Cooling System Preventive Maintenance

[artbuc]

Thought I would start a new thread with a more descriptive title. I have two vehicles with V6 3.0L engine - 99RX300 and 99 Avalon XLS. Both have about 86k miles. I asked both of my dealers why Toyota does not recommend an interval to replace coolant hoses. Toyota said coolant hoses should last the life of the vehicle. They should only be replaced IF they show obvious signs of pending failure such as seepage, bubbles, soft spots, etc. Lexus said coolant hoses are not necessarily designed to last the life of the vehicle, but they did say hoses should only be replaced if visual inspection indicated it is necessary. Lexus went further to say that even if, for example, the upper hose looked bad, they would replace it only and not automatically replace the lower hose.

Doing some Internet research I came across various preventive maintenance recommendations from Pat Goss of Motorweek. He says coolant hoses should be replaced every 4 years or 60k miles. Furthermore, he says a coolant hose could look perfectly fine but be close to catastrophic failure. The problem I have with Pat Goss is that his maintenance recommendations seem so conservative, almost bordering on ridiculous. For example, he says you should flush your cooling and brake systems every year. If I did everything Pat Goss said, I would be working on my cars non-stop.

I'm not sure what I will do. I may replace just the upper/lower radiator hoses. I may also repace the heater and IACV hoses. However, I will not remove the intake manifold just to replace the by-pass hose.

[lenore]

I have a 99 Lexus RX purchased in 11/1998. It has 152k miles, and the original hoses. I live in California, so no extreme temperatures, and the hoses look great, however I too am considering replacement. Just the preventative so as not to have failure on my wife.. Funny seems in the 60's and 70's you would hear of ruptured hoses all the time, but maybe the construction or rubber is better now, just dont hear of any problems. Still makes me nervous, the unknown secret degradation inside the hose. they arent expensive, but are the new ones better than my originals, who knows...

by the way, at least the bypass hose is not flexing, seems this would make it more durable other than it sitting on top of the engine baking...

[AdamIsAdam]

On my other cars, I replace the hoses while replacing the antifreeze. As long as the system is empty, it's too cheap and easy not to. I also put a new thermostat in. But you said something about another hose that requires removal of the intake manifold. that sounds like a pain.

But yes, there used to be A LOT more people who'd break down in the summer over heating. Another change over the years is that when someone broke down, 3 other cars pulled over to help push the car off to the side of the road. Nowadays, drivers sit in their disabled cars on the cell, IN THE MIDDLE OF THE ROAD, BLOCKING TRAFFIC FOR HOURS!

Sheesh.

[RX in NC]

Not only are today's hoses better made and more durable than the hoses were in the 1970s, so are the coolant fluids they conduct. I inspect our hoses periodically but haven't had to replace one in at least ten or fifteen years. If your hoses remain flexible, don't flake when you rub them, and aren't showing surface cracks in the areas where they are clamped to their fittings, I would simply leave them alone and keep driving. Today's vehicles have far fewer hoses than the vehicles did back in the '60s and '70s - my 1974 Datsun 260Z had more hoses than your local Wal-Mart Garden Center....

[artbuc]

Not only are today's hoses better made and more durable than the hoses were in the 1970s, so are the coolant fluids they conduct. I inspect our hoses periodically but haven't had to replace one in at least ten or fifteen years. If your hoses remain flexible, don't flake when you rub them, and aren't showing surface cracks in the areas where they are clamped to their fittings, I would simply leave them alone and keep driving. Today's vehicles have far fewer hoses than the vehicles did back in the '60s and '70s - my 1974 Datsun 260Z had more hoses than your local Wal-Mart Garden Center....

Well, my obsession to do unnecessary preventive maintenance struck again. Just replaced upper & lower radiator hoses on my 99 w/86k miles. Used Toyota factory replacements which I got from Discount Toyota ($41 including S&H).

The old hoses looked pristine. I cut them open. Rubber was smooth and supple. No cracks, soft or hard spots. I now believe Toyota when they say coolant hoses should last the life of the vehicle.

I'm glad I did it since my wife drives the car. But, there is no question in my mind that these hoses would have lasted a very, very long time.

[RX in NC]

Man, nobody listens to common sense anymore....

[artbuc]

Man, nobody listens to common sense anymore....

Here is my idea of common sense. I want the car my wife drives to be reliable. Many experts, most notably Pat Goss of Motorweek, say to replace coolant hoses at least every 4yrs/60k miles. Toyota says this isn't necessary but Toyota also says my AWD transmission doesn't have a design problem and doesn't have an unusually high failure rate. My brother-in-law is a master mechanic who owns his own garage. He only replaces hoses if they are too soft or too hard. I certainly can't feel a coolant hose and tell you if it is too hard or too soft. Visual inspection of hoses is at best an art, at worst totally worthless. I have the time, money and interest to work on my cars. Replacing upper & lower hoses cost me $41 and less than 30 minutes time. Over the years, I have seen many components fail well before their expected life time.

I posted my experience to help those who may not know as much as you do.

[RX in NC]

Your point about high failure rates in RX300 transmissions is duly noted and correct - simply perusing this board and others like it will provide even the novice RX owner with plenty of evidence that the early transmissions are flawed and require a ridiculous maintenance schedule of changing the fluid regardless of what Toyota proclaims....

But where is that same type of evidence concerning coolant hoses? It doesn't exist because coolant hoses (in general, not just in the RX series) have been improved dramatically over the past decade or so, as have the coolant compounds themselves....

If you naively perform all of the maintenance tips and suggestions that Pat Goss and others like him encourage you to do, you'd waste all of your disposable income and time working on your vehicles. You have to temper what the industry wants you to do (hand over as much of your hard-earned money to auto parts suppliers and service providers as they can pull out of you) with what common sense and component failure history empirically prove to you. In this particular case, coolant hoses rarely need to be replaced these days unless they are more than ten years old or showing signs of breakdown, usually at the clamp joints....

I'm glad that you obtained some peace of mind in performing this task on your wife's vehicle. But my original point remains that this is overwhelmingly an unnecessary and wasteful procedure unless signs of failure have been detected....

[artbuc]

Your point about high failure rates in RX300 transmissions is duly noted and correct - simply perusing this board and others like it will provide even the novice RX owner with plenty of evidence that the early transmissions are flawed and require a ridiculous maintenance schedule of changing the fluid regardless of what Toyota proclaims....

But where is that same type of evidence concerning coolant hoses? It doesn't exist because coolant hoses (in general, not just in the RX series) have been improved dramatically over the past decade or so, as have the coolant compounds themselves....

If you naively perform all of the maintenance tips and suggestions that Pat Goss and others like him encourage you to do, you'd waste all of your disposable income and time working on your vehicles. You have to temper what the industry wants you to do (hand over as much of your hard-earned money to auto parts suppliers and service providers as they can pull out of you) with what common sense and component failure history empirically prove to you. In this particular case, coolant hoses rarely need to be replaced these days unless they are more than ten years old or showing signs of breakdown, usually at the clamp joints....

I'm glad that you obtained some peace of mind in performing this task on your wife's vehicle. But my original point remains that this is overwhelmingly an unnecessary and wasteful procedure unless signs of failure have been detected....

Point taken. Hoses were 9 1/2 years old and will be 11 1/2 years old when I do the next coolant replacement. I could have deferred spending $41 two years and made a little extra interest (about $1.70 after tax). But, for me, I would rather have peace of mind.

I do agree that many of Goss' recommendations are downright silly. In this case, just too cheap and easy to do when I already have the coolant drained. OTOH, I would not even consider removing the intake manifold to replace the by-pass hose. It all comes down to cost/effort vs perceived benefit.

Thanks for your help.

[Grumpa72]

Fwiw, I used to replace hoses periodically. Now, I just watch for obvious signs as the OP noted. Again, as a side note, I have a 37 year old Corvette that I just took the original hoses off. They are absolutely immaculate other than being a little stiff compared to new. One of the reasons that they still look new and are functional is the low mileage of the vehicel. That said, I believe that the new compounds will last a lot longer than the old school products and I just keep an eye on them.

[wwest]

"..coolant replacement..."

WHY...? When....?

Test the Ph of the coolant and if need be the freeze point but otherwise leave it in the car.

I replaced the original factory coolant in my '92 LS400 after 12 years and 110,000 only because it began to look a bit murky, not because it wasn't still fully functional.

[artbuc]

"..coolant replacement..."

WHY...? When....?

Test the Ph of the coolant and if need be the freeze point but otherwise leave it in the car.

I replaced the original factory coolant in my '92 LS400 after 12 years and 110,000 only because it began to look a bit murky, not because it wasn't still fully functional.

Like I said in an earlier post, cost/effort vs perceived benefit. By "fully functional" I assume you mean your coolant still protected against boil-overs and freeze-ups. OTOH, I bet your anti-corrosion package had been depleted for a long time. I think you need more than pH to measure the effectiveness of your anti-corrosion package. For me, I would rather replace the coolant per Toyota recommendations than run the risk of a premature heater core and/or radiator failure, both very expensive PITA problems to fix. By replacing every two years, I can do a simple drain & refill. No flushing required - nice and easy.

On this and other Toyota forums, you often read about folks who have had timing belts run for over 150k miles. Yet, I replaced mine at 85k. Why did I do that? Because I don't want my wife stranded somewhere. OTOH, I did not change out the water pump because it was not leaking and the impeller turned freely with no evidence of a sticking seal. If the water pump fails before I install a new TB at 175k miles, it most likely will not be a catastrophic event.

[Grumpa72]

"..coolant replacement..."

WHY...? When....?

Test the Ph of the coolant and if need be the freeze point but otherwise leave it in the car.

I replaced the original factory coolant in my '92 LS400 after 12 years and 110,000 only because it began to look a bit murky, not because it wasn't still fully functional.

WOW! I would be that your coolant was no longer "fully functional" unless you had it tested.

I don't know of any antifreeze manufacturer; the green stuff, the orange stuff, or the yellow stuff, that recommends a change interval (or lack thereof) that is that long. As mentioned, you will still have freeze protection but even the long life coolant loses its anticorrosion protection after about five years. That is WAY TOO LONG imo and not worth the associated risks. A coolant flush and change, even an expensive one will only run $100 +/- while a major engine component change will run into four figures.

Just my two cents.

Gary

[wwest]

Are you sure, are any of us sure (I'M not) that the Ph measurement doesn't tell us of the state, status, of the anti-corrosion chemical components of the coolant...??

If the Ph is neutral, no acidity nor alkalinity, what is the coolant's "corrosion" factor with/for an aluminum block and head..???

[wwest]

Hmmm.....

My "driving" and engine mechanical repair expereince goes all the way back to the early fifties, mostly back then 1940 vintage farm tractors, Deere, Farmall, Allis Chamlers, and Ford Ferguson. but throughout the succeeding years I don't know, cannot remember, any engine or component failure that I could say was the result of the corrosive effects of the engine coolant. Not even the ones that never had anything but water used, many times ditch water.

The Allis Chamlers had a coolant leak, a slow one, and we had to always keep one eye on the temperature gauge. Once it began to rise it was off to the nearest ditch with a bucket....

Even so, that's a fairly small sampling so does anyone know of any modern day engine or engine coolant component that was so "damaged" by coolant corrosiveness that it lead to engine failure, or for that matter any coolant component.

my one and only expereince in that venue was with a 1966 T-bird engine. But engine failure was the result of a faulty coolant formulation that resulted in a clogged up radiator and the coolant manufacturer ended up buying me a new engine.

[RX in NC]

I don't analyze our vehicles' coolant chemical makeup to determine when to replace it. I simply glance at the color and consistency of the coolant in the radiator overflow container every weekend when I'm doing my standard 5-minute check of the fluids and tire pressures. When the coolant begins to look cloudy or murky, I'll make a mental note to drain-and-fill it during my next oil and filter change for that particular vehicle. My current 1999 Dodge Ram pickup with the 5.9-litre V8 has had its coolant changed twice in 9 years and 51,500 miles. My wife's current 2004 RX330 has never had its coolant changed in 4 years and almost 75,000 miles. Of course, whenever I have to top up the coolant level (probably a couple of times per year per vehicle) due to evaporation (yes, it still occurs even in a closed system), I add 100% fresh coolant, no water....

This has been standard operating procedure for me since the mid-1970s. I've had one radiator failure in 38 years of driving, but that was in my 1974 Datsun 260Z that tended to run hot as hell regardless of whether it was 100 degrees or 15 degrees outside. And that particular radiator didn't fail until I had more than 200,000 miles on the car so I can't exactly blame it anyway....

[artbuc]

I don't analyze our vehicles' coolant chemical makeup to determine when to replace it. I simply glance at the color and consistency of the coolant in the radiator overflow container every weekend when I'm doing my standard 5-minute check of the fluids and tire pressures. When the coolant begins to look cloudy or murky, I'll make a mental note to drain-and-fill it during my next oil and filter change for that particular vehicle. My current 1999 Dodge Ram pickup with the 5.9-litre V8 has had its coolant changed twice in 9 years and 51,500 miles. My wife's current 2004 RX330 has never had its coolant changed in 4 years and almost 75,000 miles. Of course, whenever I have to top up the coolant level (probably a couple of times per year per vehicle) due to evaporation (yes, it still occurs even in a closed system), I add 100% fresh coolant, no water....

This has been standard operating procedure for me since the mid-1970s. I've had one radiator failure in 38 years of driving, but that was in my 1974 Datsun 260Z that tended to run hot as hell regardless of whether it was 100 degrees or 15 degrees outside. And that particular radiator didn't fail until I had more than 200,000 miles on the car so I can't exactly blame it anyway....

RX, did your 04 RX330 come with pink (vs red) coolant? I think the pink is good for 100k miles, right?

[RX in NC]

Yes, the coolant appears more pinkish than it does reddish. These long-life coolants are indeed marketed to go 100,000 miles or more, but I pay no attention to that hype. I just glance at the fluid every weekend when I have the hood open. When the familiar cloudiness or murkiness appears in the overflow container, I'll change to fresh coolant. The existing coolant still looks rather pristine right now with the vehicle approaching 75,000 miles. I've never run a factory fill of coolant to 100,000 miles before, but maybe this one will indeed go the distance....

[jgr7]

The worry for anti freeze is more the anti-corrosion package that protects the Aluminum as well as the steel components in your engine. In as little as 2 years the anti corrosion inhibitors can start to go bad, and while it may not ruin your engine in that short of time it starts the process that will allow your freeze plugs to fail. I had this happen on a car with an engine that never had the anti freeze changed because it looked good and the car never overheated. When I used to have the Eldorado it was mandatory you changed the coolant every two years. This however had the all aluminum North Star engine. If you didn't do this you would eventually get the dreaded blown head gasket from the corrosion inhibitors being gone.