Very rusty coolant: how urgent?

[erocksteady]

So I bought my 90 CV about a year ago, and at that time, I remember seeing some evidence under the hood of a prior brown/rusty coolant explosion. At the time I bought it, I checked the radiator, and the coolant seemed fine--green and fresh. I know the guy I bought it from just put in a new thermostat and water pump, so he obviously had to at least top it off with some fresh coolant. Now that it's been a year, and I actually just checked the coolant again for the first time since then (oops). It's a very nasty brown, with some pasty brown crud around the seal of the rad cap. It's either rust, or perhaps sludge from leak stop. Who knows what the guy did. Anyway, my question is how quickly I should address this? Is it particularly harmful to keep driving with nasty coolant? I'm not talking long-term...just several weeks. The reason I ask is that I'm super busy the next couple weeks and there's no way I can get to it. If it's something I should do ASAP, I'll take it to the shop for a flush. If it can wait, I'll do it in about 4 weeks myself. Any favorite methods? How well do those flush kits work? What about special product to get the rust out? I've heard that stuff might be hard on the head gasket? Thanks fellas!

[sly]

I'd flush it real good and make sure it's not just a bunch of hard water sediment first. This may create other problems of course... leaks, etc.

[gadget73]

Flush it. I had that on my car and every day for a week I would drain the radiator, flush it till it ran clear, and fill it back up with water. By the next day, it looked like mud again. Keep doing that till it comes out clear, then fill the radiator with straight antifreeze. The water in the block will mix with it and you'll be darn close to 50/50.

[91grandmarquis]

Flush it. I had that on my car and every day for a week I would drain the radiator, flush it till it ran clear, and fill it back up with water. By the next day, it looked like mud again. Keep doing that till it comes out clear, then fill the radiator with straight antifreeze. The water in the block will mix with it and you'll be darn close to 50/50.

+1

[erocksteady]

Flush it. I had that on my car and every day for a week I would drain the radiator, flush it till it ran clear, and fill it back up with water. By the next day, it looked like mud again. Keep doing that till it comes out clear, then fill the radiator with straight antifreeze. The water in the block will mix with it and you'll be darn close to 50/50.

Sounds like a straightforward solution. Thanks mangs! What's the capacity of the rad approximately? Just wondering if my pan is big enough :smirk:

[gadget73]

If you crack a smaller hose loose somewhere (EGR spacer, heater hose, whatever is convenient), you'll get about 2 gallons drained out of it. Use a bucket if you have one that fits. If you have the stock radiator, you'll find a nipple just below the drain valve. Put a short bit of rubber hose on that and direct it out from behind the rad support and it will drain very cleanly into the bucket, otherwise it will run all over the place and make a mess.

[erocksteady]

...you'll get about 2 gallons drained out of it...

Wait a sec--if the total capacity is 14 gallons, and I can only drain 2 out of the radiator, how does 2 gallons of antifreeze out of 14 make for a 50/50 mix? Or am I missing something?

[sly]

14 gallons? I've only ever needed 2 gallons for a complete drain and fill.

[gadget73]

total capacity with a bone dry engine is 14 quarts, or three and a half gallons. You'll never get more than about 2 gallons drained out of it though.

[sly]

ah... 14 quarts. that makes more sense.

[91waggin]

14 gallons?? Maybe in a detroit diesel

[erocksteady]

Wait a sec--if the total capacity is 14 gallons, and I can only drain 2 out of the radiator, how does 2 gallons of antifreeze out of 14 make for a 50/50 mix? Or am I missing something?

arg. I'm a total retard. I meant 14 quarts, yes. But my own mistake tripped me up and I was thinking 2/14 gallons. Retard.

[erocksteady]

If you crack a smaller hose loose somewhere (EGR spacer, heater hose, whatever is convenient), you'll get about 2 gallons drained out of it. Use a bucket if you have one that fits. If you have the stock radiator, you'll find a nipple just below the drain valve. Put a short bit of rubber hose on that and direct it out from behind the rad support and it will drain very cleanly into the bucket, otherwise it will run all over the place and make a mess.

Alright, I'm missing something major here, or do I just have a major problem with crap in my radiator? I pulled the drain plug (plastic wingnut with a small threaded stud attached, right?), had the cap off, the EGR spacer hose off, and the top hose off. Nothing. A couple drips when the drain came off, but after that, not a drop.

Am I dumb, or do I have so much shit in my radiator that it won't drain? Or perhaps both

[grandpaslincoln]

14 gallons?? Maybe in a detroit diesel

That's about the same amount of oil they need too lol

[91waggin]

Alright, I'm missing something major here, or do I just have a major problem with crap in my radiator? I pulled the drain plug (plastic wingnut with a small threaded stud attached, right?), had the cap off, the EGR spacer hose off, and the top hose off. Nothing. A couple drips when the drain came off, but after that, not a drop.

Am I dumb, or do I have so much shit in my radiator that it won't drain? Or perhaps both

It's not a drain plug, it's a valve. You open it maybe a half-turn and stuff comes out the bottom. It might be possible that the drain is completely crudded over, but make sure you're opening the drain right. But yes, it does look like a plastic wingnut.