Boomer111

Mine has started to rip along the seam were the 2 different materials are mated.

Anyone know the replacement cost for the part and what is involved in replacing.

I did a search but did not find my answers.

This is the cause of the well known buzzing.

thanks

Johns67

The lower cowl on my 08 had done the same, it had split where the rubber is vulcanized to the vinyl/plastic and I would get an annoying buzz sound at freeway speeds over 65mph.

I replaced mine and it was easier than I expected, just taking it slow and cleaning the dust from the cowl area it took a little over an hour.

I ordered the lower cowl from the local dealer arrived in 3 days price
$85.00.

I took these pictures during the process.

Part number and new cowl.
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Use some tape on the windshield to mark the wiper arm locations so you can put them back on the way they came of the posts.

Pry of the caps on the wiper arms and remove the wiper arm retaining nut.



Remove screws retaining the plastic trim pieces.

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The next thing to do is to pull off the thick piece of weather stripping that is just pushed over the lip of the cowl.

You will see 4 or 5 spring steel clips that you need to gently pry off careful to hold a rag or something behind them as they can pop off and are easy to lose.

The weather strip and clips are on the fiberglass lip shown in the photo below.



Now just pull off the cowl and reverse the process.

Watch that when you put the new cowl on that the rubber portion of the cowl lip does not get turned under on the passenger side.

Also you need to pull the washer hoses of to remove the cowl.

Hope this helps didn't take pics of everything.

Boomer111

Thanks much you answered all my questions.

What is the part number? I am little confused looking at the packing slip.

Johns67

You can see it on the part label about half way down GM# 25778761 thats is the P/N.

Boomer111

Thanks again.

RogerRamjet21

Hey, I'm about to do this to my 08. Any chance you can resurrect your photos to help me out?

Edit: I see you did this in 2012 for $85.00. I'm happy to say I just bought the part today for $89.00 from the local Chevy dealer. Has to be the least increase in cost of a car part in history...

RogerRamjet21

Did you do the replacement for the Cowl? Johns67 posted photos, but they no longer show and I want to know what to look out for as I'm going to do this on the weekend (found the part at the local dealer). Looks like the clips John mentioned have to be transferred to the new part as the new part doesn't seem to have them. Anything else you can remember about doing it? Use anything extra when installing the new part (lube, sealant, etc.)?
Thanks!

RogerRamjet21

Did this swap on Saturday and it was pretty straight forward. Got tips from both Johns67 and Boomer111 (thanks guys!) which certainly helped. Even though I had a puller, it was not deep enough for the wipers (go figure). The drivers side wiper came off by just wiggling a bit, but the passenger side decided to be a bit more of a pain. I shot it some WD40 and let it sit for 15 minutes and then it wiggled off as well. Even though I marked their positions on the windshield with tape, putting them back on in the same position was the most difficult task of the whole process though after some minor adjustments, I got them there. Anyway, annoying buzzing gone! Mine was split where the rubber seal meets the plastic part for about 3 inches right at the point on the passenger side where it starts to wrap around to the passenger door and it was getting progressively more annoying. At first, it only buzzed if it was a cooler morning and above about 65 mph. At the end, it was buzzing in all temperatures at 50 or above. There were no sealants or adhesives under the old cowling and I used none during the install of the new one. I figure if the original lasted 10 years without any, this one will last until well after I've sold it.

BTW, I paid $89.00 plus tax at my local Chevy dealer for the new part which they had in stock.

If anyone else is looking at doing this and decides to buy a puller first, don't buy this one ( ). It's great for battery terminals and I'm sure for some vehicles it's great for wiper arms, but not ours.

Boomer111

I assume all 5 clips where in working order?

The sealant around the clips where they contact the glass was not done at the factory and GM made it a TSB upgrade.

I agree dealing with the wipers is the most trying part.

Hopefully you get another decade out of it.

RogerRamjet21

Yeah, I read the TSB and it seemed to be for cowlings that were exhibiting issues. I figure a new item won't have any and mine is fine (at least to 95mph). All the clips were fine and I had no trouble other than not having the right puller on hand. As for the wipers, if I had it to do over, I would mark the stud they sit on and the wiper instead of the windshield.
Thanks for your tips!