dadgummit

A little while ago I started this thread asking about a start-up noise:

https://www.jk-forum.com/forums/show...oise&p=2316039

Some people suggested it may be the famous and dreaded dry start caused by a bad anti drain-back valve in the oil filter. so I called Donavee Jeep in Placentia and the service manager says one way to verify the anti drain-back valve in the oil filter is when you remove the filter, oil will flow out of the engine from the threaded pipe that the filter screws on to If it does then the valve was working correctly. I decided to also take the good advice in that thread and try a Napa Gold filter and Royal Purple oil. I let the jeep sit for 2 days to give the faulty filter valve a chance to drain and then I went to chance the oil. When I removed the Fram filter lots of oil flowed out of the engine meaning the anti drain-back valve was working just fine. I figured that since I was already dirty I would complete the oil change seeing as how the royal purple is supposed to be better. It has now been 2 days and the engine is still making the exact same noise every morning.

This tells me the noise has nothing to do with dry start. Does anyone else have any ideas as to what the noise is?

Tuto

Question: Did any oil came out the oil filter ?

If the answer is no. The antidrain valve was not working, It did not hold oil in the filter. Is like an Air pocket if the filter is empty. Once the filter is fill at start up (1-2 seconds) the noise (dry start) stops.

kik

Heat shields are known to rattle.

dadgummit

Yes the filter was quite heavy with oil and it took a while for it all to drain out in the catch pan. Also the center pipe that the filter threads on to leads toward the top of the engine and a really good amuont of oil came out of that. if the anti drainback valve was bad the oil would have flowed through the filter and back into the oil pan in the the two days the jeep sat in my garage.

dadgummit

yes they do LOL, I have one that makes some noise but that noise happens all the time under moderate accelleration.

dadgummit

The noise happens about 2-3 seconds after the engine starts and the starter disengaged. it lasts for about 1 second or less and it is kind of a soft rattling sound that tapers higher in pitch and lower in volume over the second that it lasts. It only happens on a cold start-up when the jeep has cooled down for 10 hours or more.

I wonder if it is something totally different like valve lifters, power steering pump etc?

Bucko

I have had this since day one of ownership. I have found the solution to fixing it...

Just try to get video of your start up with your cellphone and it will never grind...
I have recorded every startup for the past week and it hasn't done it once.

I have been turning the ignition to the ON position for a few seconds before startup, thinking maybe that would get the oil pump going (don't know if it is driven seperate from the engine). Haven't had the problem since doing this ????

It really sounds like the starter is grinding, like mentioned above, maybe staying engaged too long...

dadgummit

I carefully listened to the noise again this morning and I can clearly hear the starter motor disengaging from the flywheel a second or two before the noise starts.

Maybe I will need to take it into the dealer to look at it. I have the lifetime warranty but with the mods in my signature I am sure they will try and play some games to get out of taking care of the customer.

SLIM_SNOOPY

Hello to all:


Same sound here as well. Also feels like a rumble effect, especially if not started within 3 days or more. Def gets worse as days go by without starting. I also get the oil light within 3 days of not starting. I have some friends who are mechanics and they told me as long as you are not lossing oil and the oil and filter are clean with no burn smell, all is ok. Also was told that these new pressure switches they have a tendency to stick , causing the oil light to stay on longer. He serviced quite a few Wrangler's in his lifetime, and told me not to worry.

That might all be true, but that metal to metal noise that the op and others on this thread described, can not be of any good news. That just sounds like a future repair bill in the future that can be prevented.

What is really crazy , is when I recently changed my oil-- non synthetic, with a new Mopar Oil Filter, the noise did not come back until a week later. Eventhough some folks did not see a change, I am going to try the Napa Gold Filter,, which I beileve is made by Wicks ???. Other good ratings were Donaldson, and MotorCraft.
I change my oil and filter every 3,000 miles, due to trying to keep the 3.8 engine alive for many many years...lol


I agree with everyone on here, something is not right mechanically or just the design of the 3.8 Liter is very bad.

P.S.- Has everyone notice even the filter itself is on a angle . Open your hood and look down, it is leaning more toward the serpentine drive belt pulley,,,weird...



SLIM

Bucko

I'm now thinking its the AC system. Starred my engine them turned on the ac a few seconds later and there it goes again.