Crud Under Oil Cap

s_watts · Post by **s_watts** » 08 Sep 2016, 20:18

When I took off the oil cap the other day, I noticed some dark brown/black solid crud on the grate and the oil cap. Any ideas what and why this is?

Its a 2006 S60 2.5T

Post by **MadeInJapan** » 08 Sep 2016, 21:18

Pretty common- I see it a lot on regular oil... My son's car was like that when we bought it- his an '07 S60 2.5T. We switched to Mobil-1 synthetic...after 2 oil changes, it is much better!

Post by **oragex** » 08 Sep 2016, 21:26

Neglected oil change and/or clogged pcv. Perhaps there is some sludge in the oil pan

zanzabar · Post by **zanzabar** » 08 Sep 2016, 22:28

Run several short interval oil changes. Say 3000 miles each or every 3 months. Use a good quality synthetic, or even better a good synthetic diesel oil like Shell Rotella T5 which has extra detergent additives to handle heavy soot loads.

fixer333 · Post by **fixer333** » 09 Sep 2016, 07:57

zanzabar wrote:Run several short interval oil changes. Say 3000 miles each or every 3 months. Use a good quality synthetic, or even better a good synthetic diesel oil like Shell Rotella T5 which has extra detergent additives to handle heavy soot loads.

I had a 2000 toyota corolla that I bought new and started burning oil( a quart /1000 mi) at about 30,000 miles( these engines were notorious oil burners).
Even with 3000 mile oil changes, the rings would get stuck and let oil by. I started using Rotella and in few thousand miles the oil use was negligible. I use it in all my cars now.

zanzabar · Post by **zanzabar** » 09 Sep 2016, 12:29

Yeah diesel oil in general is stouter, slightly thicker, better at dissolving deposits and sludge, and can be used in most gas engines with no problem. The tradeoffs are that since it's slightly thicker you lose a fraction of your MPG, and the extra wear additives (zinc/zddp mostly) can foul your catalytic converter if your cars engine has a lot of blowby past the rings.

fixer did your Corolla or other cars ever have catalytic converter issues?

Oh and to the OP: take oragex's suggestions seriously, check that PCV right away! Once you are sure it is running well, a few Italian tuneups during each oil change interval would be good idea. That also helps the cat, and cleans out combustion chambers and valves and piston rings, turbo, etc.

fixer333 · Post by **fixer333** » 09 Sep 2016, 12:44

No have not had to replace the cats( knock on wood) in any of our vehicles. The corolla had 180,000 when totaled ( hit deer). Our 2005
Subaru is at 165,000, and a 94 Toyota tercel (248,000), is still passing smog in California, but just barely( needs a new cat).
I use synthetic rotella in the Subaru and dino rotella in the tercel ( much cheaper and the higher viscosity helps with the tired rings).

s_watts · Post by **s_watts** » 10 Sep 2016, 11:36

Thanks for the responses. The car has 156k and I switched to synthetic about 15k miles ago when I bought it. I have changed the oil twice since then.

I had the pcv upper breather hose break, will fix that once it stops raining and check out the pcv system. My plan is to use the hose and do a "blow test" for pcv and then I will try the nitrile glove on the oil cap.

fixer333 · Post by **fixer333** » 10 Sep 2016, 15:10

I know 7500 is the recommended oil change interval, but it is too long for engine longevity( especially if you have turbo).
3000 for dino oil and 5000 for synthetic is what I use. I worked in a auto machine shop and repair business for 25 years and the number 1 thing we saw was engine sludge/ damage from not changing the oil frequently enough. Cars are considered throw away items now( especially by the manufacturers), changing fluids, power steering , transmission, engine regularly will greatly increase you cars life span. I want, and usually get 250,000 miles+ out of an engine with out major repairs.

s_watts · Post by **s_watts** » 11 Sep 2016, 12:54

Good to know fixer333. Jiffy lube charges me $110 for a synthetic oil change, maybe I will try a new place.

I got the breather hose replaced and placed the glove on the oil cap and revved the engine. To my disappointment it stood up. Is the pcv system the most likely cause of the crud under my oil cap?