Photo: under valve cover. 16 Trax 80K.

[hardcore302]

OP here. I'm glad I could throw a hand grenade into the room

 

[dnewton3]

Depends on whether it's representative of what's going on in the ring land area or not (which is an area of even higher heat and lower flow).

The problem with varnish is that it's a precipitate. Oils are blended with dispersants and detergents to both prevent agglomeration of deposit-forming contaminants and to keep them in suspension. If they are plating out, it means the additive package isn't doing its job in this department, likely due to being saturated/overwhelmed.

So, if the oil is no longer able to keep this material in suspension, and we are seeing it plate-out in areas of low flow (like the top of the heads and on other surfaces) then the same thing is going to be going on, but in a more concentrated form, in the ring land area, where flow-through is extremely low, and the conditions are more conducive to lacquer plating accruing. Once sufficient lacquer/varnish is accumulated in the rings, particularly the oil control rings, they can start to stick. This causes problems with oil control, and the byproduct is consumption. When this starts to happen with the upper compression rings, you get increased blowby, which in turn increases the volume of contaminants entering the oil, expediting the rate of degradation. This also causes loss of power. None of this is desirable, but it's natural to see some degree of it on high mileage engines run on "regular" oils.

I am in general agreement with Overkill's statement. However, I'll add this ...

Varnish is not a result that happens in a vacuum, so to speak. Varnish is a result of the oil being challenged relative to its host; the engine. Some engines are well designed; they have good oil flow, good oil return, and not a lot of hot spots. Other engines have significant challenges; they suffer from the development of heavy varnish, which can be the precursor to sludge formation. Additionally, the OCI is a key player as well; any lube can be compromised if used for too long as the add pack gets depleted/overwhelmed.

It's not really fair to say that any particular engine or engine oil will develop varnish problems standing alone; looking at one element while not discussing what it's paired with is only looking at part of the equation. Any "normal" oil might serve extremely well, even in longer OCIs, when used in an engine that does not have a propensity for oil control problems (Ford 4.6L 2v as an example). Any engine that does have a propensity for varnish/sludge formation still might survive well if a premium lube with excellent cleaning ability is used (HPL as one example).

Also, very light varnish (slight color change with no perceptible depth/thickness) isn't really concerning. But once it starts to darken and continues to darken and thicken, then it's a tell-tale sign that things are not as healthy as they could be.

What's clear to us in the OPs photos is that varnish is forming. It's dark enough to at least question the OCI plan and lube choice. In this case, I'd suggest considering HPL's PCEO, paired with a few short filter changes at first. HPL won't scrub this engine clean overnight; that's not how it works. But given a steady diet of HPL at perhaps 10k mile intervals, this engine would likely clean up, and those unseen areas such as ring lands, etc, would also be in better shape.