How can I tell if my car engine rod is broke?

Question

My car just stop on me. When I tried to crank it back up it sounded like the motor was rumbling. I just got full service on my car about 4 month ago and I'm suprised they didn't tell me it was looking bad. I just got this car a year ago it's a 99 pontiac grand am. Do anyone have an idea about this?

Answer 1

Oh no....another Grand Am with problems......

If you had a broken rod, it would sound like someone pounding on the engie with a sledge hammer.

ADDED:
You probably have a broken timing belt and the pistons bent the valves.

You're looking at a couple thousand dollars in repairs.

Answer 2

when your vehicle stopped on you, how fast were you going? what exactly did it do? what does the rumbling noise sound like? it could be any #of things. i doubt it's a broken rod, maybe a spun bearing, and the rod is knocking? as mentioned, it would sound like something is knocking on the block with a hammer (or big object).

i've even had (small story, a few years back), a mechanic friend look at my g/f's car (as it had a knocking noise), and he thought it had something broke under the valve cover and was rattling around, he suggested i add an oil flush, and change the oil. when i went to do that (at a friend's shop), he thought i should have another friend look at it (next door), and that friend thought that a timing guide had broke and the chain was slapping around freely. now, the guy (friend) that changed my oil thought that i had a clogged (or partially clogged) fuel injector, and i should run some "chevron techron" thru the gas tank. well, i couldn't find that (at autozone), so i bought some gumout (gray bottle) fuel injector cleaner, topped off the tank with super unleaded, and the noise went away within a mile or two. i went back to talk to my friend (and tell him), and the only thing we could come up with, is it had severe spark knock (due to the clogged injector). what i'm getting at, is that is sounded like the motor had internal problems (what i thought also), and it turned out to be something else (cheaper).

anyway, more details might help? what do you mean by "full service"? g/l

Answer 3

A rod failure is not something that will be apparent by ear most of the time. The motor can run fine up until one breaks. Sometimes there's a slight knock, but it can be so muted, it's not obvious. Don't necessarily blame your shop, they don't routinely check for something like that, since it's not a routine item to break down.
You say a rumble. Is it a muted sound, or a hard knock, like hard metal on metal sound? A broken rod will be clanking around, usually, making alot of noise ( and doing MORE damage, so don't keep testing it! ) You may want to search on your car year and model on the Internet, and include engine problems in the search, to see what pops up, here's one site to check _-

http://www.automotivehelper.com/cat385-3/

Good luck

Answer 4

The only way to tell if you have a broken rod short of seeing it sticking through the side of the block is to remove the oil pan and look. Take it to a shop and have it checked as you are getting nothing but guesses here.

Answer 5

when a shop services one they cant tell if its going to throw a rod or not,you need to have it looked at and see just how bad the damage is on it,the only way you can tell anything about it is to have it checked,i cant see it or i could help you with it,a good shop will be able to tell just how bad it is,good luck with it,hope this helps.

Answer 6

Could be rods, lifters or valves, if it is that bad a rubling, than i would suspect the rods.