Need Winterization Help - OMC 4.3l

[PlanB]

A friend of mine has a 1991 Sunbird with a 4.3L OMC. I had a 4.3L Merc so I offered to help winterize. I could only find one plug in the port side of the block just forward of the oil filter and no plugs in the manifolds I could see. My merc had plugs on both sides of the block and one in each manifold. Help.

 

[Lou C]

Re: Need Winterization Help - OMC 4.3l

There is a plug on the starbord side of the block, you have to look around under where the engine mount area is. If it has the OMC one piece manifolds, there is a drain plug on the underside of each manifold that is easy to reach. Don't forget that plug on the power steering cooler (on back of engine, in the water line from the outdrive to the therm housing) If you can't reach the plug, you can disconnect the hose and point it down to drain it. <br />The outdrive has 3 screw in plugs to drain the pivot housing, you have to tilt the drive up to see 2 of them (one on port side, 2 on starbord). Mine has an after market ex bellows with slits on the bottom, so the pivot housing drains that way, but if his has the OE style closed ex bellows, you have to drain them. I put all the plugs back in and fill the hoses with PG AF.<br />If you are changing the oil in the Cobra drive, be careful, you must follow the OMC shop manual procedure for this, or you will burn out the upper gears. Takes 64 oz of fluid, OMC Hi Vis or HPF gear oil.

 

[andrewgroup]

Re: Need Winterization Help - OMC 4.3l

My 90 OMC 4.3 has drain plugs in the block that appear as BRASS hex head bolt heads instead of the usual petcock devices you may be looking for. One on starboard above and ahead of the starter, one on port ahead and above the oil filter and on the lower manifolds.

 

[Boatin Bob]

Re: Need Winterization Help - OMC 4.3l

The drain on the STBD side could be just in front of the starter and the manifolds might only have the rubber cap on the rear so you have to loosen the hose clamp and remove the end caps.