Replacing coolant in 1996 c-4 ...drain block?

[Rich C.]

I'm planning on replacing the coolant in my 96 LT-4. On my '73 I pull the drain plugs on the block. My question is do the C-4 LT engines have block drains? If so, any pitfalls to pulling them. In the old days I used to do the prestone flush 'n fill. However the first time I pulled block plugs on the '73, I was ASTONISHED how much coolant stayed in the block. So I figured that might be the way to go. I'm still not comfortable lifting this car, so would probably have the dealer do it. (4 post lift still a year or so away)



1973 LS-4 454 coupe owned 24 years
1996 LT-4 Collector Edition coupe owned 14 months
Sierra Nevada Torpedo IPA-currently on tap!

[Joe L.]

Re: Replacing coolant in 1996 c-4 ...drain block?

I'm planning on replacing the coolant in my 96 LT-4. On my '73 I pull the drain plugs on the block. My question is do the C-4 LT engines have block drains? If so, any pitfalls to pulling them. In the old days I used to do the prestone flush 'n fill. However the first time I pulled block plugs on the '73, I was ASTONISHED how much coolant stayed in the block. So I figured that might be the way to go. I'm still not comfortable lifting this car, so would probably have the dealer do it. (4 post lift still a year or so away)




1973 LS-4 454 coupe owned 24 years
1996 LT-4 Collector Edition coupe owned 14 months
Sierra Nevada Torpedo IPA-currently on tap!

Rich------


Your application has engine KNOCK SENSORS installed in the block in the location that used to be fitted with pipe plugs. You need to remove the knock sensors and their shields in order to drain the block. You DEFINITELY should do so in order to properly drain and refill the cooling system. Removing the knock sensors and shields is not difficult, at all. However, you need to be very careful with these to avoid damage. Also, they need to be installed with the specified torque value which is VERY low. Over-torquing these will ruin them and they are definitely not an inexpensive item.

The complete coolant drain and refill procedure is covered in your factory service manual. I recommend following it assiduously.

[Jim T.]

Re: Replacing coolant in 1996 c-4 ...drain block?

I have changed the coolant in my 1996 LT4 since it was bought new, I have always removed the knock sensors to drain the block. A lot of coolant is removed in doing this. I do not, have not flushed the coolant system when changing the coolant. I use distilled water and what is recommended in my 96's owners manual for a complete coolant change. I am considering using ZEREX G-05 on the next change of coolant.