase the speed.
-Incorrect installation or misaligned position of the timing belt (how to mark and tighten the timing belt).
-Natural wear and tear. If valves knock on your car, this often indicates a banal worn out part and the need to replace it.

Why there is a knock of valves on a cold engine

When checking, pay attention to one of the main parameters - engine temperature. There are situations when an extraneous sound appears only on a cold or hot engine. If you "tie" the knock of the valves to this parameter, you can draw additional conclusions. So, if an extraneous sound appears only on a cold engine, then the reasons are as follows:

Narrowing of valves. It is no secret that, during the heating process, the metal tends to increase in volume, and when cooled, it decreases. For this reason, the distance between the valves (on a cold engine) may be small, and after the engine reaches working temperature, it returns to the factory setting.
Motor wear. The second reason why the valves knock is the deterioration of the engine itself.
It turns out that the gap between the valves and the rods does not correspond to the parameter set at the factory, but this manifests itself only on a cold engine. As soon as the engine warms up, the problem goes away.

Why are valves knocking on a hot engine?

If the problem persists after warming up, the reasons may be as follows:

Lack of oil in the reservoir.
-Dirty oil filter.
-Insufficient broach of the camshaft-to-bed bolts.

In addition, extraneous sound can be caused not only by the knocking of the valves, but also by the hydraulic compensators.

How to adjust valve clearances

The easiest and fastest solution to the problem is to go to the service station and instruct the elimination extraneous sounds professionals. But, unfortunately, financial opportunities do not always allow such a luxury, and you have to solve problems with your own hands. Other situations are possible when the car owner is interested in tinkering with the car, and personally gaining experience in repair.

If you find that valves are knocking in the engine and decide to fix the problem yourself, be prepared for some serious work. One mistake is enough to make the sound even louder. That is why, for the elimination of knocking, it is not worth taking on a novice car owner. It is important here to clearly know the sequence of actions, and to follow it. To avoid mistakes, read the instructions for car repair. A short algorithm is shown below:

Drain engine oil.
- Remove the cylinder head plug. This is necessary to gain access to the valves.
-Crank the camshaft so that the mark installed on the pulley aligns with the protrusion of the installation.
- Determine the gap between the valves and the rods by touch. At the same time, change the distance using the adjusting washer.
-Scroll the washer a certain number of times (it all depends on the make and modification of the car).
- Replace all the parts, then check whether the knock of the valves has been eliminated or not.

If, after the work carried out, the problem has not been eliminated, go to the service station and hand the car into the hands of the craftsmen. In such a situation, adjusting the gap with your own hands is unlikely to work. There are situations when other breakdowns are the cause of extraneous noise. But it cannot be ruled out that the previous adjustment was performed incorrectly.

With regard to a car, a jerk is a short-term spontaneous change in the speed crankshaft engine regardless of the position of the accelerator pedal. In daily use, there are usually a series of jerks. The extreme case of a jerk (failure) is a perceptible delay in the response of the engine to pressing the accelerator pedal.

Conventionally, three types of jerks can be distinguished:

At the moment of the beginning of the movement;

During overclocking;

With steady motion, i.e. with a constant position of the accelerator pedal.

To determine the causes of jerks when driving a car with injection engine special diagnostic equipment, therefore, we recommend contacting a service specializing in the repair of fuel injection systems. However, as practice shows, in most cases jerks are caused by insufficient fuel pressure in the fuel rail or a malfunction of the position sensor. throttle built into the throttle body cover. In addition to this, the specific cause of jerking of the car Ford focus 3 equipped with a system electronic control throttle assembly, there may be a malfunction of the accelerator pedal.

If you have some skills, you can determine the cause of the jerks yourself.
At the moment of the beginning of the movement, the limiting case of a jerk-failure most often takes place. The most unpleasant sensations are associated precisely with the delay in the response of the engine to pressing the accelerator pedal. Sometimes the engine even stalls. A jerk occurs at the moment the throttle valve starts to open, when, according to the signal from the throttle position sensor, the ECU determines the moment of transition from the mode idle move to load mode and should increase the amount of fuel supplied through the injectors. With insufficient pressure in the fuel rail, even with an increase in the duration of injection, there is not enough fuel for a smooth start-off.

In addition, a jerk may occur due to a malfunction of the electromechanical part of the throttle unit and contamination of the throttle valve with deposits from crankcase gases.

The cause of jerks during acceleration can be, as in the previous case, insufficient fuel pressure in the fuel rail. The electronic unit engine control, having received a signal from the throttle position sensor about the intensive opening of the throttle to a large angle, it seeks to maximize the fuel supply, but due to the reduced fuel pressure, it is not able to do this.

In addition to these reasons, jerks when accelerating a car with robotic box gears can be caused by both an insufficient number of working fluid in the box, and a malfunction of the box itself.

Jerks when driving Ford Focus 3

Such jerks are most often caused by a malfunction of the ignition system. Diagnostics and repairs are required. On the way, you can try to do the following yourself:

Examine the engine compartment carefully. Switch off the ignition and check the tightness and seating of all wires and connectors at the ignition coil and high voltage wires. Start up the engine and listen to its work: the crackle during the breakdown of the high voltage current to the "ground" is weak, but distinct. In complete darkness, a spark is clearly visible during breakdown;

Replace spark plugs regardless of condition and mileage. Pay attention to the condition of the candles: if it is not correct, it may be necessary to repair the engine or its systems.
A specific cause of jerks during steady motion of the Ford Focus 3 can be a failure of the throttle position sensor built into the throttle cover.

Additional symptoms confirming a malfunction of this sensor:

Uneven engine idling;

Decrease in maximum engine power.

The throttle cover is non-separable, so it is not repairable. If the sensor is found to be faulty, replace the throttle assembly with cover.

Hello everyone!

lexa264
Your problem is one to one like mine. It just started somewhere 1500 km before TO-1 (on a run of 12500). At TO-1, all filters were changed, everything was checked, looked at, lubricated where necessary ... All that took place in my personal presence. No crime was found.

I will describe in more detail what is happening on my car (FF3 1.6 PS 125 hp Trend Sport sedan, currently running at 14,500).
1. The first 20-30 km of the trip after the usual overnight stay - everything is perfect (starts smoothly, rides smoothly, nothing crunches / creaks, etc.)
2. Then begins:
- I smoothly get under way after the traffic light (disclaimer: if the traffic light is short for about 10s, then I leave the box in D and hold the brake, if the traffic light is long, 15-30c I switch the box to N and hold the brake, or put it in P if keep the pedal on slope)
- I feel that a vibration starts in the nose of the car
- at the same time, the car does not jerk back and forth, just a kind of wave starts to go along the body
- approximately at the transition from 1 to 2 gear, the vibration becomes very noticeable, the steering wheel is already shaking and the passengers in the car feel
- then the vibration wave, as it were, goes to the center of the car, weakens a little and, finally, once again shuddering noticeably (approximately transition from 2 to 3 gear), it fades with further acceleration somewhere in the area of ​​the box
3. I would like to emphasize that with all this, the car moves smoothly, i.e. it feels like it just sausages from some incomprehensible vibration, but does not twitch back and forth, it seems to go evenly
4. Metallic clangs at the same time, it seems, is not audible
4. More features:
- if it isoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooheadouight was home was on, just press the gas pedal a millimeter, then there is NO vibration (well, or quite insignificant, which indicates that the engine is straining and starts to accelerate)
- if you put the sneaker into the floor, then there are almost NO vibrations either
- it happens that vibration disappears AT ALL, even if you do not follow the position of the gas pedal at the time of acceleration

That is, if you add everything together, then the conclusions are:
- the car vibrates noticeably during acceleration, but does not jerk back and forth, it goes evenly forward
- this whole thing manifests itself only on a sufficiently warmed up car
- there is a certain resonance at a certain position of the gas pedal, which significantly sausages the car
- it rolls over from time to time, i.e. the malfunction does not always appear

After reading all the topics about vibrations and so on, I figured out the possible options:
- engine mounts are unlikely, because otherwise the symptoms would not appear on a warm car (although maybe I'm wrong?)
- I don’t sin at the box, I looked at everything, it’s dry at the junction with the engine, the firmware is fresh (just in case, reloaded, but nothing has changed); Photo:
- here, too, nothing seems to flow at the joints; Photo: ,

Such is the information, comrades! I would like to hear who thinks about this, otherwise I already broke my head, trying to determine the joint myself. Of course I will go to the dealer, but as practice shows, it is better to tell them what the problem may be, and a lot of time and money will be lost.

P.S. probably later I will make a detailed report on the passage of TO-1 and throw here a link to the topic
P.P.S. I apologize for the sea of ​​text, all the best!