I just joined this forum even though I have been using it to try to troubleshoot my problem. I just bought a 1996 Chevy Blazer 4x4 last September and it currently has 70,800 miles on it. When I bought it, everything was fine. After winter however, I began having issues. For example, my serpentine belt started making a horrible squealing sound so I replaced it and my thermostat was shot and my engine began to run hot so I replaced that. Now I have a rough idle (my seat and steering wheel shake at idle) and there is a ticking noise once the engine is warmed up. This leads me to believe the issue is not lifters because I would imagine the ticking noise would occur all the time and not only at operating temperature if it were the lifters. The noise itself is coming from the top of the engine. I tried cleaning the EGR and it got quieter but is still there. About a week ago I pulled my intake boot off and noticed that my throttle body is covered in carbon as well as my intake. I used seafoam to try to clean out as much of the intake and upper cylinder as possible and it cut the ticking noise down by 30-40%. I am going to get another can when I have a chance and try it again. Hopefully it works. (Oh I also used throttle body cleaner and cleaned out the throttle body)

 

What is oil pressure at idle in drive with engine completely warmed up?

 

Oil pressure while warming up is 60 psi, fully warmed up while driving is between 40 and 50 psi, and fully warmed up while idling is just above 20 psi

 

OK - you are reporting normal oil pressure. Is it clacking like in the video? Or something different? That video was of mine on the day I brought it home back in 2014.

It might sound a bit different because 1996 was flat tappet lifters and 2001 was roller lifters.

Oil pressure should be evaluated with 5W-30 oil.

What about the noise?

 

Mine sounds more like a ping. Part of me wants to pull the sparkplugs because I am wondering if it could be spark knock. Also the noise goes away around 1,000-1,500 RMPs. I just finished using a spray can of seafoam and it did not do much for the noise, the idle however is smoother and my cabin does not shake anymore. While I was waiting for the seafoam to "hot soak" the engine, I decided to pull my EGR off and take a look at it again. It seems to have a lot of carbon deposits in it and the spring when compressed makes a very similar pinging/ticking sound that the engine makes. Could this be my problem? It kind of makes sense, since the noise doesn't start until the engine is warmed up which would be right around the time that the EGR would be "kicking in". Correct? Lastly, I don't think it is anything with lifters or cam/crank because I don't have any codes. Thanks again for trying to help me figure this out, it is much appreciated.

 

We will try to help if we can. Can you provide a video of the ticking? Is the frequency of the tick (timing of the ticking) the same as mine at idle? That would indicate something in the valve train.

I really doubt that the EGR is the issue.

 

Sorry, I have not been responding to this thread in a bit. I just got through finals week so I have been taking a break from diagnosing this issue. Also a couple days ago I called my mechanic to see if he is able to take a look at the Blazer. It is going in the shop next week and I will keep you posted as to what my issue ends up being. Thanks again for the help.