View Full Version : i would like to know how should a healthy northstar sound?

09-19-10, 03:26 AM
ok i need a little bit of info on this. I would like to know what sounds i should hear and shouldnt hear on the northstar. the year of this northstar is 1994 in a seville sts with 87162 miles on it. I lately have heard new sounds coming from underneath the car towards where the engine would be. I also hear kinda like a knocking sound(i talked to 3 mechanics and they all said the same thing its normal/nothing to worry about) and i truly want to know if that is normal. And as i asked earlier if someone could list the sounds i shouldnt hear from a northstar would be nice

09-19-10, 08:07 AM
With the hood open a "normal" Northstar is extremely quiet: smooth, even idle; no evidence of air (vacuum) hiss or leak noises - but you can hear air moving in the TB if you stick your ear down close; practically no belt noise from either the main accessory drive belt or the smaller water pump drive belt; with either the flat tappet or roller cam follower engines, maybe the slightest hint of a valve tick when cold. Some alternator whine if the battery is low. Maybe the A/C compressor puttering away. Otherwise, the engine is mechanically quiet. (Open the oil fill cap on top of the chaincase and you will hear the 3 cam drive chains............)
Go up to the Cadillac Technical Archive and read the entire thing - then go back and study "Occasional full throttle operation is good for your engine". Your cold knock may just be the common "cold carbon rap" which comes from sedentary, city-driven cars.

BTW - Welcome Aboard !!!!:bug::welcome5:

09-19-10, 08:40 PM
jeez well then, mine is not quiet at all i hear like a heavy knocking and clicking i cant even hear the alternator(sry if i spelled that wrong) its kinda loud. is there anyway to fix the heavy knocking besides the open throttle i could get a video so you can hear the engine

09-19-10, 09:52 PM
The WOT procedure is for "cold carbon rap" aka piston slap. That sounds more like ticking (dry) lifters, not a "heavy knocking" like you describe. That sounds more like a rod knock, but that's not very common on a Northstar.

09-21-10, 03:47 AM
well i did a WOT still no change and is rod knock a bad thing. is rod knock a sign that i am soon to throw a rod

09-21-10, 09:31 AM
well i did a WOT still no change and is rod knock a bad thing. is rod knock a sign that i am soon to throw a rod

If the noise is, in fact, a rod (bearing) knock, NO - that is not good. A knock like that is caused by excessive bearing-to-crank journal clearance, leading to rapid loss of lubrication and metal-to-metal contact. A rod knock will only get worse, and the chances of eventually throwing the rod are 100%.

Thicker oils and magic potions will not cure the problem - mechanical overhaul will.

Before you do anything else, take the car to a good local shop that is known to do engine work and ask them to check it out. A half hour's labor may just save you a ton of money. Know that "rod knock" is uncommon in even high mileage Northstars. You may have something as simple as a loose alternator, A/C compressor, or some such external mechanical problem. If the problem surfaces as low oil pressure, then that's a whole new ball game, but a shop can tell you.

I don't want to appear to use a crystal ball, but from your first post it would appear you are not a hands-on Northstar gearhead. Engine noise diagnosis on the Internet is chancy at best - even with a high quality YouTube clip to work with. You need a good, honest, local mechanic for this one.

09-21-10, 11:44 AM

09-21-10, 06:54 PM
thanks. i want to be a hands on northstar gear head but dont know where to start i dont want to mess with the engine for fear of breaking something

09-21-10, 07:14 PM
well, first off you'll need a service manual - http://helminc.com for a new one - ebay etc for used (might be new ones on ebay too, but helm is the official publisher)

09-22-10, 10:10 AM
thanks. i want to be a hands on northstar gear head but dont know where to start i dont want to mess with the engine for fear of breaking something

Rebuild a couple of Briggs & Stratton lawnmower engines for starters, then study your new Northstar shop manuals and multiply the Briggs cylinder by 8. :thumbsup:

09-22-10, 10:26 AM

I still remember starting my first B&S rebuild..... what ever happened to shop class?

09-22-10, 12:15 PM
first semester of college - freshman engineering class we had a lab on the B&S (or some similar 1 cyl engine)

09-23-10, 12:26 PM
IMHO this is what a Northstar should sound like. :worship:




09-23-10, 12:29 PM
Same here, first semester I had similar.

Didn't really understand how it pertained to my field, CIVIL engineering. The class seemed like it was mainly geared towards using shop materials. The B&S lab focused on using a micrometer.

I had already taken 3 years of metals class in HS and the year before I had rebuilt my first engine...being my '92 4.9. That said, I'm no expert but mic'ing up a briggs crank journal and throwing it back together was pretty lame. I found the class to be incredibly boring, which turned into an attendance problem for me. I was pretty upset that I paid hundreds of dollars for that class.

09-23-10, 05:01 PM
all the engineering students (from civil to computer) all took the same first semester class - it had a mechanical lab, a civil lab, and an electrical lab - i really liked that class (most didn't though, it was pretty tough and involved a lot of excel w/ pivot tables)