Carbon under the filler cap --- arrgh!

[earlgrey]

I unintentionally fell off my change schedule for my 1MZFE Toyota 6 cyl engine on the last fill. I had been doing a 5000 cycle with M1 10-30, then bumped it up to 6000 for the previous change. I lost track of time, and when I woke up and looked at the numbers I found I had put 7500 miles on the oil.

Changed it out right away on a warmish Sunday. To my surprise, there was a black layer deposited evenly under the filler cap. It was hard and dry, and gritty when scratched off with a fingernail. It looked to be about a mm or more thick. This area was clean as can be privious to this change. The engine has about 32000 miles on it.

My mechanic was not too excited about this. He doubted I hurt the engine and didn't see a reason to pop the cover or worry about it. Just go back to the regular pattern.

I guess that's probably true, but I hate the see that gunk in there. My '93 sentra has 188K on it and I'm planning to do the same with the toyota.

Any thoughts?

 

[m2pc]

I have the same engine, am kind of suprised that you are seeing this with synthetic as well as using 10w-30. Do you do mostly city driving? Over what time period was this 7.5k put on? What model is this? A Camry...Sienna? Just curious.

[ December 30, 2003, 10:36 AM: Message edited by: m2pc ]

 

[earlgrey]

Yes it was a surprise. The car sees a 40 mile round trip daily commute with a mix of highway cruise and city stop and go. Relatively few instances where the car is started and not brought up to temp. It's a similar workout to the one the old sentra did most of the time.

Time on the oil was 5 months. The car has run a few hundred miles on the new fill and the dipstick looks clean and clear.

 

[earlgrey]

And oh, it's a Solara.

 

[newtoncd8]

Our 99 ES300 (V6) had the exact same carbon under the filler cap. It had oil changes every 5,000 miles (never missed) since new.

I ran a treatment of AutoRX and the carbon is still there.

We recently traded the car for an RX330 (new with 15 miles) and after a trip on the highway (~ 2,000 miles), there is carbon under the filler cap of the RX.

So, I am certainly no mechanic, but I consider it to be normal.

 

[yannis]

Why don't you try a thicker oil? Maybe the new 5W40 mobil in spring.

 

[TR3-2001SE]

I also noticed this on my toyota cressida with 250,000 miles. It had received 3000 mile oil changes with Castrol GTX. I have cleaned it out and done a auto-rx treatment. It has stayed clean for 2000 miles now but sounds like this stuff builds up from vapor depositing this stuff with time. I have noticed I don't have any on my miata with 32000 miles so maybe it is engine dependent.

[ December 30, 2003, 12:55 PM: Message edited by: TR3-2001SE ]

 

[TheNauseator]

I have the same problem in my VW 2.0 engine. The junk on oil filler cap builds up pretty much all the time. I wipe it with paper towels but it keeps coming back no matter which synthetic oil I use. The only difference is that my buildup is dark brown, not black.

edit: this can't be good for positive crankcase ventilation system.

 

[Bror Jace]

" ... it keeps coming back no matter which synthetic oil I use. The only difference is that my buildup is dark brown, not black."

"I had to scrape it with a knife and then delute it with 409 to get this stuff off ... Very hard deposit. And yes it is dark brown not black."

It's at times like this when I'm glad I own a Sentra.

I would have figured that a little Auto-RX or Neutra would have removed this stuff or at least prevent it from occuring ... but no dice? Yeesh!!

Anyone here try running Red Line 5W30 or 10W30? That'd be interesting to see as the best result we've ever seen with Red Line Oil was in a Toyota.

--- Bror Jace

 

[earlgrey]

This isn't a buildup on the cap. It's a deposit layer on the interior metal surface that's visible when you remove the cap and look inside. It is hard and dry and cannot be wiped off with a cloth.

 

[TR3-2001SE]

Amen earlgray. I had to scrape it with a knife and then delute it with 409 to get this stuff off. Took many cleanings to get it all off. Very hard deposit. And yes it is dark brown not black.

[ December 31, 2003, 01:47 PM: Message edited by: TR3-2001SE ]

 

[BlackF250]

I am a manager at a major car rental company that rents nissans, GM's, mitsubishi, hyundai, and Chrysler's. Of all of them The nissan's have by far the most engine and transmission problems. The new altima's with the 2.5 4cyl pop engines like it is there job!

However the sentra with the 1.8 is the only Nissan we have that has not experienced an engine failure. There is a service bullitan for the 2.5L sentra and altima for the pre-cat disintegrating, sending debris into the engine causing cylinder scoring. This leads to excessive oil consumption. If not checked RELIGIOUSLY they will run dry and go BOOM!

Nissan's remedy for this is to just replace the pre-cat and live with the oil consumption! However if you let it pop, they will replace the entire engine at no cost. I think option #2 is the much wiser decision!

 

[Chris B.]

quote:

---

Originally posted by BlackF250:
I am a manager at a major car rental company that rents nissans, GM's, mitsubishi, hyundai, and Chrysler's. Of all of them The nissan's have by far the most engine and transmission problems. The new altima's with the 2.5 4cyl pop engines like it is there job!

However the sentra with the 1.8 is the only Nissan we have that has not experienced an engine failure. There is a service bullitan for the 2.5L sentra and altima for the pre-cat disintegrating, sending debris into the engine causing cylinder scoring. This leads to excessive oil consumption. If not checked RELIGIOUSLY they will run dry and go BOOM!

Nissan's remedy for this is to just replace the pre-cat and live with the oil consumption! However if you let it pop, they will replace the entire engine at no cost. I think option #2 is the much wiser decision!

---

BlackF250, What kind of noises do you hear in the engines of the different brands at your work? Do you hear a lot of the infamous GM piston slap?

 

[Bror Jace]

I must have gotten one of the good ones because I've already been in for the recall, my cat' was inspected and found fine. The car hasn't burned a drop of oil in over 12,000 miles.

--- Bror Jace

 

[segfault]

quote:

---

Originally posted by BlackF250:
The new altima's with the 2.5 4cyl pop engines like it is there job!

---

I took my used Altima 2.5 in for the precatalyst recall at about 24,000 miles. The precatalyst was replaced and the oil changed at no charge. I'm still not burning any oil. I have heard of very few cases of engine failure, but still consider myself lucky!

 

[dickwells]

Better hold your "gladness" Jace. It is running across the worm that a bunch of Sentras are being recalled for engine defects!

 

[JohnBrowning]

Wow, this strange. While I have seen this build up on vechiles running dino oil with long OCI I have not seen it in a syntetic application. Betwen my family and myself we have owned one of everthing Toyota has every made since 1971! My family uses M1 almost like a religion. I am the only one that trys expensive synthetics like RL,MT, AMS......

Have you tried adding Lube Control to to the oil? I would try this as it helps a lot of the V6 Toyyotas that have under hood heat problems!

 

[earlgrey]

I have to defend Bror's comfort with his Sentra to a point. My '93 1.8 has run great for 188K with only routein maintenance, Pennzoil every 3 to 5K and very little repair. Terrifically low cost of ownership for this car and engine.

The generation starting with the '95 year was a decontented POS unfortunately. My girlfriends '95 1.8 has had dried out seals, and lots of ancilliary parts (alterators, h20 pumps, belts, idlers, O2 sensors) failing repeatedly right and left. 10x the repair costs and 2/3's the miles! My impression is that the current gen is somewhat better. I hope so. I don't see any crud under the cap of my 1.8! On the other hand, Toyota hasn't gone on crazy decontenting jags like Nissan did - I'm glad I got the Solara.

Like TR3, I had half a mind to scrub under the cap of the Toy to get rid of that carbon. I thought about Auto-Rx, but the very helpful post by Curtis has put things in perspective for me. I guess these hot-running Toyota six's just want to coke things up a bit. I guess I'll watch things more closely and leave the thing alone. I haven't really considered using a tweek oil like Redline.

Has anyone been able to run a Toyota six for any length of time w/o these deposits? John, what's Lube Control?

 

[newtoncd8]

I will add one more case....my Mom has a 99 Camry V6 and has used Mobil 1 5W30 since new. She has her oil changed every 3-5,000 miles, usually about 4,000 miles. Her Camry just turned 36,000 miles and I looked at her car; she also has the carbon under the cap.

 

[earlgrey]

Just did a search based on Johns LC comment, and read some threads about the toyota six's I hadn't seen before. Makes me think the cokeing is due to running the miles up too far for my driving pattern at least - I think I'll keep the OCI to between 5 and 6K from here on out.