Rusted block from tap water

Hi there I have 06 tacoma 4 cyl. Had the usual coolant loss from the plastic coolant bypass line and ended up putting tap water in the truck for a while (yes I know I'm already an idiot for doing this) eventually got to fixing the bypass after like 9 months. So was just refilling the car with tap water whenever I got low with whatever coolant I had left. Car lasted for about 9 months with no issues after fixing the coolant bypass line. Then I had intermittent overheating issues and coolant pressure test that failed so assumed head gasket. Took engine apart and this is what I found. All coolant jackets/passages are rust/sediment filled throughout the whole block. I've read on forums of people putting different sorts of acids in the block and letting it sit. But I really don't want to take the block out of the car to do this as I would assume that flushing this out with tap water would be a bad idea as it would most likely get into my oil pan even if I had a towel over it. I contacted a machine shop here in sacramento and this is what he said,
"
So your best bet is to strip it down and take it to Chem Strip. They have a chemical bath that will take care of the rust. Of course by doing this the block will have to be completely machined after. Also depending on the corrosion this might do even more damage as it could cause porosity in cylinder walls. I would only do this if there is something special about the block.

Otherwise get another block. "

The fact that he said this is a risk to have porosity on cylinder walls does not make me want to do this. I've read on some other forums of some that have had chunks like this and they removed the freeze plugs and scraped out as much as they could. Please let me know thoughts on what I should do based on the pictures. I really want to save this block as there is nothing wrong with it besides being clogged.

 

Dang them jackets are severely rust filled.

Years ago I helped someone prep his block to run alcohol. The goal was to fill the coolant passages with an epoxy since he wasn’t going to use coolant or a radiator. Apparently alcohol has a cooling affect so it isn’t needed. We used some sort of acid cleaner to get the calcium buildup out first. We were very careful to not get any cleaner in the cylinders or oil passages. Water hose ready to wash it off quickly if reeded. Of course his wasn’t close to what yours looked like but it came out looking like clean bare metal. I didn’t get to see the end result, shop closed down. This was in the 90s, slap a turbo on an import era.

If the chemical place plans to simply dunk the block in acid and give it back, I wouldn’t bother. Every gasket surface and the cylinder walls will be messed up. Acid isn’t going to cause porosity in the cylinder walls, but it will eat at it enough to require machining, most likely more than a hone would cure. Then upsized pistons and rings. Since it’s overheating due to the blockage you could try the acid cleaner yourself. Or go to a replacement junk yard engine.

 

You could probably pick up a used 4 banger for less hassle and probably still come out ahead on cost.

 

Just a thought.

Unless you visually saw that the passages were perfectly clear before your tap water coolant change I am not convinced that was the cause.

The fact that this could happen in 9 months time is a stretch for me to believe.

Still....that really sucks man sorry to hear

 

Wow, looks like a boat anchor thats been sitting on the bottom of the lake all summer.

Id think your first step would be to do some detailed cost estimating. The chemical strip vs finding a used engine. Either way sounds like its going to have to come out of the truck.

 

The problem isn’t that you used tap water. The problem is that you continued to run it with a leaking head gasket. I’m no chemist, but I think the exhaust gas in the coolant does something that causes the rust. The problem is compounded by running straight water.

The issue is going to be that rust flakes are going to plug up the radiator and heater core. I’m guessing that you used the temp gauge as a coolant dipstick and overheated it multiple times. I’d say the engine is done and you should put in a used engine.

 

Getting another engine is a no brainer. Yours is a 2006 with likely high mileage so not worth even fixing with it's current extensive internal issues.

 

Time for a new block. Trust what the machine shop said.

 

........ and you drink that water too?

 

Yuck. It is hard to believe all that built up in just 9 months. I suspect the cooling system had issues before your leaking bypass hose, or your tap water is extremely mineralized.
I also vote for a used engine. Will take a lot of time, money and work to get the existing one back into reliable condition... but if you have all that to spare then it's up to you.

 

Make sure to back flush your radiator and heater core when you are at it.

 

In the ole days we never heard of distilled water we always grab the garden hose.

 

I took a cylinder head to a machine shop and the machinist told me in his 30 years the best thing people should do is never ever let coolant stay in the block for more than 2 years and always use distilled water. Always use OEM or highest quality coolant you can. Prestone and Peak are junk. Pentosin or OEM which is typically used by German and Japanese mfgs. Extended life coolant is a joke he said. So I change my coolant every 2 years on my vehicles.

 

Well our bodies benefit from minerals in water, engines and their metallurgy do not.

 

It is very unlikely that "tap water" was the cause of your rusting. The reason that distilled water is used in cooling systems is that it has little to no minerals. Mineral deposits greatly impact heat transfer and can clog the coolant passages, especially in the radiator. Tap water and distilled water have similar impacts on rusting. In addition, if you used any antifreeze it most likely had some rust inhibitors mixed in. So, unless your tap is contaminated with either high levels of salt, or is very acidic the rust you see was probably not the result of tap water in the short time you noted

 

I bought an aluminum champion 3 core to replace a plastic single core. I thought all would be great, oops, made in China got me again. 9 months later it sprung a leak from a weld stop start spot. Lifetime warranty so they sent another. Another leaker 4 months later. They sent a third. That one cracked along the entire weld seam top to bottom. It was my only car so I kept driving it, filling with distilled water. It needed 1.5 gallon of water for every 10 minutes worth of driving. Lifetime warranty doesn’t cover your time an coolant. NEVER buy a champion radiator.

Distilled water does make a difference. A car I bought had some calcium inside the radiator so I drained it, flushed 3x with distilled water, then filled with coolant and distilled water. I looked a couple years later and it looked the same, no increase in calcium.

Changing coolant every 2 years won’t hurt anything. It just isn’t as necessary as it used to be. Coolant technology has improved. You could do an electrolysis test to determine if you need to change it or not. Very simple with a multimeter.

 

This is true. And sometimes well water. I've even filled the radiator with water from the river when I needed too.

 

In the old days, doctors used to suggest patients to take up smoking, to lose weight.

 

Reminds me, I’m behind on my blood letting.

 

I’ll give you the unpopular opinion. First check the block and head for flatness. Will either require machining/work or do you just need a new head gasket? If you just need to put on a new head gasket To tell you the truth I wouldn’t worry about the rust. Yes the surfaces have rust and will remain rusted but it’s not the end of the world and a lot of that will come off with new coolant. The heat exchange efficiency will be lower but these aren’t high output engines anyways. In your pics I’m seeing water with fine oxidized iron particles in suspension so it’s got a weird look to it making it seem far worst. Possibly some blow by in there too. Personally I’d disconnect the radiator and the heater core and flush them out. Use a pressure washer to flush out the block really good to get rid of all this dirty water mixture and use compressed air to get rid of as much water as you can and dry whatever you can. It will be messy, and I wouldn’t worry about getting water in the oil galleries. Drain the oil pan at the end with new oil. Take out the coolant plugs if you’re feeling brave enough for the task of putting new ones in. I’d pour some 50/50 coolant in the jackets once you’ve flushed it out so that whatever water that sits at the bottom mixes with the coolant to prevent further corrosion while you do your repairs. Use a square tap to chase the threads in the block and do your head gasket. I bring this up because it’s something most people ignore when doing head gaskets on a cast iron block. Makes a huge difference in how smooth the new head bolts go in and how good of an even torque/clamp you get on your new gasket. Once all is said and done I’d run your engine for about a minute for the first time, turn it off and see if you have milky oil, just in case you had excess water sitting in the oil pan. If milky, change the oil again. If not, start driving the puppy. Do two coolant flushes each 1 month apart after your repairs just to make sure your coolant is nice and clean since some more rust will most likely come off. The rusted metal itself isn’t going to be an issue, you don’t want all the metal particles in your coolant to wear out your water pump.

the 3vze had a lot of head gasket issues and I’ve seen coolant jackets in far worst condition with major pitting and scales from people just putting more and more water in their radiators to get by. None of them had pinging issues after. There’s plenty of surface area to accommodate for the slightly less heat transfer and unless you plan on boosting your engine I wouldn’t worry about it.