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Hi All---

 

2003 Forester. 5spd. 143,600 miles. 

 

5 months ago, did HGs, t-stat,cap,w/pump, timing belt and idlers,tensioners,etc, new hoses.

 

Since then, we've taken several trips over the Grapevine and up the Central Valley to UC Davis, some seriously loaded (not me, the Subie.) No issues at all with the Forester.

 

This week, my son and I took a trip through the Mohave Desert to the Sierras in the Subie, a trip of about 280 mi. with an elev. gain of @10,000 ft., A/C on.

 

When we arrived at South Lake(what's left of it!) and parked to survey the trailhead,  coolant began pooling on the ground under the radiator. I checked the coolant tank, and it was not totally empty(kinda like the lake). We got in and drove around 1000 ft. down the mountain and camped.

 

Before returning up the mountain to the trailhead early the next cold morning, I again checked the coolant levels. None to be seen in the filler neck and little in the coolant tank. I added around 3 qts. of mountain water to get up to levels. When we returned to the car that evening, levels were OK but it had been a short uphill drive in the cold air.

 

I spoke with a guy at a radiator shop in Bishop who said he was familiar with the Forester and had owned a Suburu, and that he was sure the fans were turning too slow, and that they worked together as a unit. The too slow thing made sense, although I know each has its' own relay. 

 

We continued our trip up the Sherwin Grade to Mammoth Lakes, and then after dark, home, downhill to LA(like the aqueduct) eyes on the gauge, alternately speed-coasting and babying 'til we made it home.

 

This morning, low, but not empty. 

 

Searching for answers and asking for helpful suggestions...

 

Thanks,

 

JW

 

 

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you did use the large OEM or OEM-style thermostat right?

 

 

I'd say have the system pressure tested. It's a good thing that the
reservoir didn't have all the fluid pushed into as happens mostly with
bad headgaskets. I wouldn't discount the possibilty of some bad temp sensor feeding the ECU incorrect temp info. The fans are 2 speed but run operate at the same time I THINK on a 2003.

 

 

but, kinda surprising you didn't find the source of a leak so......

Edited by 1 Lucky Texan
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Thanks,1 Lucky Texan

 

I bought the w/pump and timing components from All Wheel Drive Auto in WA. I trust it was the right stuff.

 

I was thinking bad sensor. Maybe OBD scan will tell?

 

Yeah, the source of leak. Looks like some escaped thru top of coolant tank and sprayed on belt shroud. Not so much at the cap. The cap's a new Stant. I never think about this stuff until it's a problem, but the cap is supposed to release before too much pressure builds up in the radiator, right? 

 

I haven't pulled the plastic pan to get a good look, I can't tell if it's cause or effect, but the bottom seam of radiator looks like it may have failed and I'll have it checked, but it's not as if I could top with coolant and race up a grade without the temperature gauge coming right up.

 

Edit: Searched fans for this car and came across a note from one manufacturer that said to be sure to reboot computer after installation. I'm wondering if that would be a one time syncing deal or if you need to reboot every time you disconnect the fan. I didn't and had never heard of this.

Edited by quazi
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Slow leaks will lead to overheating when the fluid level gets low enough, even if the guage does not reflect that the engine is running hot right away.

If the coolant is above normal operation temp when the engine is turned off there's a good chance it will boil over. This is also when coolant is most likely to push out of a crack in the radiator, since the system pressure spikes and pushes the crack open. Not saying the radiator is definitely cracked, a pressure test would confirm.

 

 

Some vehicles have to have the computers reset anytime a component is disconnected. Your Subaru is not one of them.

 

The fans are easy to test. Find the two green plugs under the dash on the drivers side. Connect them and then the key ON. There will be a multitude of clicking as the ECU cycles all of the relays and solenoids in the car. The ECU will cycle the fans on in both speeds for roughly 1 second intervals.

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I'd give you ten likes for that!!! Just the kind of thing I come here for before I start pulling things apart. I have a Haynes manual, and maybe this info is there, but I find that the info you're looking for is buried.

 

Super easy test. Fans are working at both speeds! 

 

Thanks

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coolant leak

radiator clogged

radiator cap not sealing - either the cap is problematic or the radiator neck won't alllow a proper seal

headgaskets

 

thermostats are rarely an issue but you can throw it in a pot of boiling water and test if it's opening/closing properly

water pumps almost unheard of

 

what brand HG's were used?

were the heads resurfaced?
add coolant conditioner with the new HG's?

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The fans tested OK.

 

OBDII scan clear

 

Radiator shows no evidence of leakage and internals look brand new. I pulled it and looked it over really well. I plugged the inlet with a rubber cap with a hole punched in it to shoot compressed air and  capped the outlet. Then added water to the radiator and slowly shot-in compressed air, enough to bulge the caps a bit. No leaks. It took very little air pressure to blow past the cap and thru the overflow nipple, but 16 lbs isn't much, anyway.

 

The HG are Six Star.

 

The upper hose is filled with hot water, and the t-stat is 4 mos old and purchased from AWD, so I assume it's correct.

 

I did not resurface the heads, but cleaned them up as best I could to the desired finish. My HG failure was on the oil side and never contaminated the coolant as far as I could tell visually. Been dry as a bone since.

 

I did not add the the conditioner. I got the impression that it was mainly to aid the old-style gaskets.

 

 

I re-installed the radiator and fan assy. and took a test drive full A/C up hills. Temp gauge read between the lines, just South of center.

 

 I'm at about 800ft above sea level and it's now 105 *.

 

First boil-over was at high altitude, but not necessarily overheated, just a hair above the upper-center line on gauge. 

 

Could it be the freakin' 4 month old  cap?

 

My son's taking the Forester with him to college in Davis, Ca. next week, so I'd like to figure this out!

 

I'm going to change the cap, then drive the hell out of it this week. It'll be in the 100s here for the next 4-5 days. I guess what I'm watching now is mostly coolant consumption. I don't see how I could be losing the quantity of coolant into the crankcase without getting milky oil on the dipstick. I suppose I could pull the valve covers and look for it if I continue to lose coolant after the new cap goes on. 

 

I'll drain the mostly distilled water solution and get the coolant right. If I still get boil-over, I'll just save what I drain and re-use. Stuff ain't cheap! 

Edited by quazi
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I just rigged-up a test for the radiator. I don't know that it was even definitive for the radiator, but I could see no evidence of leakage around the seams under air pressure in the driveway or in the car.. The only place I ever saw evidence of coolant leakage was on the ground and at the top of the coolant tank and the pulley guard right next to it.

 

I've read posts here during search where folks have mentioned the radiator clogging properties of the conditioner. If I go to Subaru for a cap on Monday, I'll probably pick up some conditioner, anyway.

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I filled-up the car with guinea pigs family and friends, and in the 107* heat drove 45min hard over the mountains to the coast, A/C on. No coolant loss, needle below midpoint. 

I dropped by and spoke with mechanics from two seperate recommended shops, one, the owner drives a Subaru.

 

I talked to them about a coolant "hydrocarbon sniff-test" and related my sad story. Both said that given the drive (which they both know), current heat wave and the fact that the car retained all the coolant and maintained its' cool, the test would be unnecessary. 

 

I'm ignoring my natural inclination to suspect the worst, but I took the advice, paid too much for Subaru coolant, and added the Subaru stop-leak magic conditioner.

 

I haven't had the 5 month old Stant cap tested, but I intend to, although I know I'll feel a bit like Moses, tapping the rock TWICE...

 

 

P.S.  I refilled with the nice, clean, coolant, in the freshly flushed system. Then I added the clotting agent magic conditioner. Instant floating crapola fairy-dust. Jes' don't sit right, but if Subaru thinks it protects my HGs and doesn't clog my radiator, I'll drink the lumpy kool-aid.

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Final update, I hope...

 

On Friday(above entry), convinced I had my coolant problems on the run, I drained the mostly distilled water solution and filled up with Subaru Long-Life and Subaru Coolant Conditioner. On the coolest Saturday morning in recent memory, my wife takes the Forester to the local Farmer's Market, a three mile run on surface streets.

 

I get a call from her saying that there was steam coming from under the hood.

 

Now, not trusting anything I know from experience, I researched the correct cold fill level in the overflow tank and had added coolant almost to the full line. I thought "dang, I must've over-filled it and it overflowed."

 

I opened the hood, started the engine, and observed the $20 Subaru coolant flowing from the upper seam of the radiator.

 

It was 12pm and I was able to have my local independent parts guys load up a new radiator on their last parts run of the weekend. 

 

I saved the drained coolant and installed the new radiator, arrived comfortably late Saturday afternoon at my wife's family reunion and hoisted some cold ones.

 

Next morning in my truck, I followed my wife and son driving the Subaru over the Grapevine, through the Great Central Valley, to UC Davis. Forester ran cool and smooth and lost no coolant.

 

I think it was the magic conditioner forcing the failing radiator to show itself. Or, the cool ambient air, after days of 107* heat allowed the seam to shrink apart, or ????

 

 

 I used to know quite a few guys to bounce ideas off of, but fewer and fewer do their own mechanics anymore.

 

Many thanks, again, to those here who offered their thoughts on what might me ailing my Subie

 

JW

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I've replaced 5 radiators in the last couple months, all due to split end tanks or leaks at the seams. It's the most common failure mode for a radiator. Sometimes you have a small leak for a very long time before it finally splits open and becomes evident, sometimes it just blows out all at once. Just depends on your luck that day.

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I've replaced 5 radiators in the last couple months, all due to split end tanks or leaks at the seams. It's the most common failure mode for a radiator. Sometimes you have a small leak for a very long time before it finally splits open and becomes evident, sometimes it just blows out all at once. Just depends on your luck that day.

I'm counting myself damn lucky it didn't blow in Buttonwillow the next day!

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