C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Brown Sludge In Cooling System?

Thread Tools
 
Search this Thread
 
Old Jun 28, 2003 | 09:50 PM
  #1  
Atok's Avatar
Atok
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Default Brown Sludge In Cooling System?

While changing my coolant today I noticed I have about an inch of brown slimy sludge in the bottom of my surge tank up by the firewall. What causes this crap to build up? I'm wondering how much is stuck in the radiator passages. I can remove the surge tank easy enough and clean it out but what about the radiator? The car runs around 188 while crusing so it's not like it's causing me any problem right now.

Thanks
:steering:
Reply
Old Jun 28, 2003 | 10:08 PM
  #2  
plumb95's Avatar
plumb95
Advanced
 
Joined: Jun 2001
Posts: 89
Likes: 0
From: Oak Lawn IL
Default Re: Brown Sludge In Cooling System? (Atok)

I had this same problem when I first bought my car (used). I was a nervous wreck thinking that I had oil mixed in with my antifreeze....I flushed the system and I took the surge tank out, cleaned it out good and replaced it...Never had that brown sludge problem again....I have no idea what it was, but it scared the crap out of me.
Reply
Old Jun 28, 2003 | 10:09 PM
  #3  
Southern Comfort's Avatar
Southern Comfort
Le Mans Master
 
Joined: May 2003
Posts: 5,203
Likes: 0
From: Las Vegas Nevada
Default Re: Brown Sludge In Cooling System? (plumb95)

flush flush flush flush flush.......and flush again. Cured my sludge problem.
Reply
Old Jun 28, 2003 | 11:07 PM
  #4  
STL94LT1's Avatar
STL94LT1
Race Director
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
Default Re: Brown Sludge In Cooling System? (Atok)

While changing my coolant today I noticed I have about an inch of brown slimy sludge in the bottom of my surge tank up by the firewall. What causes this crap to build up?
It could be from those factory sealant pellets.
Reply
Old Jun 28, 2003 | 11:25 PM
  #5  
Rich B.'s Avatar
Rich B.
Melting Slicks
20 Year Member
 
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Default Re: Brown Sludge In Cooling System? (STL94LT1)

It could be from those factory sealant pellets.
That's exactly what it is. GM recommends the pellets for iron blocks with aluminum heads. Without them, the heads will "weep" coolant.

I did the same cleaning and flushing last Summer. this Winter, in very cold weather (15*F), the heads leaked about a shotglassfull each night the temp dipped. Starting the car up, there was no leak.

A fellow Forum member finally answered my post by listing the URL of the GM Tech Bulletin of the sealant pellets, and a lively discussion of aftermarket sealants followed.
http://forums.corvetteforum.com/zerothread?id=509456

Your GM dealer should have the pellets. They cured my weepage problem. And yes, the slime in the plastic bottle is unavoidable.


[Modified by Rich B., 11:34 PM 6/28/2003]


[Modified by Rich B., 11:34 PM 6/28/2003]
Reply
Old Jun 28, 2003 | 11:36 PM
  #6  
STL94LT1's Avatar
STL94LT1
Race Director
20 Year Member
Conversation Starter
All Eyes On Me
Liked
 
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
Default Re: Brown Sludge In Cooling System? (Rich B.)

Rich B, GM must have solved this problem on their new generation small blocks. I work at a GM truck plant, and we no longer use these pellets.
Reply
Old Jun 29, 2003 | 07:58 AM
  #7  
Rich B.'s Avatar
Rich B.
Melting Slicks
20 Year Member
 
Joined: Aug 2001
Posts: 2,516
Likes: 0
From: Lockport NY
Default Re: Brown Sludge In Cooling System? (STL94LT1)

Rich B, GM must have solved this problem on their new generation small blocks. I work at a GM truck plant, and we no longer use these pellets.
I was skeptical at first, too. When I read the TB (it's also available on-line), I figured "why not". It's worked so far.

I imagine the engineers and technicians finally got the head gasket problems figured out. I'm guessing that the pellets are a GM "band-aid" so that new gaskets didn't have to be installed (or they weren't available yet).

I live near the Tonawanda Engine Plant. There's a lot of funny stories about the plant, the workers, and the parts they made during the '60's & '70's (back when that plant made sbc's and bbc's). One of my longtime friends (he runs that "street sign" concession at Carlisle) ran a speed shop in Niagara Falls during the '60's & '70's; lots of funny stuff about GM/Chevy engine parts making their way *directly* to the street... :D
Reply

Get notified of new replies

To Brown Sludge In Cooling System?





All times are GMT -4. The time now is 09:47 AM.

story-0
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-1
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-2
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-3
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-4
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-5
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-6
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-7
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-8
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-9
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE