Noisy Engine... Thoughts?

lfhoward · **Posted:** Thu Feb 13, 2014 12:33 pm

Hi Jeepers,
My 3.7 has been noisy since the day I got it, when it had 23K on the clock. I just passed 83K yesterday, and nothing much has changed. I thought I'd see how many other 3.7 owners have this noise, and whether it ever caused a problem.

The noise can be heard at idle, sort of a clicking. But no biggie.

There is no significant engine noise in the cabin during normal driving or acceleration when the engine is under load, like when getting up to highway speeds or maintaining speed on the flat or climbing hills.

Here is where I notice it: There is a clattering or tapping sound from the engine when it is at high RPM's and coasting, when not under heavy load. This happens at the top of gears just before upshift, like when you are cresting a hill in 3rd, just before it shifts into 4th. It happens when coasting down long hills on the interstate in 4th, or when descending steep hills in a low gear (at high RPM's). It happens when in tow/haul mode on the highway when there isn't a heavy load in tow. (I use tow/haul on 45-50 mph roads with undulating hills to keep the transmission from shifting between 2-3-4 all the time. Tow/haul keeps it in 3rd.)

What I've found is that RPM's usually have to be over 2500 for this to happen, when there isn't a heavy load on the engine. The tapping or clattering or hammering sound corresponds to the turning of the engine/cylinders. It sounds like metal banging on metal. I have had my oil tested by Blackstone Labs and there aren't any extra metal deposits in it, and I haven't noticed any change in performance or an increase in noise over the last 60K miles. 1 qt of Lucas Oil plus 4 quarts of regular oil makes it a little quieter. I was on a long trip through the PA mountains yesterday and noticed it a lot.

Thoughts? Thanks in advance!
--LFH

Gageraid · **Posted:** Thu Feb 13, 2014 12:38 pm

Hmmm well I think every 3.7 has the tick at idle. I don't even notice mine anymore. Seems to be more prominent on the driver's side, not sure though.
I'm thinking most likely normal because I've seen quite a few threads about this sort of thing in KJ's and KK's.
Ever notice if it's any louder if you were to go up a hill when the engine is still cold? Are you using 5w-20 or 5w-30?

lfhoward · **Posted:** Thu Feb 13, 2014 12:47 pm

Hi Gage, most of the time I notice it the engine is not cold, but I think it still happens if the engine is cold. Most of the cold-engine driving I do is in town, and this is usually a highway issue. I have always used the recommended 5w20 oil until this last oil change, when I went with 4 quarts of 5w20 and 1 quart of Lucas. This helped quiet it a bit, although the engine still makes the clattering noise in those situations. I am getting close to 3000 miles on this oil change so I am about to change the oil again in another week or so.

Gageraid · **Posted:** Thu Feb 13, 2014 12:52 pm

lfhoward wrote:

Hi Gage, most of the time I notice it the engine is not cold, but I think it still happens if the engine is cold. Most of the cold-engine driving I do is in town, and this is usually a highway issue. I have always used the recommended 5w20 oil until this last oil change, when I went with 4 quarts of 5w20 and 1 quart of Lucas. This helped quiet it a bit, although the engine still makes the clattering noise in those situations. I am getting close to 3000 miles on this oil change so I am about to change the oil again in another week or so.

I only ran 6,000 miles of regular oil before using synthetic. It may have quieted it down slightly. Don't have much to compare it to.
My engine is much smoother and quieter on the highway compared to city. I would think the noise would be quieter in overdrive on the highway.

Marlon_JBT · **Posted:** Fri Feb 14, 2014 10:53 am

Just another 3.7L quirk.

Tickiest engine ever. Ticks upon startup, ticks at idle, ticks at high revs. Ticks when off.

Cherrie 274 · **Posted:** Fri Feb 14, 2014 11:43 am

Marlon_JBT wrote:

Just another 3.7L quirk.

Tickiest engine ever. Ticks upon startup, ticks at idle, ticks at high revs. Ticks when off.

.

carlosburitica · **Joined:** Sat Jan 05, 2013 1:07 pm **Posts:** 309

when i first showed my car to my father in law he thought it was a diessel. the knocking sound is normal on the 3.7.

ajohns1288 · **Posted:** Sat Feb 15, 2014 7:01 pm

carlosburitica wrote:

when i first showed my car to my father in law he thought it was a diessel. the knocking sound is normal on the 3.7.

Heh, I was coming back into the US from Canada once and the border guard said "Nice Jeep, you got a diesel in there?" I'd love the extra torque though. :JEEPIN:

lfhoward · **Posted:** Sat Feb 15, 2014 8:45 pm

Thanks everyone. Seems like this is pretty normal for the 3.7. It makes more noise than the 4.0 in my old XJ. :shock:

I'll keep an eye on it and post if anything changes. So far so good, the last 60,000 miles!

Gageraid · **Posted:** Sun Feb 16, 2014 10:00 am

lfhoward wrote:

Thanks everyone. Seems like this is pretty normal for the 3.7. It makes more noise than the 4.0 in my old XJ. :shock:

I'll keep an eye on it and post if anything changes. So far so good, the last 60,000 miles!

I know you take care of your KK, so it should be okay.
I don't think it would really change anything (or maybe it would), but have you changed your PCV valve yet?

lfhoward · **Posted:** Sun Feb 16, 2014 2:33 pm

Gageraid wrote:

lfhoward wrote:

Thanks everyone. Seems like this is pretty normal for the 3.7. It makes more noise than the 4.0 in my old XJ. :shock:

I'll keep an eye on it and post if anything changes. So far so good, the last 60,000 miles!

I know you take care of your KK, so it should be okay.
I don't think it would really change anything (or maybe it would), but have you changed your PCV valve yet?

No not yet. I've done plugs and air filter on schedule. Those will all be due again in another 8,000 miles (when I reach 90K). Oil changes every 3000-4000 miles too. I'll be planning on changing all the fluids (coolant, power steering, diffs, tc, and trans) as well once I get to 90K. That'll be an expensive milestone! The TB isn't really all that bad-- I looked into cleaning it not long ago and it wasn't full of carbon.

Gageraid · **Posted:** Sun Feb 16, 2014 11:48 pm

lfhoward wrote:

Gageraid wrote:

lfhoward wrote:

Thanks everyone. Seems like this is pretty normal for the 3.7. It makes more noise than the 4.0 in my old XJ. :shock:

I'll keep an eye on it and post if anything changes. So far so good, the last 60,000 miles!

I know you take care of your KK, so it should be okay.
I don't think it would really change anything (or maybe it would), but have you changed your PCV valve yet?

No not yet. I've done plugs and air filter on schedule. Those will all be due again in another 8,000 miles (when I reach 90K). Oil changes every 3000-4000 miles too. I'll be planning on changing all the fluids (coolant, power steering, diffs, tc, and trans) as well once I get to 90K. That'll be an expensive milestone! The TB isn't really all that bad-- I looked into cleaning it not long ago and it wasn't full of carbon.

What is "tc"? I think coolant will be close to as much as it cost to do the trans.
I don't know off hand, but you should be do for the PCV. It was relatively easy.
Do yourself a favor and clean the throttle body, but like I did, take it off and clean the other side, too!

lfhoward · **Posted:** Mon Feb 17, 2014 8:23 pm

I meant Transfer Case by tc. Too many acronyms! :-)

Do you have a good how-to thread you could point me to for the PCV? And how will it benefit gas mileage/engine performance? I've never changed one.
Thanks!

Gageraid · **Posted:** Tue Feb 18, 2014 9:00 am

lfhoward wrote:

I meant Transfer Case by tc. Too many acronyms! :-)

Do you have a good how-to thread you could point me to for the PCV? And how will it benefit gas mileage/engine performance? I've never changed one.
Thanks!

I don't have a how to. You'll need pliers to get the clamp off and an open ended wrench if I remember correctly.
Careful when you pull off the rubber part, sometimes it's easy, sometimes it requires some effort.
$20 from the dealer for the part.
I think it effects emissions most, but wouldn't be surprised if a bad one would hurt mpg. They get gummed up after a while. Pretty sure you're due at that mileage. It was the first thing I did when I got my KK.

tommudd · **Posted:** Tue Feb 18, 2014 10:43 am

PCV should be changed on a regular basis, mines done every 20,000 or so , cheap and easy to do, 90,000 is way past due for changing one
As far as the noise, have to remember with plastic intake, thinner valve covers etc all of that leads to hearing more noises within the engine. The 4.0 was a noisier engine as well you just can't hear them as much.
I never pay any attention to the little ticks its just the 3.7 being happy :wink:

lfhoward · **Posted:** Tue Feb 18, 2014 1:50 pm

Thanks Tom and Gage,
I will definitely put the PCV on my to-do list. I'll probably do it the next time I do spark plugs, which isn't too far into the future.
Thanks for the reassurances about the rattly 3.7. She's not unhappy per se, just a bit rambunctious at high revs.

lfhoward · **Posted:** Tue Apr 22, 2014 5:48 pm

Just for completeness...

A rod bearing gave out at 86,000 miles. :dead:

Engine swap in progress...

Noisy Engine... Thoughts?

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