I was cranking my 90 bronco the other day and had to get out to give my 3 year old a hug before I left. When I bent down I heard a small tick, not bad or loud but it worries me. My bronco has a 302 and just turned over 166000 miles. Should I worry or just wait and see what happens? I've heard vehicles that have lost their bottom ends but only after they are shot. If the mains or rods go do they normally just go with no warning or do they start out with a tick. Its not a exhaust leak, as far as I can tell and I am pretty sure its coming from the bottom end. I don't have a oil gauge other then the factory one, so I can't tell if my pressure is down or not. Other then the tick and not really wanting to stay cranked after sitting overnight (common problem from what I can tell on here), it runs great.

P.S.
Should I be counting my pennies for a rebuild or new engine?

 

It's quite possible w/ 166k miles that the tick is a lifter. Because the lifters are in the block it can be difficult to specifically locate the tick. Another possiblity is the AIR pump, though these going bad generally sound more like a knock (made me really nervous when i first heard it!). A stethescope would be helpful in specifically locating your tick. Not too expensive at parts stores. Hold it up to the oil pan and various other places to locate the noise. I'v never herd a bottom end "tick" per se, it's usually more of a knock in my experiance. Just trying to give you some more options. Good luck!

 

I must of misspoke earlier. It is more of a light clunk then a tick. Its not really that loud but it got my attention. I drove it for a coulple of miles and it went away. I'm hoping it was just a fluke and it will stay away. It worried me when I first heard it. All I could think of was the Bronco owner's motto "how much is that gonna be to fix?".

 

if you stand there with the hood up and listen and bring the rpms up slowly what happens to the noise? DW

 

When the rpms pick up the noise seems to disappear. Its full of oil. The oil is clean (recently changed). I'm running 10-w30.

 

Bottom ends knock, top ends click. A bottom end knock that goes away as the rpms pick up could be a rod bearing; eventually it will knock all the time and then you only have a few days... It could also be piston slap, but that is not generally something that develops over time. It is usually a manufacturing defect. Could also be a cracked ring. Or it could be something basically harmless, like the AIR pump. I use a very long screwdriver, I put the handle to my ear and the end on the engine, it works like a stethoscope. That might help you isolate where the noise is coming from. Even that is hard, though; as the sounds transmit. I was doing this to try and isolate a noise that I knew was either coming from the idler pulley, the alternator, or the AIR pump. Wherever I put it, it sounded like that was where the noise was coming from. So I replaced the easiest and cheapest part first, the idler pulley, and still had the noise. Then I replaced the next easiest, the alternator, and that was it.

 

usually rods or mains are pretty consistant, you could be hereing piston slap when its at idle which is piston rocking in the cylinder bore. but it kinda hard to diagnose a noise when you cant here it. DW

 

I had an old Cadillac that I got a brand new Cadillac motor for, for free. The reason was piston slap. It sounded like a rod at idle, but went away with RPM's. It was never a problem, I put around 20,000 miles on it before junking it (the motor still ran fine).

If it is a rod knock, it doesn't necessarily "go away" with rpms, it's just that at first it is so faint that the rest of the noises drown it out as you give it gas. Eventually it will knock all the time. I remember another old car, a 74 Regal with a 455 (hauled butt!) that developed a rod knock. I drove it until it gave out, climbing a hill about two weeks after the knock started. It was pretty funny, it got really, really loud in the last few miles, there was smoke coming from under the hood; and then it felt like a giant chain just snapped and the whole car jerked to one side (my friend who was in the car described the feeling in exactly the same way) and that was that. There was smoke pouring out from under the hood so we made a quick exit from the vehicle. I had someone behind me, I got my stuff out of the Regal and left it there on the side of the highway for whoever wanted it.

 

It must just be piston slap. I climbed under my truck and using a screwdriver listened to the bottom end. The noise isn't as bad as when I first heard it and pretty much cured itself. I'm not as worried about as I first was. I have decided if it does go, I'll just get another engine. A engine ever 170000 miles sure bets car payments every month

Thanks for the input

 

Dump a can of "restore" in it. That stuff is AWESOME and it the only thing I ever had work for high mileage cars/trucks. It fills in the cracks and gouges in the cylinder walls and bearings.

 

Personally I would run 20w/50 in it with a good Motorcraft filter.Throw in a can of STP oil treatment.I don't know where you're at but down here it's hot all the time.I run 20W50 in everything.A little extra viscosity helps to create a bit more film between the bearings and the surfaces.Just my 2 cents.