JKOwners Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
188 Posts
Discussion Starter · #1 · (Edited)
So, my 2008 has had the issue for literally years now, but has been getting worse in the last 6 months or so. I've read all the "use this filter", "use this oil" threads and I've tried them all with no luck.

Here's my observation. Maybe I'm way off, but it's just a thought.

Everyone says it's a dry start issue. I'm not sold it is. The reason I say this is because if I use my block heater overnight, it NEVER dry starts. Now, I know the primary job of a block heater is to warm the engine coolant, thus warming the engine.

The concensus is that the dry start issue is because the oil filter drains back into the crankcase, and a filter with a good anti-drainback valve will cure dry starts. If this is the case, then what does a block heater have to do with the oil filter? It isn't keeping oil in the filter. I agree that it is technically warming the oil, but....

Maybe actually warming the oil allows it to travel to the valve train quicker? Could, but then why do some who switch to 5W-30 report less clatter? It's a thicker oil, and shouldn't travel as quickly.

So, is it possible that the noise at start up is actually what's referred to as "piston slap" by most GM Vortec owners? Cold temps = more clearance between engine components. Engine warms in the first 2-3 seconds after startup, and less clearance.

I can attest that the dry start issue is directly related to temperature. I live in a cold climate, and when it's below zero, my JK let's me know by clattering like mad. I never hear it if the temps are above 40f.

So what are your thoughts? Why would plugging it in prevent dry starts?
 

·
Registered
Joined
·
250 Posts
The oil is colder which makes it a little thicker and harder to get moving. Mine does this when it gets down super cold. A block heater would keep the oil possibly warmer or the block therefore not letting the oil thicken up quite as much. If I leave mine outside in cold it will chatter at first start. If I park it inside the shop overnight it never does.
 

·
Registered
Joined
·
188 Posts
Discussion Starter · #3 ·
The oil is colder which makes it a little thicker and harder to get moving. Mine does this when it gets down super cold. A block heater would keep the oil possibly warmer or the block therefore not letting the oil thicken up quite as much. If I leave mine outside in cold it will chatter at first start. If I park it inside the shop overnight it never does.
So why less noise when using thicker oil, such as 5W-30?
 

·
Registered
Joined
·
77 Posts
The whole dry start thing is a whole load of crap started by some Honda moped riding pussies that have never heard a real engine warming up.

Get them off of their freaking mopeds and have them listen to the sounds that a dead cold Harley makes in the morning, they'll stop whining about their damn mini van motors after a few days of air cooled valve clatter!

:flipoff:
 

·
Registered
Joined
·
1,492 Posts
mine did this today, less than 3k miles on it. it was in lower 20's last night.
just obvious valve chatter from lack of oil there for a sec. just like you would get if say you didnt put any oil in your oil filter during an oil change.
 

·
Registered
Joined
·
188 Posts
Discussion Starter · #7 ·
Either I'm hard headed or stupid...could be both. Guess I don't understand why,

A. Using a block heater cures it; because as stated that keeps the oil warmer, thinning it, and allowing it to travel quicker to the top end.

B. Thicker oil helps to keep the upper valve train lubricated because it stays there longer after shutoff.

So, thinning the oil prevents it, and using thicker oil does too?

This is why I'm not sold it's a dry start issue.
 

·
****
Joined
·
415 Posts
Ya same shit here..... i just want the fuckin noise to stop.....

I can confirm the following....

A) Using the block heater overnight = no noise on cold start up :mad:
B) On warm nights (summer) = no noise on start up :mad:


FYI i have tried 5w20 5w30 and 10w30 (always royal purple) all with the same findings.....
 

·
Registered
Joined
·
2,578 Posts
I understand the frustration here but let's face it, it's a feature of the 3.8. A filter with a good ADB valve helps (NAPA Gold fits the bill, as well as the Motorcraft mentioned), and different oils might help a little....but it is what it is, and what it is is what the 3.8 does. Its annoying but nothing can *really* be done about it, so there's little point in obsessing over it. :beer:
 

·
Registered
Joined
·
146 Posts
The clatter is lifter noise. The problem is the lifters fill holes are too small and get blocked up by sludge. Common issue on a lot of hydraulic lifters.


Thinner oil will fill it faster. Hence why the problem will go away when the oil is warm.

If you run lifters when they are not filled, it will eventually destroy the lifters and there is nothing you can do short of replacing the lifters to rid of the noise.

On your next oil change, drain out one quart of oil from your pan and add one quart of Dextron ATF to the engine (yeah you heard right). ATF is highly detergent and will clean blocked lifter holes helping to quiet the noise. It does not always work. Again if the lifters were run with no or little oil in them, they will make metal to metal contact and become damaged over time and will make noise. Run the ATF in your engine for a good 10-15 minutes at idle and then change your oil. If everything quiets up, you are good to go until next time sludge blocks up the fill holes. Situation the same? Well either the lifters are shot or you have nose coming from bead bearings. There is no such thing as piston slap IMO. If your pistons are so loose they are making noise, chances are your motor is leaking compression so bad it would not start any way or it would burn 5 quarts of oil a day.

Keep in mind that cold will shrink metal and engines are machined at room temperature. You can shrink metal a few thousands of an inch just by subjecting it to below freezing temps. That is enough to make lifters rattle and bearing noise is more pronounced.

As the guy with the Harley mentioned earlier in this thread, you aint heard engine noise till you cold start a Shovel Head. By god if it is not making noise, its broke.

Anti drain back systems are not a big necessity on engines whos lubrication loop on the high pressure feeds is kept withing a few inches of the oil pump. In just about every plain bearing engine, the only place that require lubrication to be pressurized is at the crank and rods. Everything else in the engine relies on splash lubrication. Now some DOHC engines with plain bearing cams will require pressure topside and that is when an anti drain back system is handy. Outside of that, on the 3.8 and many older style engines, the entire oiling system loop is so short and so close to the pump, pressure is built in a mere split second of running. The oil only has to travel from the pump which is always going to be filled since it is below the oil line to the main galley which is probably less than 6 inches away. Same with the lifters. Everything in the head is splash lubricated which means you can spit on it and it will still run.
 

·
****
Joined
·
415 Posts
Tried the ATF trick....... next morning after the change..... noise is still there..

looks like i might need to build a pre-oiler pump
 

·
Registered
Joined
·
803 Posts
I also don't see it as a "dry start" issue, doubtfully that exists unless there is someone that dismantled the engine, cleaned all the oil residue off the components and reassembled the engine before starting. Otherwise there would always be an oil film remaining on the components preventing a dry start.
What most see as dry start is simple valvetrain clatter until the lifters are pumped up again to close the gaps in the system
Thicker oil less train back from the lifters so less or shorter clatter.
With a very cold engine the gaps are bigger and the thick cold oil takes longer to pump up the lifters to close the gaps thus more and longer clatter.
Annoying as the start-up clatter is, it doesn't do any damage. Only a problem if the clatter remains when the engine is up to operating temperature.


.....
This is why I'm not sold it's a dry start issue.
 

·
Registered
Joined
·
1,519 Posts
Ya same shit here..... i just want the fuckin noise to stop.....

I can confirm the following....

A) Using the block heater overnight = no noise on cold start up :mad:
B) On warm nights (summer) = no noise on start up :mad:


FYI i have tried 5w20 5w30 and 10w30 (always royal purple) all with the same findings.....
If you are in a really cold region try using a 0W oil like a 0W-30. No oil is thinner when cold than 0W. If it still has the issue pull the valve covers and check for crud buildup.
 

·
Registered
Joined
·
271 Posts
I have tried the Motorcraft filter and several different oils. I live in a warm climate and it still makes a ton of noise. It's even worse if I do not drive it for a few days. I have started to hold the gas pedal to the floor and crank the engine for a few seconds some times twice if it's been setting for a week or so. The engine will not start when the gas pedal is mashed to the floor so it kind of primes the oil passages. I still makes a little noise but not as much.:beer:
 
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top