4.3 Liter GM drain plugs

BillM2

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Jul 19, 2006
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22457
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Are there just two drain plugs (port and starboard) on a 4.3 engine. I'm only finding two and thought that there might be plugs higher up closer to the exhaust manifolds.

Thanks!
 
Go here: Page 1B-33, Draining Instructions. Two block, two manifold, possibly 1 for the anti-knock sensor. One each side...except for the sensor.

LINK
 
Msibley - I have the same setup as BillM2 - 2006 Bayliner with the 4.3l and Alpha One. Looking at the link you sent, it appears that if I had a knock sensor, it would be Y'd into the block where the drain plug would go. Did I get this right? If so, my engine doesn't have the knock sensor - just a blue drain plug on each side of the block. I also found the 1 plug per manifold and 1 additional plug at the base of the big hose running to the engine circulating pump, for a total of 5 blue plugs. Sound right?

This is a new boat to me, and my first I/O, so if you wouldn't mind another question... I pulled my plugs and drained yesterday, then replaced the manifold and water pump plugs, removed all the hoses at the thermostat housing and backfilled with antifreeze until I had antifreeze come out:
- the raw water intake in the outdrive
- the open block drains (the antifreeze did flush out a bunch more rusty water)
- and out of the 'gear housing water drain hole' and what appears to be two exhaust ports at the bottom of the gimble housing

While the raw water hose was filled with antifreeze, I turned over the engine (not started) to pump a little antifreeze through the impeller and outdrive. I expected some antifreeze to flow out through the prop, but I think I found from another post that the ports at the bottom of the gimble housing are the first point of exit for the exhaust. Does all this sound right? If so, I think I'm sufficiently winterized, but figured it was better to ask questions now than when diagnosing a cracked block in the spring.

Sorry for the long post, thanks for all the great information on this site.

Lars
 
Thanks Mike! Found both the block and manifold drains (not quite what is illustrated in the manual but the page was of assistance). Really tough to spot in such tight quarters -- up, behind and around. I wear XL gloves so access is always a challenge.

Bill
 
Bill - my hands are XL too, and my engine is now wearing a protective coating of knuckle blood in a few strategic spots.

Lars
 
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