72455

Greetings all ye Oldsmobilers!

One of the things I need to do to my 72 Cutlass Supreme is replace the underhood insulation. My concern is heat. Right now there is no insulation and my 455 will cruise at 70mph all day long and she holds steady around 185 degrees. If I add the hood insulation willl that affect the underhood temperature and thus increasing the running temperature? It does have twiin hood scoops but I don't want to cause myself any issues.

Thanks,
Dave

Gerald Nickels

Don't worry about it I drove my 70 Cutlass SX for 5 years without one. Just make sure it has a shroud and good clutch for the fan. If your car is judged in a Olds Nats YES install it.

joe_padavano

No factory fiberglass hood came with insulation. The insulation used on metal hoods was more for sound deadening than thermal control.

35tac

Hood insulation for my 66 Cutlass. It seems to me after reading a number of posts about installing hood insulation that there is no consensus of what side faces the engine, hard side or soft side. I don't know which is correct. 1966 CSM shows the insulator in FIG 11-26 however it does not indicate what side of the insulator goes where. Use of cement is indicated by position. There is nothing in the assembly manual nor the Fisher Body manual. Can some one address this.
Thanks
Wayne

jaunty75

As I mentioned in the other recent thread on this, the hood pad that I ordered for my '78 Toronado could be installed only one way because of where the cutout is for the underhood light. The only way to install it was to put the hard side facing the engine. I always thought this made sense as the hard side protects the insulation material from any fluids or dirt or dust or whatever might get on or into it from the engine compartment.

35tac

I saw what you said. I understand but others ay different. I am hoping for something definitive and I appreciate what you said. The 66 Cutlass hood interior does not look like it requires a cutout.
Thanks for your help
Wayne

jaunty75

The '66 A-body assembly manual would seem to indicate that the hood insulation pad did not have a "hard" and "soft" side. There's no mention of proper orientation in the lower left of this diagram, and you'd think there would be if it mattered and if it were possible to install the pad the wrong way. The inset figure in the upper left that shows how the clips are installed shows the "insulator," and that little figure doesn't show any difference in the sides of the pad, not that you can see the bottom side.

I'm wondering if this hard side/soft side business isn't just something that the hood pad suppliers of today do for manufacturing purposes or whatever and that the pads installed by the factory didn't have a hard side.

35tac

Thanks for the feed back. I agree with what you are saying. That said, I beleve that most hood insulation pads other than the more expensive formed versions have a soft side and a hard side. Given that the illustration shows adhesive would be used, it would seem that the hard side would be against the inside of the hood matching up with the adhesive for strength. Thus the soft side would be exposed toward the engine. The clips installed reinforce the insulation. Unfortunately that exposes the soft side to heat more so it exposes the soft side to wind, some rain and forced air from the cooling system which beats up the soft side. I see that note "E" indicates that the insulator is only used on models 35, 36 and 38.Those are the higher end models. I guess the higher end models get more insulation.
I would like to see more input on this subject. I will need to install a new one in the spring. Which brings me to the next question. Besides the expensive formed insulation pad where should I buy the replacement?
Thanks
Wayne

tsgutlass

My 1968 4-door Cutlass was all original and still had the factory hood insulation on it. I can only speak to that particular car and it may be different with others, but it did not have a hard side. It was just a material with some fasteners that held in place exactly like which is pictured above. I can understand somebody putting a hard side on it because as it aged it did end up sagging more in some places than it did in others and did not look so great. I always keep it on as it was an original feature that was typically gone. In hind sight, I never drove the car in the winter and it probably made the engine compartment as well as the motor run hotter with it on. Unfortunately, it was also one of the first things to further fuel the fire I had on the car and helped it spread more quickly.

jaunty75

I did a little more looking around, and what I found suggests that you may not have a choice in the matter, assuming whatever you buy actually has hard and soft sides. More on this below.

Or, perhaps, it was only high end cars that got insulation. Remember, the insulation is there only as a sound deadener. This was more of an issue in the high-end models like the 88 and 98, where the idea was to exude quiet luxury, than it was in the lower-end models, where it was more about basic transportation and cost savings. Obviously, yes, they did put insulation in the A-bodies as well, but I wouldn't necessarily assume that all A-bodies got it. Maybe the Cutlass Supremes got it and not the F-85s. Did your car have one originally?

This is where I found something that may make the issue moot, at least for you. I also have a '67 Delta 88, and I purchased hood insulation from Rubber the Right Way. The piece I bought did have a hard side and a soft side, it was symmetrical, so it could be installed either way, and I installed it the way you're thinking, with the hard side against the hood. I don't remember exactly why I did it this way, but I'm guessing it was for the same reason you suggest, that the hard side is a better surface for the adhesive.

But after about two years, I'm not happy. The soft side is getting dirty and dusty, and I've decided to order a new one (they're only about $25 plus shipping) and install it with the hard side facing the engine. The issue of adhesive is really a secondary concern because the pad is held in place primarily by the clips. The adhesive keeps the edges and so forth tight. I doubt it matters which side the adhesive is applied to. I used 3M headliner spray-on adhesive.


But for your car, a 1966 Cutlass, the pad shown at Rubber the Right Way's site is NOT symmetrical. The cutouts at the lower corners are not the same size. Assuming these people know what they're doing and that this really does conform to factory originals as they say, this apparently makes the issue of which side to put where moot. You'll have to install it in whatever way necessary to accommodate that cutout.







I want to go back one more time to my '78 Toronado. As I said earlier, the pad for it has a cutout for the hood light, and that dictated which way to install the pad. I did not purchase this pad. That website does not show availability of a pad for any full-size '78 Oldsmobiles. The pad I put on was in the trunk when I bought the car from a private seller back in early 2017. He didn't mention it during the transaction, and I assume it was purchased with the intent of one day installing it, but he never got around to it, and he threw it in the trunk before the car was loaded onto the carrier and shipped to me. So I have no idea how old this pad is. It was in fine shape, and I doubt these things deteriorate just sitting on a shelf, so for all I know, he could have bought it 20 years ago, or it could even be an NOS piece purchased back when you could still buy something like this over the parts counter at your local Olds dealer. But I do take the fact that it could only be installed one way. with the hard side facing the engine, as a strong indication that that's how it should be installed, and my recent experience with the pad on my Delta is backing this up.

jaunty75

Interesting. That's consistent with what the assembly manual appears to show.

jaunty75

Fusick also shows availability of a hood pad for a 1966 Cutlass, but they don't show an image of it. It's $36.50, or $12 more than the piece from Rubber the Right Way.

Fusick does show an image of the pad for '68-'72 Cutlass, and it would tend to refute everything I just said above.

This is one of the few pads they actually have an image of. Note that it is not symmetrical in that the top corner in the image has a cutout apparently for the underhood light. If the light is low on the hood on the driver's side like they usually are, this suggests that the pad is installed with the side we're looking at facing the engine. The side we're looking at appears to be the soft side. But they don't show the other side of the pad, so we don't know if this pad actually has hard and soft sides. Either way, it does show a situation where a soft side faces the engine.

jaunty75

I think that, in the end, this issue is taking way too much time and thought. Get a pad, slap it on the car, and forget about it!

35tac

Well thanks. This did add some clarity. I will probably order from Fusick since they are closer to me. I will call the them soon. I appreciate everyones opinion. It wood be interesting if Joe P chimes. Have a good day everybody.
Thanks
Wayne

jaunty75

It would be interesting to know if the Fusick pad is also non-symmetrical and can only be installed one way.

35tac

I checked in with Fusick yesterday. The insulation for the 66 Cutlass is designed to have the hard side against the inside of the hood. Therefore fuzzy side toward engine. I have my answer. Thanks to all on CO that were in the discussion.
Wayne