Originally Posted By: uart
Let me guess. You've got an enameled baking dish that you cook a lot of roast potatoes in, and you don't wash it up properly so it's got a baked on brownish coating.
Originally Posted By: friendly_jacek
That was my first reaction when I first heard about it.
Please tell us more about it. What oil, what happened?
Originally Posted By: Shannow
Linoleum is pretty well the end oxidation product of linseed oil with heat and exposure to oxygen, which is always my first reaction to any oil in a warm, oxidative environment...pretty much why no oil that forms a crust around the cap in the pantry ends up in my pantry.
Now I feel obligated to embarrass myself!
It basically happened because of OPs exact scenario. A few years back, I'd read something (perhaps that same paper in OP) that piqued my interest, and the article seemed official which I found really compelling. So began the (brand inspecific) search-engine'ing around for "specs" on various common cooking oils. They're rated very differently, and rarely is a KV listed, but instead things like "Iodine value". I ignored that, because I was all about the pour points, smoke points and flashpoints of these oils (which often look comparable to motor oils). After comparing, I decided to use CORN OIL. It had the lowest pour point of commonly available cooking oils. Installed a 50/50 mix with some 0w30 into the Toyota 2.2 and went about business as usual. The engine had some leaks, so it would smell pretty bad when it got on a hot exhaust pipe... like really rancid cooking oil. Eventually, about 3-4K I noticed weird chunks on the dipstick. The oil itself looked normal brown, not syrupy but the solid particles concerned me. I dumped the oil, and refilled with what I don't remember. After that, more miles driven, but begin to notice a loss of compression on startup. At this point, I was sure I needed a new engine. It must have had 4 changes and numerous flushes in the next couple thousand, one with PYB which actually "cured" thestuck ring. I kid you not, I have no interest or affiliation with Shell/PZ, but the PYB was in there, when that ring got unstuck!
All seemed well, finally, and the daily commutes continued, then the weather got cold again and then the oil pump started making noise when the oil was cold. Thinking now, that the pumps been bunged up, I bought a new one and had a TB, OP, WP and seals job done. Mechanic calls me and says "we did the work, but now the oil pressure is really low and the light is flickering. Went to the shop, checked it out, cars running fine, just oil light flickering @idle. We put a gauge on it (to the head, where toyota puts their dummy light switch) and I was seeing a solid 6psi avg, max of 10-15psi. I told him to find the problem. Couple of days later, he gets back to me, and says "the oil pick up tube was completely clogged". We had to clean it out, and also there is a hard layer of 1/2inch thick SLUDGE, what could only be described as plastic (or linoleum as Shannow mentions) all in the engine. I'm thinking "oh. shoot. that." and then "how did they not notice it before?" So buddy cleans it to get it functional, reassembles and send me on my way. After that an OP gauge was promptly installed, and what I learned from the OP gauge behavior was more about different types of oil filters, rather than anything else. (Stay away from TVI brand!)
Put short, unsaturated veg oils are deadly for IC engines. The iodine value is something to really pay attention to. Even though some veg oils are "extracted with hexane" and are heavily processed, still leave them unstable- and arguably far more unstable (and bad for our health). I didn't doubt the lube properties were there, the engine was running really nice and smoothly, but whatever it saw in that crankcase was just a chemical nightmare. Still, the engine lives to this day- with good compression, minimal consumption. Gotta hand it to those mid-90s Toyota engines.
