Engine Undercover

[Canopy]

Within the space of two years I've had two "engine undercovers" (what a weird name) (it's the plastic sheet underneath the engine compartment which appears to have the dual functions of keeping the engine clean from underneath and keeping the road noise down) get torn and droop down in front and drag along the road. It may have something to do with the fact that I live on a dirt road and have a mile to drive in and out every day.

The first one was on my wife's 1996 LS400. The front left edge had torn away from the bolt, but a large washer and another bolt has kept it OK for at least two years.

The second one occurred on my 2000 LS400 and, although I have yet to crawl under and check it for sure, it seems to be bolted OK, but has torn about 6 inches from the front left bolt and is hanging down and dragging. Frankly, I'm embarrased to drive it so have been using the Suburban for about a week.

I did a search on this and other forums and came away with the impression that it would cost between $200 and $400 for the engine undercover part. That seemed high for a plastic part, so I started thinking of getting a used one from a wrecked vehicle if I could find one. Before I started looking seriously, I drove over to the local Toyota dealer (we don't have a Lexus dealer in Tallahassee), and they priced a new one at $149.46 delivered plus tax, still high but not as bad as I was expecting.

When I got home I emailed IronToad and they quoted $99.00 before delivery.

Question: Has anyone ever repaired one of these with duck tape? Did it stick and work? Or, should I just go ahead and purchase a new one?

[VBdenny]

I can tell you exactly why you are having this problem. This cover needs to be removed to perform routine oil and filter changes. For whatever reason, Lesus uses very small washers to secure the shroud.

Careless removal and replacement causes some of the threads to become stripped and some are overtightened. Others are just plain not replaced (because who ever looks under their car) figuring if 9 or 10 bolts is good, 5 will do it okay. I had my local Lexus dealer leave mine off completely when the did an oil change I specifically told them I did not want.

This rough treatment o the underbody shroud, not to mention the forgotten mounting screws or bolts (10mm) that hold it on soon causes it to fail.

You must remember that there is a great deal of air prssure under the car so there is quite a bit of force on the mounting bolts. Without this cover your alternator will take on water which will not cause immediate failure but will limit the longentivity.

I would repair it with fiberglas cloth and resin, kind of a messy job but very do-able. Glue it together good with JB Weld first. Go to a hardware store and buy some large washers and place them as the final contact against the shroud plastic. You will be good to go.

[harjp]

I noticed mine drooping, so I removed it and threw it away. As I did the misc. plastic under the hood that cover up the word "Toyota" on the radiator.

[blake918]

I'd just toss it out--that's what I did when mine broke (one of the screws fell out of my undercover while traveling down I55, and a good portion of the cover was actually ground off, so it went in the trash can!). Throwing that cover away was the best thing I've ever done! The bottom side of the engine is just as clean as it was before, oil changes are a cake walk, and my fuel mileage hasn't changed either, so I'm very happy!

[LScott400]

Part of the purpose is noise suppression.

[flanker271]

Been driving mine without the cover for over 5 years now. The cover slightly improves the aerodynamic efficiency underneath the car, which ultimately lessens the wind noise. And yes, my cover mysteriously disappeared after an oil change.

[Canopy]

Thanks to all who responded, especially VBDenny. All of your comments were taken into consideration, but after crawling under the car and snipping off the dangling chad "The Decider" in my family suggested that I didn't want to ruin a perfectly good LS400 by letting all that dust filter up, cover the engine, and get in the electrical parts.

So I, being a man who's been married for 31 years and knows when to pick my battles, ordered one from IronToad for $99.64 plus $11.98 shipping and expect it to arrive in a couple days.

Now, if I play my cards right, maybe I can get her to crawl under the car again and remove what remains of the old one and bolt on the new one with larger washers.

[anthonyiez]

for that price i can't see why you were debating.

believe me, if they weren't needed lexus wouldn't put them on. imagine a piece of debris coming up at just the right angle to pierce something important.

[blake918]

believe me, if they weren't needed lexus wouldn't put them on. imagine a piece of debris coming up at just the right angle to pierce something important.

They aren't needed; it's not a life or death item. The increase in aerodynamics must be extremely minor because my car consumes no more gas and is equally as noisey as it was with the undercover in place. There are plenty of quiet, smooth running cars that do not have these undercovers. To me, it's like those oil addatives--if they were that wonderful, everyone would use them. :whistles:

That undercover isn't going to protect the car from anything serious. If the piece of debris is big enough to punch holes in heavy duty, metal engine componets, then a dinky little piece of plastic isn't going to help much if any at all.

Canopy where did yours break? I think the first bolt or two on the pass side of mine fell out while traveling down the interstate, and as the cover got ground on the pavement, more of the bolts were ripped out.

I look back on the day when I tossed that piece of garbage in the trash can with great fondness! :D

[Canopy]

It tore away from the first two bolts on the driver's side. I believe larger washers will help keep it on. Maybe I can even figure out how to put a metal strip across the front bolted next to the plastic. My guess is that the stress is greater at the corners on the front, either driver's or passenger's side. The part arrived from IronToad in two days, so just need to take the time and make the effort to put it on. Thanks all for the comments.

[Shareque]

Hey Canopy, by now you have had some 6 months with the Iron Toad shroud. What do you think about it? Satisfied? I'm facing the same decision.

Sharky

[qha_vn]

mine has gone too before i started being the owner.

its cheap here (VN) to get the undercover made by a local bodyshop (of course made by metal, not plastic)

am just wondering if it is really beneficial to have the new undercover?? will it really reduce some road noise beside its known purpose of engine dust protection. anybody and prove it?

[LScott400]

am just wondering if it is really beneficial to have the new undercover??

My definition of really beneficial is replacing a bad tire when the steel cord is showing, so I'd have to say probably not.

will it really reduce some road noise beside its known purpose of engine dust protection.anybody and prove it?

Well, I know having a wall between my rooms reduces my kids' noises. However, a metal undercover is unlikely to have the same sound dampening effect as plastic. As far as proving it, I guess you'd have to put one on to tell. I bet if you remove your hood blanket you'll hear more noise. :)

[SKperformance]

I would repair it and put it back .

It has a lot to do with cooling the engine , aerodynamics noise suppression and protection of engine components. also reducing strange animals from finding a warm home.

[dcfish]

I would repair it and put it back .

It has a lot to do with cooling the engine , aerodynamics noise suppression and protection of engine components. also reducing strange animals from finding a warm home.

I would replace it. Like everything on a lex, It is there for a ( many ) reasons.

[nc211]

I would definelty replace it. One good rock shot on a cooling hose, vacuum hose, etc.... could really cause some problems. Plus, it keeps the crap from getting tangled up in your belts, connectors, alternator, coolant hose, etc.... Personally I would be more concerned about the protection aspects it offers than the noise aspects. Think about all the sticks that thing has blocked from getting tangled up in your engine bay, or accidental road kill guts, water, dirt chunks, broken glass, rocks, anything and everything you encounter on the roads....etc....

[tofu]

mine has gone too before i started being the owner.

its cheap here (VN) to get the undercover made by a local bodyshop (of course made by metal, not plastic)

am just wondering if it is really beneficial to have the new undercover?? will it really reduce some road noise beside its known purpose of engine dust protection. anybody and prove it?

gha_vn, you probably hear more noise if it is made by metal because with all the rocks and debris on the roads in VN ...

[wrpsuite]

I was noticing my hood bouncing a bit while at high speen and upon investigation the plastic shroud is missing. I'm going to get one right away. Anyone haveonelaying around or a line on a junk yard with one? thanks

mine has gone too before i started being the owner.

its cheap here (VN) to get the undercover made by a local bodyshop (of course made by metal, not plastic)

am just wondering if it is really beneficial to have the new undercover?? will it really reduce some road noise beside its known purpose of engine dust protection. anybody and prove it?

gha_vn, you probably hear more noise if it is made by metal because with all the rocks and debris on the roads in VN ...

[pishta]

I was noticing my hood bouncing a bit while at high speen and upon investigation the plastic shroud is missing. I'm going to get one right away. Anyone haveonelaying around or a line on a junk yard with one? thanks

I would replace it, with a yard piece, or a sheet aluminum resto-mod. It't there for a number of reasons, I would imagine the updraft from the under side would ruffle the hood along with weak hood struts, cooling and it also has to do with aerodynamics and noise supression. any time a void is at a right angle to a wind stream, youll get buffeting and noise, roll down your window at speed and hear the difference. the new Benz C class has a "bottom as aerodynamic as the top" that is for a reason(s).

[Canopy]

Hey Canopy, by now you have had some 6 months with the Iron Toad shroud. What do you think about it? Satisfied? I'm facing the same decision.

Sharky

It's been over a year now that it's been replaced. No problems, just like brand new. And I feel better about having fixed it.

[Alfalfa]

I would think that thoes of you that replaced the plastic one with metal, if you would coat it with Line-X like they spray into pickup beds it would go a long ways for wear and sound deading.

I think the sheild goes a long way to help your engine look like this. But that's only me, I want everything to look good, even where you can not see it. By the way, I have fixed the rear engine compartment seal since the picture was taken.