I have a problem.

In the last few years I have improved my day to day life.

I now own 2 sports cars, a light truck, a boat and my partner and I live less than 5 miles from our workplaces which are less than 1 mile apart.

Every morning it's a tough decision: If its snowy, we take the Jeep. If we want some fun, we take the MR2. If we want luxury and snobbery, we take the crossfire. What to do?!

As a result, we end up carpooling most every day and between all 3 vehicles, we put less than 5000 miles on each one per year.

This horrible dilemma has banished us to making a lot of very short trips. One thing is clear: the Crossfire takes a while to warm up and our typical trip is less than 10 minutes.

I have owned my 2006 crossfire limited coupe for over a year and my FSS says it is time for an oil change. So I bought some Mobil 1, 0W-40 at Walmart, some MANN filters off E-Bay and a Mity-vac and began the process.

The Crossfire oil cap has sludge deposits. I use blended oil on the Jeep and Castrol Syntec in the MR2 and sludge is not present. I have NO IDEA what oil was used in the crossfire when I bought her. The previous owner had her for a year but could not afford to own her. I have put less than 5K on the car since I purchased her.

I decided to treat the engine with Marvel Mystery Oil before and after the change. Hopefully this will do some needed cleaning, but what I am wondering now is how best to prevent this from being a problem in the future.

I am looking for some practical ways to modify my vehicle use to minimize sludge formation in my Crossfire on an on-going basis.

 

You should never see sludge with synthetic oil if you do the following. Change your oil and filter either once a year or before 5k miles. I change mine every 3.5k or once a year and since I don't drive that much it's usually once a year. People forget the once a year rule.

 

Good point. Considering that I bought her in Aug 2012 and have only put 4.5K on her, that means the prev owner may have had the change done months earlier and I know he lived close to work too. So it may have been as much as 7000 mi and 2 years since the last change. 3500mi seems pretty short even for regular oil but I am definitely on the "once a year" schedule with my vehicles unless I take a long trip.

 

Well, that is all I needed to hear. The car was probably driven the whole time they had it with NO oil change. If they DID do a change, I'd bet they used the cheapest 10W30 they could buy.

I drive mine every day. I change the oil at around 5500 miles, no matter what the FSS says.


As for a practical answer to keeping this from being a problem: DRIVE the damn car. It sounds like your commute to work is an engine killer, many commutes are. Take the Cross into the country on weekends and DRIVE IT: Tear thru some curves, get that tach to 4000, etc.

And change the oil much more often, at least for the next 10,000 miles. Mabye change it every 2500 miles - if it IS slugged up, and you DRIVE IT, the oil is going to get bad quickly.

I had 110,000 on my Duster when I sold it in 1980. I'd always driven it fast and kinda hard - changed oil every 3000 miles. After I sold it, the guy who bought it gashed the oil pan on an object in the yard. He had to remove the pan and have the gash welded. He called me and said,, "Come over here and look at the bottom of your engine."

I did. The interior of that 110,000 mile+ motor was immaculate. And THAT was on cheap conventional oil. The secret was the 3,000 mile change and DRIVING the car.

 

I figure they probably added regular oil to the synthetic oil and never changed the filter...drive the car 1500 miles and change the oil and filter again. After a few changes it should clear up...

 

It sounds like a good idea to do some short oil changes to clean out the gunk.

The extracted oil from the bottom is dark, but after running a bit the cap gets brown with sludge. I suppose the emulsified oil tends to rise to the top of the engine.

I bought some MMO and replaced 20% of the old stuff with the MMO as recommended on the product. I plan to drive it to work and back, then change the oil and use another 20% as recommended.

This may clear out some gunk, but I won't really know unless I can inspect the pan or perhaps I no longer get gunk on the oil cap. That said, if I want to do a few short changes, often that is done with cheap oil so that you don't waste money on synthetic.

However, there is a sort of religious attachment by many to using ONLY rated 0W-40 as stated in the manual. Some suggest using a 5W-40 for short changes.

I bought the Mity Vac so it would be easier to change oil, but perhaps a drain might be better in this case.

I cannot agree more with actually driving the car to prevent this, but that is my problem. It's winter here in MN and driving is not always a good thing to do. The only thing I can think of is to start it 5 minutes before I leave home and work and use MMO regularly.

 

What you're seeing on the oil cap is not so much sludge as it is an oil and water (moisture) mixture ... very common on the 112 and 113 MB engines IF driven short distances (engine didn't reach optimal operating temp.) which appears to be all that your Crossfire was driven. Fear not as this is not necessarily a bad sign ... just a sign to get out and drive it on longer trips.

 

Yeah, live dangerously at 4,000 rpm.

 

Thank you for that o4fire.

As a result, I did some more digging and found out that "Sludge" can refer to two different things:

"Oil sludge" and "Cold water sludge"

Oil sludge is a tar like substance that forms when the oil breaks down. This is more indicative of failing to change oil when needed and forms throughout the engine.

Cold water sludge is a brownish creamy substance that forms commonly as a result of moisture condensing under the oil cap due to short trips and cold weather. This tends to accumulate under the cap because the filler cap is plastic and colder than the rest of the engine. Moisture mixes with oil to form a residue. The oil, however remains normal.

Most people, as I somewhat mistakenly did, seem to call this "sludge" and that can be somewhat misleading.

As you say, this apparently is not serious and pretty common and can be burned off with higher engine temps.

Thank you all for your help.

 

This creamy sludge can also be indicative of a coolant leak into the oil, often caused by a head gasket leaking. If you suspect this or any other fault such a bearing failure, an oil analysis can put your mind at rest. It could also prevent further damage to the engine if something is amiss.

 

I've seen bad head gaskets and what you find there is emulsified oil throughout the engine and you can see it on the dip stick as well and smell it. I wasn't clear about this, but my oil looks OK. It's dark without any sign of coolant. Nor am I losing coolant.

I am pretty sure this is simply what 04fire says it is - Oil cap condensation.

 

i dont drive our croosfire a whole lot either 1,000 to 1,500 miles a year here lately ! FSS lets me go 2 yrs before it time to change generally around 1,500 mile mark & two yrs ! I never had any sludge issues so it must be your short trips ! We only drive ours in warm weather & it sleep all winter ! but when we do drive it we go on lots of long trips too !

 

This is a XF engine @ 53k someone posted on this forum a while ago. This had a steady diet of Mobil 1. No sludge what so ever! After seeing this, I switched ALL my vehicles to Mobil 1.

 

I have been a mobil 1 nut since the early 80's. I would definitely drain from the pan until it's clean. You will not suck out enough oil to help clean this engine...good luck...

 

Can't that oil change monitor count months? Where's the water going to go if the oil doesn't get hot enough to evaporate it. YOU GOTTA DRIVE IT?

 

Here's a pic I took just today at work ... it is not uncommon.

This ML obviously does a lot of short trips.

photo.jpg

 

Wow, what is that gunk?

 

???
what is that?

 

That isn't normal. That isn't moisture, that is water...Where did you get this car again?

 

Agreed Doc.. reminds me of when my 68 Chevy had a crack in the cylinder wall.. Sure miss that 327..

I'm guessing you could still get bubbles out the fill cap on our systems if its a crack or head gasket?