A question about varnish (photos) 98 Civic 145K miles

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24,382
Location
Central Florida
This sounds like a silly question. But I was wondering.... Why does varnish get baked onto the valve cover, but the valvetrain (cam, rocker arms, valve springs, etc) doesn't have any crud baked on like the valve cover does ? [I dont know]  -  -  - Auto-RX treatment will be done in about 3 months.
 
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699
Location
Texas
Oil vapor simply sticks (burns) to the underside of the valve cover. The valvetrain keeps getting splashed with a higher volume of oil to keep it from vaporizing/burning.
 
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2,435
Location
Mizzou-land
The valve cover is a lower temperature (sheet metal exposed to air). Vaporized stuff will condense on the valve cover whenever the engine is hot enough to create the vapor and the valve cover is still cool. This phenomenon occurrs at just after start-up and as the engine cools regardless of ambient temps. In cooler temps, it can occurr while the engine is running.
 
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11,656
Location
Illinois
Magic, like how does Santa fit everything in the big bag. Why don't the presents for good boys and girls not have coal dust on them since we only see Santa carry ONE bag?
 
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2,698
Location
Silicon Valley
quote:
Originally posted by GMorg: The valve cover is a lower temperature (sheet metal exposed to air). Vaporized stuff will condense on the valve cover whenever the engine is hot enough to create the vapor and the valve cover is still cool. This phenomenon occurrs at just after start-up and as the engine cools regardless of ambient temps. In cooler temps, it can occurr while the engine is running.
I would expand on this to suggest that the valve cover is made of something less corrosion resistant than the other engine parts, and the water and other nasty vapors are condensing on it and attacking it.
 
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3,481
Location
Millbrae, CA
quote:
Originally posted by GMorg: The valve cover is a lower temperature (sheet metal exposed to air). Vaporized stuff will condense on the valve cover whenever the engine is hot enough to create the vapor and the valve cover is still cool. This phenomenon occurrs at just after start-up and as the engine cools regardless of ambient temps. In cooler temps, it can occurr while the engine is running.
Agree and since the "light" ends or volitle components from oil, fuel blow by and condensation will form on a "colder" surface that is where they form varnish where the valve train is a lot hotter. Also valve train looks pretty good for 145K. bruce
 
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1,463
Location
CA
quote:
Originally posted by javacontour: Magic, like how does Santa fit everything in the big bag. Why don't the presents for good boys and girls not have coal dust on them since we only see Santa carry ONE bag?
the coals don't come out of his bag but rather out of his.... [Big Grin] I think honduh valve covers are aluminum
 
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6,902
Location
Louisiana
quote:
Originally posted by bruce381: Also valve train looks pretty good for 145K. bruce
That's what I told him when he showed ME those! Outstanding for high mile 8 year old 4 cyl.
 

Mr Nice

Thread starter
Messages
24,382
Location
Central Florida
I changed the oil every 6000 miles with the cheapest dino oil I could buy and the oversized oil filter was changed every 18,000 miles. The first 70K miles, I used Mobil 1 (8k OCI) and then dino the last 5 years. In about 3 months I will do an Auto-Rx treatment and post more pictures. The way this old Honda runs, I'm sure it could rack up another 150K miles no problem.
 
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4,478
Location
Southern California
But it's a well known BITOG "fact" that conventional oils (especially cheap ones) will sludge and varnish up an engine well before 80,000 miles. (C'mon, LT4 Vette, admit it - you're really using GC in your little ricer, huh? [Wink] )
 
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3,481
Location
Millbrae, CA
""I changed the oil every 6000 miles with the cheapest dino oil I could buy"" [Eek!] [No no] now all the "must change at 3K with dino or die group will be haveing a cow. Bruce
 
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23,894
Location
CA
I'm gonna pull the valve cover on the Saturn one of these days. For the first 30k or so, it got changed every 2500 miles as the vehicle was only used 5k a year. Now it gets done every 7-10k with cheapest oil and filters but gets topped up every 2500 miles (1 quart). Can't wait to see what it looks like.
 
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809
Location
Granville, Ohio
Personally, I think it has something to do with your driving habits (short trips?) or OCIs, but I don't buy the "cooling vapor" bit. The sludge buildup likely has something to do with water condensation on the cover. My '95 Corolla had an aluminum head cover as well, and it didn't have this buildup after 205,000 miles (picture is a few years old):  - The OCIs were around 3K-3.5K miles using mostly SuperTech oil & filters. I finally gave the car to my kid with 295,000 miles. Note that there is absolutely no sludge.
 
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