95 Riviera 3800 supercharged knocks, help please!

Hello,

Newbie here, so I'm lookin for some help. I recently purchased a 95 Buick Riviera with the the 3800 supercharged V6. The car ran and drove fine for about the first 100 miles or so and then I noticed a "knock" in the motor. I checked the oil and it was 4 quarts low. I am assuming that it was low when I bought the car because I put the oil in and I have not used any since. However the "knock" did not go away! In fact at idle it is not even noticeable, but at Rev it is pretty good. I was told by a mechanics shop that the Rod bearings are most likely the cause. If this is the case, my question is can I replace the bottom end and be okay, or do I basically have no choice but to do what the shop says and look at a full engine replacement. How much should I expect this to cost me if I use a salvage motor. And further more, is the engine swap something that I could do on a weekend , or is this going to be a real expensive, labor intensive job. As this is my only car, I would REALLY appreciate any comments. Thanks so much...God Bless.

Hello. I'd agree with the rod bearings being the source of the knock. As soon as you said "4 quarts low"... and I really applaud your desire to save this car as old as it is. A lot of folks would just throw in the towel. But if you really love the car, THERE IS NO GIVING UP, right?

Repair or replace? Depends on a few things. What's more important to you, time or money? How much of each do you have to put into the car? You can replace only the rod bearings, and save some cash if you know how to do it, but then you'd be putting new parts on a motor that could be damaged, only to fail later on down the road. On the other hand, you can throw a pile of money at the shop, and know the engine they put in should last a long time. Everyone's different in how they handle something like this.

If it were me, I'd not want that engine in the car. Look for a good used motor from a salvage yard or used parts dealer. I have to think that Series I engines like yours are becoming harder to find. Maybe you go the extra mile and replace with a Series II engine? Again depends on how much time and money you are willing to "invest". Whatever route you choose, someone here can surely guide you along the way. Best of luck!

95Rivman wrote:

Hello,

Newbie here, so I'm lookin for some help. I recently purchased a 95 Buick Riviera with the the 3800 supercharged V6. The car ran and drove fine for about the first 100 miles or so and then I noticed a "knock" in the motor. I checked the oil and it was 4 quarts low. I am assuming that it was low when I bought the car because I put the oil in and I have not used any since. However the "knock" did not go away! In fact at idle it is not even noticeable, but at Rev it is pretty good. I was told by a mechanics shop that the Rod bearings are most likely the cause. If this is the case, my question is can I replace the bottom end and be okay, or do I basically have no choice but to do what the shop says and look at a full engine replacement. How much should I expect this to cost me if I use a salvage motor. And further more, is the engine swap something that I could do on a weekend , or is this going to be a real expensive, labor intensive job. As this is my only car, I would REALLY appreciate any comments. Thanks so much...God Bless.

Id have to listen to it to say for sure, I have heard crank balancers on buicks sound just like bad rod bearings but with the oil 4 qts low you might need a short block. Are you anyplace close to Sarasota FL?

Dave

OUCH. 4 qts low is not a good sign. And you have no idea how long it was run while almost completely out of oil, by the seller. Always a very good idea to check all the fluids in a car you are considering buying. That includes engine oil and trans fluid.

Depending on where you are, it may be best to drop in a replacement engine that has been checked out and is in good running order. Rebuilding that engine will take time, that it sounds like you don't have. Heck, swapping in a used one will take time too. Problem with the original engine is that you have no idea how much damage you'll find until it is torn down. There's no real value in keeping the original engine in a 95 Riv, imho, I'd suggest replacing it.

man, that really sucks. The first thing I do when considering buying a car is to check under the hood. 5 minutes under there can save a lot of headaches down the road.
Ok, it is too late to do that, so now you need to either fix it or live with it until it goes. For a novice DIY'er, the engine swap would be the way to go. It would take about a day with the help of a buddy or two. Maybe a weekend by yourself. Expect to pay about $800 or more for a lower mileage engine with a warranty. IMO this is the way to go. You might be able to find a used engine through ebay or other private party for half of that, but what are you getting? I always ask myself "why are they selling this engine?". If you go the private party route, look for someone who is parting out a wrecked car were you know with a reasonable assurance that the engine is good.
Now, you could just drive it as-is if you aren't too worried about being stranded should she blow. I would do this while waiting for the right used engine to become available. If its not too cold were you live, you might try using HD30 oil which might quiet it down a bit.