Occasionally, my batter light will come on while driving. Someone here suggested that the squeeze clamp on the radiator hose might be loose, causing a leak, which causes the fan belt to temporarily slip. I did notice that the coolant level in my overlow resoirvoir was low. I removed the cap and noticed the radiator somewhat low. Most noticible was red sludge around the radiator cap opening. The vehicle is five years old. No oil consumption. Is this sludge just degraded Dexcool? Should I do a radiator flush, and if so, should I replace it with glycol coolant? recommendations please.
Radiator sludge, 2005 Iimpala?
- Thread starter otis24
- Start date
- Status
What engine? 3.4 or 3.8?
Five years is the MAXIMUM for Dexcool in any engine. You should do a fresh water flush and fill as soon as possible.
IMO most of the Dexcool issues are a result of poor or lack of maintenance. I don't believe any coolant should be in an engine for more than 2 years at the very most.
I have used Dexcool for the past 10 plus years without issue.
IMO most of the Dexcool issues are a result of poor or lack of maintenance. I don't believe any coolant should be in an engine for more than 2 years at the very most.
I have used Dexcool for the past 10 plus years without issue.
You have sludge and the cause. Need to resolve both. Whether you stay with DexCool is your choice. Your basic alternatives are Peak Global or G-05. If you think you have a leaking hose clamp, replace it, as its cheap. Replace the radiator cap also.
If you have one of the GM engines that has an intake gasket that degrades with DexCool, that gasket needs to be replaced. Then choose your replacement antifreeze.
If you have one of the GM engines that has an intake gasket that degrades with DexCool, that gasket needs to be replaced. Then choose your replacement antifreeze.
I haved the 3.4 engine. The previous owner purchased it new in January of 2005. I purchased it in Dec 2010. With only 23333 miles, I'm sure that the previous owner saw no need to change anti-freeze because of the "low miles".
It is my understanding that the 3400 engines in the 2005 year model were not prone to the gasket failures.
I'll do a flush and replace the anti-freeze, the clamp and the radiator cap.
It is my understanding that the 3400 engines in the 2005 year model were not prone to the gasket failures.
I'll do a flush and replace the anti-freeze, the clamp and the radiator cap.
Why not replace the hose(s) too, while you're at it. Good Luck.
Originally Posted By: otis24
I haved the 3.4 engine. The previous owner purchased it new in January of 2005. I purchased it in Dec 2010. With only 23333 miles, I'm sure that the previous owner saw no need to change anti-freeze because of the "low miles".
It is my understanding that the 3400 engines in the 2005 year model were not prone to the gasket failures.
I'll do a flush and replace the anti-freeze, the clamp and the radiator cap.
I would use Peak Global and distilled water after a really good flush.
I haved the 3.4 engine. The previous owner purchased it new in January of 2005. I purchased it in Dec 2010. With only 23333 miles, I'm sure that the previous owner saw no need to change anti-freeze because of the "low miles".
It is my understanding that the 3400 engines in the 2005 year model were not prone to the gasket failures.
I'll do a flush and replace the anti-freeze, the clamp and the radiator cap.
I would use Peak Global and distilled water after a really good flush.
What is different about Peak Global?
Bbut Dexcool doesn't form sludge! Must be your imagination... just like tens of thousands of other GM owners' imaginations.
Seriously though, all of the later-vintage 3400 engines have the intake gasket problem. GM came out with some 'improved' gaskets around 2004- but they're still plastic and they still fail. In any 3100 or 3400 GM engine made after roughly 1994 (when GM started using the plastic gaskets), lower intake manifold gasket failure is not a question of 'if'. It's a question of 'when'. FelPro has come out with an improved gasket that actually fixes the problem.
About coolants- Dexcool will form sludge if it gets old and putrid... particularly if the cooling system is leaky, lets air get in, is overheated, or is run low. Vehicles with a non-pressurized coolant overflow tank are the most vulnerable to the problem, and I personally wouldn't put Dexcool back in unless it's a system with a pressurized coolant reservoir. I've run G05 in my '01 Lumina (with a 3100) for about 6 years with no issues, and that would be my replacement of choice. But Peak Global Lifetime is reputedly another good choice for replacing Dexcool. It uses the same OAT inhibitor as G05 (sodium benzoate), but without the silicate. Whereas Dexcool used 2-ethylhexanoic acid... which is proven to deteriorate certain gasket materials.
FYI, most of the "all-makes" coolants out there (with the exception of Peak Global Lifetime) use the same OAT inhibitor as Dexcool... and I wouldn't consider them an improvement, IMO.
Seriously though, all of the later-vintage 3400 engines have the intake gasket problem. GM came out with some 'improved' gaskets around 2004- but they're still plastic and they still fail. In any 3100 or 3400 GM engine made after roughly 1994 (when GM started using the plastic gaskets), lower intake manifold gasket failure is not a question of 'if'. It's a question of 'when'. FelPro has come out with an improved gasket that actually fixes the problem.
About coolants- Dexcool will form sludge if it gets old and putrid... particularly if the cooling system is leaky, lets air get in, is overheated, or is run low. Vehicles with a non-pressurized coolant overflow tank are the most vulnerable to the problem, and I personally wouldn't put Dexcool back in unless it's a system with a pressurized coolant reservoir. I've run G05 in my '01 Lumina (with a 3100) for about 6 years with no issues, and that would be my replacement of choice. But Peak Global Lifetime is reputedly another good choice for replacing Dexcool. It uses the same OAT inhibitor as G05 (sodium benzoate), but without the silicate. Whereas Dexcool used 2-ethylhexanoic acid... which is proven to deteriorate certain gasket materials.
FYI, most of the "all-makes" coolants out there (with the exception of Peak Global Lifetime) use the same OAT inhibitor as Dexcool... and I wouldn't consider them an improvement, IMO.
I don't trust Dexcool in this radiator cap on the radiator application, especially not any Dexcool that aren't GM/Chevron formula but even it can have some sludge problems on this application if the coolant level is not always completely full.
What I would recommend is to replace the cap with a spring center Stant 10230/11230. These do a better job of keeping coolant in the radiator from the overflow bottle than does the original style drop-center cap. Switch the coolant over to either Peak Global Lifetime or G-05. I would say go with Peak Global, as it is most similar to Dexcool being an OAT but is a benzoate OAT that is not known to have as much issues with air as Dexcool. Keep your radiator full and your overflow bottle at above the Full cold mark.
What I would recommend is to replace the cap with a spring center Stant 10230/11230. These do a better job of keeping coolant in the radiator from the overflow bottle than does the original style drop-center cap. Switch the coolant over to either Peak Global Lifetime or G-05. I would say go with Peak Global, as it is most similar to Dexcool being an OAT but is a benzoate OAT that is not known to have as much issues with air as Dexcool. Keep your radiator full and your overflow bottle at above the Full cold mark.
Originally Posted By: onion
Bbut Dexcool doesn't form sludge! Must be your imagination... just like tens of thousands of other GM owners' imaginations.
Seriously though, all of the later-vintage 3400 engines have the intake gasket problem. GM came out with some 'improved' gaskets around 2004- but they're still plastic and they still fail. In any 3100 or 3400 GM engine made after roughly 1994 (when GM started using the plastic gaskets), lower intake manifold gasket failure is not a question of 'if'. It's a question of 'when'. FelPro has come out with an improved gasket that actually fixes the problem.
About coolants- Dexcool will form sludge if it gets old and putrid... particularly if the cooling system is leaky, lets air get in, is overheated, or is run low. Vehicles with a non-pressurized coolant overflow tank are the most vulnerable to the problem, and I personally wouldn't put Dexcool back in unless it's a system with a pressurized coolant reservoir. I've run G05 in my '01 Lumina (with a 3100) for about 6 years with no issues, and that would be my replacement of choice. But Peak Global Lifetime is reputedly another good choice for replacing Dexcool. It uses the same OAT inhibitor as G05 (sodium benzoate), but without the silicate. Whereas Dexcool used 2-ethylhexanoic acid... which is proven to deteriorate certain gasket materials.
FYI, most of the "all-makes" coolants out there (with the exception of Peak Global Lifetime) use the same OAT inhibitor as Dexcool... and I wouldn't consider them an improvement, IMO.
What are your thoughts on using regular conventional green coolant?
I may use it for the next change on my 02' Buick 3.1 (which had a FelPro problem solver i-m gasket installed at approx. 80K).
I change the a/f every couple of years so the regular coolant should be fine, I think?
Bbut Dexcool doesn't form sludge! Must be your imagination... just like tens of thousands of other GM owners' imaginations.
Seriously though, all of the later-vintage 3400 engines have the intake gasket problem. GM came out with some 'improved' gaskets around 2004- but they're still plastic and they still fail. In any 3100 or 3400 GM engine made after roughly 1994 (when GM started using the plastic gaskets), lower intake manifold gasket failure is not a question of 'if'. It's a question of 'when'. FelPro has come out with an improved gasket that actually fixes the problem.
About coolants- Dexcool will form sludge if it gets old and putrid... particularly if the cooling system is leaky, lets air get in, is overheated, or is run low. Vehicles with a non-pressurized coolant overflow tank are the most vulnerable to the problem, and I personally wouldn't put Dexcool back in unless it's a system with a pressurized coolant reservoir. I've run G05 in my '01 Lumina (with a 3100) for about 6 years with no issues, and that would be my replacement of choice. But Peak Global Lifetime is reputedly another good choice for replacing Dexcool. It uses the same OAT inhibitor as G05 (sodium benzoate), but without the silicate. Whereas Dexcool used 2-ethylhexanoic acid... which is proven to deteriorate certain gasket materials.
FYI, most of the "all-makes" coolants out there (with the exception of Peak Global Lifetime) use the same OAT inhibitor as Dexcool... and I wouldn't consider them an improvement, IMO.
What are your thoughts on using regular conventional green coolant?
I may use it for the next change on my 02' Buick 3.1 (which had a FelPro problem solver i-m gasket installed at approx. 80K).
I change the a/f every couple of years so the regular coolant should be fine, I think?
I'll give you my thoughts on Green for the '02 3.1 that has the problem Felpro problem solver gaskets. Green works good but only for about 2 years (although some like Zerex claim longer, I think this is mostly marketing). If you run it much longer or too long without changing, it can cause a lot of problems especially with aluminum. It has silicates and borates and a high pH optimized for iron protection. Once the silicate deplete the borates can attack the aluminum. G-05 has silicates and borates but a lower pH and a longer service life probably due to the benzoates. Of the two might as well go with G-05 and get the longer service life.
Peak Global sounds like a better replacement for Dexcool. It is an OAT and more similar to Dexcool but doesn't use 2EHA (uses benzoate like G-05), doesn't have the borates or silicates and has a long service life. All these coolants, Green, G-05, Peak Global and Dexcool are D3306 and would work but it's the fine details that makes Peak Global then G-05 the most sensible replacement in your application.
Peak Global sounds like a better replacement for Dexcool. It is an OAT and more similar to Dexcool but doesn't use 2EHA (uses benzoate like G-05), doesn't have the borates or silicates and has a long service life. All these coolants, Green, G-05, Peak Global and Dexcool are D3306 and would work but it's the fine details that makes Peak Global then G-05 the most sensible replacement in your application.
Last edited:
See my pics in this thread. I don't think coolant ever degrades into sludge, but oil getting in the coolant does. Is it greasy poopy looking sludge? If so I bet you have or will have IM gasket problems. I've seen it on 4 out of 4 3.1L GM engines from 2001-2003. I'm no expert but I doubt GM "fixed" anything throughout the life of these engines. Sure poor maintenance might be a factor, but tons of cars have less problems on 10 year old coolant.
http://www.bobistheoilguy.com/forums/ubb...rue#Post2145370
FWIW I don't think toyota "fixed" sludge engines either until they went to the 3.3L or even the 3.5L V6.
IMO I can rag on GM IM gaskets and Toyota sludge engines b/c I own both
http://www.bobistheoilguy.com/forums/ubb...rue#Post2145370
FWIW I don't think toyota "fixed" sludge engines either until they went to the 3.3L or even the 3.5L V6.
IMO I can rag on GM IM gaskets and Toyota sludge engines b/c I own both
- Status
Similar threads
