Motors like this I always let warm up and idle before I put some type of load on them. My dad was always an advocate of this process. Mind you, technology has changed, but he drove his cars for decades without issues.
Noisy 4.0
- Thread starter MrBClark
- Start date
The "experts" say you are to start the vehicle and immediately drive off. Otherwise you are wasting fuel and hurting mpg's.
But I have always believed in treating an engine like a person. When young
you can get going quickly, but an older engine, like an older 
man, takes a while for everything to get up to speed and start the day. Dosen't take too long, but 15-30 seconds after start before driving away. Colder weather
takes a bit longer.
But I have always believed in treating an engine like a person. When young
you can get going quickly, but an older engine, like an older man, takes a while for everything to get up to speed and start the day. Dosen't take too long, but 15-30 seconds after start before driving away. Colder weather takes a bit longer.I start mine and let it get to idle speed on its onw. Do this on any of my vehicles. Perhaps, because this is how I was raised and all I saw as a kid, but never had a problem with it.
Meh. Like others say, I let it sit for 30 seconds or so. 1-2 minutes when it's cold out.
Sounds like a little cold piston slap, common on a worn in 4.0L. Nothing to worry about.
Your engine makes noise when it is cold and you are running an oil that is thinner when cold than Jeep recommends. Most people run 10w30 or 15w40. Why run thin oil if you have noise cold? Not trying to be critical but it seems odd.
OP
OP
Mine has 136,000 miles on it and sounds identical. I don't worry about it or my noisy 5 speed NV3500 trans..
OP
Inspect your exhaust manifold close. My 2.5 would do that when cold but would quiet after 5 min of driving. I just replaced the manifold with a header.
TJ2
TJ Expert
OP
Anyone have experience with Castrol High Mileage 10w-40? I would love it if Rotella still came in 10w-40 but it doesnt. I definitely want a 10w-40 for the warmer months, then want to drop back down to Rotella T6 5w-40 for colder months.
EzPeezy
TJ Enthusiast
10w40 quieted mine down a little bit.
I thought I had a lifter tick - two mechanics told me it was lifter tick. It was a cracked connecting rod that made itself apparent shortly after I replaced the lifters. I don't want to scare you since it's probably unlikely but I thought I'd mention it in case you run out of places to look.
I thought I had a lifter tick - two mechanics told me it was lifter tick. It was a cracked connecting rod that made itself apparent shortly after I replaced the lifters. I don't want to scare you since it's probably unlikely but I thought I'd mention it in case you run out of places to look.
10w40 offers nothing over 5w40 except higher cold starting viscosity, which is a negative.
Only positive maybe price
OP
Did your sound quiet down when warm? Mine goes away in a few minutes. I've heard people run 15w-40, but that's way too thick. I will be running 10w-40 for the warmer months and 5w-40 for colder months.
I have been a Valvoline fan for years. Most all brands use a quality oil. It's the additive package that makes the difference. New engines use new oils that are formulated with far less zinc in them. Zinc is one of the critical wear and lubrication additives that older engines require. Using a 5W in winter helps with cold weather starting over a 10W. But for even better protection try adding in 1/2 to 1 quart of diesel specific oil. The zinc and phosphorous levels are much higher to help with cam and lifter protection.
After decades of talking with oil reps I think Valvoline offers one of the best oils on the market and dosen't charge $8 a quart. Fram duragaurd is a quality filter at an excellent price.
After decades of talking with oil reps I think Valvoline offers one of the best oils on the market and dosen't charge $8 a quart. Fram duragaurd is a quality filter at an excellent price.
OP
So if I used Castrol 10w-40, would I be able to mix in 1/2 quart of Rotella 5w-40? Would the viscosity difference matter?
I advise against mixing oils. Dont overthink it. Any name brand oil in the proper weight second number will be good, thats 30 or 40 .
Generally speaking lower weight oils yield better fleet fuel economy. Which is insignificant to an individual engine, like ~1% better.
Higher weight oils provide better protection.
I use rotella 5w40 instead of 10w30 because 5<10, 40>30 and it has increased zinc and detergents. Maybe the zinc will cause my cats to blow up, who knows.
I was about to switch to castrol edge 0w40 European blend, it's about the same price and 0<5, but I'm having no problems as far as leaks or noises with rotella so I decided to just stick with it.
Also another reason I use rotella is many 4.0 owners on the bitog forums had analysis done on their oil, rotella comes out on top and Mobil 1 does the worst as far as wear indicators.