Nissan Frontier Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter #1
Just got a 2002 xe 2.4 with 51,000 miles. It’s in great shape. There are a few frustrations though. It has an exhaust drone between 800-1,500 rpm. I have what seems to be a hidden rattle. I think it is a heat shield. Lastly, the mpg seems low. The gage drops like a lead balloon. I’m getting between 17-18 mixing driving. Since I got it I have replaced:

spark plugs and wires rotor and
All vacuum lines
Air filter
Oil and filter
Fuel filter
PCV
Alternator
Belts
New tires. Went to 235/75/15

And ideas why the mpg is so low. No codes.
 

·
Registered
Joined
·
1,617 Posts
That's normal. I was just as shocked when I got my 2004 KC KA24DE w/ auto tranny. The same KA24DE engine gets better mileage when paired with a manual transmission.
My previous truck, a 2006 Tundra DC w/ 4.7L V8, got better gas mileage.
 

·
Registered
Joined
·
1,617 Posts
I had a rattle that would happen at every stop light. But every time I got home determined to find the source....it wouldn't rattle. I even tried setting the parking brake, chocking the wheels and putting it in Drive and still nothing.
All heat shields were good so I slid under and just start yanking, pulling, pushing and shaking every section of exhaust and found the culprit.
It's directly under the driver side floor board. I had to remove it and close it up some so it would be tight and hold the exhaust pipe instead of loosely surrounding it. I basically took the round out of it with a 3 lb sledge.
 

·
Premium Member
Joined
·
5,548 Posts
Original exhaust/muffler, or aftermarket?
My '00 XE original tire size was 215/65-15...what is your factory size?
Since you're on taller tires, you're traveling farther than your odometer is indicating, fwiw.
 

·
Banned
Joined
·
583 Posts
maybe that rattling sound is broken crumbling media inside your cat converter, that would be detrimental to your mileage,thru the messed up short-long term trims.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #8
Is a metallic sound. It speeds up with the rpms. Almost a waaawaaawaaa rhythmic sound. As far as I can tell it is coming from the right front of the engine. I don’t see a heat shield where it is coming from.
 

·
Registered
Joined
·
2,849 Posts
Is a metallic sound. It speeds up with the rpms. Almost a waaawaaawaaa rhythmic sound. As far as I can tell it is coming from the right front of the engine. I don’t see a heat shield where it is coming from.
Hopefully, it's not a timing chain rattle.
 

·
Registered
Joined
·
2,849 Posts
It's always hard to diagnose noises on a forum level. By they time they get recorded, placed on YouTube and heard on computer speakers, especially on a laptop, they never sound the same as hearing it in person. To me it sounds like upper timing chain rattle. What would happen on KA24DE engines is debris would restrict the oil flow in the tiny oil channel that feeds the chain tensioners. For a while, there was a timing chain guide that sat above the top length of the upper timing chain and was bolted to the top of the cylinder head with two, 8Mx1.25 bolts (12MM head). So, the oil would get restricted and the chain would slack a little, which caused it to contact the upper guide. It would make that rotational, grinding or rattling noise and often would stop if you ran the engine at a higher RPM than idle. The correct fix of the problem would involve taking apart the front of the engine and clearing out the tensioner channel with brake cleaner and compressed air. Nissan released a technical service bulletin with a half-assed fix that instructed the tech to removed and discard the upper chain guide, which did eliminate the noise. The only way you would know if you had that guide would be to remove the valve cover and see if it's there, but 2002 is pretty late in the KA24DE's run and I'm pretty sure Nissan stopped installing that guide by then (not 100% sure, but "pretty" sure). If you have a mechanic's stethoscope, you would hear the noise loudest at the top/front of the valve cover and near the top part of the upper timing cover. Still, using the stethoscope could be used to help isolate the noise. You could also remove the drive belts and run the engine (for a short time) to see if the noise is in the engine or due to a bad pulley bearing.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #12
Thanks. I do have a stethoscope. I diagnosed the problem today. It’s the Alternator. It new also. The valve cover was quiet. I put it to the alternator and it sounded like marbles. It goes back tomorrow.
 
1 - 12 of 12 Posts
Top