Major Oil Leak Front Side of 3.1L

2001 Grand Prix 3.1L 140K

Help, I have a major oil leak on front side of engine and the oil filter is covered in oil. Took filter off (it was tight) and it is not split and gasket looks good. Is there an oil pressure sending unit right above the filter? Any special wrenches to take it off? Anyone have any other ideas?

I added 5 quarts of oil and started it. Oil poured out and oil pressure light stayed lit the whole time that I drove it up on ramps and it was knocking pretty good.

You need to spray some engine cleaner on your engine and get it clean, then fill it up with oil. Have someone else start the car and as soon as you see exactly where it's leaking holler at them to shut it off.

The oil pressure sending unit is just above the oil filter. It sounds like yours is bad and leaking badly either from the sensor itself or from around the threads. No special tools are required to change it.

Are you sure the filter is not double gasketed?

When did the leak start? (ie, right after an oil change?)

I hate to say this, but if the motor has already been knocking, its probably toast.

Are you sure the filter is not double gasketed? This was the first thing that I looked for and then I inspected the filter.

When did the leak start? (ie, right after an oil change?) It has been about 4K miles since last oil change and filter is AC Delco. The car sat all weekend and then I drove it. There was a puddle where it had been parked.

I hate to say this, but if the motor has already been knocking, its probably toast. I don't think it is toast. Even if there is damage, I am not going to give up on it. I am going to fix the leak and keep on driving it or trade it in. I have seen an engine start knocking due to lack of oil and then run for another 50K miles.


Thanks to all for the help

AC Delco oil filter? :shakehead

Did you find the leak? Was it the oil pressure sending unit or was oil blowing past the oil filter seal?

AC Delco oil filter? :shakehead

Did you find the leak? Was it the oil pressure sending unit or was oil blowing past the oil filter seal?

Did not find leak, could not get the sending unit out and ran out of daylight. Will try again after work today.

But is the source the sending unit for sure? Or was oil blowing out past the oil filter o-ring seal? The reason why I mention this is there is a pressure valve located behind the oil filter mounting assembly. When the rod gets stuck open it will cause oil to blow past the filter seal and in bad cases even blow the oil filter off. Also, be sure to use another oil filter other than the AC Delco PF47. A lot of quality issues now since they are outsourced by GM to Champion Labs.

Thanks to all for the help

I guess he told me... :iceslolan

Good luck with the leak.

But is the source the sending unit for sure? Or was oil blowing out past the oil filter o-ring seal? The reason why I mention this is there is a pressure valve located behind the oil filter mounting assembly. When the rod gets stuck open it will cause oil to blow past the filter seal and in bad cases even blow the oil filter off. Also, be sure to use another oil filter other than the AC Delco PF47. A lot of quality issues now since they are outsourced by GM to Champion Labs.

I will check it out after work.

If it is coming from around the oil filter seal, what can be done about the stuck rod?

Thats what I thought. You have to remove the oil filter mount from the engine. Then get the rod unstuck at the valve. Check for excess oil crud buildup and that will need to be cleaned out. And be sure to use another brand oil filter just to be safe. What brand engine oil are you using?

Thats what I thought. You have to remove the oil filter mount from the engine. Then get the rod unstuck at the valve. Check for excess oil crud buildup and that will need to be cleaned out. And be sure to use another brand oil filter just to be safe. What brand engine oil are you using?

I usually use Valvoline but lately have been using Shell 5W-30.

I usually use Valvoline but lately have been using Shell 5W-30.

I'm not a fan of Valvoline but never used it or Shell. After you get the issue resolved you might consider running some Seafoam engine treatment directly into the crankcase to help clear all the oil passages out. The issue of the rod sticking has something to do with oil deposits forming and building up. After that replace the engine oil again along with the oil filter.

Ok, got a chance to take a look at the car and the oil pressure sending unit was indeed the problem. It was shooting a 1/4" stream of oil out. The OPSU is located directly above the starter about 8 inches from the oil filter. The sensor that is directly above the oil filter is the knock sensor.

I am going to add oil to bring it up to level and change the filter and then add motor flush and idle for 15 minutes and then change the oil again. Hopefully this will take care of the metal particles that are probably going to be floating around.

After doing all of this, there is significant knock but it sounds like it is coming from the top of the engine. Other than the noise, everything seems fine. Power is normal. Idle is smooth. I will probably get less MPG do to knock sensor picking up the noise.

Any suggestions on which weight oil to use or any additives to use to help reduce noise. I did substitue 1 quart of Rislone for 1 quart of oil.

Sounds like a lifter.

If you live in a warmer state, you could run 10w30.