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Posted 10 August 2003 - 05:59 AM
After browsing through the entire forum and reading the various posts regarding head gasket failure, it has sent a shudder through my body!
I'm planning a trip next weekend which will be anywhere between 300 and 500 miles round trip. I was planning on changing my coolant and t-stat this week in preparation for the trip, but now I'm a bit scared to do it. You see (and I know this is very bad of me), my '99 Outback Wagon is still running with its original coolant after 46k miles. I know that I should have changed it a while back, but for a variety of excuses I never did. Now I'm a bit scared to change it for fear that it may disturb the seemingly delicate balance between the cooling system and the head gaskets. I am going to change it for sure as well as flush the system, change the t-stat and I'm also going to do the test for exhaust gases in the existing coolant as well. In my gut, I feel that all will be well after flushing the system, but I just can't help worrying that something may get f---ed up!
This leads me to a couple of questions. 1) How difficult is it to change the t-stat on the H-4? I"ve never done anything more than change the oil and spark plugs on a Subaru engine (this is my first Subaru) and was wondering if the t-stat is easy to get at. 2) Is there any air bleeding procedure for the H-4 cooling system? Is there a air bleed valve for bleeding trapped air?
I suppose that my trusty Haynes manual can give me some insight on these questions, but I felt that I'd rather tap the resources of the local Subaru experts on this forum. I trust your insight more than the manual!
Boy, with all the talk about failing head gaskets, one thing is for sure. Once the Outback is resigned to part-time status, I am going to preemptively change the head gaskets before they have a chance to fail on me. Hopefully they won't fail before then, for right now it is my wife's daily driver.
Thanks in advance for any and all responses!
'99 Outback Wagon
'90 Mazda MX-6 GT (2.2 liter turbo, 5-speed, 68K miles)
Posted 10 August 2003 - 06:20 AM
If it ain't broke, don't fix it.
At 45 K miles, your car is just about broken in. You shouldn't have any problems. However, I would change the oil and oil filter if they haven't been touched recently.
Check your service booklet. It gives you "typical" service intervals, and what's normally done at each service. Just follow these recommendations.
Your proposed 500 mile trip is nothing. I often do these on a weekend, and 2,000 mile trips (over a week or two) aren't unheard of either.
Posted 10 August 2003 - 06:30 AM
I'd say, hands off!!
I don't have experience with the 2.5 engine but i do have with all other Subaru engines and i never, repeat NEVER, change the coolant as long as there is enough frost resistance.
Even when i have to drain it for any reason i will re use it unless it became 'muddy' or rusty, but in such cases we're talking about engines with 150000 or more miles.
In my opinion, draining and flushing the cooling system should make you more scared. The same for the thermostat, if it works fine now, don't touch it.
My two cents.
Posted 10 August 2003 - 06:41 AM
The bleeder screw on your car is on the top of the radiator on the right(passenger) side. Bleeding the system with the car on an angle is a little easier, I like to use my car ramps. Open both the radiator cap and the bleeder screw and add coolant slowly until the level reaches the bleeder screw. Start the car and run the car. Add more coolant as it will take it then install the bleeder screw and the radiator cap. Make sure that your overflow tank has a good amount of coolant in it, as your system will still have some air in it and you want it to be able to pull coolant back in from the overflow. I would carry a screwdriver and coolant around and check it each day for a few days. Always remove the bleeder screw when adding coolant. Check it when it's cold. Be VERY careful after changing the coolant. Watch the temp gauge! It's pretty easy to have some air trapped in there when you are done. Make sure you use quality anti-freeze and distilled water.
Our headgaskets on our 99 obw went at 119k miles. I don't know if I would do a job this big preemtively, but that is your decision. Definately inform your wife of the symtoms and tell her to watch that temp gauge like a hawk. Our car is my wife's daily driver and I remember her saying "What is a temerature gauge"? AAAAHHHHH!!!!!!
For trips I like to take a box with lots of stuff. Tools, fluids, etc. I just ran our car 2000 miles round trip and did have a little trouble with the A/C work I had just done to the car, but I had the tools and quickly fixed it.
Posted 10 August 2003 - 07:41 AM
Posted 10 August 2003 - 09:25 AM
as for preemptively changing the head gaskets...don't. it is a ton of work. just keep an eye on your expansion tank after a long drive. leave the car idling after the drive, pop the cap off the expansion tank. if you see bubbles, that is a pretty good indication of a blown head gasket (even if the car is not overheating), as that means that something of higher pressure (from the cylinders) is getting into the pressurized cooling system. some people have had no problem at all with the original head gaskets...
Posted 11 August 2003 - 12:45 AM
Why? Because things like thermostats tend to fail at the most inopportune times, so they are one of those things you should replace BEFORE it goes bad. Which would you rather do, spend 15 bucks replacing your thermostat, or spend like 150 replacing your head gaskets, or even more replacing the engine, because the thermostat stuck shut and overheated the motor?
Posted 11 August 2003 - 01:48 PM
As for the Thermostat, you only need to change these when they stop working. Thermostats tend to be very cut and dry, they work or they don't. They don't really ever "kind of" work. When it fails (marked by higher than normal heat), then you replace it.
Posted 11 August 2003 - 02:56 PM
The problem with waiting for a thermostat to fail before changing it is that it may take the engine with it. Aluminum engines in general aren't very tolerant of overheating. Changing the t-stat when changing the coolant is cheap insurance IMHO.
Posted 11 August 2003 - 06:45 PM
As for the thermostat; again 46K miles? And I've yet to see a thermostat that didn't warn you with uneven temps before it actually failed.
Posted 12 August 2003 - 02:30 AM
I say, coolant should be replaced every two years, no matter how low the mileage. The boling point altering chemicals in the coolant will tend to lose their effect after time, having cycled from cold to warm many times over in two years.
If you do more than say 30K miles a year, you might want to change it more often.
Since the cooling system needs draining to replace the thermostat, why not do these at the same time? A original thermostat is relatively cheap.
With respect to bleeding the cooling system, I have a few points to add:
Cabin heat should be on max heat, and you need to idle the engine quite a long time to get some heat into the system while the bleeder screw and radiator cap are off. Screw the bleeder in after it starts to overflow slightly. Then bang on the rad cap and as mentioned earlier, make sure the overflow bottle is full to the "hot" mark.
Posted 12 August 2003 - 06:28 AM
You've given you're input, there is absolutely ZERO need to be bickering about this. If I want to change my coolant & thermostat every year.....then so be it. You may not agree with it, but who cares. The parts are cheap, and if he's doing the labor himself, what's the harm......a cleaner/longer lasting cooling system......yeah that sounds bad.
BTW.....If it has not already been said, make sure you use an OEM thermostat. Aftermarket units do not have the same opening lift, nor the resistance to change of temperature that the OEM one does. There is a thread in the archives about it.
Posted 12 August 2003 - 09:08 AM
Posted 13 August 2003 - 07:41 PM
I did change the coolant today, however I didn't change the thermostat since it is working okay right now. I know that there were some posts about it being cheap insurance and you are absolutely right. I fully intend to replace the thermostat before the cold weather sets in this fall. I will also replace the upper and lower hoses and the rad cap at that time as well.
edrach: I have seen an original thermostat fail at less than 46K miles. The one in my Mazda MX-6 failed at around 20K, if I recall all those years ago. Fortunately, it got stuck in the open position and all it did was take a long time for the heat to come up. Of course, it had to be dead of winter when it failed! I agree with you that there would probably be some sort of warning with uneven temps.
Hondasucks: not only do I agree that Honda sucks, but I also agree that I would rather spend 15 bucks replacing my thermostat, than spend $1000 or above having to replace the head gaskets and have the heads milled after they warped due to overheating.
Setright: The owner's manual actually states that coolant should be changed/flushed every 30 months or 30K miles, so your 2 years or so is about right. I have always heard, since I've been working on cars, that 2 years is about the most that coolant should be left in the cooling system. Of course, it could be let go a bit longer depending on how many miles the car is driven. I did let it go longer than I should have, at 46K.
To all of you who said 'if it ain't broke, don't fix it': Perhaps you are overlooking the value of preventive maintenance. I'm sure most of you would never let your engines go longer than 3K miles on the same oil. Why let broken down, acidic coolant circulate through the cooling system. The fluids are the car's life's blood. Perhaps there is some truth in what wrxsubaru says that the acidic coolant is eating away at the head gaskets, causing them to fail prematurely. Maybe there is a design flaw in Subaru's OEM head gaskets, but could it be possible that those who have had the head gaskets fail are the ones that NEVER changed the coolant in their cooling system? Maybe some PM on the cooling system would have prevented this from happening.
So far, the cooling system appears to be full and the temp gauge is sitting happily where it always has, just slightly before 50%.
I am happy and less scared than my original subject led everyone to believe.
BTW, changing the head gaskets will be a project that I will do only after the Outback is designated for backup car status, which may be a few years and tens of thousands of miles from now. I think some of you believed that I was going to do it now at 46K miles!
Posted 13 August 2003 - 08:27 PM
Posted 14 August 2003 - 02:20 AM
Posted 17 August 2003 - 10:02 PM
Anyway, enough of my ranting about NY. I highly recommend that everyone regularly flush their cooling system and replace the aging coolant. I believe that regular maintenance of the cooling system will keep it clean and working properly, thereby reducing the chance of anything causing the system to overheat. I would even go as far as recommending that the thermostat be changed with each flush and refill. It is definitely cheap insurance.
Posted 18 August 2003 - 03:04 PM
Fast forward three years, upper radiator hose blows out next to the clamp. Coincidence???:madder:
Yes, if it ain't broke, don't fix it.
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