I have a question about the engines cooling system (antifreeze).
A friend of mine has NEVER changed or had his coolant system flushed..EVER.
He only adds to it when it is low. He's had the 4 cyl Chev Cavelier for 15 years now and it has 200k on it. And it runs great.

Witht that said. Is ever really necessary to flush or drain your coolant system and add fresh antifreeze? I've heard of many other people as well who never change it. What could happen to an engine if you dont?

 

The biggest problem with not changing anti freeze is that the corrosion protection goes away. When this happens the engine rusts or corrodes, with all the nastiness from that. If the water is brownish red, then you have rust. Not sure what color an all aluminum engine will make, but aluminum needs even more protection than iron.

IF, a guy is lucky, he "burns" enough antifreeze and replaces it regularly so that the protection is boosted with fresh antifreeze often enough that you don't get corrosion, but this is rare.

Most of the time, the antirust protection will wear out if you keep it in there too long, and then rust starts.

The other problem is that no cooling system I have seen is completely sealed to the point where it doesn't get contamination. All the cars I have owned or worked on in over 30 years have had some coolant contamination, usually a greasy residue. Not a lot, but enough to make the coolant look murky after about 25,000 to 50,000 miles. Even the 150,000 mile coolant change is bogus. The coolant might still have enough protection, but it will get murky and leave a "bathtub ring".

Over time the contamination will coat things and with some older formulations of coolant, you will get deposits in the radiator and engine. The deposits can build up enough that the tubes in the radiator get plugged and then you get to learn what Rodding Out the core means.

It is better to change the coolant at least as often as recommended and I believe no longer than every 50,000 miles. Comeon, coolant is cheap, and besides most of us are nuts enough to like tinkering with our engines.

Just my opinion,

Jim Henderson

 

I wish I had a picture of the '89 Sentra's cooling system that I serviced... I pulled the drain plug, and TADA!!!! Liquid rust. Your cooling system is nearly as important as your oil system, and should be treated as such...

 

It's quite necessary to change the coolant. Just because it's gotten to 200K without a flush doesn't mean it doesn't need it. Flushing the cooling system and replacing it with brand new coolant prevents scaling and corrosion. Everything Jim said is right on the money.

 

I had a car about 15 years ago that had at least an inch thick deposit in the radiator -- enough that when I opened the drain plug at the bottom, nothing came out!! Had to remove the hoses to drain the coolant, then remove the radiator, put some mild acid in, shake, drain, wash, etc., until the radiator was finally clean. Said car had only about 120k miles when I got it, and I suspect the coolant has never been changed before. In any case, YMMV, but I wouldn't even go 100k w/o changing the coolant.

 

Jim Henderson (as usual) made a great summary. I recently bought a Buick with 100,000 miles on it that supposedly had its (Dexcool) coolant changed at 60K. As you know, GM claims this will last 150,000 miles, but it is already "murky" and the overflow tank has the "bathtub ring". I cleaned the overflow bottle and the soot returned. I think that's also whats triggering my "low coolant" light.

Certainly you can go longer, but if you want a reliable vehicle, I would not go past 4 years or 50,000 miles even with "extended life" coolant.

PS: I usually replace all hoses at 100,000 miles, but the heater hoses are increasingly difficult. Is it safe to run these smaller hoses to 150,000?

 

A hose is a hose. The heater hoses are subjected to the same heat, pressure, UV light, grease, oil, etc., as the radiator hoses.

 

Probably even more so, as most heater hoses on late model cars are tucked DEEP in the engine compartment, and thus are harder to keep clean and inspect for damage or deterioration...

 

O.K., but structurally, a smaller hose under the same pressure (PSI) will have less force acting on it. But maybe the walls aren't as thick either.

 

I'll second that!!

My mother inlaw had a little Plymouth with a 4cyl transverse engine in it that had a freeze plug rust enough to finally pop out! The plug was in the head directly behind the timing belt and when it came out it went into the timing belt and destroyed the belt! it was a real mess!

Change that Coolant! and put Dexcool or equiv in!

Here's some interesting info on that: http://baldwinfilter.com/engineer/pdf/97-2.pdf

Regards,

Rick

 

I just changed the Dexcool on my 2000 Cavalier. This is the first change and the engine had 100,000 miles on it. The DexCool needs changing at 5yrs/150,000miles according to the manual.

I drained the old DexCool put and it looked just as good as the new DexCool I was putting back in. No rings, no murkiness, no nothing. The corrosion inhibitors may have been wearing out, but the color was still the same.

Next question, can I drain the green antifreeze out of my '02 Explorer and then replace it with DexCool? Is there a Ford equivalent or is DexCool universal now. I have only used it on GM products.

 

I'm glad you've had a good experience with the Dexcool in your GM car. However, this does NOT imply that you should use it in your Ford truck. In fact, my Ford Owners Manual specifically says NOT to use it. I don't know the reasons for this, but it is likely that some part of the Ford system is incompatible with Dexcool.

If you feel the need to change what the Ford engineers have specified, I would recommend Zerex G-05 (aka Ford Premium Gold coolant). Like Dexcool, it claims long life, and is approved for recent Ford vehicles. In any event, it is good practice to thoroughly flush the old coolant. If you decide to put the Dexcool in, this is critical.

 

I will stick with what the Ford engineers specified. I was just curious to know if there is a Ford equivalent of DexCool. Thanks.

 

There is a Motorcraft coolant that is Dexcool compatible, & here's a picture: