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-   -   How critical is the plastic "belly pan" beneath engine? (

screedchan 01-02-2001 01:59 AM

My 94 E420 has the plastic belly pan which extends from the front bumper to the rear of the engine. It has the propensity to fall down at inopportune times, despite my having ordered new hardware. I have been forced to employ a "Rube Goldberg" fix which includes some thin gauge wire, a washer, and a nut and bolt to keep everything tight. Is there any major downside to simply removing it altogether? I live in San Diego, so water, salt, etc. really are not a problem. I think my homebrew fix will hold everything together, but I just wonder what the major benefit is to keeping the belly pan.


JDUB 01-02-2001 02:44 AM

In San Diego the belly pan is probably not a problem if it is left off. I live in chicago and the crummey speed nut type inserts would not remain in place that hold up the belly pan even after purchasing new ones from the dealer. Here where there is road salt snow and ice it is important,I have purchased nylon type inserts to hold up the belly pan. It keeps the underside of the engine a whole lot cleaner a protects the alternater from excessive moisture. Even though it is a pain to remove it for frequent oil changes.

LarryBible 01-02-2001 08:13 AM

I see many reasons and purposes for the belly pan. Regardless of where you live, it probably rains there sooner or later. Without the belly pan, water on the drive belt can cause slippage which is sensed and will turn off the air conditioner. Even if you don't need the air conditioner, slippage is not healthy for the drive belt.

It is worth keeping it on. You may have to keep a handful of the captive nuts handy, and maybe add a little tension to keep them from popping out. You know, bend them a little.

Good luck,

Deezel 01-02-2001 09:41 AM

A better mouse trap!
Hey guys,

I will try to help you out if I don't get overwhelmed. I too have suffered with this problem, and have refused to pay the 1 or 2 dollars each for these cheap stamped steel nuts. I have not replaced all of mine, just the ones at the front of the most forward pan. I have used an aviation nut called a clipnut. I don't have all the fancy photo capability at my finger tips that Mike Tangas has, but here is a simple description that I hope you can follow. A clip nut is captive threaded nut, that is designed to slip over a thin flange (the MB chassis). When another panel is laid over the top (the plastic belly pan), a screw can then be driven in (no access to the back side is required). The standard nut is held captive in a u-shaped spring steel clip. Not only does the spring of the clip keep the nut press against the back side of the stationary surface, the bottom of the u contacts the attaching surface during screw installation to provide the wrenching resistance needed for screw installation. The only thing I don't like about my installation is that the large rectangular whole for the MB spring nut is kind of too large for the clip nut to be totally idiot proof. On installation, I need to carefully position it so it bridges the large gap. Once you get the screw started, the front pan will never fall off.

If any one wants a set of four or five clip nuts, 10-32 Phillips head screws and large diameter washers, please send me an e-mail and I will put them in the mail to you, no charge, unless the volume gets ridiculous! Consider this a late Christmas gift or advance payment for technical help I will need in the future!

engatwork 01-02-2001 09:47 AM

I purchased my '95 E320 in May and it did not have the belly pan. I called the MB service manager where I purchased the car and he said not to worry about it. He indicated to me that the only reason it is there is to contain any oil leaks. Heck, if mine is leaking I want to see it. I will say that I have not had any problems NOT having the belly pan in place.

Jim H 01-02-2001 10:32 AM

My Audi has a similar belly pan that uses 1/4 turn plastic cam-lock type fasteners. Various "mechanics" mistook them for screws and used brute force to undo them. :eek: Eventually all were broken. I discovered this when I hit a bump and heard it dragging down the street. :mad:

I had all the hardware replaced with OEM and now take it exclusively to my favorite independent Audi shop, even for oil changes.

I think the pan plays an important part of reducing vehicle drag, and is important for proper cooling airflow in the engine compartment. I'd vote to keep it on, with any method that's convenient for you and whoever does your oil changes.

BCingU, Jim

yal 01-02-2001 11:39 AM

If you have an oil leak the belly pan (if in good condition with no dents or kinks)is built to still drain it onto the floor. Apart from what Larry mentioned above having the belly pan also reduces the drag co-efficient of your car which translates to better gas mileage, etc, etc. All these reason might be superficial and unimportant to you but hey, you asked.

jeffsr 01-02-2001 08:45 PM

Get a new one and don't leave home without it. This piece of thermoplastic saves a lot of expensive parts from exposure to abrasion, road salt and the like.

Southern 01-03-2001 12:07 AM

I had belly pan screw break on me when I went to screw it back on after an oil change. The broken screw was corroded. I purchased new screw from the dealer and applied antiseize compound to all of the belly pan screws. Now the screws go in and out freely. I also apply antiseize compound to my lug bolts, engine drain plug, and other bolts as required. This makes easy work of removing screws/bolts.

Ashman 01-03-2001 02:24 AM

My 1992 doesn't have plastic screws, it has metal screws, that actually have to be unscrewed with a good ol ratchet.

In fact I have to drop the thing out when I want to do an oil change. I was thinking I might just cut a nice round hole directly under the drain plug. that way I'll save myself some time when doing oil changes.

Its not a big deal to me if I have to take it off, just an inconvienience because it has to come off to get tot he drain plug.


Arthur Dalton 01-03-2001 09:28 AM

I cut a hole with a 3" hole saw. Works fine.

I positioned it so the plug was on the circumference
of the hole.
That way the wrench fits well and the oil drains nicely.

Ernest Dixon 01-03-2001 11:11 AM

Keep It Installed
I think there is a post from Michael that he had removed his belly pan, and that at higher speed the wind pressure forced some wheel well moulding (or something like that) to rub on the front tire. Maybe no problem unless you have a Blitzen ;)

Southern 01-03-2001 09:16 PM

I prefer to drop the belly pan when doing an oil change. This allows me to take a good look around for potentional problems: oil leaks, condition of rubber boots, etc. The inside of the belly pan will also indicate if there are any leaks.

msyoder 01-03-2001 10:38 PM

Belly Pan
Another benefit to the pan that I didn't see mentioned is the noise reduction. I have my first MB and I thought it was there most for noise shielding.

In fact I just remembered where I got that idea. The marketing catalog for my '87 TD calls the belly pan "a system of acoustic encapsulation". I know my uncle always comments on my car's quiteness compared to his '84 diesel.

I have found the pan frustrating when dropping tools and parts down from above. It seems that lately there hasn't been a job I've done that didn't require removing the pan for this reason.

At least with the topsider oil changing isn't one of them.

Johnson Chan 01-04-2001 07:45 AM

The belly pan or (noise encapsulation panel) is more critial when you have a diesel. It helps with the noise problem. But since your car is a gasoline, you dont have to worry about that. Another reason to have it is for protection from salt, gravel, speedbumps, etc. if this is not applicable to you either, then just leave it off.

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