spartan99

Thicker oil

Clean your injectors

Clean your valves

Replace aged plugs and wires

My 3.8 purrs like a kitten at 90k miles.it was getting noisy until I did these these.

Poor ignition and a dirty combustion chamber and dirty valves creates noise in a variety of ways.

This thread is for novices and experts looking for an intelligent discussion on the matter so don't embarrass yourself with trolling or negativity..

There are no stupid questions for those who want to learn more and quiet their3.8. Not everyone has a technical background.

wittys-jk

Interested since I just turned 90K.

Already changed plugs and plug wires so can you elaborate on the other items on how to actually do these?

Can you start with the fuel injectors?

spartan99

You can get the injectors and valves cleaned by a mechanic or you can use injector cleaner like techron or other cleaners to put in your tank, whichever you prefer or gets you the results you want.

These tips apply to any engine. The combustion process is pretty extreme so no engine is immune to getting carbon build up and other forms of byproduct from the process. The 3.6's will get noisy as they age too. It's just the3.8 gets REALLY noisey lol.

People who've let their plugs in too long will have noisier engines because the poor combustion will leave more debris to build up from an incomplete combustion. These engines seem to rip through the OEM plugs. It seems that most people here have found them in bad shape by 60k.

wittys-jk

What about cleaning the valves, what is your approach there?

Thanks for the previous answer by the way.

ezndo

I had a noisy 3.8 after my daughter drove it for less than a mile with the low oil pressure light on (oil level was good btw).....I quieted it by selling it!

spartan99

Valves can be cleaned with fuel additives and newer plugs and wires. Good plugs and wires and an additive to clean the combustion chamber will clean them.

You can find valve cleaner additives at most stores. It all works together. Plus these 3.8's like to sip oil past the valve guides and or piston rings which of course leads to contaminant build up which leads to poor ignition which leads to noise.

And 10-40 is the more appropriate viscosity for this design. 5w-30 is too thin which creates noise for obvious reasons.

spartan99

Anything that works to create good combustion is what you want to do to quiet your motor. Oil aside that's another issue. Most of the noise comes from ignition. Lots of stuff on Google about how poor combustion leads to noise if you want more info.

Ryan0260

Mopar combustion chamber cleaner. It works better if you let it sit longer than recommended to let it really soak in.

lowendrider

Mine seems to run pretty smooth..only 60k miles..except for one problem. I get a rattle on start up that annoys me. I run 5w30 and have used Purolator, Motorcraft, and Mopar filters. Any suggestions? Also, it doesn't always do it. Maybe the way its parked? Uphill vs Downhill?

wittys-jk

Thanks for the info, so far she is still quiet but I want to stay ahead of allowing it to happen.

Been changing all my other fluids latetly, transmission, diffs, transfer case next and serpentine belt at 100K.

Hoping to get another 100K out of my rig so my son can enjoy it as much as I have when he is ready to drive in 3 years.

And yes I will get another Jeep a Rubi to be exact.