Burnt oil dipstick

Looking at buying a used rig. Noted that the oil dipstick had what appears to be a hard glazed on "varnish" of what appears to be burnt oil (dark brownish) all the way up the stick.

My 20-year corolla and 25 year-old tercel, both have "clean" dipsticks. Is this a cautionary thing. What caused this?

Reply to
timbirr
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I have a Corolla GTS and a Celica GTS, both 1985's. The Celica's is clean as a whislte, the Corolla's is like you describe.

I met the original owner of the Celica; he's a car nut and did all the maintenance on time.

I bought the Corolla in '86 with 10,000 miles and changed the oil every

3,000 miles. Why one is varnished and the other isn't???
Reply to
HachiRoku

Could it be the location of the dip stick tube with respect to the exhaust manifold?

Merritt

Reply to
Merritt Mullen

=A0Is this a cautionary thing.

Yes. Indicates condition of the inside of the engine block, however, varnish is not particularly harmful. Would be better if clean.

What caused this?

Heat. Conventional motor oil "breaks down" over time. That is, viscosity index changes, volatile compounds flash off. Some varnish on the upper end - valve cover, is considered normal, less so on the dipstick.

You could check auto-rx.com.

When buying a used car, I often perform a couple of extra oil changes, to help clean up the oil. Surprisingly, even if you drain it out fairly soon, it still comes out dirty. That's the detergent working, so perhaps that helps a little. In terms of operating efficiency or longevity, probably doesn't make a lot of difference. Varnish coating internal parts interferes somewhat with the cooling effect of circulating oil. If there's enough varnish that the pistons rings begin sticking in their lands instead of sealing against the cylinder walls you'll see increased oil burning and / or loss of compression and power. Those conditions are more cause for concern.

Reply to
Daniel

Yeah. most likely. The one complaunt I have with this car is that the dipstick and the filter are on the 'hot' side of the engine, with the filter located directly below the exhaust manifold. Know how thay tell you to change the oil with the engine hot? I have a couple of small scars from that little bit of advice...

On my '85 Celica GTS, the filter is hidden away down on the block, but on the 'cool' side of the engine.

Reply to
HachiRoku

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