Drain cock on cylinderhead 455?

Hi I have a 72 Riviera with 455. Going to flush the cooling system but cant find the drainers that are supposed to be on each side of the engine. Can only find the radiator drain.

another question: isnt it supposed to be running coolant out of the engine if you remove the tempsensor on the end of the cylinderheads? Mine seems to be dry.
Thought about mountin a temp gauge there, but not much use if there isnt any coolantp

 

I bought a 455 from a Riviera, and removed those temp sensors, they do not go into the water jacket so you wont hit any coolant there.

Last rad I replaced, I only drained from the rad, not the block.

 

If by temp sensor you mean the one that screws into the 3/8-16 hole in the back that is just a switch that activates when the engine just warms up. No water is present there. It really doesn't tell the temp other than the engine is not cold.

You have to use one of the openings at the front of the intake that go into the water passages.

The drain plugs are toward the back of the block on the same level as the motor mount bolts. The driver side is barely accesable and the passenger is behind the starter. Not really worth the trouble. Way easier to use a flush kit that hooks up to a heater hose.

http://cgi.ebay.com/ebaymotors/Pres...r_Truck_Parts_Accessories&hash=item2562675ba1

 

There are screw in plugs on both sides of the block. They will stick out. They could have square or Hex heads. Some later blocks did not have any plugs. Not sure what year they stopped.

 

I disagree.

Draining the flush water from the block is reasonably important; in part because it helps remove rust and scale that are too heavy to "float" out the flush kit outlet fitting; and in part because then there's no water left in the block to dilute the antifreeze. I've known folks that thought they had a 50/50 mix of coolant--but they poured it into a block that still had a gallon of flush water in it, diluting the mixture.

All my engines get draincocks where the block drain plugs used to be.

Yes, there are Buicks that do not have drain plugs. Another enormously silly bit of cost-cutting from GM.

 

If your's doesn't have the specific drain plugs then remove the bottom timing cover bolts as they are usually drilled through into the water jackets.

Tom

 

Interesting. They are easy enough to drill and tap though. I drilled an existing one out and re-tapped it for a knock sensor. Cast iron is pretty easy to work with in that regard.

 

That's a good point about the leftover water in the block. Whenever I refill the engine after having to flush an engine that way(usually my regular use type cars) I start off with a gallon of 100% antifreeze. That should make up for the water left behind. Then go for the 50/50 after that. I figure most of the heavy scale will drop to the bottom of the block anyway you do it short of removing block and hot tank.

Sneaky maintainence tip: If you look at the motor mount holes they are basically on the same centerline as the factory drain plug. What I do with with all my 455 blocks when I'm prepping them is drill out the #1 motor mount hole(most big cars can't do it because they use that hole) with a bit that is slightly smaller than the threads(don't want to ruin them) then I plug it with a spare motor mount bolt that I wrap lots of teflon tape around. I've even done the petcock in them but these days they are so cheezy I've had the "T" part break off. Easy access from underneath the front of the car either way you do it. I normally don't run antifreeze in any of my hobby cars, just water and some Waterwetter, since I'm always draining the water for one reason or another and antifreeze just makes a mess. I really don't use them in the dead of winter so I always drain them before the first freeze(and blow out the heater core).

 

Bumping this old thread :-D
Anyone knows the size of the drain cocks needed?

I bought 1/4 but they didnt fit :-(

 

This is on my '71 350 block, later blocks did not have drain plugs.
Drain plugs on the head would do no good, they're too high to do any good as far as draining.

 

My 430 that i removed for a 455 in my Riv here, had a plug on one side and nothing on the other, so i grabbed a hammer and a punch and gave it a little tap, to my amazement it broke through and water came spooting out. It must have had a rust and crud plug.