O.K., just finished yet another phase of my 'on the road in 30 days' project. I had to replace the heater core and put a seal kit in the housing.

Here is the question: the heater core has one large tube (5/8" hose-?)and one smaller tube. What size hoses do you run from the larger and the smaller tubes to the water pump and radiator. Also the top is to the manifold and bottom to the water pump, right? The heater core was missing the bottom tube when I bought the car and a bypass hose was on the 6 cylinder.

Thanks again for all the advice guys!

i believe they are 3/4" and 5/8" and they go where they fit, meaning that there either the water pump or the intake manifold is 5/8" and the other will be 3/4"

those sizes are the same as my Pontiac, so your chevy might be different
and easy way to tell is slip and open end wrench over the fitting, the smallest one that fits is the size hose you need

400bird you need to get more sleep 1am-?

Thanks for the response. I was able to get the info also from NPD. The large is 3/4" the small is 5/8". The large is from the water pump and the small is to the manifold.

Thanks again!

Yes, 5/8" is supply for the core from the manifold. Other hose, 3/4", is core return to the water pump just above the lower radiator hose.

Hoses get clipped on the fenderwell just above midpoint of upper control arm.

I won't be at this point for probably another 5 days or so, but I like having the info. up front. Thanks again guys!

400bird you need to get more sleep 1am-?


Im up until 2 most nights, I get off work late and get to sleep in until noon