'72 Underbody heat shield

[Michael M.]

I have 2 1972 LS5 / A/C cars. One 4 speed and 1 Auto. Each has the underbody heat shields on the outer firewall. The earlier one (Oct 71) just has the shields with an air gap between it and the firewall whereas the later one (Apr 72) has some kind of foam insulation stuffed between the heat shield and the firewall.

Which is correct? Has the earlier cars insulation fallen out or has someone added insulation to the later car???

[George Romano]

Re: '72 Underbody heat shield

My Jan 72 car has no insulation, just the steel shield.

George

[Harmon C.]

Re: '72 Underbody heat shield

Mike Those heat shield were used on many years of sharks and I have never seen insulation behind them. The owner must have been overheated and trying to cool the interior. Lyle

[Jim T.]

Re: '72 Underbody heat shield

Lyle my orignal owner 68 came with insulation under the seating area to the top of the footwell and was/is installed on the underside of the body. The metal shield is attached to the frame and is horizional with the car's frame and attaches to the front area of the floor pan. My 70 is like the later models.
There is not much insulation left on my 68, but what is there is the original insulation.

[George Romano]

Re: '72 Underbody heat shield

My early 69 had insulation.

George

[Rich Grant]

Re: '72 Underbody heat shield

I have a very late low milage 69 435 convertible and I have the heat shields with no insulation and I don't see any trace of it. I have seen it on some early 69's that I've looked at. Does anyone have any idea when the cut off was?

[Jeffrey S.]

Re: '72 Underbody heat shield

Heat insulation was added later in the '68 model run after customer complaints of hot passenger compartments. A Technical Service Bulletin was issued to dealers to retrofit the insulation on customer cars. I'm not sure if it ever was added at the factory until the '69 model run. My '69 built October, '68 has the insulation. Later '69's did not although they all had the heat shields. I don't know the cut off date. I am looking for the copies of the TSB's but I will have to post the numbers when I find them. One way to tell if the insulation was retrofitted is to look at the pointed "fasteners" that hold the insulation to the underbody (assuming that the car is original). According to the TSB, the dealer was to pop rivet the fasteners to the underbody whereas factory installations were riveted with the soft aluminum rivets as are all other underbody brackets. If your car does not have any of the fasteners and no holes for the rivets then the insulation was not there. There is also no mention of this insulation in the AIM.
Hope this helps.
Jeff Salz #13182

[Terry M.]

Re: '72 Underbody heat shield *TL*

No idea on the end point(s), but observations indicate that it differed with engine horsepower and transmission type.
The beginnings are detailed in Technical Service Bulletin 68-T-43 (April 22, 1968) and its supplement (December 17, 1968).
Step 1 - addition of heat insulation pads to the rear storage compartments starting with 1968 s/n 9315.
Step 2 - addition of heat insulation pads to the underbody starting with 1968 s/n 9939.

[Jeffrey S.]

Re: '72 Underbody heat shield

Terry
Thanks for posting the numbers. I just found them and was going to post when your posting came on.
Jeff

[Harmon C.]

Re: '72 Underbody heat shield

Jim I thought the original post was refering to the lower metal firewall shields and that their was foam behind them. Now some of the post are about tunnel insulation so I am not sure what or where were talking about. Lyle

[kelly theaker]

Re: '72 Underbody heat shield

Concerning TSB 68 T-43 April 22 68 the addition of heat insulation to underbody
jUST FINISHING A BODY OFF ON A 69 AND ALL CLIPS AND steel are there but unable to figure out where to place the L shaped piece of insulation . Hoping the tech bullitin would show propper placement , and did the battery cable run under the trans insulation or over top of the trans area insulation ?

[Jeffrey S.]

Re: '72 Underbody heat shield

Kelly
The insulation goes on with the rear end of the piece going over the transmission crossmember and being attached to the clips on the other (rear) side of the crossmember. The sides of the insulation go up the side of the tunnel and, according to the TSB, got cemented to the underbody with weatherstrip adhesive. I take this to mean that it goes on top of the tunnel insulation. On your '69 adhesive is not necessary since you have clips installed on the floor pan to hold the pads in place.
Hope this helps.
Jeff Salz

[kelly theaker]

Re: '72 Underbody heat shield

thanks for the post but not clear enough, the insulation has a sort of T shape. i need a better or more clear explanation, if you can , i am getting the tsb from another member, i hope this is a clear explanation, and hey does the battery cable go under tunnel insulation or over?