LOUD noise while cranking 3.8 V6
#1
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LOUD noise while cranking 3.8 V6
Just helped a friend buy a very low miles (60,000mi) 1994 Olds 88 w/ the 3800 V6. It was owned by his (now) 82 year old mother, and looks it. Not a scratch, ding, or dent, and the interior (except for a sagged headliner) looks absolutely new.
When starting it when looking at the car, heard 2 kinda' loud "clanks" as the engine started, which the seller said was the exhaust banging (he had just replaced the cat only to find it was a bad O2 sensor).
My wife was standing at the rear and confirmed that the noise sounded like it was under the rear of the car.
I shut down the engine and re-started. NO noise then or on subsequent starts. Drove the car about 10 mi, and it drove like new (I owned a '96 Bonneville, so I remember well how they SHOULD run and drive).
Today on cold start, my friend had the hood open, and as it started (I was standing right at the grille) it let out 2 very loud "clanks" that could have been someone smacking a piece of thick metal with a hammer as it fired off. Oh, oh.
After start, the engine idles PERFECTLY smoothly and silently, and runs fine. Subsequent starts are quiet.
Hot starts are quiet, but the engine "hangs" as it starts as if the timing is somewhat over-advanced, but then starts and idles/runs perfectly.
Ideas?
Thanks,
Bob
When starting it when looking at the car, heard 2 kinda' loud "clanks" as the engine started, which the seller said was the exhaust banging (he had just replaced the cat only to find it was a bad O2 sensor).
My wife was standing at the rear and confirmed that the noise sounded like it was under the rear of the car.
I shut down the engine and re-started. NO noise then or on subsequent starts. Drove the car about 10 mi, and it drove like new (I owned a '96 Bonneville, so I remember well how they SHOULD run and drive).
Today on cold start, my friend had the hood open, and as it started (I was standing right at the grille) it let out 2 very loud "clanks" that could have been someone smacking a piece of thick metal with a hammer as it fired off. Oh, oh.
After start, the engine idles PERFECTLY smoothly and silently, and runs fine. Subsequent starts are quiet.
Hot starts are quiet, but the engine "hangs" as it starts as if the timing is somewhat over-advanced, but then starts and idles/runs perfectly.
Ideas?
Thanks,
Bob
#2
Senior Member
True Car Nut
You might want to check out the starter, to confirm the solenoid is not sticking, and it is engaging properly. Also check to see if the starter has been done recently.
#3
Senior Member
True Car Nut
look for corrosion issue on cars that sit for long time. normally older folks who dont drive their car much dont do anything special, it probably could use some seafoam for a little while then an oil change, and take all the electrical connections loose, clean them them then put them back together with some dielectric grease or terminal spray
#5
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On the corrosion, fortunately it'* a Texas car, and for the most part, the car is extremely corrosion-free. I pulled several electrical connectors and they all were oxidation free.
I do plan to run a container of 100% Techron through the fuel system, which is very much like SeaFoam. Also, of course, change the oil/filter.
It is possible that the starter may not be disengaging properly until the started engine slams it back (the noise always happened right after the engine started and built RPM). Since the car really hadn't been driven in 3 months or so (when the guy'* aged mom stopped driving it, and the registration/inspection ran out), maybe a little use WILL free things up a but. It did NOT make the "bang-bang" noise when started cold today for the first time in 3 days.
I do plan to run a container of 100% Techron through the fuel system, which is very much like SeaFoam. Also, of course, change the oil/filter.
It is possible that the starter may not be disengaging properly until the started engine slams it back (the noise always happened right after the engine started and built RPM). Since the car really hadn't been driven in 3 months or so (when the guy'* aged mom stopped driving it, and the registration/inspection ran out), maybe a little use WILL free things up a but. It did NOT make the "bang-bang" noise when started cold today for the first time in 3 days.
#7
Senior Member
True Car Nut
Pull the starter and check for signs of damage on the starter drive gear as well as on the flywheel ring gear. Sounds to me like the starter drive gear is hanging up and getting kicked back at higher RPM'*.
#8
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If part of a tooth is broken off, it will always make that noise when the starter gear engages it I am afraid.
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