OK I feel like an idiot but I need some advice. My oil pressure gauge has been low for a week with the light on. Today I changed the oil and only about 1 or 2 quarts came out. 5.4L, 96,000 miles, no sign of oil leaks or burning except an occasoinal blue puff of smoke at startup. I just made the assumption that the gauge was bad since the engine sounds perfectly normal and no loss of power. How much damage have I done to the engine and do you think is causing the engine to lose 5 quarts over 3,500 miles?

 

I think you and my wife must be twins separated at birth.

Did you measure the amount of oil that you drained, or are you guessing? How many times have you checked the oil in the last 3,500 miles, and did you notice any loss at 1,000, 2,000, or 3,000 miles?

 

I'm guessing on the oil drained. I could measure it if that would help give any clues. I have to admit I don't remember checking it since the last oil change. The engine never lost oil in the past when I checked. I put a lot of miles on the truck. It has only been a couple months since the last time I changed the oil.

 

If it were my truck, I would keep an eye on the dipstick and do an oil analysis if you see a notable loss.

 

Believe me I will be checking daily. 4-5 quarts of oil loss is the sign of a major problem is it not? Gaskets, valves, heads? Again the truck has never used oil. One other thing, on the past oil change I switched to Castrol high mileage oil.

 

My '91 Jeep Commanche recently experienced a similar occurance. Although not to that extreme (only 3 quarts low out of 6). Anyway, that engine has 120K miles on it in a lot of city traffic. It didn't seem to be burning oil (plugs looked ok). But after a thorough evaluation, it is both burning (slightly) and leaking oil. The rear seal is going and it probably needs a valve job (valve seals need replacing). If there is no oil in your coolant, I would bet you've got the same thing going on. For the time being, I'm just adding engine restorer to the oil and driving it till it can't take it anymore. Then, I'll replace the engine with a rebuild....or just sell it as is.

 

Get on your back and lay under the truck. Look at everything, all the way back to the transmission and check it all for oil leaks.

 

Do you notice any loss in oil volume now? Do you notice any difference in how the truck is performing? Running that low on oil has a snowball effect as you lost more than 2/3 of your lubricating and cooling fluid. It could have starved the heads long enough for the valve seals to give up.

Runningon only 2 out of 6 quarts of oil is bad. But that is just a speculation. Keep an eye on your oil level and have it tested at a lab after 3K miles or so. Be very honest with them and they will give you good information.

 

OK, I just checked the oil after the engine has cooled off for a few hours. It is in the middle of the max/min range. Engine would appear to have used some oil today. I put 6 quarts in yesterday. There was a big puff of blue smoke this afternoon after it sat for a couple hours. The engine was not entirely cooled off. What do you think?

 

So you changed oil, and put in 6 quarts but didnt not check the level??

Running a big V8 on 2 quarts of oil for 3000 miles is probably not good for the engine at all. Bearing require oil to "cool" and lubricate them. The higher the heat the higher the probability of damage. I would say with only 2 quarts of oil you had some serious issues with internal heat in the engine. This would have cause high amounts of sludge and varnish in the engine, you could also have coked up your rings, which would allow high amounts of blow-by(your blue smoke).

What I would do, is to do an engine flush, run a couple of short drain intervals say 500-1000 miles (any cheap oil will do.)

After that I would find a good synthetic run it 3000 (while monitoring the level religeously) Then I would take an oil sample. Find out if there are any high wear metals which would indicate damage.

Otherwise, I would start putting some money in the bank for a new engine. Blue puff of smoke is a sure that something isn't right.

 

Six quarts will put your oil level in the middle of the max/min range. Chances are you will not notice much oil loss in one day of normal driving.

My old Chevy's used to puff a cloud of blue smoke when I started them in the morning because the valve guides needed replaced. The oil would leak through them when the motor cooled down.

 

Right after I put 6 qts into mine that is where the oil level is on the dipstick.

I would do as msparks said and do a short oil change interval once or twice.

Keep an eye on the oil level, be on the lookout for leaks, etc.

For future reference, the oil light usually comes on as a last resort. You should have checked the oil level as soon as the light came on.

 

If you continue to get the puff of smoke.

It wouldn't hurt to do a run with Auto-RX in there. That should clean and rejuvinate the seals and piston-ring seal

www.auto-rx.com

 

600 miles since the oil change. I have checked the oil every day. Had to add over half a quart today to get the oil level to where it was after the change. So the engine is burning about a quart/1000 miles. I get the blue puff of smoke about once a day. Sometimes not in the morning but often in the afternoon after the truck has sat for a couple hrs. The engine is not totally cooled off. Valve seals?