What can I do to clean out a badly varnished engine?

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Feb 16, 2004
I have a friend who purchased an abused honda accord 4cyl (@ 60K and now has 118K) and the valvetrain (what I can see through the oil fill hole) is rather badly varnished. Aparrently the previous owner was REALLY slack on oil changes and other maint as the dipstick is coated in varnish up to the top of the handle.

They cannot afford the 2 $25 auto-rx treatments, but do change the oil with 10w30 at 3-4k with either supertech syn blend or syn and a supertech filter.

What should oil they run in order to clean out some of the crud? I've heard rotella and mobil/delvac 5w40 have better detergency than regular oil. Any opinions?

Is it safe to run a 5w40 oil in a 4cyl that uses 10w30? Will it affect gas mileage a lot?

Thanks for the advice.
I used the Rotella-T 5W-40 synthetic in the 94 Corsica 2.2L 4-cyl. It really DID clean out the engine!..I think. It started and ran fine, even in the colder temps. The only thing I noticed was maybe some lifter-tappet noise. However, the lubrication must have been fine. The MPG did suffer, by what measured 4-6MPG, ever 5W-30 Castrol. The engine also seemed a bit doggy. I don't know if that is detrimental, but it still works fine and the oils since then ahve stayed clean much longer! The parts I can see appear clean. Good luck!
If he they want to get brave, ever think of putting some B-12 Chemtool in the oil? I have and the oil comes out like sludge, but I haven't much knowledge if that process is harder on internals than just leaving things alone. A piece of something could be cleaned and let loose, too. Several items to consider. I hope all goes well!!
First, just about any engine that used dino oil will have a varnish color on the inside. Just the nature of the oil. If engine is running good and not using oil and compression is OK, don't worry about it. Second, a good synthetic oil will gradually clean an engine. AutoRx will not make the engine look brand spanking new inside or any other additive or oil for that matter.
My recommendation would be to run 1 quart of ester based synthetic with 3 quarts of whatevers on sale.

Run the oil 2,000 repeat. Next time put 2 quarts synthetic and 2 quarts whatevers on sale. run that 2000.

Run 3 quarts synthetic 1 quart whatever is on sale run that 4000 miles do a filter change at 2,000.

Run full synthetic 6000 and continue on with this program until the engine dies or you get rid of the car.

Make sure that you check the oil at least weekly. Make sure if there are leaks you keep an eye on them(I would degrease the engine really good so you can see where the leaks are and how much they are leaking. I would be in about 15,000 miles things will be okay.

I would use Amsoil 10w30 for the synthetic and whatever you can find at the store cheap.

Hope this helps
Of coarse all of this would be easier if you did the Auto-RX right from the get go.
While it may be a bit more difficult to find, both Delvac 1300 and Delo 400 are manufactured in a 10w30 grade. Maybe you can find a distributor/jobber to order up a few gallons. Probably won't do much to alleviate the varnish but it could help to otherwise clean the engine internals up over time.

[ May 05, 2004, 10:19 AM: Message edited by: doyall ]
I can guarantee that the car recieved poor maint. b/c the of dark discoloration of the engine, oil leaks, oil splatters around the engine and underside of the hood, and the fact that the dealer had absolutely no records on the car before purchase. It also looked like crap when they bought it (interior and exterior).

I know my friend was ripped off, but that's in the past.

Also, I have a '95 Accord w/ 130K+ that has run dino havoline or kendall 5w-30 for most of it's life with 3-5000 OCI (wasn't me driving) and the engine is a clean as a whistle, with no varnish on the valve cover, valvetrain components or dipstick. So I don't believe that these cars automatically build up varnish over time.

I can also attest that the other vehicles that my family have owned are the same way, with no varnish even with high miles (150K+) and 5k OCI's.

I can only assume that the condition of my friend's engine is the direct result of the negligence of the former owner (woman) and the dealer.
Since the original question was "Varnish" buildup, I'm confused.

HDEO's and Syns can maintain cleanliness and remove some nasties from neglect.

I was under the impression that no engine oil can actually remove varnish once it's there.

I don't know about ARX, but I doubt any SYN or HDEO will impact varnish.

Isn't it only acetone soluble?
well $50 for two doses of auto-rx isnt asking a lot, if the person really feels $50 is too expensive to afford then just put in the cheapest oil you can find and drive it til she dies. Using more expensive oil at this point likely wont help anything. I'd push hard for the auto-rx, its pretty cheap for what you get and you can feel better about running regular oil after that. just my opinion
Since the folks in question are on a budget, I'd recommend a low-cost diesel lube as others have. The least expensive I know of is the 15w-40 Motorcraft lube at WalMart for about $1.46, and that should help clean things out a bit over several thousand miles. This weight should be fine over the coming Spring and Summer months; after that I'd go back to a 5w/10w-30 gas or diesel lube.

While many synthetics do have high TBNs (long term cleaning capability), diesel lubes tend to be a bit higher, and are less expensive as well. Personally I wouldn't put syn into that semi-beater engine, simply due to cost.
I just want the car to last as long as possible, since this my friend is taking a vow of poverty (teaching)

I know varnish isn't a big deal, but what it's hiding is. I'd love to put the engine in a dishwasher and clean it out.

My friend can't afford a new car so that's why I'm asking for advice from you guys.

Any cheap things to do to keep the engine running well.

Is a 15w-40 safe to use in an engine that uses little to no oil? Is it too thick for a 4 cyl econocar?

Is B12 chemtool a safe thing to use?

Since this engine is not a 5w-20 luber, 15w-40 would be perfectly fine over the upcoming Summer months. Perfectly safe, although a diesel 10w-30 would be the preferred weight, although much tougher to find. (Some may say that even the "5w-20 engines" could safely use a 15w-40, but I'll defer that to the 5w-20 talk-a-thon threads.)

I'd say that any of the over-the-counter "flushes" and "cleaners" are safe when used as directed. Simply using a diesel lube is the safest bet of all, as it will slowly do its cleaning over several thousand miles, not likely dislodging any big deposits into the oil channels in the process. "Slow is better" when cleaning sludge/varnish seems to be one of the few absolute truths on this board -- most everything else is open to debate.

Originally posted by seotaji:
Any cheap things to do to keep the engine running well.

Is B12 chemtool a safe thing to use?


They may actually do radical things (I assuming you mean in the crankcase, not the gas) that will not keep the engine running well. Then your friend will need to come up with the bucks for a new engine. I wouldn't want that on me.

If there are no problems - smoking, consumption (sounds like vices some of my friends have) then it could simply be cosmetic. No worries! Put it on a gentle cleaning regimen. Anything goes wrong, it wasn't because of your radical measures.
Unless you can verify that the engine oil and filter changes were neglected, I'd have to say what you're seeing is normal.

My '87 Acura Legend has 346K miles on the engine, egine oil and filter was changed at 3000 miles, it has never been apart for any kind of mechanical repairs (belt changes, gasket changes, etc. not withstanding). The inside of the engine (what I can see thru the oil fill hole) has a nice brown color.

Castrol GTX 10w-40 was the oil of choice of the original owner. I switched over to Delo 400 15w-40 (dino) at 273K miles.

The engine uses 1 qt. of oil every 4500 miles (I extended change intervals to 5000 miles). The valve train is a bit noisy at times (nothing like it was when I first got the car), a peculiarity of these engine with high miles.
For the top end just remove the valve cover and shovel and scrap the junk out. I have used a shop vac before with a screw driver to get it out. Then flush with junk out of the top with a solvent brush and solvent.

If you feel comfortable droping the pan then dro it and do the same thing.

I would have the friend save up $5 dollars per pay check and order a bottle of Auto-Rx. Auto-Rx is a bargin!

The only oils that really claen out an engine are high ester content oils and they cost more then AUto-Rx and will not work any wear near as well.
Does anyone know where I can find delvac 5w40 locally?

Would wal-mart stock it? All I saw yesterday was delo 15w40. Would I have better luck at advance or autozone?

Would the rotella t synthetic 5w40 work as well or is it not a real synthetic?

I'll try the motorcraft 15w40 first, since it is readily available.

I'm a little worried that the 5w40 or 15w40 is too thick? Are my concerns without merit?

I'm going to see if I can remove the valve cover and start scrubbing using a solvent.

Thanks for all the advice

[ May 07, 2004, 11:16 PM: Message edited by: seotaji ]

Originally posted by seotaji:
Does anyone know where I can find delvac 5w40 locally?

Delvac 1 is available as Mobil 1 Truck & SUV 5W-40. It's available at some Wal-Marts. I don't know if you have Checker/Schucks/Kragen on the east coast, but they carry it also. My local Wal-Mart just started carrying it 3 months after Schucks did, so if yours doesn't have it now, it may in the near future.
I guess jugs of delvac would be sold at truckstops or jobbers, not wal-mart.
Note that Delvac-1 (5w-40) and Mobil-1 truck and SUV oil costs anywhere from $20/per gallon to nearly $30/per gallon. If this isn't out of you budget then Auto-RX definitely shouldn't be.

I'd do what was mentioned earlier and use Wal-Mart branded cheapy oil and change it frequently (3000 mile intervals).

Repair things as they wear out and don't put yourself in the position to have to pay $100 for a tow truck. That's $100 that could have been spent on something useful.
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