94 regal gs 3.8 engine knocking

[neoretromax]

so my 94 regal gran sport has developed a knocking sound lately. It only seems to knock under load (in drive) and only when the engine oil has warmed up to operating temp. anyone have any idea what this would be? Most recently is has had a new lower intake manifold gasket, new water pump, new plugs, wires and coils, new egr valve and new pcv valve, and new oil pressure sender. It had minimal oil usage before the plugs, wires and coils, but now it uses more oil. about 1/4 quart a week for about 300 miles of travel. There is no oil dripping or leaking under the car and the exhaust from the muffler looks normal. I am most concerned about the knocking as it sounds deep in the engine and it is not lifter tick or pinging which i am hearing. thanks in advance!

[stripe]

Originally Posted by neoretromax

so my 94 regal gran sport has developed a knocking sound lately. It only seems to knock under load (in drive) and only when the engine oil has warmed up to operating temp. anyone have any idea what this would be? Most recently is has had a new lower intake manifold gasket, new water pump, new plugs, wires and coils, new egr valve and new pcv valve, and new oil pressure sender. It had minimal oil usage before the plugs, wires and coils, but now it uses more oil. about 1/4 quart a week for about 300 miles of travel. There is no oil dripping or leaking under the car and the exhaust from the muffler looks normal. I am most concerned about the knocking as it sounds deep in the engine and it is not lifter tick or pinging which i am hearing. thanks in advance!

Tranny oil has detergent in it.

You could change your oil useing 1 quart of tranny oil (the other 3 quarts reg oil too).
Then change it again after 3-4 hundred miles.

Worth a try.

Cheers
Stripe

[neoretromax]

how does that work, i have never even heard of this before.

[GTP Dad]

What viscosity of oil are you currently using? You didn't say how many miles on the engine but I am assuming that it is high mileage. One thing you might try is to put a can of Restore engine treatment. It is designed to control oil blow by which could cause the oil issue. Since you are using a quarter quart per 300 miles it may not be enough to show up on the muffler as the cat may be burning it. If it continues it could damage the cat.

As for the tranny fluid in the oil, forget it. It will clean everything up but it could further damage the engine. If you want to clean the engine internally there are products for specifically that purpose.

[neoretromax]

the oil is 10w 30 shell and the mileage is only 85,000

[stripe]

Originally Posted by neoretromax

the oil is 10w 30 shell and the mileage is only 85,000

I had 2 of those cars.

I had better luck with the 5W-30 oil.(as suggested by GM)

You must be either leeking oil or your measurement is wrong as to how much you used.

Cheers
Stripe

[Ruley73]

Originally Posted by stripe

Tranny oil has detergent in it.

You could change your oil useing 1 quart of tranny oil (the other 3 quarts reg oil too).
Then change it again after 3-4 hundred miles.

Worth a try.

Cheers
Stripe

Most engine oil has detergent in it too. The only kind that doesn't specifically says so (i.e. ND-30 - the "ND" stands for non-detergent) and is usually meant for use in small engines.

Originally Posted by stripe

I had 2 of those cars.

I had better luck with the 5W-30 oil.(as suggested by GM)

You must be either leeking oil or your measurement is wrong as to how much you used.

Cheers
Stripe

There's no difference between 5W-30 and 10W-30 until the temps get below 20*F. Then the 10w-30 begins to get thicker.

I agree that the OP likely has an oil leak somewhere. Either at the lower intake (the side rails blow out if not correctly installed), the oil pan, or at the rear main seal.

[Fire7]

I use 10w 40 in my car, could that have anything to do with the piss poor exceleration or poor gas milage i get?

[neoretromax]

after further investigation it seems there is an oil leak near the timing gear. would this be the main bearing? i know there is some issues with these years on the 3.8 with bearing clearance, i am wondering if there is any quick fix like some sort of oil additive that might help. Has anyone done a main bearing on a series 1 3800, and if so how hard is it. I'm a bit worried as this may be a car ender if i dont fix it.

[mcmalloy]

could be piston slap , these engines have long skirts on the pistons , after a while they make a knocking noise, i have a 95 grand am does the same thing when i first take off at low rpm,

[neoretromax]

Originally Posted by mcmalloy

could be piston slap , these engines have long skirts on the pistons , after a while they make a knocking noise, i have a 95 grand am does the same thing when i first take off at low rpm,

that is exactly what my car is doing

[stripe]

Originally Posted by neoretromax

how does that work, i have never even heard of this before.

well tranny oil is soapy and it cleans the engine.
I asked the Master mechanic that lives here, again, and
he said it does work.

It more cleans your valves etc.

Cheers
Stripe

[stripe]

Originally Posted by Ruley73

Most engine oil has detergent in it too. The only kind that doesn't specifically says so (i.e. ND-30 - the "ND" stands for non-detergent) and is usually meant for use in small engines.



There's no difference between 5W-30 and 10W-30 until the temps get below 20*F. Then the 10w-30 begins to get thicker.

I agree that the OP likely has an oil leak somewhere. Either at the lower intake (the side rails blow out if not correctly installed), the oil pan, or at the rear main seal.

I have driven well over 1,000,000 miles in 3 of these cars.
3 things I swear by with them.

1: change the oil each 3,000 miles

2:5W30 you never need to add oil between the 3,000 miles.(10W30 you will need to add oil)

3: The faster you average the better mileage you get.(adds 100 miles to tank if you are at 100 MPH)

Cheers
Stripe

[neoretromax]

i put 5w 30 in it the other day when i got the oil change, hopefully it will use less oil. The knocking is still present, but seems to be better the colder it is. I bought some "RESTORE" but havent put it in yet, havent decided to use it yet.