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Guest Message by DevFuse

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17 replies to this topic

#1 Guest_pjsemmer_*

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Posted 10 August 2003 - 05:59 AM

Hello all,

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)

#2 Guest_canajun2eh_*

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Posted 10 August 2003 - 06:20 AM

Why on earth would you want to change the coolant and the thermostat? Is there something wrong with them?

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.

#3 Guest_Tolerance02_*

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Posted 10 August 2003 - 06:30 AM

If the car behaves normal now i don't see any reason why you should mess around with coolant or thermostat.
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.


#4 Guest_99obw_*

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Posted 10 August 2003 - 06:41 AM

The t-stat is easily changed from underneath. Two bolts hold it on to the water pump. Follow the lower radiator hose from the radiator and it will lead you to the t-stat housing. Make sure you use an OEM t-stat.

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.


#5 Guest_edrach_*

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Posted 10 August 2003 - 07:41 AM

I'm with the first two posters on this....if it ain't broke, don't fix it. Also, head gaskets normally need a reason to fail (overheating is one). Pre-emptively changing them doesn't make sense on a car with 46K on it. My GL wagon ('86) has 260K on it and the head gaskets have finally failed; but not for the reason you fear (HC's in the coolant); this car is leaking oil from there. I bought my '91 Legacy with 98K on it and took it on a 500 mile trip the first weekend I had it without any fear. Why do you want to replace the thermostat? Any symptoms to indicate that it's not working as it should? As said in an earlier post, check you owner's manual; I think it will suggest changing/flushing the cooling system at 60K. No reason to pre-empt these repairs if you don't have any symptoms indicating otherwise.

#6 Guest_theotherskip_*

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Posted 10 August 2003 - 09:25 AM

like 99obw said, changing the tstat is easy. it's on the bottom and easy to get to. should you, well, that's a mixed bag. 2 years is a common mark, and i think i will stick to that more closely in the future. my head gasket blew recently. i have the engine apart and am waiting to get the heads back from the machine shop.

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...

#7 Guest_Hondasucks_*

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Posted 11 August 2003 - 12:45 AM

"Why on earth would you want to change the coolant and the thermostat? Is there something wrong with them?"

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?

#8 Guest_HBDad_*

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Posted 11 August 2003 - 01:48 PM

What's wrong with changing the coolant? It is general maintanance ALL cars need at regular intervals (like changing oil and what not).

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.

#9 Guest_99obw_*

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Posted 11 August 2003 - 02:56 PM

I have seen them work sort of. The one I just replaced on my other car would hold the temp steady most (99%) of the time, but sometimes I would look down and it would be really cold or hot. I think that it was just slow to respond under certain conditions. Now it is rock solid.

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.


#10 Guest_edrach_*

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Posted 11 August 2003 - 06:45 PM

Nothing wrong with changing the coolant--but at 46K miles?? I'm not sure what the owner's manual suggests as a proper interval.

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.

#11 Guest_Setright_*

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Posted 12 August 2003 - 02:30 AM

Holy smokes! Poor poster must be getting in even more doubt now!

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.

#12 Guest_Legacy777_*

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Posted 12 August 2003 - 06:28 AM

Listen guys......let the guy change the coolant if he wants!!

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.

#13 Guest_wrxsubaru_*

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Posted 12 August 2003 - 09:08 AM

after time the radiatitor fluid will turn more acidic. This could help eat at the head gasket to make it prematurley go.

#14 Guest_pjsemmer_*

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Posted 13 August 2003 - 07:41 PM

anks to everyone who has responded so far.

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. :D

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!


#15 Guest_edrach_*

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Posted 13 August 2003 - 08:27 PM

Glad to hear that you've recovered from the "scared" status. Sorry I was wrong about the interval on changing coolent. I'm apparently lucky since my wagon has 256K on it and I changed the coolent when I bought it at 123K and I'm still on the original head gaskets. I'm about to replace them not for failing in the coolent area but the oil o-rings are shot and I have oil seeping out while I drive from between the cam cases and the cylinders. I'm more conscientious with the oil (every 2000 to 2500 miles). Coolent info was good for me; you CAN teach an old dog new tricks. My original comments were really intended to foster more confidence in your car; these subarus are really sturdy little beasts and thrive well with minimal (periodic) care--and I don't mean skipping the suggested maintenance intervals. My personal feelings are pay attention to the noises it makes, watch the guages, and respond to what the car tells you. Almost every failure gives some warning. Glad to have you on board!

#16 Guest_Flowmastered87GL_*

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Posted 14 August 2003 - 02:20 AM

I know my double core radiator said... to keep the warranty valid change (and flush, but I say screw that part) the cooling system every year. I dont think antifreeze goes bad that fast though.... I think more of a 3 year 30K system is good for me.... my car drips enough through the NEW heater hose :mad: for me to top off the system every 10K or so

#17 pjsemmer


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Posted 17 August 2003 - 10:02 PM

Just to let everyone know, I came back from my trip to Pennsylvania on Saturday evening. Drove about 470 miles altogether. The coolant change proved to work out well. Temps were right where they should and have always been. Even with sitting in an hour-and-a-half worth of 5 MPH traffic with the A/C running in 90-degree heat on the Belt Parkway the day after the big East Coast Blackout. (It seems everyone decided to go away that weekend after all had the day off! Encountered the same thing coming back on Saturday night as well. BTW, New York sucks, just to let everyone know. I don't think that there is anywhere in the U.S. with such a clusterf**k of a highway system. As soon as you get out of New York, you basically fly all the way to your destination unless there happens to be an accident (which we did encounter on the Jersey Turnpike to boot!)

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.

#18 bbart


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Posted 18 August 2003 - 03:04 PM

I had a Prizm that the Fstone service people did a power flush. To make their life easier, they cut the upper radiator hose and inserted a T-fitting with a pair of hose clamps.

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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