This one has be a bit concerned, and stumped. My '74 Olds Cutlass Supreme, 350, made a weird noise yesterday, after starting it back up after a 600 mile drive. It was a knocking at idle, would go away when I would rev it up, and seemed to only last a few minutes. Oil pressure is fine, and level was full. I started it just to check it this morning and the noise was gone. I am concerned, however, as I am making my trip back home tomorrow. This engine has 30000 miles since it was rebuilt in 2013, at which case before, it had 493000 miles on it.

 

I'll suggest a thorough inspection of items. Act as if this is a maiden voyage, first trip scenario. I would narrow these things down before condemning the engine.
Exhaust system, pipes, manifolds
flywheel
engine accessories
brake cables
suspension fasteners
Make sure all things tight and tidy

 

It had nearly a half-million miles on it? This has to be a typo. I'm guessing 93,000.

 

Good plan. I hadn't thought of the flywheel. I look for troubles like this all the time for others, but I get flustered when it happens to me, especially this far from home.

 

I would smell the oil. Maybe a quick oil ?

 

Nope it was not a typo. And it was just weak, no knocking or smoking.

 

I did. No gas or burnt smells. 10w30 Driven oil. Wix filter. Is due for a change when I get back home. Engine temp yesterday never got over 190 , but I am sure the oil was hot after dricing on an interstate over mountains for 600 miles.

 

Yeah, go over the whole thing. Exhaust pipes banging on various parts of the undercarriage can masquerade as different engine ills. If you have access to a stethoscope you can use it to isolate sounds.

If you don't find anything, just shrug and make sure your Triple-A is paid up before you go.

 

Seems to me like a lifter was temporarily stuck. Happened to me once on my 67 Cutlass 330. Started her one morning and got on her too quickly. I am not talking lifter tick, the sound was horrendous. I thought I damaged the engine. It was a loud clanging noise. My mechanic of 30 years took a look/listen and literally told me don't get on it, just wait it out it's a stuck lifter. Idled the car here and there throughout the afternoon and it was gone by the end of the day. Like magic, and it never happened again. Had the car for years after, drove her and got on her occasionally as always.

In my case she was around 100,000 original miles and never rebuilt. That may explain why yours came back to normal that much quicker.

Outstanding ! How many rebuilds on components of powertrain ? And at what mileage for each if you can recall.

 

Impressive!

 

The engine kept going like the Energizer bunny. I did have the TH 350 rebuilt 3 times, I had to put all new bearings and a new axle in the rear end at about 275000. A family member had the car prior to me purchasing it from her in 1989. It had 135000 on it at the time, and she had meticulously maintained it. I continued to do so. I have put several water pumps on it over the years. Car has AC. I replaced the A6 compressor twice. Overall, it has been an extremely reliable car. I had the engine finally rebuilt in 2013 at that high mileage, because it finally started missing on the number 7 cylinder. I suspected the valves (which is exactly what it wound up being) but I went through the whole engine, because I didn't trust rebuilt heads on a half million miles engine .

 

Thanks. It was remarkably clean inside for the high mileage

 

Most likely a lifter. Could also have been a piece of carbon that broke loose. Since the oil is ok and the noise is gone, IMO it's fine, drive on...have fun. Real issues such as bearings do not suddenly stop making noise.

 

That is a good analogy. Sometimes, when it is your own car, you tend to think the worst. Hard to reason it out sometimes.

 

I found it. It was the pulley coming loose on the power steering pump. The nut was still on there but not tight. Put it on with loctite

 

I found it. It was a loose nut on the power steering pulley. Tightened with loctite and just got back home from the 600 mile trip

 

Good find, I've not encountered that before.

 

It was weird. I replaced the ps pump a few years ago, but the nylon lock nut backed off just a little. I happened to notice it wobbling with the hood up last night

 

it shouldn’t be a nylock nut in the first place..it should a crimped nut .

 

Correct. I made the mistake of using the garbage they had with the new pump, instead of my old nut. The one on my '66 Pontiac still has that crimp nut on there. Need to locate one and Chuck that thing.

 

It's almost like if you regularly use and take care of them these cars can last for a really long time or something. We'll done good sir, I hope to get my car to the half million mile+ club.

 

Yes. They have simple, solid mechanical engineering. If cared for they can last a really long time.