I have a 02 trailblazer 4.2l. Driving down the freeway I started to hear what sounded like and from the drivers side the oil pump running with nothing going through it. (Somewhat of a flickering sound) Rpm started going down and the motor stopped and I pulled over.
The truck does have a gauge in the oil pan. Opened the hood and pulled the dipstick and smoke started billowed out. I know the immediate thought is that the motor sized due to no oil, but wouldn't there have been a thud or knocking noise first before that happened? I do know that the oil pressure switch was going bad so could it be that the computer locked the motor to keep it from taking more damage? I don't know if that is even possible.
Answer: When you pulled the dipstick and smoke came out- that is very bad. Was there oil in the engine? If not, the the engine is cooked. Even if there was oil in it, it sounds like the engine is junk and will need to be replaced or removed and repaired.
Engine failure can make many different sounds, or no telltale sound at all until a major failure. No, there does not have to be a thud, just the noises you were hearing prior are the indication something bad was happening already.
The computer on newer vehicles can shut down the motor when it sees no oil pressure. But there would be a warning message on the dash telling you to stop the engine first. The fact that is was making noises and loosing power is enough that you should have shut it down, but would probably have been too late anyway to prevent any damage.
Question: I recently purchased a Chevy Trailblazer, after the engine runs for a short time ( 10-15 minutes ) during cool down there is a loud slapping / tapping noise coming from the drivers side of the motor. Any suggestions? It is not the ticking you hear as metal cools down. It is quiet loud. It has a cadence of : TAP .......... about 30 seconds TAP....etc.
Answer: It has to be metal cool down. Possibly you have a few loose exhaust bolts, or even a broken one allowing the exhaust manifold to flex. Or the the manifold could even be cracked. Check the exhaust pipes all the way to tailpipe while the noise is happening. The noise may just be pipe cool down /flex. A noise anywhere in the exhaust will travel and can be difficult to determine the source.
Also check that the intake manifold bolts are tight. They also are common to loosen up over time. That could give you a strange noise that you are not used to hearing since the manifold is not metal, it is plastic and can make cool down noises as well. Normally ith this problem you would have other conditions like rough idle, engine misfire and a check engine light with codes.