Whats causing Freeze plugs to deteriorate internally????
07-23-2021, 10:16 AM
#21
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What is causing my freeze plugs in my heads to deteriorate internally that they will start to leak coolant? First was my front pass side head a few years ago and now something is leaking again and it may be the driver rear head freeze plug as its dripping onto the exhaust. When I took off the the front freeze plug off of the passenger head, the inside looked like it was deteriorating slowly over time. Well something slowly ate the metal away and it finally starting leaking. The car had dexcool but since the leaks I've just been putting in distilled water. Is dexcool that bad to deteriorate metal? I thought even distilled water is ok to run as it has no inpurities that are bad. Now what sux is I may have to replace all the freeze plugs to eliminate any more issues. But I need to fix what is eating up the freeze pluge first or it may happen again over time. I am the second owner for about 10 years and do my own maintenance on the 99 ws6 and it only has 85000 miles on it.
07-23-2021, 10:38 AM
#22
TECH Senior Member
Dexcool is run in thousands of iron block LS engines all the time with no issue. They come from the factory with it.
I have a Tahoe with 190k miles on it, running Dexcool all its life with no leaks.
You have other issues.
I have a Tahoe with 190k miles on it, running Dexcool all its life with no leaks.
You have other issues.
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01CamaroSSTx (07-23-2021)
07-23-2021, 11:10 AM
#23
^^^ This ^^^
Dex will leak in a traditional small block. It goes right through the paper type of gaskets. (guess how I know this) It's completely fine in LS motors though, which were designed for it.
Usual reason for corrosion in / around engines is electrolysis. Dissimilar metals create a battery. The least electronegative element gets eaten; usually that's aluminum. Anybody with a boat has probably run into this, especially if it has any stainless steel on the outside. Usually it's not the iron or steel. Probably not the issue here although it may be a factor in the big picture.
I don't think a zinc will help this, although it certainly can't hurt either. In fact, the reason those "krome" water necks ALWAYS develop leaks, is BECAUSE they are a zinc alloy: they actually PROTECT aluminum engine parts by sacrificially eroding. Nobody seems to know that, but it's true. Which is what the radiator cap anode, or the zinc anodes you put on boat outdrives and such, will do to keep aluminum engine parts from corroding.
More likely though, the freeze plug problem is something else. Most likely it's acid in the system; tap water would be my guess as the source.
I have a LM7 with just at a quarter-million miles on it. Dex-Cool and distilled water for as long as I've had it, which is 11 years and starting around 60k or so. No problems.
Dex will leak in a traditional small block. It goes right through the paper type of gaskets. (guess how I know this) It's completely fine in LS motors though, which were designed for it.
Usual reason for corrosion in / around engines is electrolysis. Dissimilar metals create a battery. The least electronegative element gets eaten; usually that's aluminum. Anybody with a boat has probably run into this, especially if it has any stainless steel on the outside. Usually it's not the iron or steel. Probably not the issue here although it may be a factor in the big picture.
I don't think a zinc will help this, although it certainly can't hurt either. In fact, the reason those "krome" water necks ALWAYS develop leaks, is BECAUSE they are a zinc alloy: they actually PROTECT aluminum engine parts by sacrificially eroding. Nobody seems to know that, but it's true. Which is what the radiator cap anode, or the zinc anodes you put on boat outdrives and such, will do to keep aluminum engine parts from corroding.
More likely though, the freeze plug problem is something else. Most likely it's acid in the system; tap water would be my guess as the source.
I have a LM7 with just at a quarter-million miles on it. Dex-Cool and distilled water for as long as I've had it, which is 11 years and starting around 60k or so. No problems.
The following 2 users liked this post by RB04Av:
01CamaroSSTx (07-23-2021), G Atsma (07-23-2021)
