1999 Mazda Miata under valve cover pics at 110k

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3,431
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USA
I just bought a '99 Miata as a cheap car to have fun with. The previous owner really knew nothing about cars. I know nothing about how this car was maintained. I inspected it pretty closely in person before buying. I looked in the oil fill hole with a flashlight and noted it didn't look too bad in there. Now I'm going through the car fixing the little things I found and giving it a more thorough once-over. The valve cover gasket was leaking. I took the cover off tonight to fix it and take a look at the timing belt. There was no paperwork or labels indicating the timing belt had ever been replaced. Overall, it looks like good news to me. This isn't the cleanest engine I've seen, but it's not the dirtiest, either. The timing belt also looks really good. It is pretty clear to me that it's been replaced and it sure looks to me like it hasn't been too long since it was replaced. The oil is pretty dark as it needs to be changed, but I don't see too much buildup beyond what's on the inside of the valve cover.
 
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9,783
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Saskatoon canada
Originally Posted By: Merkava_4
That's pretty bad; loads of varnish.
Loads of varnish? Your posts have become beyond absurd. At 110k miles that's what I'd consider stellar. There's barely any varnish and I bet no matter whether you run pennzoil ultra or M1 it's not going to get any cleaner,not appreciably anyway. So the previous owner wasn't too bad anyways. He's given you a decent place to start off with. Put on a turbo and have some real fun with that car.
 
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9,783
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Saskatoon canada
Originally Posted By: Merkava_4
Originally Posted By: Clevy
Loads of varnish?
That's what I said yes. Engines aren't supposed to be black, brown, and tan.
I will concur that there is some varnish. A very light layer by the looks of it. So you are right about there being varnish,however "loads" isn't quite how it looks to me. And I'm just wondering what harm exactly a light coat of varnish does? Sure if it was thick enough to impede oil flow I could understand posdible concern however this particular engine looks like there is very little and it's possible the darkness we see is just old oil that hasn't drained off. Either way it's absolutely not harmful nor is it to be a cause for concern. In my opinion anyway
 
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5,707
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WatUpDoc
It's fine. Use something like Pennzoil Ultra, Mobil 1 High Mileage, etc for a year if driving highway miles. Make sure if there is a PCV system that is taken care of, too. You could always after a couple good OCIs use an idle engine flush before dropping the sump; I have had good success with Amsoil's engine flush and Lubro Moly. Lubegard is a good one, too. That'd be my approach at first, full synthetic or high mileage + idle engine flush for 15-20 minutes before oil change(no driving required for the amount you add). If you do your own oil changes and can just let it drain a good hour to remove as much of the soot at possible. When I got my older Civic I used this method described above and noticed small, harder deposits removed after my first couple of OCIs. I had also used Amsoil's Power Foam in the crankcase injestion/soak method prior to a couple changes as well. All combined it seemed to help clean it out some. A year or two later I got pics of the valvetrain and it was clean as a whistle for the age. NOTE: I did not have before pictures. However, oil consumption improved (perhaps sticky rings, pcv system etc) and then visually seeing deposits when I drained the used oil up for recycling and then reaching a point with no more soot like that in my used oil were positive enough signs for me. In tank fuel system cleaners like Red Line, or any PEA containing cleaner is probably a must and see if your vehicle has a fuel filter as well. Looks like it can be a champ for a long time! PS: Also, if you don't really know the service on the timing belt may as well replace it if mileage is really high.
 
Originally Posted By: Merkava_4
Originally Posted By: Clevy
Loads of varnish?
That's what I said yes. Engines aren't supposed to be black, brown, and tan.
Racist. Also a bit of varnish never hurt anything, looks perfectly fine
 
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2,011
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War Eagle
That looks fine. That little varnish will not hurt anything. Change the oil and go have your fun with the car. If she was mine, I would not worry about that at all
 
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7,485
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S California
When using low-solvency basestocks (hydrocracked and PAOs) that are more thermally and oxidatively robust they can lay down, coagulate and leave behind small amounts of oxides, salts and carbon leading to future sludge and varnish. Then along comes an oil change and you start over, again. Look at it this way. Your pictures might just be proof that the previous owner used good oil and changed it now and then.
 
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215
Location
Festus MO
There is nothing wrong with the engine. Run the heck out of it. And I agree, a Turbo Miata is a beast. I've been in one with a home made patched together 40mm turbo and a small intercooler, it's a blast, really surprising.
 
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14,843
Location
Illinois
We have seen engines with more varnish, but this is BITOG and we should know any varnish isn't good. Varnish is caused by the oil oxidizing(thickening)and can, at times, lead to ring coking. It appears your engine probably was run on dino, so a quality synthetic will in time start to clean up some of the deposites left behind. Since the only oil I use is M1 my engines show no varnish at all. Just sayin.
 

pbm

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8,914
Location
New York
The small amount of varnish in that engine wouldn't have kept me from buying the car.....it shows that it did have oil changes even if it's not up to BITOG standards. Highway miles and regular oil changes (preferably with M1, PP PU etc...) will clean that engine up after a few OCIs...
 
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9,105
Location
Houston, TX
A can of Berryman B-12 Chemtool will have the underside of the valve cover looking like new (e.g. bright shiny aluminum). The varnish in the engine will likely be reduced over time by running a synthetic of your choice. For an engine with a questionable maintenance history, unknown oil type and OCI, it looks pretty good.
 
Having a clean engine is nice, but aside from some bragging rights to the total strangers on internet, it means nothing to the average car owner. Most cars, under the care of most "non car people" will have a bit of varnish and will function just the same as the clean engines. It takes a lot of varnish and sludge to actually have an effect on engine operation. This brings me to another topic. A lot of people here like to idolize the Europeans for their use of synthetics and the long term intervals. Well, let me tell you one thing, there are practically no high mileage engines over there that look like the pics Merkava posted and that see the super long OCIs even on synthetics, that are practiced over there.
 
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