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Hey Guys, I am having another problem with my 3.8L 1996 bonneville. While driving home from work today, I started to here a tapping noise. The noise got louder so I pulled over and had the car towed home. When the noise got louder I noticed the oil press. gauge red lining and bouncing back and forth. I pulled the dipstick when I got home and noticed a thin vertical line of oil up to the full mark. I added some oil and restarted engine. Same loud tapping. I am assuming that it may be the oil pump. 3months ago I had intake manifold gasket leak but repaired it with new upper and lower gaskets and new intake. before i start tearing into the oil pump I was wondering if anyone had any suggestions on where else to look? Thanks.

Driveway Al

I'd drain the oil and check for metal flake. I'd bet there's a bunch. These oil pumps are pretty reliable. I'd bet it's a rod bearing. Kinda typical in the months following a failed LIM gasket if a lot of water got in the oil.

We can pretty much guarantee you that it's not the oil pump. How much coolant got into the oil before your manifold gasket repair? How long was it there before the oil was drained? Or is it one of those things that you don't know when it started or how long?

J Wikoff wrote:I'd drain the oil and check for metal flake. I'd bet there's a bunch. These oil pumps are pretty reliable. I'd bet it's a rod bearing. Kinda typical in the months following a failed LIM gasket if a lot of water got in the oil.

willwren wrote:We can pretty much guarantee you that it's not the oil pump. How much coolant got into the oil before your manifold gasket repair? How long was it there before the oil was drained? Or is it one of those things that you don't know when it started or how long?

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Unfortunately I've been there and done that.

It was kind of sudden, the drop in oil press. and the noise. Before the noise it was running perfect. I changed oil twice after I did the intake job. I could not get to the car this week, but first thing I will do is drain the oil and drop the pan. Is there any possibility the pickup screen could be clogged?

Driveway Al

willwren wrote:How much coolant got into the oil before your manifold gasket repair? How long was it there before the oil was drained? Or is it one of those things that you don't know when it started or how long?

These questions are referring to BEFORE the gasket change.

If there was coolant in the oil before the gasket change, it tends to damage the main and rod bearings. Many people fix the gaskets and then a short time later it will spin a bearing.

So, Was there coolant in the oil before the gasket change and how long did it sit in there before the gaskets were done?

driveway Al wrote:It was kind of sudden, the drop in oil press. and the noise. Before the noise it was running perfect. I changed oil twice after I did the intake job.Driveway Al

That's basically the same thing that happened to me.
If it ate a bearing all you have to do is check the dipstick, you'll see the glitter and know its over. As you can see in my signature how much metal a spun bearing can put into the oil. That was less than 2 blocks of driving once the bearing was spun.

If it is verified that the motor is toast, you're not limited to the same year and make for motor replacement. I would locate a L26 (series III) motor, 2005 on up were built with the updated aluminum gaskets. These gaskets and the aluminum UIM eliminated the coolant passage failures that can wreck these motors.

All you have to do is strip the (L26) down to a long block and you have the same thing only newer and with less miles.
They (L26's) can be had for a reasonable price with decent mileage, for about the same cost as what a high mileage L36 (series II) would run.

Just my 2 cents

The coolant sat there for maybe a couple days, until I realized what happened and then dumped the oil, coolant, removed plugs and made the fix, followed by 2 oil changes.

Driveway Al

Your bearings probably rusted, causing pitting on their surfaces, this pitting ultimately lead to the failure of the bearings.

So have you had a chance to check the oil out yet?
If theres metal flake in the oil you'll be able to see it, just use a white paper towel for the visual contrast.

i had the same problem a few year ago with my oe engine. mine spun a rod bearing and i didnt have the money to replace the engine so i replaced all the rod bearings and ran it with valvoline 50wt oil and limped on it till i had the money for an l67