1999 Toyota Corolla Varnish Under Valve Cover

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Oct 15, 2022
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I bought this car used at 123k miles. I changed the valve cover gasket around 125k miles and have since driven it to 128k miles.
Engine pics are from a 1999 Toyota Corolla CE
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I know it's not as clean as some engines, but I'd like to get it there, what are your thoughts?
 
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Looks mostly cosmetic with some varnish on the cam lobes. Depending on how much you want to spend you could run Mobil 1 or some highly additized boutique oils like Amsoil, Redline, HPL, etc. for a couple of OCIs. I wouldn't expect miracles though.
 
Make sure the PCV is functioning properly, choose low NOACK oils that meet the mfgr's specifications and change it at severe service intervals. That's about all you can do. Don't do those foolish flushes or spend a king's ransom on oils that will never provide you any return on the investment. That car owes you nothing and it's actually in quite good shape from a visual standpoint. Hopefully the rings, bearings, cam lobes, valve train components and the drivetrain are all in as nice of shape.
 
Make sure the PCV is functioning properly, choose low NOACK oils that meet the mfgr's specifications and change it at severe service intervals. That's about all you can do. Don't do those foolish flushes or spend a king's ransom on oils that will never provide you any return on the investment. That car owes you nothing and it's actually in quite good shape from a visual standpoint. Hopefully the rings, bearings, cam lobes, valve train components and the drivetrain are all in as nice of shape.
Replaced the PCV valve recently actually
 
Varnish shmarnish. It's fine. Spend bucks on some cleaner if you want but a bit varnish at that mileage isn't an issue. Keep changing the oil regularly. I'd probably use a euro oil just since it's about the same price if not a bit more and 40 grade ain't a problem for it. I'd use quaker state euro for it's price and availability at Walmart. Costs the same as a standard 5w-30 but it's much better.
 
At 5,500 miles per year, it probably did a lot of short trips around the neighborhood and never got fully warmed up. You can add a dose of Kreen at the next few oil changes, or if it bothers you, spray it down with brake cleaner and use a tooth brush on the varnish.
 
To me, this seems like a great candidate to try @High Performance Lubricants HDEO that @wwillson has been using, which has yielded significant carbonaceous materials, which we assume is from the ring land area, in his oil filters. I'd skip any specific cleaners and just run the oil. Dave may also recommend something different/more affordable, depending on your budget.
 
Interesting find under the cover. I always understood as VARNISH=Poor OC history, and a top thats not clean is prone to engine issues.

1998-2002 Corollas the biggest concerns are oil burning. If you are not burning any oil, even with the varnish (which to some here it seems that its cosmetic if anything) then continue on your way with your current OCI interval.

0w30 if its the same price as 5w30 if you are in colder climates.
 
Interesting find under the cover. I always understood as VARNISH=Poor OC history, and a top thats not clean is prone to engine issues.

1998-2002 Corollas the biggest concerns are oil burning. If you are not burning any oil, even with the varnish (which to some here it seems that its cosmetic if anything) then continue on your way with your current OCI interval.

0w30 if its the same price as 5w30 if you are in colder climates.
Yeah it does burn oil, but it's not bad, I don't think rings are seized up but the oil control rings are always going to be an issue unless the engine is rebuilt. My last OCI was 2800 miles and the oil filter had a little bit of sludge in it, so I'm just going to continue doing what I'm doing until the filters are mostly clear. I notice the oil burning is not as prominent on brand new oil(when it's thin).
 
Sludge is poor maintenance interval. Varnish is usually textbook religious scheduled OE/dealer recommended intervals.

Vary the 5w30, 10w30, 0w40 full synthetic oil brands/grades. And, keep the oil/filter change interval every 5000 miles or less. Engine will clean up all by itself with current spec oils. Go thicker if there is oil consumption. Follow the HTHS ladder. You will find a grade/brand that might reduce consumption, especially if excessive now. If not excessive, then its normal!

Use an oversized filter. The PH4967 thimble can be upsized to the 4386, 3614, and 3600 filters.

Replace the PCV valve, plugs, thermostat, coolant, cap, transmission fluid, PSF, belt... normal maintenance to get it running good, efficient, and clean. Most of my o2 sensors failed at around that mileage on my Toyotas. Run a quality FI cleaner.

Add a can of BG MOA 110. Its discontinued but still available. Was replaced with lspi MOA 115 and greenie MOA PE06. Other cheap and easy to use cleaners would be a pint of solvent from MarvelMysteryoil or Rislone, detergents from STP Synthetic oil treatment(gold botle), or maybe some help from the ester in Lubegard Biotech. Honestly, I don't see the need to clean it if you start using synthetic oil and a sane interval, and keep it full always. Check that dipstick often. My 1.8's never developed the known oil consumption issues but ran 5k synthetic intervals since new.

Being a Toyota, other than the current tuneup, don't see it needing much, other than timely maintenance and full oil levels. Don't see the need for overpriced additives or oils. Local autopart stores and walmart have fluids/filters and looking for rebates, sales, clearance fluids... will keep it running for a long time. If you're ok with 3k interval, don't even need synthetic oil either.
 
To me, this seems like a great candidate to try @High Performance Lubricants HDEO that @wwillson has been using,
Boutique oil in a 23 year old Corolla seems like a fool's errand.
Why pay double the price for a product that's harder to get only to put it into a 20+ year old vehicle???

Any reasonable person looking at that picture and reading OPs comments would conclude to carry on with the same regimen that got the car to this point.

The varnish isn't hurting anything.
 
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