86 Toy truck,carb'd 15w40.If i change my oil and drive 300 or more miles, the oil is already starting to get pretty dark.I have been using this same oil weight for a few thousand miles now,ever since i got the truck.It has an oil leak that loses a qt. every 400 miles or so.Even with the oil loss and the new oil being added,it's still pretty dark.
oil gets black fast!
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It's black as coal the first time you turn the key in a diesel. Oil color means nothing, especially with an old leaker that goes through a quart every 400 miles!
we're going off-track here with diesels,lol! Shouldn't it stay clean-looking at least a little longer?
Originally Posted By: daves66nova
86 Toy truck,carb'd 15w40.If i change my oil and drive 300 or more miles, the oil is already starting to get pretty dark.I have been using this same oil weight for a few thousand miles now,ever since i got the truck.It has an oil leak that loses a qt. every 400 miles or so.Even with the oil loss and the new oil being added,it's still pretty dark.
Pull the carb off and rebuild and retune it-it could probably use it anyways. Also, make sure the air filter is sealed good and not sucking in unfiltered air.
86 Toy truck,carb'd 15w40.If i change my oil and drive 300 or more miles, the oil is already starting to get pretty dark.I have been using this same oil weight for a few thousand miles now,ever since i got the truck.It has an oil leak that loses a qt. every 400 miles or so.Even with the oil loss and the new oil being added,it's still pretty dark.
Pull the carb off and rebuild and retune it-it could probably use it anyways. Also, make sure the air filter is sealed good and not sucking in unfiltered air.
According to my w/b meter,it runs at 15.1- 16.5 almost all the time,no choke at all.I get consistent 32-33mpg on the hwy
How many miles are on the truck?
209,xxx .I've used mmo,seafoam many times in the past.
Originally Posted By: daves66nova
86 Toy truck,carb'd 15w40.If i change my oil and drive 300 or more miles, the oil is already starting to get pretty dark.I have been using this same oil weight for a few thousand miles now,ever since i got the truck.It has an oil leak that loses a qt. every 400 miles or so.Even with the oil loss and the new oil being added,it's still pretty dark.
Do you know the previous history of the truck? You've had it for a few thousand miles and have been using an HDEO. That could be cleaning all kinds of garbage that was in the engine from the previous owner.
The other alternatives are, as others mentioned, fuel dilution, or possibly even a faulty PCV system. Fuel can definitely darken things up. I know it's not very scientific, but how does the used oil smell when you do the change? If the gas smell is extremely noticeable, that might tell you something.
86 Toy truck,carb'd 15w40.If i change my oil and drive 300 or more miles, the oil is already starting to get pretty dark.I have been using this same oil weight for a few thousand miles now,ever since i got the truck.It has an oil leak that loses a qt. every 400 miles or so.Even with the oil loss and the new oil being added,it's still pretty dark.
Do you know the previous history of the truck? You've had it for a few thousand miles and have been using an HDEO. That could be cleaning all kinds of garbage that was in the engine from the previous owner.
The other alternatives are, as others mentioned, fuel dilution, or possibly even a faulty PCV system. Fuel can definitely darken things up. I know it's not very scientific, but how does the used oil smell when you do the change? If the gas smell is extremely noticeable, that might tell you something.
I just remembered that the pcv valve is hooked up,but the other hole on the opposite side of the valve cover is open,no filter,nothing.
It's rare to find a diesel engine that doesn't turn the oil black almost immediately -- not unheard of, but still rare.
The oil is still good. I stick with 10k-mile oil change intervals, and the oil is black after the first 5 miles.
The oil is still good. I stick with 10k-mile oil change intervals, and the oil is black after the first 5 miles.
I don't have a diesel!!! I'm not writing about diesels
The other valve cover hole should have some kind of breather (possibly going to the air cleaner)-I can't imagine what could cause black engine oil in a carbed gas motor other than a lot of sludge buildup. Personally I don't think I would run out an OCI that far in a carbureted motor, too much unburned junk from the fuel.
Originally Posted By: bullwinkle
Personally I don't think I would run out an OCI that far in a carbureted motor, too much unburned junk from the fuel.
I do 3-4000 mile changes,plus a lot of the oil gets leaked out and new oil added in.I think as far as oci's that's pretty good.So any other reasons why it darkens fast? No more diesel talk,please.
Personally I don't think I would run out an OCI that far in a carbureted motor, too much unburned junk from the fuel.
I do 3-4000 mile changes,plus a lot of the oil gets leaked out and new oil added in.I think as far as oci's that's pretty good.So any other reasons why it darkens fast? No more diesel talk,please.
IMHO, black oil just isn't that common in a gasoline powered engine (the only one I've ever had was a carbed 302 Ford pickup that was so neglected the drainback holes were clogged)-still think you've got some crud in there that's getting picked up by the oil (which is the job of the detergents).
Had a Dodge 318 that would get black fairly quickly. Good condition, short OCIs, and well maintained.
60% highway.
Heard of other Chryslers engines that would do similar.
60% highway.
Heard of other Chryslers engines that would do similar.
Excessive blowby past the rings
should i keep adding mmo to loosen up more junk?
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