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Despite all the work I have done on my car, till recently I had never changed the oil or removed the engine undertray myself!
So after 18 years (due to looking closely for signs of a leaking compressor) I thought I better have a closer look at the tray and save some dollars and change the oil myself.
Normal for a car of this age (unless you have been extremely careful, which I now am lol) to have some cracks or scrapes in the tray in a few places. What I didn't expect is so much crud in the tray! I wouldn't have expected the (few) mechanics that have had to remove the tray over the years to clean the tray but they could've given it a wipe here or there.
The cracks I had to repair were probably caused by me scraping over a gutter or two over the years but the front bumper undertray rip I know the panel beaters apprentice caused along with large rips he inflicted on the front two plastic inner wheel arches as well... Lack of training there and they were very difficult to glue back together but fortunately they have kept glued for some time now.
The STR engine undertray has more cooling vents and due to this is missing the second noise insulation pad of the regular cars. Also my x202 STR does not have the transmission undertray; other than catch a bit of leaking transmission oil, not sure what that tray is useful for?
The engine tray does also have a NASA style vent. This directs air to another vent to cool the alternator; a smart idea.
The factory plastic covered foam insulation pad does touch the crossmember rail and over the years its plastic coating had deteriorated. I decided to cut a bit of firewall insulation material which is largely impervious to oil etc and use this as a more permanent insulation replacement. To keep it in place I fabricated four round shape rubber washers from some truck tyre tube. I punched a 7mm hole in the middle of each washer and these held the new insulation in place very well.
Also had some angled aluminium, some very small SS counter sunk bolts, 4 small brass washers and 4 nuts which were all placed around the cracks.
The factory screws, nuts and bolts that hold the engine undertray in place were all wrong as well - the workshops over the years would have mixed all these up. Ripped front bumper undertray that was Flapping around 18 years worth of different leaking oils, road grime and soil. Evidence on the right of leaking compressor oil (green dye). Red liquid is when I did not follow proper Workshop Manual procedure of draining the supercharger radiator properly through its drain plug; I let it pour out of the house.. NASA style duct that directs air to a vent that cools the alternator. Closer look of insulation pad with evidence of where it presses on the crossmember and most of its protective plastic coating having perished. Bottom view before cleaning both sides which wasn't much fun. I scaped off about a kilo of crud! Cleaned tray with secured firewall material ILO factory foam pad. Reinforcement repair shown which stopped tray bending and cracking further. Bit of right angle aluminium cut to size. Another reinforcement repair on other side. The other side only needed 3 bolts to hold it in place. Similar repair on the front bumper undertray, which had to hold the factory washer.
I don't like rivets, hate drilling them off..
I like riv-nuts though!
Aarcuda, I gathered yours was missing entirely? You manage to get an STR tray? Early or later style, as I thing there were two types?
The rivets are a permanent solution to marry 2 sections of broken material, plus they are aluminum so not prone to rusting and the hope is the repaired area is permanent.
As far as the "attachment points" of the under tray to the vehicle, of course threaded bolts are a necessity.
I don't like rivets, hate drilling them off..
I like riv-nuts though!
Aarcuda, I gathered yours was missing entirely? You manage to get an STR tray? Early or later style, as I thing there were two types?
yes when I got my car it was missing the Belly pan and a wheel liner and the top radiator plastic cover. And mine is a 2006 STR so it wasn’t easy to find the right belly pan. I ended up finding one from England and sure enough they packaged it up w some cardboard boxes taped together it shipped to the states and I got it in the same condition they sent it in. So yes it’s the later model style. But the front connection points which connected to the front pan under the radiator was ripped out for two of the hose. So I patched in a small cut strips of aluminum that I had and riveted it into place so that I could slide the speed nuts over it and have it hold on I think there was maybe some mushed up parts near the back as well but It fixed up nicely and was pretty clean when I got it. Think I paid 100 bucks for it
For some reason I can’t find a picture of the pan I bought bought!
I couldn’t find an affordable top radiator cover for an STR so I bought one four a different engine and then had to cut out this section here for the radiator Reservoir tank
$100 for the pan is a fair price, you did okay. They can repair quite well.
Didn't realise there were differences in the radiator covers. You did a good job to modify the one you have to fit.
I can't tell too well from your photos if what you have has a similar lip. It may not be too important to you but I have attached a couple of photos of my radiator cover which shows a downward protruding lip. Not very clear in these photos but it does protrude down a fair way into the grille opening.
It looks like it's designed to direct some of the cool air entering from the grill opening in an upward direction onto the engine air intake directly above rather than allowing the air intake to suck in hot engine bay air. May be worth a few more horses?
Lip protrudes about a 1/4 of the way down.
This downward lip directs cool air from the grille entry to the intake above.
Aluminum and pop rivets cured my S Type R issues, as well. For future reference to those also experiencing trim panel or undertray tear issues. In all likelihood, these black/grey panels are made of polypropylene, the most commonly used plastic material in recent autos. Often you'll find molded into the panel a code or initials like "PP" "PPO" "TPO" etc. Sometimes you can make repairs using specialized adhesives obtainable from auto body supply stores. A lasting repair is most likely on thicker panels. For a lasting repair that offers original panel strength and flexibility, visit one of your local collision repair shops and ask if they can perform nitrogen plastic welding. It's a quick and very solid repair. It may save you considerable $ outlay versus purchasing a new or good quality used panel which may be hard to find. This applies to all current vehicles which primarily use polypropylene, plus ABS, nylon, polycarbonate (lenses) and other hybrid plastics in their build systems.
Bob in KC
Past S type R owner and collision equipment specialist
Is it not possible to buy new factory noise insulation pads to attach to the undertray? I have been searching for those with not luck. I am considering going with the firewall material fix you used.
02-03-2021, 02:57 AM
Engine Undertray repair
, : icon_bowrofl:, : icon_banana:.
