1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

[patagoniac-in-sc]

Century 180LX was winterized and block and manifold drained as usual. However, this weekend when getting it ready for the lake I started the engine with the water hose muffs and noticed water running out the underside front hole of the manifold just above the alternator. I've attached a picture of the open hole and a picture showing the other untapped one toward stern. (Not sure what this open hole in manifold is called). Where to start after reading all the threads about cracks, thermostats, pumps, etc? Any ideas about water coming from this hole would be much appreciated.

 

[GMC2003]

Re: 1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

Looks like the freeze plug is missing.

 

[Bondo]

Re: 1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

and block and manifold drained as usual.

Ayuh,... You'd better double check yer technique on Drainin'....

That missing core plug was blown out by freezing Water....

 

[patagoniac-in-sc]

Re: 1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

I hate to hear that and am a bit surprised as I didn't do anything different that previous years and even left the petcocks removed. Must have been some water in that chamber. This may be a stupid question, but I will ask anyway in an attempt to save some money first: Is there a way to repair without replacing the manifold?

 

[HT32BSX115]

Re: 1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

I hate to hear that and am a bit surprised as I didn't do anything different that previous years and even left the petcocks removed. Must have been some water in that chamber. This may be a stupid question, but I will ask anyway in an attempt to save some money first: Is there a way to repair without replacing the manifold?

You might also want to check the engine over closely too. What happens is that the cooling passages become "filled" rust flakes. THose particles of rust sometimes clog the drain petcocks such that it appears that the block manifolds etc are drained, but there's still a fair amount of water left in there that can freeze.

You may still be OK ......... Just get yourself some sand paper and a replacement (brass) CORE plug of the appropriate size, clean up the hole and knock it back in there with a hammer and a large deep socket.

Then see if you have any other leaks and be on the look out for water in the oil (oil level rising, milky oil etc)


You may have dodged the bullet after all!!


Cheers, .......... Welcome aboard!


Rick

 

[patagoniac-in-sc]

Re: 1992 OMC 3.0 140 hp GMC Leaking Water at Manifold

Thanks for the advice. I will order a brass plug and check it out. Hopefully I've dodged a bullet!!