Originally Posted by master tech
Could a lots things,Piston slap,connecting rod bearings,or broken rocker shafts. Is the noise coming from the lower end or the top end? Be sure the oil is full.
Thanks will look tomorrow to see closer wherre it is coming from.
Since the engine was revved this way only 4-5 times and for 5 to 8 seconds each time, hope it has not caused damage? If the noise comes on only when revving past 3,000 rpm does this mean the engine is still basically OK?
Another worry relating to possible engine damage, was that twice in the last 32 days the coolant temp shot up, once near red and I believe I drove about 6-10 blocks like that, the other time in red (stopped the engine in 2-3 secs as I was already at a stop). Otherwise the car runs well til 55 mph, I have driven it slow in the last 2 days so it won't heat up, because I am waiting on a radiator fan repair. When driving the power seems OK like before, but at 2000 rpm there is a rumbling noise that is not loud though, hearing it inside the passenger area, on that side in the engine area, seems located near the top.
Another important circumstance that might enlighten this, the first time the coolant temp was hot (2 days ago), there was a terribly strong chemical smell inside the car, I thought it might be from antifreeze but more precisely, there were like 2 smells, i.e. both chemical and burnt rubber. The second time it got hot (yesterday), there was no smell at all. This may be a topic for another post, but I'm mentioning this in case it bears on the engine noise. I've never revved it that high before, so I have no means of comparison, someone else did this today. Normally, shouldn't the engine noise be the same, (just louder), when you revv it up to let's say, 7,000 rpm?