Coolant drain plug

[mathd]

Hey, ok i dont want to sound stupid but well, stupid question that matter to me.
This week i went ahead installing my knock alert/knock sensor at the bottom of the block in the coolant drain plug.
Before to remove the drain plug i thought coolant will leak and make a mess.. so i removed the radiator cap, squeezed the hoses and then put the radiator cap back on(hopefully creating a small vacuum inside the cooling system to prevent coolant from leaking out the drain plug too much).

Now, i dont know why, but when i removed the drain plug no cooland leaked at all, it looked like there where no coolant in that part of the block.. but the plug end LOOKED to be wet/oiled with some coolant.
Now i am confused, maby its normal coolant wont drain out because the radiator cap is on or maby the passage is plugged inside the block?

Why is that?, is it because the engine hasn't run since a few month?, is it because i somehow created a small vacuum in the coolant system that did prevent coolant to drain out by the drain plug with the radiator cap on(hopefully that is the reason)?, should i worry or should i live it that way as the engine has no overheating problem?
I guess next time i get it started i get the infrared temp indicator and check for temp variation on that part of the block?
If someone tell me its normal, coolant wont drain when the radiator cap is on that will make my day

thanks you

 

[Indycars]

I know several times I've had to use a screw driver to poke a hole in the crude that has built up in the drain plug. Did you stick anything thru the hole to remove any crude ???

 

[grumpyvette]

yeah ! its very common for a fine layer of silt or powder rust and mixed trash too form a layer in the lower coolant passages over several years time, especially if you don,t use fresh anti freeze in higher than 40% solution ratios and like INDYCARS mentioned its frequently requires you to use a piece of wire or rifle bore brush to get the stuff pushed out away from the knock sensor to allow coolant to flow easily.
Ive also seen guys forget to install a plastic or metal tube in the lower coolant passage to allow the block to drain when they partly fill blocks to add block rigidity on thin cylinder walls

 

[mathd]

Thanks for the reply,
I will follow the advice and take the sensor out and use a piece of wire to see what's going on inside that drain hole.

Ive also seen guys forget to install a plastic or metal tube in the lower coolant passage to allow the block to drain when they partly fill blocks to add block rigidity on thin cylinder walls

I also feel like this is what happened, will see after inspection with a piece of wire. If that is the case, is there something wrong with having no tube in the lower coolant passage to allow for coolant drainning? can this cause premature failure/wear?

thanks you,

 

[grumpyvette]

if thats the case any the blocks had a partial coolant passage fill its just going to be a P.I.T.A. to drain, due to the lack of previous fore thought,its otherwise not a big issue