4.0 SOHC engine noise
#1
4.0 SOHC engine noise
I got a Ranger in disguise 2009 Mazda B4000 about 2 weeks ago. Engine has 70,000 miles on it. The only thing I have done to the engine is change the oil. 2 days ago it started making a loud peck/knock. It will still start and run smooth except for the noise. The noise will change with RPMs and is present from start up and doesn't change if the truck is warm or cold. I think the noise is coming from under the front of the driver's side valve cover, had a mechanic in the family listen and he said it sounded like it was under the intake. Both of use suspect a broken timing chain guide.
My current plan is to get a borescope and check the pistons and valves for damage. Remove the hydraulic tensioner and try to see anything through that hole. If nothing is found, then remove the valve covers for inspection. Once I find out the issue, I will then have to decide whether to fix it myself, pay to have it fixed, or drop in a low mileage replacement engine.
Also been looking around at used engines, and most sights do not show a 2009 Mazda 4.0 and a Ford 4.0 interchanging. Is there any difference at all between the Ford Ranger and Mazda B4000 as far as the engine?
Is there anything I am missing or should do instead? I have attached a video with the sound.
Thanks!
My current plan is to get a borescope and check the pistons and valves for damage. Remove the hydraulic tensioner and try to see anything through that hole. If nothing is found, then remove the valve covers for inspection. Once I find out the issue, I will then have to decide whether to fix it myself, pay to have it fixed, or drop in a low mileage replacement engine.
Also been looking around at used engines, and most sights do not show a 2009 Mazda 4.0 and a Ford 4.0 interchanging. Is there any difference at all between the Ford Ranger and Mazda B4000 as far as the engine?
Is there anything I am missing or should do instead? I have attached a video with the sound.
Thanks!
#2
RF Veteran
iTrader: (1)
Welcome to the forum
2004 and up 4.0l SOHC engines had the newer designed timing chain setups so didn't have the previous problems seem in the 1997 to 2003 engines
But things still break on any engine.
Drivers side front is where timing chain is on that side.
Passenger side has the front and rear chains
Cold engine
Remove/loosen fan belt
Start engine
It is often easier to localize an engine noise when fan and accessories are quiet
Don't run engine more than 2 minutes this way as there is no water pump circulation, also Battery Light will be on because alternator is not working.
Neither is an issue for a few minutes.
If you use your current lower and upper intake and exhaust manifolds then you can use any 4.0l SOHC engine from 1997 to 2011, from Ranger, B4000, Explorer, Mountaineer, or Mustang(Mustangs used different Cams, more HP, less Torque)
So basically a Long Block swap.
As said the 2003 and earlier needed the timing chains swapped out to newer design.
Things that should also be changed while engine is apart:
Knock sensor
Heated PCV Valve, if so equipped
Rear main seal
Thermostat housing on these often cracked and leaked, judgement call
2004 and up 4.0l SOHC engines had the newer designed timing chain setups so didn't have the previous problems seem in the 1997 to 2003 engines
But things still break on any engine.
Drivers side front is where timing chain is on that side.
Passenger side has the front and rear chains
Cold engine
Remove/loosen fan belt
Start engine
It is often easier to localize an engine noise when fan and accessories are quiet
Don't run engine more than 2 minutes this way as there is no water pump circulation, also Battery Light will be on because alternator is not working.
Neither is an issue for a few minutes.
If you use your current lower and upper intake and exhaust manifolds then you can use any 4.0l SOHC engine from 1997 to 2011, from Ranger, B4000, Explorer, Mountaineer, or Mustang(Mustangs used different Cams, more HP, less Torque)
So basically a Long Block swap.
As said the 2003 and earlier needed the timing chains swapped out to newer design.
Things that should also be changed while engine is apart:
Knock sensor
Heated PCV Valve, if so equipped
Rear main seal
Thermostat housing on these often cracked and leaked, judgement call
#3
#4
Noise is the same with the belt removed.
Removed the timing chain tensioner and still seemed stiff and did not see anything through the hole that looked out of place but could not see much. Is there any chance the tensioner is bad causing the noise. Noise is the same hot and cold though.
Pulled spark plug and looked at piston. I attached a picture. Looks like a valve shaped mark, but not sure. Is this piston normal or damaged?
Thanks
Removed the timing chain tensioner and still seemed stiff and did not see anything through the hole that looked out of place but could not see much. Is there any chance the tensioner is bad causing the noise. Noise is the same hot and cold though.
Pulled spark plug and looked at piston. I attached a picture. Looks like a valve shaped mark, but not sure. Is this piston normal or damaged?
Thanks
#5
RF Veteran
iTrader: (1)
Can't tell from that picture
This is what it looks like if valves hit pistons: http://www.explorerforum.com/forums/...ngs-jpg.77924/
But engine will no long run at that point.
MPG is about vehicle power to weight ratio and YOUR driving habits
Different cam timing wouldn't change MPG if driving habits were the same, so mustang or truck 4.0l would be the same if everything else was the same
This is what it looks like if valves hit pistons: http://www.explorerforum.com/forums/...ngs-jpg.77924/
But engine will no long run at that point.
MPG is about vehicle power to weight ratio and YOUR driving habits
Different cam timing wouldn't change MPG if driving habits were the same, so mustang or truck 4.0l would be the same if everything else was the same
#6
Can't tell from that picture
This is what it looks like if valves hit pistons: http://www.explorerforum.com/forums/...ngs-jpg.77924/
But engine will no long run at that point.
This is what it looks like if valves hit pistons: http://www.explorerforum.com/forums/...ngs-jpg.77924/
But engine will no long run at that point.
#7
I suspect that the truck went a long time since the previous oil change. Would it be possible that some crude broke lose in the engine causing the chain tensioner to fail, or that it just wore out? It would be a lot easier to put a new tensioner in than to remove the valve covers as a next step.
#8
RF Veteran
iTrader: (1)
You can remove the tensioners and then disable spark(unhook coil wire connector) and crank engine a few times, that should clear tensioner oil passages.
But a rattle is what loose tensioner sounds like, not "knock"
Yes, if valve touches piston it will bend and then not seal that cylinder, so loss of compression and that cylinder will no longer fire.
Bending 1 valve would be a long shot with overhead cam, if timing slipped then 3 valves would be effected on a V6.
Engine could run but you would know something major was wrong because it wouldn't run well and noise would be "knocks" not "a knock"
What you describe is more like 1 valve is effected not several, so valve cover needs to come off
But a rattle is what loose tensioner sounds like, not "knock"
Yes, if valve touches piston it will bend and then not seal that cylinder, so loss of compression and that cylinder will no longer fire.
Bending 1 valve would be a long shot with overhead cam, if timing slipped then 3 valves would be effected on a V6.
Engine could run but you would know something major was wrong because it wouldn't run well and noise would be "knocks" not "a knock"
What you describe is more like 1 valve is effected not several, so valve cover needs to come off
#9
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