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 10:35 PM.

story-0
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-1
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
story-2
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE
story-3
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-4
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE
story-5
10 Things C8 Corvette Owners Hate (But Won't Tell You)

Slideshow: 10 things C8 Corvette owners hate, but won't tell you.

By Joe Kucinski | 2026-04-01 18:36:07


VIEW MORE
story-6
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

Slideshow: Should you add one of these incredible Corvettes to your garage?

By Brett Foote | 2026-04-01 18:14:05


VIEW MORE
story-7
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

Slideshow: Every Corvette Grand Sport explained

By Joe Kucinski | 2026-03-26 07:13:44


VIEW MORE
story-8
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!

Slideshow: Breaking down the 2027 Grand Sport, Grand Sport X, Stingray, and LS6 V8.

By Michael S. Palmer | 2026-03-26 13:48:45


VIEW MORE
story-9
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!

Slideshow: 5 reasons bad drivers crash sports cars & 5 ways to avoid a costly shame!

By Joe Kucinski | 2026-03-25 16:32:55


VIEW MORE