Oil leak does not register on dip stick

I have a pretty bad oil leak from front valve cover but whats odd is that it suddenly stopped showing low on my dip stick. Now it ALWAYS says a quart overfull no matter how much oil is leaking out. Also after driving for awhile it gets a terrible knock. There is no smoke however and engine runs like normal. The car is a 2005 Hyundai Elantra.

It’s very rare in truth for an oil pump to “go out”, but I think yours has. Specifically, the oil pump drive gear may have failed. The oil has pooled in the engine’s bottom and is not being pumped into the bearings. That’s what’s causing the knocking.

Don’t drive this until it gets fixed. With luck, you may have not shortened the bearings’ lives by too much. Continued driving will probably result in bearing seizure and that’ll mean the engine is toast.

I believe that mountainbike is correct, but I want to comment on another element of the situation, namely–
“it ALWAYS says a quart overfull no matter how much oil is leaking out”.

Is it possible that you have been checking the dipstick for the transmission, rather than the one for the engine?

Think about it:
If there is a persistent leak, how could the level on the dipstick never show a loss? The only possible explanations would be either what I posited above or–that the oil is being diluted with coolant, as would happen with a breached head gasket. Hopefully your oil is not being diluted with coolant, but the way to tell is by the appearance of the oil. If it looks like a chocolate milkshake, then the oil has been diluted with coolant, and that would lead to very extreme bearing wear and knocking.

If my dipstick theory is correct, your engine’s crankcase could actually be extremely low on oil at this point, so it bears immediate checking. As well as checking the level of the oil on the correct dipstick, try to assess the appearance of the oil.

And if VDC is correct, the knocking may be due to the low oil level.
That man has a good head on his shoulders…

thanks for all the good advice I did have the oil checked and there is no coolant in it. Next I ll have to get someone to check the pump. Is that a long process and how much do you think it might run?

I’m not familiar with the physical setup of that engine compartment, but the test itself isn’t difficult. It’s a question of starting the engine and checking the oil pressure with a gage. What might affect the cost is whether the pressure sensor hole is readily accessible. It should be.

Does the oil smell like gasoline? If so it would be wise to drain and refill the crankcase and replace the filter before starting the engine and quickly finding the faulty component in the fuel system.

tototoo, you said “I did have the oil checked and there is no coolant in it.” Is that after you checked it with the right dipstick?
Don’t you have an OIL light or an oil pressure gauge?

I think I mite have a possible answer to this. Valve cover is leaking because oil is not returning to the oil pan. The oil is being trapped on the head. Now the oil shows low so he added more and then what was blocking the oil gave way. Now it over full. As for the knock. The oil is sill being trapped on the head (not draining back fast enough) and may get low enough in the pan to cause a knock. What do you think?

It’s a possibility. I don’t know if the volume under the valvecover would hold enough oil to allow the pan to run low, but until the problem is actually solve anything that’s possible should be on the list.

I’m wondering whether tototoo has checked the dash lights/gauges to make sure that whatever indicates oil pressure is working. If the pump was gone then the oil light should be on - or the gauge should be at zero or so.

That doesn’t really change the story of course. Immediate professional attention should be gotten lest the engine goes from only probably fried to completely fried.

Hi Yes I have an oil light but it never came on. Sometimes I needed 2 quarts but it (oil light) still never came on. That’s why the knock surprised me wouldn’t the light have come on if it was bad enough to cause the engine to knock? Now it is finally reading normal on the dipstick and the knock stopped. I had the valve cover replaced but it still leaks some oil just enough to make a little round spot under the car.

In theory the light should have come on triggered by the loss of pressure. You should test that circuit after diagnosing the cause of the pressure loss.