I just bought a 1997 Chevrolet S10 Blazer with the 4.3L V6 for my fiancé for a winter driver for her. The price was right at $1000 with new tires, CV joints, and brake lines. It has just a bit of rust on the drivers rocker panel but overall it is very straight and has good paint. I got it for that price as the guy had it listed as having a tick in the motor and his mechanic said it was a lifter or rocker arm. Of course I had to buy it as I cannot pass up a bargain and we needed a winter driver anyway. I went through it this past weekend and checked all the fluids, brakes, etc, and all were relatively new. I have tried to isolate the ticking noise and have come up empty thus far. There is no CEL and no history in the ECU of past codes. Truck only has 130K miles on it and the guy had owned it since 1999 (older gentlemen, typical Iowa nice). The sound does not make it's presence known until the engine warms up. It will make this "ticking" noise at idle and on acceleration up until about 30 mph then it goes away on acceleration. At a steady state cruise it does not make the noise nor does it when I am going up hills, as you top the hill and start back down it will start to "tick" again until you give it gas. It kinda sounds like a valve tick but then not really and it does not behave like any SB tick I have heard before.
I have tried the following:
1. Stethoscope on the oil pan - typical rotational noise, normal
2. Stethoscope on the oil pump - typical rotational noise, normal
3. Stethoscope on the rocker covers - no ticking
4. I pulled the serpentine belt off and ran it and the noise was still there at idle
5. From under the truck it seems to be coming from the right side of the engine
6. From the top the noise seems to be coming from the intake area
7. Exhaust donuts seem to be ok and not blown out
8. I drained a quart of oil out of it and replaced it with Lucas Oil Stabilizer, ran it about 100 miles to see if the pitch or frequency would change and there was no discernable difference in the noise.
I am leaning towards an exhaust leak of some kind. At this point I am just having her drive it as she is working from home and drives very little. If it gets worse I will get more aggressive in my troubleshooting but at this point I am going to just keep an eye on it. Does anyone have any ideas as to what could be the source? The truck cleaned up really well and I could easily sell it for over twice what I have in it down in SW Iowa.
I have tried the following:
1. Stethoscope on the oil pan - typical rotational noise, normal
2. Stethoscope on the oil pump - typical rotational noise, normal
3. Stethoscope on the rocker covers - no ticking
4. I pulled the serpentine belt off and ran it and the noise was still there at idle
5. From under the truck it seems to be coming from the right side of the engine
6. From the top the noise seems to be coming from the intake area
7. Exhaust donuts seem to be ok and not blown out
8. I drained a quart of oil out of it and replaced it with Lucas Oil Stabilizer, ran it about 100 miles to see if the pitch or frequency would change and there was no discernable difference in the noise.
I am leaning towards an exhaust leak of some kind. At this point I am just having her drive it as she is working from home and drives very little. If it gets worse I will get more aggressive in my troubleshooting but at this point I am going to just keep an eye on it. Does anyone have any ideas as to what could be the source? The truck cleaned up really well and I could easily sell it for over twice what I have in it down in SW Iowa.
