Question about Cars & Trucks

2 Answers

I have a knocking sound around the belt drive case or the top of the engine and it smokes people have told me valves and clutch and piston idk what to do

Posted by Anonymous on

2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Cars & Trucks Master
  • 948 Answers

First of all, always make sure you have enough oil in your engine, check often, because it sounds like you are leaking and/or burning oil. Some rods will knock for a while before your engine in ruined, but when you combine knocking with smoking, you are generally describing a dying engine. Baby your engine and see if you can keep it going for a while so you can save up for a rebuilt engine or a new car. If you look and oil is leaking around the top of your engine, you may be burning oil because your valve gasket leaks onto an engine that gets really hot and burns it. If you see it leaking, you need a new valve gasket which is usually less than a hundred bucks if you do it yourself. On some simple engines it is not hard to do, I just did one the other day. It is unlikely your clutch has anything to do with it. Good luck.

Posted on Apr 02, 2015

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert who has answered 20 questions.


    An expert that has over 10 points.


    An expert whose answer got voted for 2 times.

  • Expert
  • 60 Answers

Dear user,
In some cases, gasoline problems cause the irregular combustion that leads to knocking sounds in an engine. This can occur because of problems with gasoline octane. Gasoline's octane ratings signifies the amount of compression the fuel can handle before spontaneous ignition. When this spontaneous ignition happens instead of the normal ignition, knocking may occur and can cause damage to the engine. The lowest octane gases are typically the least capable of withstanding compression and are more likely to ignite this way.
Sometimes the sound of engine knocking is caused by something other than the typical combustion process problems. For example, some types of mechanical issues may cause these knocking sounds. Such mechanical issues can include defects in the crankshaft bearings, broken flywheels, and water pump bearings that are worn out.


Posted on Apr 02, 2015

6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

  • 315 Answers

SOURCE: loud knocking sound, complete loss of power, 1991 300zx

Wont know till you take it to a mechanic for troubleshooting.

Posted on Mar 05, 2009

  • 26 Answers

SOURCE: knocking in rear struts

bad ball joints

Posted on Apr 24, 2009

  • 1 Answer

SOURCE: Loud engine knocking on 2001 Ford Focus

Sounds to me like a very common problem has occured to your neighbor. If this is a SOHC engine, one of the valve seats in the number 4 cylinder has fallen out. I'm sure it has damaged the head and the piston. Stop trying to run it or you might blow a hole in the cylinder wall or break a rod or both.

Posted on Aug 07, 2009

  • 64 Answers

SOURCE: Cold engine knock after timing belt and water pump replaced

Hi, this could be because the cam timing is a notch or 2 out. The fact that it quiets down when the engine heats up is because the timing is retarded as the engine reaches operating temperature. You will have to look at the cam timing and make sure that they have done it correctly. If that is fine it might be that they have dropped something, like a bolt or nut into the valve cover when it was removed.

Posted on Jan 17, 2010

Testimonial: "Absolutely awesome! Thank you very much."

  • 1 Answer

SOURCE: newly overhauled toyota corolla 2e engine emits black smoke

I have toyota corona 3s engine it smokes black and fuel consuption is high we have changed the engine oil and cylinderhead gassecate but still black smoke is comming what should i do

Posted on Mar 29, 2010

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Engine knock sounds like top end,been stripped nothing found

If you can open the bottom end check the piston rod im sure ull find a loose piston rod in there goodluck

Mar 06, 2015 | 2005 Nissan X-Trail 2.0

2 Answers

What causes upper engine knock in 2003 4.2 trailblazer?

upper engine knock can be caused by a worn cam shaft worn lifters, although this is usually a ticking noise. piston skirt collapse which can sound like its in the upper engine. a bad wrist pin even a valve hitting the top or the piston like carbon build up on top of the piston.

Aug 25, 2014 | 2003 Chevrolet TrailBlazer

2 Answers

Kia sorento 2012 produce sound look like power steering problem and it gets louder when ever I acceleration gear, so I took belt out and start the engin with no belt I found that sound was in engin!!

If its a knocking sound:

1. PISTON SLAP: Makes a sharp metallic noise. Idle engine and short out each cylinder plug. The noise will disappear when plug with bad piston is shorted. Noise will also disappear at acceleration. This can be caused by worn or out of round cylinder, or broken piston ring. Correct problem by re-boring cylinder and/or replacing piston.
2. VALVE NOISE: Makes clicking or rattle noise. Caused by excessive wear on valve stem or lifter, out of adjustment, or stuck valve. Correct by adjusting valve clearance, replace worn valve or lifter, regrind cam, replace valve guide and /or valve. A stuck valve can sometimes be loosened by passing oil through the carburetor while engine is running.

3. ROD BEARING KNOCK: Makes sharp metallic noise similar to a piston slap. Detection is opposite of piston slap. Rod knock is not heard at idle. Knock becomes louder as engine speed is increased. Caused by excessive rod bearing clearance. Correct by adjusting rod bearing clearance to .0015 inches by removing shims. May require re-pouring rod bearing.
4. REAR MAIN BEARING KNOCK: Makes dull knocking or thud noise. Detected at speeds between 20 and 50 MPH. Knock will normally decrease or disappear while pulling or decelerating. Noise will be detected the loudest at normal driving speed, when not pulling or decelerating. Correct by adjusting bearing clearance to .001 to .0015 inches. If knock is excessive, crank should be checked for out of roundness. May need to re-pour all main bearings to correct.
5. TIMING GEAR KNOCK: usually the most difficult to diagnose. If gear is loose or badly worn it will knock in all ranges. Run engine slightly above idle speed. Slowly open and close throttle. Knock will continue to be present, but just as engine slows down knock will become a slight rattle. Remove timing pin and reinsert into timing hole on timing gear cover. Press timing pin tightly against timing gear and accelerate slightly above idle. Knock will significantly be reduced or disappear. Correct by replacing both timing gear and crank gear as a matched set. The two gears should have a backlash clearance of .003 to .004. If more than .009 inch backlash, an oversize (.005) timing gear should be installed.
6. WRIST PIN SLAP: This can not be detected by shorting out the cylinder plugs. Rapidly accelerate and decelerate the engine speed. The engine will pass through a certain speed range when the wrist pin will rattle at about the same pitch as a valve tappet noise. This can be corrected by installing a new wrist pin bushing in the rod or new wrist pin f badly worn. Wrist pin should fit the piston and connecting rod with a tight metal to metal fit. The pin can be pushed into the piston and rod with a slight pressure of the hand. Pin to rod clearance is .0003 to .0005 inches.

Dec 15, 2013 | Kia Sorento Cars & Trucks

2 Answers

My car is burning threw oil like supper fast

year, make, model, engine size?

How does it run?

Do you see a lot of black smoke out the tailpipe when you accelerate?

do you see anything leaking?

Apr 04, 2013 | Cars & Trucks

3 Answers

On the 960 volvo if i broke atimeing belt while driveing dont the pistons come up as far as the crank will let it and the valves stop where they are at if not why dont the pistons hit the valves while its...

If the belt is turning the bottom and top end in time,no problem.Break a belt and the top end stops with the some valves open and some closed,meantime the bottom end keeps going around and around and the pistons up and down until the engine not only quits but continues until the vehicle is either put in neutral or until it comes to a stop,either way the damage is dune with-in the first seconds of the belt breaking,sorry for the news but this is true of all overhead valve engines.

Mar 24, 2010 | 1992 Volvo 960

1 Answer

At start up car smokes like crazy but only once in awhile other times fine also when driving once in awhile you get like a spark knock and then the car smokes like crazy and somtimes dies after a minute ok...

Sounds like you have a bad valve seal (or maybe several).

Basically there are seals for your valves that keep oil from dripping down into your pistons and smoking like crazy. When these go out, oil drips down when the car sits still for a while.

It's an intermittent problem because not all of your valve seals are bad. Depending on the position of your engine when you turn it off determines whether or not your bad valve seal(s) is going to leak oil into your piston.

I had this problem on one of my first pickup trucks. From everything that people told me, you don't really have to worry about it. It's embarassing, but it's not causing any real problems.

To confirm that this is the case, you could pull your spark plugs. 1 or more (but not all) should be fairly black and even have a little bit of gunk on it (maybe like a bbq grill).

I hope this helps.

Aug 20, 2009 | 1996 Mercury Sable

1 Answer

Knocking on top of motor its not smoking and has

The timing has probably gone out of adjustment. Do not drive the car until you have it checked out. You may or may not have a valve / piston clearance. Sometimes carbon build up can make a clearance engine no longer have it. I hope this is the case with your engine. It is possible that you are experiencing pre-detonation (knocking and pinging) This can be a timing issue as well. An auto mechanic or experienced friend should help you with this issue. Good luck with your repairs. Thank you for letting me serve you on Fixya.

Jul 26, 2009 | 2002 Subaru Legacy

2 Answers

Ok I have a 1985 nissan that has a knock coming from the engine and idk what it is? what could be wrong?

If it is knocking sounds like you may have broke a piston rod. I would not drive it because its cheaper to have it fixed now if you keep driving it the rod will most likelt come thru the block then your looking at replacing the whole engine. Good luck

Jul 10, 2009 | 1985 Nissan 300ZX

1 Answer

Engine knocking

Good news is - I don't think you need a new engine.

As there are many moving parts that could create a knocking sound, it usually needs careful inspection to identify where it is from.
I will give a list of some of the causes and remedies. Yours will probably be one of them, but unless I was there - it could be any.

Loose exhaust component (causes rattles and thumps) - replace parts or joints.
Loose Engine mounts - Engine will move about a lot more than normal - Replacement of mounts.
Fraying Belts - causes continual ticking or slapping - Replace belts and check tension.
Timing is off - bad running, lack of power, pre ignition or knocking at low revs. Check timing belt - Replace, Tune engine.
Cracked valve - slight misfire worse at low revs - Replacement valves.
Clutch Problems - Broken spring or loose bolt - Check clutch plate - replace clutch plates.
Older engines - often accompanying smoke -
Broken Piston ring - continual ticking or occasional misfire - Replace Piston rings
Worn Piston bearings - Piston Slap - Replacement of all piston bearings.

Transmission Problems (only heard when in gear or with clutch out) - Broken gear teeth or worn bearings - Replacement of Transmission or rebuild.

Some of these remedies require engine removal and strip down, others are a simpler fix.

Dec 26, 2008 | 1990 Cadillac Fleetwood

1 Answer

3.3L engine jumped timing

sound like compression ring gone pressure goes in oil if noise i dont think it worth to fix that motor a good second hand one there gone engine normally hope it FIXYA our problem thanks pierre

Jul 04, 2008 | 1999 Dodge Grand Caravan

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

59 people viewed this question

Ask a Question

Usually answered in minutes!

Top Cars & Trucks Experts


Level 3 Expert

75807 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22133 Answers

Randy Ohler

Level 3 Expert

14585 Answers

Are you a Car and Truck Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides