05 Silverado pure water in reservoir

[IH784]

Good evening,

 

I added about quart of water to my reservoir three months ago. Today, my reservoir was about half to 3/4 a quart low. This time I used 50/50ish mix of the dex stuff. Would the pure water have cooked off that much quicker? How likely is it I’ve got a bad cap? I’m aware of the castech heads in this model. Just curious what y’all’s thoughts are with losing pure water, an almost 20 year old cap and some pretty extreme heat this summer. 
 

edit:210k. 

Edited August 5, 2023 by IH784

[CamGTP]

That water would have mixed with the coolant, so it really didn't matter that it was just water only.

 

Possible that some of the coolant evaporated or it was ingested into the engine, it's tough to say. A new cap is maybe $20, so it's worth a shot to replace it.

[IH784]

Absolutely. I wasn’t sure if diluting the mixture more would’ve made it more susceptible to evaporation. I just noticed the lower level when I changed my oil. No milky or hot chocolate looking oil. Oil was actually low by about a 1/2 a quart not fuller lol. I just ordered a cap. 

[dna9656]

On a V-8, 1 quart per 1,000 miles can be considered "Normal" oil consumption. ALL engines consume oil. When you hear some one say "it doesn't burn (use) any oil" the context is "it doesn't use/burn oil in excess of normal parameters". These are the unspoken parameters we are given by those that are "older and wiser" than we are. Yeah, not so wise as to knowing they are MIS-Speaking; they are making poorly constructed statements to the ignorant.

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[IH784]

I found a few drops of oil on the bottom of my oil filter. When I poured the used oil into my new oil container, I noticed how much didn’t go in as it normally does. 

[KARNUT]

11 hours ago, IH784 said:

Good evening,

 

I added about quart of water to my reservoir three months ago. Today, my reservoir was about half to 3/4 a quart low. This time I used 50/50ish mix of the dex stuff. Would the pure water have cooked off that much quicker? How likely is it I’ve got a bad cap? I’m aware of the castech heads in this model. Just curious what y’all’s thoughts are with losing pure water, an almost 20 year old cap and some pretty extreme heat this summer. 
 

edit:210k. 

My 02 avalanche did that exact thing when I bought it almost 4 years ago. My tank has a light that’s how I noticed. I run a 50-50 mix coolant. The second time about 6 months later I added bars leak and 3 years later still good. I never saw water in the oil although it did come out clumpy the beginning of the first drain. I check my oil more often and change it more frequently. My truck is my comfort vehicle that reminds my of the best run of trucks from 2000-2006. I had four in that time period. They’re like tanks you can’t hardly kill them. 

[64BAwagon]

If its a diesel its the LLY and I can all but guarantee the head gasket(s) are blown

[IH784]

38 minutes ago, KARNUT said:

My 02 avalanche did that exact thing when I bought it almost 4 years ago. My tank has a light that’s how I noticed. I run a 50-50 mix coolant. The second time about 6 months later I added bars leak and 3 years later still good. I never saw water in the oil although it did come out clumpy the beginning of the first drain. I check my oil more often and change it more frequently. My truck is my comfort vehicle that reminds my of the best run of trucks from 2000-2006. I had four in that time period. They’re like tanks you can’t hardly kill them. 

I am going to try Kseal and see what happens. I’ve got an old tractor that it worked out really well on. I know what the right fixes but it’s a 2005 with over 200,000 miles on it. I’m not sure that the juice is worth the squeeze.

[KARNUT]

6 minutes ago, IH784 said:

I am going to try Kseal and see what happens. I’ve got an old tractor that it worked out really well on. I know what the right fixes but it’s a 2005 with over 200,000 miles on it. I’m not sure that the juice is worth the squeeze.

I used bars leak because it’s the least radical for starters. If it didn’t work I’d go more intense. I watched my brother in law routinely put 300K miles on GM vehicles. His wife would run up to 150K then he use them. His first cylinder deactivation vehicle is now approaching 130K. I’m watching this one closely. Tahoe, suburban and two pickups were his preferred vehicles.

Edited August 5, 2023 by KARNUT

[thx1138v2]

Pure water sounds like a good idea but it's not because antifreeze has additives that give the mixture better adhesion to the metal in the water jacket and therefore better heat dissipation.

 

Here's a graph I put together that you might find helpful.

[IH784]

I had no clue. (Obviously). Not sure how much pressure my cooling system was holding because after I added “kseal” I started hearing pressure release from the reservoir after removing the cap. Thank you for the explanation!