Hi, I am looking at a 1970 to buy and my latest candidate has a terrible messy seam sealer job where the heater box meets the firewall. This is a non AC car from the factory so it is not a case of trying to cover up an AC firewall. At first I was thinking the older restoration was sub standard but looking at online pictures of 1970 under hood shots, I actually see a few sloppy seam sealer jobs. My question, is that just the way the factory did it? I see plenty of smooth firewall / heater core intersections but there are enough sloppy intersections that it has made me wonder. Thanks, Marc
A lot of GM 1968-72 GM Heater Boxes were installed sloppy. A lot of restorers try to duplicate the GM Slop. Pic...
One looks sprayed on and other goopped on by hand. I wonder if it's related to manufacturing location? Gary
This was mine post heater core replacement from the summer of 2019. The trick (if at all possible) is to try not to move/interrupt that heater box, so as to not "ruin" the mess the assembly line made when it was originally sealed. Dave actually suggested that Flex Seal spray bomb sealant but I lucked out during my core swap.
Buick used the slop method. Every non AC car I ever saw that was untouched had the sloppy look. Olds did not make the same mess. They only put some on the inner most part of the box. I have a good 70 magazine picture of a 70 Stage-1 with the sloppy seam sealer. It was sprayed on at the factory. Also the heater box was gloss black and firewall was pretty flat. I wanted the authentic look. The super sanitary clean heater box with same color as firewall just doesn’t do it for me. I want authentic. I did use the Flex Seal spray on my GSX.
I think do duplicate that mess requires several beers (the bar across from the assy plant had the pitchers ready @ lunch time), maybe a cigarette hanging out with smoke going up in your eyes and an "I don't give a f*@$ what it looks like" attitude. They weren't building show cars. Here's the one I have. Looks like my other (grey) one has been apart.
What’s also interesting is the location of the clip for fan motor wire. I see it sometimes on the box and sometimes on the stud. I believe the assembly manual shows on box.
All, Excellent info thanks very much. I guess I have been lucky, all the cars in my signature were pretty clean, and in most cases were unrestored cars. I will not take this as a sloppy restoration fault in the car I am considering then. It is always a tough call when restoring whether or not to clean up factory messes. My Judge, which I did restore, had the voltage regulator installed crooked from the factory. I deliberately did not fix that, but it still bothered me for a few years after the resto.
Yes correct it was a timed change. Not sure when. They moved that clip onto one of the studs at the top of the heater box at some point during 70. All 71 and 72 the wire clip was on the stud. It’s not very logical to me that they would punch the screw right through that box where the heater core was when that stud was just begging for that clip. I think they used the same clip too.
All GSX cars I have seen had the clip on the top stud so it stands to reason at least by February the clip had been moved to the stud.
I’m guessing your firewall and heater box was re-painted. They are the same shade of black as is the big washer screw.
I’m guessing the change happened around December -January. Lots of changes probably spread out. pointed to flat gauges, white to black top overflow, plastic to metal radiator cover and the wire clip. Anything I missed? One odd one is drivers side door. Top rear of door had a big gap and those doors can be ID’d by the lack of raised beads to locate blue VIN decal inside back edge of door. On those I see the decal placed higher than it was on the beaded doors.
