: 94 SLS has bad freeze plug.....

10-19-04, 02:44 AM
so, i after months of just refilling my coolant and putting up with that god-awful smell of burnt coolant i decided (with bad weather coming) to take my car in to see what was up. well, no hose leaks, no bad water pump, no bad heater core or even head gasket, it turns out it is a bad freeze plug. well,the shop said not a big problem just hard to get to and that pulling the tranny or the motor will have to be done and cost me around 600 dollars! now, is this too much or to be expected or is there an alternative?

10-19-04, 03:50 PM
Bad freeze plug...???? Where?? The block has no freeze plugs. There is a plug on the side of the head but that could be accessed and repaired with an expanding rubber plug if that is really the problem. I am surprised that a leak like that would not be sealed with the coolant supplement...???

10-19-04, 06:06 PM
It's my understanding that what everybody calls a freeze plug is more properly called a Welch plug and is not used to provide a place for expansion to protect against freeze-ups but is used to clear out mold sand after casting. Since the Northstar is an open chambered design there is no need for the plugs.

10-19-04, 08:41 PM
That is true. We actually call them core plugs because the holes in the castings left from core supports are what the plugs plug. The holes are usefull for cleaning sand out of the new castings but the real reason that there is a hole there is that the internal sand cores that make up the water jacket and such have to be supported during the casting process and the legs or runners that support them leave holes in the casting that are plugged with core/welsh/soft/freeze plugs.

They have no function whatsoever in protecting a casting from water freezing inside of it. None.

The Northstar block has an open deck face...i.e...the cylinders are free standing so that all you see at the deck is the round cylinder. This is called an "open deck" design. "Open chamber" usually refers to the design of a combustion chamber...but I knew what you meant... LOL

10-20-04, 12:46 AM
Bobbynski, any chance that Northstars will be made using permanent mold castings? Wouldn't this cut down on porosity?