Expansion tank leaks

[Joseph S.]

Last month I removed my expansion tank because I thought I had a leak at the small hose that connects to the T fitting. The calmp was as tight as it could go so I was going to replace the clamp and hose.

What I found was shocking. My 2 year old expansion tank was competely rotted out at the lower tube and along the bottom of the tank.

Does anyone have any ideas on this issue. I was thinking I may have some electrolosis going on causing a reaction between the anitfreeze and the tank.

I don't want to have a problem later on with the radiator also if that is the issue.The battery is a sealed unit so there is no Battery acid issues causing this.

Thanks, Joe

[Terry D.]

Re: Expansion tank leaks

Joseph
Are you using full strength anti-freeze or the already 50/50 mix. If using full strength you need to dilute with distilled water not tap water. Some tap water will corrode metal.
Terry

[Christopher R.]

Re: Expansion tank leaks

Joe, there's a way to test for electrolysis using a multi-meter. I have the procedure at home, but I'm not right now. If someone doesn't post it by the time I get back, I'll post it next week.

[Terry M.]

Re: Expansion tank leaks

Google is your friend:

http://www.youtube.com/watch?v=mBXZtfzHhig

There are several verbal descriptions on the 'net also. I searched Google with "coolant multimeter" and got several hits at the top of the first page.

The amount of corrosion you are reporting does not sound normal. After getting a reading on the multimeter, I would thoroughly clean the cooling system. I am partial to RMI-25 (another Google search). Then refill with a fresh 50/50 mix using distilled water and an HOAT coolant. (Zerex G5). After the fresh coolant I would check the multimeter again and report the before and after readings here.

[Larry M.]

Re: Expansion tank leaks

Joe:

Are you certain that the corrosion is INTERNAL corrosion, and not caused by the battery?? Even "sealed" wet cell batteries have small external vents. Could this be the problem?? The only battery that may not have a typical vent that I know of is gel-cell batteries like Optima and the latest DELCO Restoration Batteries. You should be able to determine internal versus external corrosion if you check carefully.

The multimeter, millivolt test can and should be done. The archives have information on this from Duke Williams....you can do a search. I followed his advice and tested my system a few times. One end of the meter was connected to a good/solid engine or battery ground, and the second lead was suspended in the antifreeze solution. My readings were around 90-130 mv. I also found that the readings slowly diminished with time.....like the probe was being passivated by the antifreeze solution. If I removed and cleaned the probe, the readings were similar again to the (higher) initial reading.

In the past, I remember reading about a few guys that had similar problems to what you described. I THINK that the problem was that the expansion tank somehow got connected/hooked to the battery ground system through the expansion tank metal retaining bands. I don't have the specifics on how this happened. It basically set up a galvanic cell with the cast iron block....and the aluminum expansion tank lost the contest.

I believe that having a new charge of Zerex G-05 antifreeze and distilled water coolant in your engine should provide excellent protection for the radiator and expansion tank under almost all conditions. It has worked for me, as my 1967 car still has the original tank and radiator after 44 years.....the last 20 years or so with G-05.

Larry

[Jeffrey B.]

Re: Expansion tank leaks

This topic brings me to ask what is the most efficient way to totally flush my 66 small block coolant system? Also my problem is coolant disposal, any suggestions?
Thanks
Jeff

[Duke W.]

Re: Expansion tank leaks

Last month I removed my expansion tank because I thought I had a leak at the small hose that connects to the T fitting. The calmp was as tight as it could go so I was going to replace the clamp and hose.

What I found was shocking. My 2 year old expansion tank was competely rotted out at the lower tube and along the bottom of the tank.

Does anyone have any ideas on this issue. I was thinking I may have some electrolosis going on causing a reaction between the anitfreeze and the tank.

I don't want to have a problem later on with the radiator also if that is the issue.The battery is a sealed unit so there is no Battery acid issues causing this.

Thanks, Joe

What kind of anti-freeze and water are you using and in what proportions?

The expansion tank and radiator should be electrically isolated from vehicle ground. This is easy to measure with a mulitmeter.

Also the maximum voltage between the coolant and ground should be no more than 250 mv. This can be measured by placing one probe in the coolant and the other on a good ground like the batter negative post.

Coolant change/flushing procedures and recommended refill products have been discussed here many times and should be easily found in the archives.

Local fire department hazmat specialists should be able to tell you how to properly dispose of used coolant. Where I live it's acceptable to dump it down the sanitary sewer system because we have a state-of-the-art treatment plant that breaks down the glycol and traps heavy metal ions.

We used to have a city recycling center that collected used oil, coolant, paint... and also "electronic waste" such as old TVs and computers, but they closed it down. California has a law that any business that does oil changes must collect used motor oil from the public, so now I take it to my local Pep Boys that has a service operation, and they take it with a smile.

Duke

[Joe L.]

Re: Expansion tank leaks

What kind of anti-freeze and water are you using and in what proportions?

The expansion tank and radiator should be electrically isolated from vehicle ground. This is easy to measure with a mulitmeter.

Also the maximum voltage between the coolant and ground should be no more than 250 mv. This can be measured by placing one probe in the coolant and the other on a good ground like the batter negative post.

Coolant change/flushing procedures and recommended refill products have been discussed here many times and should be easily found in the archives.

Local fire department hazmat specialists should be able to tell you how to properly dispose of used coolant. Where I live it's acceptable to dump it down the sanitary sewer system because we have a state-of-the-art treatment plant that breaks down the glycol and traps heavy metal ions.

We used to have a city recycling center that collected used oil, coolant, paint... and also "electronic waste" such as old TVs and computers, but they closed it down. California has a law that any business that does oil changes must collect used motor oil from the public, so now I take it to my local Pep Boys that has a service operation, and they take it with a smile.

Duke

Duke------


Used motor oil ought to be quite valuable right now. Most used motor oil is used as a fuel for refineries rather than being re-refined into new motor oil. However, either way it's replacing oil that costs about 90 dollars a barrel right now ( or, about $2.14/gallon). Even when it's refined into new motor oil, I wouldn't think it would cost more to do that than to refine crude oil into new motor oil. And, if it's used as a refinery fuel, it doesn't need to be refined, at all; it can be used just as it is, replacing refined fuel oil which costs more than 90 dollars a barrel..

[Joe L.]

Re: Expansion tank leaks

This topic brings me to ask what is the most efficient way to totally flush my 66 small block coolant system? Also my problem is coolant disposal, any suggestions?
Thanks
Jeff

Jeff------


The most efficient way is to drain all the coolant you can from the radiator drain and then use a Prestone "Flush-and-Fill" kit. However, if you use this method you can't really used distilled water to make up the 50% water of the final coolant mix. With many of the better municipal water supplies, though, it is not necessary to use distilled water. If you have less than about 50 mg/l TDS in your water, you don't need distilled water.

If you wish to use distilled water, then what you have to do is to drain the coolant, flush with the above-referenced kit, then drain again, this time opening the radiator drain and the block drains. Finally fill with a 50/50 mix of coolant and distilled water.

[Duke W.]

Re: Expansion tank leaks

Duke------


Used motor oil ought to be quite valuable right now. Most used motor oil is used as a fuel for refineries rather than being re-refined into new motor oil. However, either way it's replacing oil that costs about 90 dollars a barrel right now ( or, about $2.14/gallon). Even when it's refined into new motor oil, I wouldn't think it would cost more to do that than to refine crude oil into new motor oil. And, if it's used as a refinery fuel, it doesn't need to be refined, at all; it can be used just as it is, replacing refined fuel oil which costs more than 90 dollars a barrel..

My understanding going back to at least the eighties is that most used motor oil collected in SoCal is filtered, then mixed with No. 6 fuel oil (the modern equivalent of Bunker C) that is used in the large marine diesels that power container ships and tankers.

For those who use fuel oil to heat their house it would probably be okay to dump used motor oil into the tank just before a new load is delivered, especially if it comes out of a tight engine and has no more than 5K miles of use.

Duke

[Clem Z.]

Re: Expansion tank leaks

i know of several repair shops that have a waste oil burner used for heat in the winter time.

[Paul J.]

Re: Expansion tank leaks

In the 90's (and before) used motor oil and other waste oils were blended with waste solvents and used for boiler fuel and fuel in cement kilns. Because of the tighter air quality regulations that were phased in after 1990, many companies found it cheaper to pay for "virgin" fuel and not have to meet the more stringent air regs. In addition, the RCRA regs governing haz waste liability also became tighter with more stringent "cradle to grave" rules and de-listing standards. All of this was further exacerbated by new air quality rules intended to bring old boilers up to present standards. Consequently, burning used oil as a fuel in this Country lost favor. This doesn't mean that it's not still done (particularly in cement kilns), but I would think that it has more value for other uses, such as being re-refined. I've recently seen commercials for a Valvoline product that is 50% recycled oil.

[Paul S.]

Re: Expansion tank leaks

on coolant disposal, check with the town/city/munipality where you live--typically the department that is responsible for garbage collection.

In my city, there is curbside pickup of hazardous household waste (pretty much anything except used tires). That's how I got rid of my used coolant flush water--hardest part is collecting enough empty milk jugs (I collected the flush water until it was running clear from the engine block plugs/radiator drain valve).

Until I knew my city had this, I had lots of used brake fluid sitting in containers in my garage because I could not find any place that would take it. And from what I understand it does not cost the city hardly anything (waste disposal is actually contracted to private enterprise, and they offer the curbside hazardous pick up as a perk/incentive to the city) compared to the ongoing liability issue of people throwing antifreeze, brake fluid, ect... out in the trash or down the toilet.