Changing my Coolant

[upnorthguy]

Knock yourself out, but you gave this advice to another person, so I will give my advice as well.

 I think you should not deprive the NASIOC forum of your wisdom.  They are always looking for some good contributions.

[johnceggleston]

 

 I think you should not deprive the NASIOC forum of your wisdom.  They are always looking for some good contributions.

seriously funny.

[Fairtax4me]

Cut it out guys.

 

It is the practice of removing the upper hose at the radiator and filling it that to me is a complete waste of time. I do not disagree with filling it slowly or having the front end elevated, many cars today require that, not just Subaru's.

Painfully slow is the only way I could describe how long it takes for these blocks to fill with coolant if they airlock. If the thermostat is not a Subaru design with the jiggle valve, it will never happen. If it does have the jiggle valve it takes over an hour to get the system full, as coolant will only very slowly dribble in through the valve.

 

The waste of time is to stand there and wait. Pop the upper hose off the radiator and the block is filled in 30 seconds.

Edited February 13, 2015 by Fairtax4me

[nicholi2789]

The day you stop taking other people's advice because you think you already got it figured out, is the day you stop learning anything new. There is always more to learn.

And just because you you understand how an engine works doesn't mean that a particular type of engine can't have it's own quirks and problems that you can't foresee. Listen to these guys, they know their Subaru's. Experience is the best teacher, and they have given me sound advice on numerous occasions.

 

I for one can attest to the effectiveness of this method. When i filled the radiator the normal way (I DID open the bleeder screw) I got airlock bad, and it took me two days to get it to stop overheating. The second time I filled it, I parked on an incline, dumped coolant down the top radiator hose, then proceeded to fill it. Went off without a hitch. I have done it twice more since and haven't gotten air lock again. 

[keith3267]

The upper radiator hose is open to the top tank of the radiator, a blind man can see that.  nicholi, did you park on an incline the first time?  I think the incline had more to do with your success than removing the upper radiator hose.  I don't know what NASOIC forum is but I don't click on links that I am not familiar with so I don't get the joke.

[johnceggleston]

 

 I don't know what NASOIC forum is but I don't click on links that I am not familiar with so I don't get the joke.

it is another suabru forum, i think impreza focused originally,

and seriously into modding their cars.

as opposed to this site which seems to be more repair and maintenance focused.

but they know their stuff.

 

the joke part is ,

if you think we are being hardheaded,

just try swimming against the tide over there.

 

we are a much more gentle bunch.

and accepting of all kinds of folks,

even folks like me.

Edited February 13, 2015 by johnceggleston

[nicholi2789]

The upper radiator hose is open to the top tank of the radiator, a blind man can see that.  nicholi, did you park on an incline the first time?  I think the incline had more to do with your success than removing the upper radiator hose.  I don't know what NASOIC forum is but I don't click on links that I am not familiar with so I don't get the joke.

Yes it was parked on the incline the first time. That wasn't the reason I got airlock. 

[keith3267]

OK guys, I am not a physicist so I don't know everything about everything that is worth knowing, but I have been thinking about this and at the risk of sounding like one, I may have come up with a theory.

 

At first, removing the upper radiator hose just doesn't pass the logic test when the hose is completely open to the upper tank of the radiator.  But when you fill through the radiator exclusively, you are filling the engine from both hoses at the same time and because of the little dribble valve in the thermostat, you could trap air in the engine.

 

If you fill from the top hose only, then air can escape through the dribble hole and out through the lower hose, eventually the coolant will fill in the lower hose through the dribble hole and then start filling the radiator from the bottom.  Does that make sense?

 

You could also fill very slowly through the radiator and the block would fill through the dribble hole until it reaches the upper hose, but this would be very slow as you would not want any coolant to start spilling over into the upper hose until the coolant in the block has risen high enough that all the trapped air is gone.

 

That makes an interesting alternative filling process that might work for someone in a hurry.  If you have a camp stove, You could preheat the coolant to 180°F or so and then fill the system through the radiator.  The hot coolant would open the thermostat right away so it would fill the engine quickly.  You would want to heat the coolant outdoors as outside a pressurized system, antifreeze will give off vapors, a lot of vapors, far below its boiling point.  You do not want to do this inside your house.

 

I wonder why Subaru didn't put a bleed valve somewhere in a high point in the engine like everyone else does?

[MilesFox]

All of this advice is relative to the thermostat location and an air pocket in the engine, and the pocket settles on the thermostat, and that there is no coolant flow. It is possible to overheat during a fill procedure with a full radiator and air lock. And with an air  lock, coolant will push out if you try to add until that pocket is burped. filling by the block primes the cooling system and gets some behind the thermostat. There is a bypass hose behind the thermostat that will prevent it from opening when there is an air bubble present.

 

These tricks are specific to subarus. Only those with experience can predict the trouble of a simple coolant drain and fill. Often times it takes manipulating the idle forcing the engine under load and heat, and babysitting the thermostat to ensure that it is open to get a complete fill.

 

It is those whom are not familiar with these tricks who post here having trouble with overheats or cold heater after having the coolant system open.

 

Expertise with subaru is specific, and the general platform of a subaru is atypical when compared to the w˙ole of other makes. Often times conventional automotive wisdom does not apply the same with subaru.

[stackman1]

Hello Everyone - I am the OP - and as you may have guessed a major procrastinator.

 

In any event I finally changed my coolant using an OEM Thermostat from Subaru and added a bottle of conditioner.

It would appear everything went well.  I used the suggested approach of filling the engine core via the upper hose.

I didn't change the hoses.  

 

I put my Subaru 2002 OBS 2.5L MT on jack stands and then:

1. Disconnected and cleaned overflow bottle.
2. I twisted the plastic butterfly screw on the bottom of the radiator and emptied the radiator.
3. I disconnected the thermostat housing and replaced the thermostat.  Reconnected.
4. Filled engine core through upper radiator hose
5. Filled radiator. Filled Overflow.
6. Turned on car and let it run on stands.

Probably had it running on the stands for 45 minutes - revving occasionally.

 

Two Questions:

1. The temperature gauge looks fine just less than half - but the radiator fans have not kicked on.  Is this to be expected? Do you really need to get it on the road for the fans to go on?
2. When I pulled off the old thermostat I was expecting a gush of water - nothing!  Does this make sense?

Thoughts Anyone?

 

Thanks

Pete

[Fairtax4me]

If the outside temp is fairly cool you will likely need to close the hood to get enough heat to make the fans turn on. It could still take 20-30 minutes for them to turn on at idle.

 

The Subaru thermostat design has a jiggle valve that allows a small amount of coolant to trickle past the thermostat. If you wait long enough, there will be almost no coolant left in the block so very little will spill out when you remove the t-stat.

[stackman1]

 

If the outside temp is fairly cool you will likely need to close the hood to get enough heat to make the fans turn on. It could still take 20-30 minutes for them to turn on at idle.

The Subaru thermostat design has a jiggle valve that allows a small amount of coolant to trickle past the thermostat. If you wait long enough, there will be almost no coolant left in the block so very little will spill out when you remove the t-stat.

Well it was about 65 degrees and I did have the hood open the whole time. But maybe I am still in the dark about how it all works.  What is it that triggers the fans to go on?  

 

Also I still don't understand why - when I popped the old thermostat off - no coolant came out of the engine core. Are you saying the the entire contents of the coolant in the block had dribbled through the jiggle valve into the lower radiator hose?  If that is the case, wouldn't it mean that the engine would have no coolant until the thermostat opened?

 

What am I missing?

Edited November 3, 2016 by stackman1

[Fairtax4me]

Coolant temp has to reach 204°F for the ECU to turn on the fans. Thermostat starts to open at 170, and is full open around 192. If it's cool out and the hood is up there's usually enough cooling capacity in the radiator to keep the engine from reaching 204 at idle.

Really the only important thing is that it reaches full operating temp and maintains that for a few minutes so coolant will circulate through the entire system and push any air pockets out of the block.

 

 

Normally when the radiator is full the engine block is also full of coolant. When you drain the radiator, the coolant in the block also drains (slowly) through the jiggle valve. If you yank the thermostat housing right off, and then pull the thermostat off right away you'll get about a half gallon or so of coolant out of the block running down your arm.

[1 Lucky Texan]

just ducking in to mention I recently chaged the coolant and 3 big rad hoses on my 03 H6.

 

first, draining it made a big mess - next time I'll try to position receptacles better. Someone mentioned hose clamps. A brand GEMI was mentioned in another thread and I bought some from Amazon - they are very nice, narrower that typical screw-type and the edges are rolled up. so, you might check them out. (diameter ranges listed in mm)

 

[stackman1]

So I took my ole Sube to the gym - first test - roughly 5 miles away.  The temperature gauge looked fine until about mile 3 and then it started to climb.  It was close to the red when I stopped.

Coming home it hit the red and so I pulled over.  Got it back in my driveway.  I am getting some dripping from my lower hose (where it is connected to the radiator) - I replaced all four clamps and likely just need to tighten that one.  

 

I know from reading forums, having air pockets is often a problem, the system often requires burping.  When I changed my coolant yesterday and still had it on jack stands with the radiator cap off - I let it idle for a good long time and revved the engine - thinking that was one approach.  Not sure if air is my problem

 

I am a bit concerned about the following, it had to do with my install of the new thermostat (purchased from dealer).  When I disconnected the housing the original thermostat was stuck in place and essentially flush. I pried it out.  But the new thermostat almost seemed a micrometer larger than the opening.  The outer rubber gasket prevented me from being able to place the thermostat into the opening and let go.  I had the jiggle pin hanging down, pointing the same way as the original, but I am worried it didn't set right.  I held it in place with my fingers and then slammed the housing up to keep it from falling.  I then bolted it in place ......like I said that is the only thing I can think of but clearly I have an issue.

 

BTW, my radiator fans did go on....during the drive

 

Question:

1. Should the new thermostat be held in place on its own or is what I experienced the norm?
2. My radiator fans did go on!  And I just read a poster on NASIOC state that having the fans go on - indicates the thermostat is open?  Is this a true statement????
3. Does the temperature gauge on the dash directly reflect the engine temperatures?  

Thanks Guys - Any Ideas?

Pete

 

1.  

Edited November 3, 2016 by stackman1

[Fairtax4me]

Thermostat should fit into the groove in the water pump. The rubber gasket may not be situated properly on the thermostat. I usually wipe some coolant on the gasket to help it slip into the groove. This is probably your leak if the gasket isn't seated properly. You will likely need to replace the gasket.

 

Which way did you face the spring?

Did you use a Subaru OE thermostat?

 

 

Radiator fans running gives no indication of thermostat operation. It only means the coolant at the area of the temp sensor has reached around 204°f, which is the temperature at which the ECU is programmed to command the fans to turn on.

 

It shouldn't be that hard to get all of the air out of the cooling system on that year car. On some of the older cars it was tricky, but Subaru re-designed the radiator around 2000 and the majority of problems with properly filling the cooling system were eliminated with that change. Was your coolant mixed 50/50? How much did you pour in? Should hold somewhere around 1.5 gallons.

[1 Lucky Texan]

fair - could that install have bent/warped the t'stat enough to prevent opening?

[stackman1]

I was happy with the amount of coolant it took; about a gallon and a half - including overflow reservoir.

I filled the engine core through the upper radiator hose.

I did attempt to burp as described above.

 

No.... I could kick myself.  I should have spent a few more minutes with seating the thermostat.  

I did buy it from the dealer - $38.94 - Part # 21210AA030.

 

Well I guess in a few hours I will be making another mess pulling the housing back off to see - damn.  

Spring side was inserted up into the housing; jiggle valve was hanging facing front of car just like old one.

So I take from what you are saying, when installed, thermostat should sit tight into the housing and remain there - hands free?

That was not the case when I put it in. It would not stay up in the housing without me holding it in place.

 

I should have taken a breath and thought it through - damn. 

I'll bet I now ruined the outer gasket in the process by bolting in place as I did.

 

I'll check it out and get back to you. But I take it if it doesn't sit up in the housing hands free it isn't right.

 

So the possible takeaway is: 

1. Maybe my bad install is preventing the thermostat from opening.???  Therefore, the coolant in the block never gets refreshed.  It just gets hotter and hotter - ultimately sending the temperature gauge into red?

[Fairtax4me]

I've had a few that wouldn't stay put on their own, but they always fit completely into the groove in the housing.

 

If it didn't fit all the way into the groove, then yes I think that needs to be taken off and re-fitted, and possibly a new gasket used if it's damaged.

 

I don't think that it would have damaged the thermostat. Subaru thermostats are pretty tough.

[1 Lucky Texan]

I just mentioned is as a possibility. doesn't mean that's what happened.

[stackman1]

So if necessary I can just buy the outer gasket - if I have squished it to hell?

Heading out now for round two.

 

Thanks as usual....

[1 Lucky Texan]

the metal is thin, but as I recall, it seemed strong as fair mentioned.

 

you could test the t'stat in a pot of hot water. opens at 171*F or so.

 

(never create a situation where any animal or child/person could ingest coolant - permanent kidney damage and perhaps death will occur -  no open drain pans a cat or dog could get to, etc. ,wash things thoroughly after stove top test)

[stackman1]

Ok...........  I slowly unbolted the housing and thereby caught most of the fresh coolant before I even dropped it.  No mess.  When I finally unbolted it fully - the thermostat fell right out - it clearly wasn't seated properly.  In all I retrieved a full gallon of coolant however I asssume some of that came from the lower radiator hose before I was able to bungee it.

 

I washed the thermostat and removed the gasket.  It was a bit worse for wear - being somewhat squished - but I was able to fully thread it around the base properly and now it will sit in the base of the water pump without holding on.

 

Here are my questions:

1. Is it a big mistake to just go with it or should I get a ride to the dealer tomorrow and get a new gasket- assuming they have one in stock for my '02 OBS?
2. Also, I don't want to reuse the coolant that came out.  When I performed my refill I used Prestone which was guaranteed for all Asian cars.  But I have a nearly fully bottle of Peak Global Lifetime Concentrate and hate to have it go to waste.  Is it a big no-no to mix brands - or am I being a bit anal on both these points?
3. Should I add another 4 oz blue bottle conditioner when I replenish the lost gallon?  If so any problem adding it directly into engire core via the Upper hose?

Thanks

Peter

Edited November 4, 2016 by stackman1

[1 Lucky Texan]

just my opinion;

 

1. go with it if you feel 'pieces' won't come off. If it's  blemished a little - even deformed a little - it may resume it's molded form after a little heating. Maybe leave it on for the stove-top test even.  polymers often have a 'memory'. Plus, seems like worst that might happen is some slight amount might bypass around the seal - no different than the jiggle pin. But you don't want chunks of it to come off!

 

2. Read those jugs text. I suspect it's OK to mix them. DexCool is often the bad one to be avoided I think. glycol based coolants should be able to mix. many people DO feel you need  certain additives and low-amounts of other components but I think both those brands have been used by subaru owners. I'd risk it. Is it 'ideal' no, but, shouldn't be 'catastrophic'.

 

3. I don't think I'd use an entire bottle of conditioner. Just an amount proportional to what's being put in - maybe 1/2 bottle?

 

 

I like to clean-out the overflow bottle - shake some ice cubes back and forth in it, rinse it out. Cut the little tube's bottom at 45* angle. Use a coupla small zip tie on the other end to create a good seal on the nipple at the radiator's neck. Inspect rad cap - replace if old. I like Stant, some folks insist on OEM.

Edited November 4, 2016 by 1 Lucky Texan

[stackman1]

Hey Tex - 

 

I did the thermostat test and it worked perfectly.  I took the gasket off for the test though....  I do agree it is ok to reuse the gasket; doesn't look bad - just a bit rough.  

I am a bit of a perfectionist at times.  

 

I am going to install the thermostat and fill the engine core again through the upper hose.  

Once I do that I will need to burp it for air bubbles I guess.  

Any tips on that would be appreciated.  

 

I will leave on jack stands till done.

 

Big thanks to you and FairTax - very educational.

Pete