Another overheating question, sorry

[montana105]

Cause and effect-you're right there. Guess we need to hear whether they see any signs of coolant leaking on the ground or in the engine bay or whether the fans are working. I once had a 66 Stang that ran much better if the radiator was only 3/4 full,it would just spit the rest out as soon as it wanted,made me mad because the fan picked up all that fluid and flung it all over.

[McDave]

Cause and effect-you're right there. Guess we need to hear whether they see any signs of coolant leaking on the ground or in the engine bay or whether the fans are working. I once had a 66 Stang that ran much better if the radiator was only 3/4 full,it would just spit the rest out as soon as it wanted,made me mad because the fan picked up all that fluid and flung it all over.

 

I had to put an overflow bottle on my '66 HiPo 289 just to keep from getting black flagged at the starting line. Under filling the radiator, like you were supposed to do back then, just didn't make sense to me.

[edrach]

Add a 50-50 mix of antifreeze and water to both the radiator and to the full mark on the coolant overflow bottle.

Just to clarify McDave's comments. There are two full lines on the overflow bottle. The lower line is the proper level when the engine has had overnight to cool down. The upper line is the full mark for when the engine is fully warmed up.

 

Now let's try to keep everything simple and not suspect the worst.

 

First, replace the radiator cap with a new, OEM cap. The radiator cap is actually a two way valve. When the engine is warming up the coolant expands and the cap opens up when the pressure reaches 13 psi and allows the coolant to flow into the overflow bottle.

 

When the drive is over and the car is parked, the return valve in the radiator cap allows the coolant back into the radiator. All this works fine as long as the plastic tubing is tight at both ends and has no cracks, holes or anything that will impede the siphon action of the coolant flow (flow out is by pressure; flow back is by siphon action).

 

The other culprit is if there is an air bubble in the coolant large enough to disrupt the flow of coolant driven by the water pump. If the bubble lodges in the water pump, it stops pumping coolant and the temp guage suddenly shoots up; often momentarily. Plus if the air bubble gets to the overflow line, it allows coolant into the overflow bottle but disrupts the siphon return of coolant into the radiator. Now you have too much in the overflow tank and not quite enough in the radiator.

 

A sticky radiator cap can impede this flow in either, or both, directions with similar results.

 

The technique that McDave described to you is a way to insure that there are no longer any air bubbles in the coolant large enough to screw up the system.

 

Air in the system has all the ugly symptoms of a bad head gasket: intermittant overheating and excess coolant in the overflow tank.

 

All this being said (sorry), an experienced mechanic can eliminate the air bubble if it's there as well as run a hydro carbon test on the coolant to see if there is an actual head gasket issue.

 

So have the car checked and put your mind at ease........and let us know how you made out. I wish you the best outcome; I love every Subaru I've ever owned and wouldn't trade any of them in prematurely (even the "naughty" ones that gave me some grief).

[OB99W]

[...]The instance where heat didn't come out has only happened once, and when it happened, it lasted for maybe 3 seconds - wondering if what you all are describing is an event that happens more frequently and for a longer period of time than that?[...]

Once the engine is warm (and certainly if it's hot), unheated air from the heater (even if it happens for just a few seconds) means there is no coolant in the heater core at that time. That should never happen if the cooling system is properly filled, so a lapse in heat output points to at least some air in the cooling system.

[OB99W]

Do you mean just looking at my driveway and making sure there isn't fluid that's leaked out of my car? Now that's something I can do!

Yes, if you see some coolant on the driveway, that would point to an obvious leak. However, sometimes the leak is slow, might happen while driving or parked elsewhere, etc., so that it might not be easily apparent.

 

 

And I doubt I have the Conditioner in it. My tune-up was done by a garage, not the dealership. I've only taken the car into the dealership once, and that was years ago. But I could order the coolant from a local dealership - I've ordered parts from them before.

In order to possibly stem an external HG leak, and to perhaps qualify you for an extend warranty on the HGs and no-cost replacement by Subaru if needed, there should be Subaru Cooling System Conditioner added to the coolant.

[OB99W]

Sorry to play the dumb girl, but do you have some quick and dirty instructions on how to know when the fan is on, and how to clear dead insects, etc?

The fans (there are two) face the radiator, and are located right behind it as you look from the front of the car with the hood raised. When the engine is sufficiently warm at least one of them should be running, and if hot, both should be on. With air conditioning running, at least one should be on as well. Keep your hands away from the fans, as even if not turning they can come on unexpectedly.

 

If you look through the front grill of the car, you'll see what looks like the radiator, but with air conditioning (A/C) it's actually the A/C condenser. Since it's "sandwiched" with the radiator, anything obstructing the condenser also obstructs the radiator. Insects or other debris that can restrict air flow can be gently brushed from the surface, or removed with water from a garden hose, etc.

[OB99W]

There are two lines on the coolant reservoir. The proper level of coolant in the reservoir is between the two lines, when checked with the engine cool -- it should not be below the lower line. If it's near the lower line, it should be brought up to the upper line using a 50/50 coolant mixture, although water alone can be used temporarily if no coolant is available.

 

(The upper line isn't the "full when hot" point -- there's plenty of room for coolant expansion beyond that level.)

 

As I and others have said, the radiator itself needs to be checked to verify it's filled (when cold).

[OB99W]

Info on the WWP-99 campaign:

http://www.snedcs.com/dcsmain/service/WWP_subnet2-5-04.htm

[McDave]

Info on the WWP-99 campaign:

http://www.snedcs.com/dcsmain/service/WWP_subnet2-5-04.htm

 

Anyone here ever get their hands on the conditioner? Cadillac used to recommend a treatment for porosity in their aluminum engines. Turns out it was just the Bars Leak tablets. I'm wondering if Subaru's stuff is the same, or similar.

[idosubaru]

subaru's is "slime" it's a bottle of liquid.

 

i'd start by checking the radiator level - knowledge is power. i'd like to know how full or not full it is. let us know how much fluid it takes.

 

after that a new radiator cap and some additional subaru slime conditioner would be a good bet. but then again...you might want to avoid this is there's a chance of getting it fixed properly for free from Subaru - see below.

 

if you know how to look at the rear of the engine - that is where these leak externally. it's essentially the part of the engine that's facing you while driving, you'll have to bend around and look under hoses and need a good flashlight. look back there for any signs of leakage.

 

if it's leaking start working on that free Subaru extended 100k warranty business. this is only available on some EJ25's, not all of them - but there's a really good chance yours is one of them.

[axel]

Re: Subaru headhasket replacement. When Subaru does a head gasket replacement under waranty, they do it the quick and dirty way, while the engine is still in the car: the preferred way is to pull the engine first, to allow easy access to the head, makes for a more reliable fix.

Head gaskets can be reliably replaced with engine still in the car if the tech doing the work is very careful and meticulous, but few are.

Subaru does it without pulling the engine because it saves time and (therefore money), but the end result is often repeated head gasket failure somewhere down the line.

If you have hg replaced under waranty, consider getting rid of your Sube before the hg goes bad again; the headgasket that's replaced isn't covered for a second failure, unless it fails soon after replacement.

[bulwnkl]

OK, so I've only scanned most of this thread VERY quickly, so this may be useless input. However, that's never deterred me before.

 

I had a temperature fluctuation condition similar to that described in the initial post(s) in my XT-6 a few years ago. It was my thermostat malfunctioning (new within the previous month or three). Replaced that and the symptoms went away. That's a cheap, easy thing to replace and may solve this.