My 95 Blazer 4x4 with 4.3l vortec has been making a VERY intermittent noise. It's only happened maybe 3 times in 10k miles, but it's a strange noise and it doesn't sound good..

Okay, so the best way to describe it is like sticking a playing card in a fan or like a very small jake brake... It appears to be coming from the rear of the engine, near the distributor, but it happens so intermittently and so quickly that I can't stop and locate it.

I have been having Dist cap/rotor symptoms, so I'm changing those soon. i want to know if anyone's had a similar situation and if so what I should look for.

This is my daily driver and I do my best to take care of it, but I'm young and there are many things outside the scope of my experience, this being one of them. I need help from someone with more wisdom than I have.

thanks in advance for any replies!

 

eh. hard to help,but some of the oldschool starters did this after they heat up. metal tolerances would change and cause the starter gear to barely tap against the flexplate.. they make spacers for them. but other then thats its hard to help. maybe a video?


Check oil? maybe its low and lifters are crying.

 

I would try to get a vid but like I said it's SUPER intermittent, probably enough so to where most people wouldn't even worry about it, and it's only even happened while I'm driving and it only lasts for about 2 seconds.. good info on the starter though, mine is the original so it's nearly 20 years old so I could see it showing some wear at this point, and lately my truck has been hesitating a little when starting, almost like one of the cylinders is catching..

Judging from the sound and location, I'm thinking maybe there's carbon deposits or something under my dist cap that are coming loose and getting chewed up every once in a blue moon... The sound DEF sounds like it's coming from the dist, almost as if it's coming from inside the dash, and the nearest moving part I can think of that would make sense is the dist...

I'll be changing my cap in a couple days here, and hopefully figure something out...

How likely is it the the dist gear itself could be worn and grinding slightly? Do dist gears tend to go out? My Blazer only has 150k on it..

 

Okay so after some research I've found info on dist/rotor "Buzz" (Much better descriptive word than what I used) and it's when the ribs of the rotor rub against the dist cap.. It will show wear on the edges of the rotor, so I know what to look for now... Also, it says it will usually happen when the dist bushing wears out and allows the rotor to play too much...

This explains the misfire I'm having under light throttle, my rough idle, and this intermittent noise...

Now I'm just hoping that's what it is so I can resolve the problem.. hoping I wont have to pull the whole dist because I've never done anything that would mess up my timing before, and from what I've read about it, it's pretty tedious...

Thanks for the reply Chris, sry I wasn't more clear with my description. :-P