Rust in cooling system

[ABN_CBT_ENGR]

Hyundai had issues with water pump impellers rusting away. Seems cavitation is most likely to occur there and a likely cause

A very real possibility

 

[MParr]

I bought a new 1991 Ranger with the 3.0 and owned it until 2001. I never had any rust issues. I changed the coolant every two years or 24,000 miles, whichever came first. I only used Motorcraft coolant and distilled water in a 50/50 mix. I had to replace the radiator because of a seam leak, at around seven years.

 

[350Rocket]

When I purchased my 91 Taurus 3.0 Vulcan, it needed a radiator so I changed it and put a new water pump and hoses on it. The system has lots of rust in it. I got alot out but 2 years later, it's full of rust again. I never known a 3.0L Vulcan that didn't have rust. Is there a better than average flush for getting the rust out? Or additive to keep it from rusting further? I remember my shop teacher saying it was because of electrolysis. How do you fix that though?

I worked at Ford and as far as all the techs said it was indeed electrolysis. They needed very frequent coolant flushed to keep them from turning black.

 

[350Rocket]

That is only partially true, I mean if the thing is rotted to Hades inside it may lead to gasket issues especially if it uses a shim stock HG (I dont believe yours does) and not a multi layered one but over the years I have seen lots of rusty cooling systems, you could say it was more common than not with engines that that had used alcohol antifreeze.

You may need to do a couple of cleanings with the citric acid but with the thermostat out and removing the lower hose and heater hoses to flush fresh water through you can get it clean. A thorough flushing is mandatory if you want it all out.

Reminds me of when I was a service advisor at Goodyear, all the techs used CLR for cleaning plugged Hester cores and rads. One day we had a QMI rep there to train us on their additives they wanted us to sell. He asked what we used for coolant flushed, told him CLR. He wasn't happy. Said we couldn't do that. Lol. I'm not sure long term what they went with.

 

[350Rocket]

@Trav
one mechanic told me once the rust has started and you have rusty color coolant you are done and cleaning won't help and just delaying the inevitable
Is that true?

it was many years ago and I was talking to him about purchasing an old car and he was saying take that into consideration. In this case the coolant was all rusty color with no green.

I had the same issue a few years after installing my 76 Oldsmobile 350 in my car. It had been sitting a long time and had rust, leaking freeze plugs. It started to run hot on the highway and coolant was very dirty looking after 3 years so I did a major flush with the machine at work, just water until it was clean, and put in modern multi vehicle coolant. It lasted a good few more years before looking dirty again and I flushed it again, so the rust seems to be under control in my case.

 

[Brons2]

CLR, which actually is a variety pack of different weak acids

what size bottle do you use?

at Home Depot they have a 28 oz size, which I would call the traditional size I've seen in stores for years, and they have a 1 gallon size, which ironically looks like a coolant bottle.

 

[Ursatdx]

Northern Radiator | Electrolysis 101

www.northernradiator.com

 

[350Rocket]

The Griffin aluminum radiator in my 84 Olds is like 16-17 years old roughly and it started leaking like 5 years ago. The most popular local rad shop that I bought it from said it was unrepairable and I needed to buy a new one. Another smaller (less well known) shop looked at it, welded the leak up, said they saw evidence of electrolysis and recommended a ground strap. Years later, with the ground strap, still no leaking.

 

[JHZR2]

I’d agree on the citric acid flush, it’s the standard prescription from Daimler on old vehicles.

I am almost scared to do it on this one with 438k miles. I just swapped the first fill of JD Cool Gard II so that I have consistent chemistry in there. Still cools fine even with full payload. Do you experience any cooling issues or just see the rust?

 

[Blinker]

The Taurus was plagued for years with heater cores that would fail. My guess is maybe yours is going too.

 

[mpack88]

The Taurus was plagued for years with heater cores that would fail. My guess is maybe yours is going too.

My evaporator also has a leak so heater core will be replaced also.

 

[mpack88]

Well I did the flush today. I used the citric acid and loads of rust and scale cane out. Water was almost black. I installed the correct motorcraft 197°f thermostate and guage now stays on the middle instead of bouncing around like it did before with a after market 195°f. Who knew 2°f would make that much difference.

 

[350Rocket]

Well I did the flush today. I used the citric acid and loads of rust and scale cane out. Water was almost black. I installed the correct motorcraft 197°f thermostate and guage now stays on the middle instead of bouncing around like it did before with a after market 195°f. Who knew 2°f would make that much difference.

Probably not the 2 degrees but the better quality thermostat and or cleaning all the garbage out. I recall us having to flush a 3.0 Sable 3 times over a period of a couple months to keep the heater core from plugging up. I can't remember if we ended up having to replace it, but it wasn't leaking, just had no heat and very black coolant.

 

[mpack88]

Probably not the 2 degrees but the better quality thermostat and or cleaning all the garbage out. I recall us having to flush a 3.0 Sable 3 times over a period of a couple months to keep the heater core from plugging up. I can't remember if we ended up having to replace it, but it wasn't leaking, just had no heat and very black coolant.

Agree. Motorad was the aftermarket brand.