PontiacBonnevilleClub.com

I'm here because I'm about to buy a 2001 SE out of desperation. The desperation is probably caused by my Shortstar. I saw this board, I thought I'd tell my story.

I have an 01 Aurora 3.5. It had an oil leak from the valve cover gaskets. I paid someone to replace them. The oil started disappearing faster. My (now ex) mechanic decided the engine was just using oil. By the time I was able to get it to another mechanic, it was down three quarts and I hadn't been able to top it off.

New mechanic tells me about the three quarts and tops it off. I drive it about 150 miles the next day with no problems at all.

Now, a week later, it's making a godawful noise in the first three gears and is severely underpowered. In fourth, it ticks but is otherwise quet and smooth.

I've blown an engine before, and it was just as noisy regardless of rpm, velocity, or gears. Is this engine blown, did I coincidentally have the transmission take a crap, or is this something else entirely?

Putting on my armchair QB diagnosis...

Losing 3 quarts of oil, and you don't see it on the ground means it's burning it. If it is burning it at that rate, my guess is a either a head gasket and/or oil control rings on the pistons. The reason I added the rings is since you mention a "ticking", it may be those oil control rings as well as others, including the compression rings (which would explain your lack of power if it can't build the proper cylinder pressure) causing piston movement other than normal vertical movement (I.E. up/down). Because of those bad rings, it (the piston) could be "rocking" in the cylinder bore, creating noise.

Again, just a theory and is not a concrete diagnosis.

More than I've gotten from anyone else, thanks.

If a piston is "rocking" in the cylinder bore, does that mean the end of the block, a la a thrown rod, or is it possibly still worth repairing? And how does an engine suddenly start burning more oil after a repair that's meant to keep oil in it?

Again, a vague response until one gets in there and finds out what's really wrong...

Lets say that is the problem. A lot depends on the amount of piston damage, and how long it's been doing that in the cylinder bore. If it just started, and you're not hard on it, and the damage is minimal, you could probably get away with repairing it by either boring it out the iron sleeve/liner (being a Northstar/Shortstar, it is an all aluminum block, which requires iron sleeve/liner inserts for the actual cylinder bores), to remove the imperfections, up to removing and replacing the iron sleeve/liner if the requirements to bore it out would push the limits of that sleeve/liner. This would need to be done by an engine/machine shop once the engine is removed and dissassembled.

OR, just get a shortblock or used engine and R&R.

I don't think it's necessarily the parts that are expensive if you do a little home work ONCE the proper diagnosis is done and the problem found. It's more the labor.

Again, just giving a worse case scenario. I don't know what the issue is.

But it has to be the engine? I ask only because of the DRAMATIC difference in performance in fourth gear. As in, except for the tick you'd think the car was brand new.

But it has to be the engine? I ask only because of the DRAMATIC difference in performance in fourth gear. As in, except for the tick you'd think the car was brand new.

Honestly... I don't know. There could also be other problems (transmission, catalytic converter plugged, etc) too.

However, once you pour oil into a crankcase there are only two ways it can leave it. 1) Draining it or leaking it Or 2) Burning it

If you're going through three quarts of oil in a short time frame and there is nothing on the ground (three quarts would be noticable), well... Process of elimination leads me to...

Now add in engine parts making noises as it runs! I'm gonna go out on a limb and say that the engine isn't in a healthy state.

Unless of course that car has an oil cooler in the transmission and is losing it into the coolant. I'd look at you coolant reservoir for signs of oil, or possibly the radiator cap.

I had major oil consumption on my 5.7 vortec and it didn't show signs of smoking oil and it did leak, but not so much that I thought I was loosing a quart per tank of gas ( 250 miles ).

The engine ultimately gave up the ghost as it ate a bearing and turned the oil into glitter. However, I lost all oil pressure on the gauges when it happened and oil pressure at idle was hovering under 20 psi ( by the gauge ).

You could very well have a problem with the transmission. I believe 4th and reverse use the same drum..I assume reverse doesn't give you any trouble? There's no reason the engine would run better in 4th than the other gears. It could be using more oil if the first three gears are putting enough strain on the motor that it's just sucking oil through higher vacuum under load.

Again, hard to say without hearing, driving, or seeing the data first hand.

No radiator caps on N*'s and the same on Short star's if I recall. The only way to tell would be the milkshake like color in the resevior

ayup, I forgot which forum I was in. I don't know if I necessarily like having a cap on my Bonneville. I realized after buying it that every time I open the cap, the overflow tank empties out through it...

redfury wrote:ayup, I forgot which forum I was in. I don't know if I necessarily like having a cap on my Bonneville. I realized after buying it that every time I open the cap, the overflow tank empties out through it...

My experience is only if there is an issue with the over flow tank, like maybe over filled, or some other problem with the tank. - BC