Rubber radiator mounts -- why?

[Peter Cripps]

I'm referring to the thick rubber spacers that go between the bottom radiator brackets and the front subframe. They presumably provide some isolation from vibration, but why?

Reason I ask is that my radiator cap comes very close to the underside of the bonnet .. so close in fact that I've had to adjust the stops so that the bonnet sits a little bit higher than the rest of the front bodywork. If I removed the rubber spacers, I could possibly close it a bit further.

Peter

[Huib]

I occasionally wonder myself too why the rubbers are there. They have been there from the first Fulvia in 1963 till the last one in 1976. There must have been very good reason for the rubbers being there to have survived the Fiat book keepers. Another, perhaps better, reason I can think of is to allow for thermal expansion. Radiators are usually made of brass which has quite a high coefficient of thermal expansion, about twice as high as steel.

Another possibility might be to put the thicker rubber under the subframe and the thinner one on top. Or look again at the whole set up very carefully. With the grille removed you have a good view of what the distances under the hood are. Leaning the radiator backward a bit more often solves the problem. I once achieved that by using a piece of rubber fuel hose with a bolt inside in lieu of the rubber strap. And slide the rubber top radiator hose a bit further over the thermostat housing.

It also helps to use a radiator cap with two ears instead of the four ears on some replacement caps.

Or replace the subframe mounting rubbers so that the body is lifted a few mm's higher from the subframe

[P. de R. Leclercq]

I always assumed that the flexible mountings were to protect the (fragile) radiator from movement transmitted from the engine via the quite stiff top hose.

I have seen many radiators that leaked because of failure of the connection between the metal brackets and the bottom of the radiator; flexing would exacerbate this.

And after all, radiators are always mounted on some sort of rubber mounts - on all cars as far as I know.

Paul

[Peter Cripps]

Thanks Huib and Paul for your comments.

I did pretty much as you suggest, Huib. Used thinner spacers on the topside, and also fabricated a longer top bracket that pushes the radiator back a cm or so. I used a rubber grommet to provide some 'give' to the new bracket.

This has given more clearance between the radiator cap and the underside of the bonnet, but I still can't get it to close fully. If I adjust the rubber buffers so that the top of the bonnet is flush with the rest of the body, then they no longer have enough 'spring' to pop the bonnet open when I pull on the release knob inside the car.

(I think I'm losing interest in this little project. It's not as if it's a particularly important issue to fix!)

Peter

[Huib]

The spring action to pop the hood open comes from the rubber strips along the front. Sometimes these have gone missing. If not, they have become too old. It may help to glue a small diameter plastic hose in the knee of the rubber. Best is to replace the rubbers.

The earliest coupes did have spring leaves, two sort of boomerang shaped pieces of thin spring steel bolted to the underside of the lock with the two bolts at the front of the lock. The things where shaped such that the knee was under the pin taht goes into the lock.

[Peter Cripps]

Huib, I'm not sure about the rubber strips. Here's a picture of what I have:




The two rubber bumpers left and right are what appears to provide the spring action. If I screw them down far enough for the bonnet to sit properly, they lose their spring, and the bonnet wont pop open.

The only rubber strips I can see are the ones on the left and right hand side of the engine compartment opening. They are new, but don't really provide much spring action as they stand.

When I got the car, there was a large spiral spring mounted around the central catch, but I think this was a non-standard add-on by a previous owner. It didn't work, anyway! At that time the rubber bumpers weren't there ... but when I installed them, and adjusted as described above, the bonnet did open OK.

Peter

[Geoff]

radiator mounts - how about thermal expansion/contraction? Radiators get hot, expand in size. if mounted rigidly to the subframe (no expansion, maybe contraction when cold...), the brackets and perhaps the radiator will crrack. imagine 100 degree C radiator, and -20 degree C subframe. Not a pretty picture. Thus, rubber mounts.

[Huib]

Right

[Huib]

The rubber strips are under the front of the bonnet. One on each side of the lock and they run till the side of the bonnet.

In the past I also tried to get the hood to pop up by adjusting the rubber stops on the cross member. Did not help. I also tried lowering the lock by putting the washers of the 4 M6 bolts on the "wrong side" of the lock. This worked but led to pimples on the nose as the hood did hit the rad cap and one of the banjo bolts of the carbs when dropped shut.

If you study the S1 parts catalog you see that very early in the production the coupes had the spring leaves under the lock. From the moment they were discontinued, the rubber strips were mounted. It might have something to do with the introduction of aluminium bonnets which are less stable than steel ones.

From your picture I also notice that there is no rubber in the air scoop for the heater. Instead the rubber is on the black tray. This is wrong. Depending on the combination of driving speed and fan speed, you will have a false air (and sound) flow between the upper skin of the bonnet and the frame of the bonnet.

The air scoop (presa aria) rubber has a rather square part and a flexible flap. Almost everybody mounts it the wrong way and puts the small flap inside the bonnet. This is wrong. The square part should be put inside the bonnet. It gives stability to the bonnet.

[Peter Cripps]

Ahh!!!

So there should be rubber strips on the front underside of the bonnet? That makes perfect sense ... I'll find some suitable material and report back. Won't be for a few days though -- I'm going away for the US Thanksgiving holiday.

And thanks for the pointers on the scoop rubber. I must admit I wondered whether it was in the right place.

And Geoff's comments on thermal expansion make sense. I think Paul suggested a similar idea. Even with the thinner rubber mounts, I still have enough 'give' for relative expansion to take place, so it should be OK.

Thanks again to all for the suggestions.

Peter