2001 Eclipse cold start knock

[Scout1]

Maybe I should post this in the mechanical forum but I'm wondering if it's a lubrication problem. Maybe somebody can educate me on this engine; my son's fiancée has a Mitsubishi 3L V6 in a 2002 Eclipse GT. The car has 140k but has only been in the family for about the last 10k miles. The motor doesn't seem to have any sludge when you look through the filler cap and it doesn't darken the oil much over time. Last oil change was PP 5w30.

The issue is a heavy knocking noise when first started that takes quite a while to go away - she says it sometimes takes several minutes. I heard it once when we first started up after a starter change. The car was still jacked up so I thought it might just be the tilt of the engine hampering the oil pick-up. Once we de-jacked and re-started, it sounded normal. It just sounds like the oil hasn't pumped up so that sort of knocking. The oil level is fine and the filter is a Microgard. We took the filter off and cut it open but no sign of any sludge. When warm the engine is always nice and quiet.

Any characteristics of this engine that would cause this behavior? Seems to be an issue when cold since we didn't hear it last summer. Thoughts?

 

[skyactiv]

Hopefully it's something simple like the oil filter having the wrong bypass setting.

 

[901Memphis]

Try a filter with a silicone anti drain back valve. Micro guards have nitrile which doesn't always seal well. I recommend a Fram Tough Guard which will eliminate any noise if it's a adbv issue. Others that are silicone, Wix, PureOne, Bosch.

 

[Brybo86]

What is the filter orientation?

 

[Scout1]

The filter is vertical meaning it screws straight up into the block so the filter can't drain out if the ADBV is defective. So does that rule out that being the problem?

 

[Scout1]

We installed a Mobil 1 filter so we'll see how that does.

 

[bvance554]

If it takes several minutes to go away i don't see how the filter could be causing the issue.

 

[vssjim]

Might be the timing belt hyd. tensioner

 

[Clevy]

Originally Posted By: bvance554
If it takes several minutes to go away i don't see how the filter could be causing the issue.



I agree.
Cold start knock could be a few things. What octane fuel is being used? Does this car come equipped with knock sensors.
I've seen tuned vehicles with cold start knock. We figured out that at start up the ecu had the timing advanced too much and it took the ecu a moment to retard the timing enough to stop the knock.
I'm not familiar enough with your car to say this is the issue however knock is usually a fuel/timing issue in my experience.
My 04 ram had a knock in the bottom end that was audible with 0w-20 oils,last spring when I changed it to 5w-20 the knock wasn't audible anymore. I used defy and the knock was gone.
Where's the knock coming from,top or bottom end?
Maybe a grade thicker will help.

 

[OVERKILL]

Originally Posted By: bvance554
If it takes several minutes to go away i don't see how the filter could be causing the issue.


Bingo. Sounds more like piston slap if that's the case.

 

[Ram01]

Move up in weight on motor oil

 

[kschachn]

This would help, how?

Originally Posted By: Ram01
Move up in weight on motor oil

 

[jrustles]

Originally Posted By: kschachn
This would help, how?

Originally Posted By: Ram01
Move up in weight on motor oil


Cushion the excess piston/wall clearance if it is indeed slap.

But there's something else going on that IMO,viscosity is not the solution for.

 

[aquariuscsm]

Drain and refill with a good dino oil (GTX,PYB,VWB 10W30 or 10W40). Oil filter choice won't matter. My 3000GT would do this only with synth oils. I tried every different filter under the sun,still had cold startup noise. Car didn't "like" synth oils for some reason.

 

[SLATRON]

Are you using premium gas, as manual says supposed to. This engine can run on regular gas but may cause it to have "knock" pre-ignition problems, especially when car gets older. I was told this by Mitsubishi dealer when I have an eclipse. With regular 87 gas the car has to adjust timing

 

[kschachn]

Well, my Sienna developed a similar noise recently when it was very cold and the van happened to sit outside overnight. At the time it was running M1 5W-30, but a switch to 5W-20 made the noise go away.

On the other hand, my Accord which has the typical piston slap, is unaffected by any oil weight. I have tried everything up to and including 20W-50 and it makes no difference whatsoever.

I'm not advocating the OP go to 5W-20, I just don't think a thicker oil is going to help that noise.

Originally Posted By: jrustles
Originally Posted By: kschachn
This would help, how?

Originally Posted By: Ram01
Move up in weight on motor oil

Cushion the excess piston/wall clearance if it is indeed slap.

But there's something else going on that IMO,viscosity is not the solution for.

 

[Cooper]

My Eclipse did this when I had it. I had all the lifters replaced and it was fine. Probably lifters....they are known to have bad lifters in those.