About a year ago I finally bought my first Corvette (it only took 40 years). It is a 1984 silver over gray with a graphite cloth interior. Had it for about a week and put it away for the winter. Over the summer I have addressed various issues that the car had and now have a sweet running good looking C4. One issue that I have not been able to solve is this: there is a coolant hose on the right side that I believe is coming from the water pump and is going to the heater core. There is a Tee in this line with a rubber elbow that is plugged with a bolt and a hose clamp. I thought it might be a replacement line from a later model that would hve a surge tank and the plugged line would go there but I'm not so sure now. I can't find a clear enough photo showing this line and haven't had the time to get to any shows for reference. Anyone out there knows where it should go to? Thanks in advance for any help.

 

So I solved my own problem. The elbow that is plugged should go to a hot water valve .Another line off this valve goes to the heater core and a third line goes to a nipple just behind the EGR valve. The valve has a vacuum diaphram to control water direction as directed by the heater/AC control. The valve was apparently removed by the previous owner and a length of heater hose installed in it's place supplying coolant to the heater core full time. It works fine the way it is so I'm just going to leave it as is. This past summer was the hottest in memory and the AC worked fine. Many thanks to Davies Corvette Parts for the best parts diagrams I have seen which enabled me to figure this one out.

 

If it were me, I'd get some fittings and assemble a T so you can reinstall that small 1/4" line from the back of the manifold. That small line will T into the heater line. You really need that path for the hot EGR coolant to escape from the rear of the intake so its not trapped and forced to flow to the front. This also provides some good hot water for the heater core IIRC.

That metal line assy is called the hot water valve assy...and the common problem is the seal in the valve shaft starts leaking. Not repairable, they get tossed as soon as the owner hears the price of a replacement. There ARE options however...that same
(or VERY similar and adaptable) tube/valve assy is common on a doz other makes/models and when it does not come from a Corvette parts book its about 25% of what you'd normally pay.

They're $5 at LKQ if you don;t mind hacking one out and a few minutes in the bone yard.

The valve simply directs the hot water around the core when the a/c is running, and allows hot water to enter the core when the heater is turned on.I bypassed mine yrs ago, kept the fittings all in place, all hoses connected and let hot water flow thru the core all the time. My a/c cools fine....except for the fact that it was miserably HOT the last couple summers Along the Tx gulp coast...with ambients of 100+ and the sauna like humidity of 90%....

 

Thanks for your reply. So what you're saying is that the plugged elbow should tee into the heater hose to allow coolant to circulate thru all paths all the time in place of the valve controlling the flow. Correct me of I'm wrong here. In any event, if I do make a change it'll be next year as the car will be going back into storage in about 4 weeks. I appreciate your guidance and input.