Wtf - H6 rad hose?

[jonathan909]

Normally parts are pretty easy to find, but here's a weird one - the lower rad hose for the '01 3.0 H6.  I blew two rad hoses (the long upper and the lower) over the span of a couple of weeks.  Grabbed the upper from the wrecker, but they ruin all the lowers when they drain the incoming cars.  But every aftermarket lower (Gates, AC Delco, etc.) I've seen so far is completely wrong, and I wound up ordering one from the dealer.  Did I miss something?

[Numbchux]

Most aftermarket hoses are "cut to fit" as they fit multiple applications.

I just put a Gates lower on our '04 H6 and had to cut some off both ends, but then it fit great.

[jonathan909]

I saw that they were all cut-to-fit, but the Gates didn't even look like that would work.

 

[1 Lucky Texan]

could be they used a 'generic' photo but, could have also been a disappointment to get the wrong shape completely.

I have had to trim a coupla aftermarket hoses too.

[GeneralDisorder]

We only use OEM hoses at my shop. Aftermarket fit like garbage and often require trimming to avoid hitting fans, pulleys, etc. 

GD

[1 Lucky Texan]

I could definitely see a shop not wanting to waste time trial fitting aftermarket hoses of questionable durability.

[idosubaru]

On 7/22/2021 at 7:35 PM, jonathan909 said:

I saw that they were all cut-to-fit, but the Gates didn't even look like that would work.

 

It happens. Aftermarket arent as sturdy, can end up with kinks and collapsed bends, and ends not entering and exiting the same angle as the inlet or outlet they’re bolting too, or not working at all.

It could also be confusion over naming conventions/listings. Some listings are poor and will show 4 cylinder parts for a 6 cylinder, etc  

Aftermarket has issues in general. Its unsurprisingly worse with less common engines/models like Subaru H6s. 

[GeneralDisorder]

When the cost from Subaru is typically $20 to $25 per hose and they last 10 years/100k miles..... I don't even see the value in buying anything other than OEM. 

When it comes to the radiator - we buy Denso or Koyo exclusively. Both are excellent quality. OEM is 4x the price and no better. 

It just depends on what part you need and experience. Hoses and Axles - OEM are the only good options. Seems like Alternators and Starters are headed that way also. Have had a lot of Denso reman failures in the last few years. Seems like quality took a dive. Subaru has remans for most applications. 

GD

[Numbchux]

8 hours ago, GeneralDisorder said:

When the cost from Subaru is typically $20 to $25 per hose and they last 10 years/100k miles..... I don't even see the value in buying anything other than OEM. 

I generally agree. But, my local dealership is 2-3 days out, and doesn't stock much for 20 year old cars (I don't blame them). Where the parts stores generally stock the aftermarket ones. With some patience, they do fit, but they're generally thicker rubber and will not fit the factory clamps. 

When I was putting together this Forester this spring and had time, I ordered OEM. When I've had hoses blow out, I grab aftermarket.

[el_freddo]

^ that’s probably the difference between some planning for the work to be done compared to replacing blown parts ASAP.

It’s probably also the difference between a specialty workshop that keeps a small amount of stock on commonly used items and someone working in their driveway with no stock to work from.

Cheers 

Bennie

[jonathan909]

AFK for a while, but back and with more related questions.  Regarding the hose, I was lucky to have a second '01 H6 here (a cheapie waiting for a head gasket, as previously discussed), so I was able to loot a couple of hoses from it to keep my DD running, and I picked up the replacement lower from the dealer today.  Rather more expensive than aftermarket, but in general I jam econo, so on the rare occasion I have to shell out a few extra bucks it doesn't hurt too much.

But...  The weather has been unusually hot here over the last month or so (as with a lot of places - it was hard to believe that a town in the BC interior set a record higher than that ever recorded in Vegas, and then was promptly destroyed by fire), and this car has been running a little hotter than it should.  First I had to deal with the two sequential blown hoses out on the highway, after which I was nervous about potential damage to the bearings, but it seems to have gotten through it okay and settled down.  But it's hot again this week, and on the way home an hour ago it was clearly struggling to keep cool - any extra load, whether it be a hill, going a little faster, or running the AC, was the difference between "somewhat hotter than normal" and "pushing toward the red".  So I could use some suggestions.

AfaIk, this is the original rad, but I haven't looked closely.  I'll mos def drop the thermostat and make sure it doesn't have some low-flow aftermarket in there.  Also, I recall from unrelated discussions years ago (regarding my old 318 Dodge Dakota pickup, I think) someone bringing up surfactants (added to the coolant) to improve the thermal transfer between the coolant and the metal.  Is that real or bogus?  Anything else I'm missing?

[Numbchux]

My '04 H6 was running warm. Approaching 250k miles, about 115k since I bought it and put an aftermarket radiator in it (I bought it crashed). It passed the hydrocarbon test with flying colors, doesn't pressurize the coolant while revving, doesn't loose any coolant (leaking, burning or pushing it into the reservoir). So, even though these engines are prone to head gasket failure, I do not believe that's what I was seeing.

I tried Water Wetter, the only one of those additives I've heard good things about. It's supposed to reduce surface tension, and therefore improve molecular contact between the liquid and solid. Might have made a small difference, but not much/enough.

Then I did 2 rounds of Gunk/Motor Medic Radiator flush. The first time, I removed the radiator and back-flushed it with the hose (as well as washing the outside of it, and spraying quite a bit of degreaser/water through the condenser). I disconnected the heater hoses, and back-flushed the core. Removed the thermostat and tested it, and flushed the engine through the top heater hose and radiator hoses. Second time I just drained it out and refilled. It seems to run great, now. I did buy a ScanGauge so we can actively monitor the temperatures, as the factory gauge really doesn't show much.

 

I've heard good things about this Golpher aluminum radiator on the Six-swapped Subarus Facebook group, so I was thinking about buying one. Might still for the next car....we'll see:

https://www.aliexpress.com/item/1005001893254265.html?spm=a2g0o.store_pc_groupList.8148356.20.664f421a5EchJf

[jonathan909]

Obviously I considered simple cloggage as well - a new rad was what solved the overheating problem I had with that old Dakota.  But I haven't used any of the rad flush concoctions for a long time, so maybe I'll give that a go after I check the thermostat.  If anyone's had good luck with any in particular, I'd appreciate the recommendations.

That rad looks slick, and I"ll bet it works a treat.  But more than $550 (Canadian, landed) for a rad?  I paid less than that for the car.

[Numbchux]

3 hours ago, jonathan909 said:

If anyone's had good luck with any in particular

That rad looks slick, and I"ll bet it works a treat.  But more than $550 (Canadian, landed) for a rad?  I paid less than that for the car.

Good luck, with a thermostat? Truth is, I've never had a problem that was definitively solved/caused by a thermostat, regardless of source. I had purchased a Duralast stat for this car when we bought it, which is still on the shelf. And I bought an Aisin one for the Forester I'm working on. When I took the one out of this '04 a couple weeks ago (likely original, *might* open about 4 degrees F cooler than factory rated, opens fully), I compared it. The Aisin one was the stereotypical small aftermarket one, where the Duralast one was identical, down to the markings, to OEM. Complete opposite of what I expected.

 

Yea, that's why I haven't bought one either. There's a couple sources for those, and Aliexpress is the cheapest to me, but still expensive as they all have to come from the far East. If it were half as much, I'd probably buy 2....Then again, I have a few of these cars, and intend to keep running them for many years, so it might be a good investment.

[jonathan909]

Thermostat:  I'm not talking about opening temp, because by the time it's that hot it's either already fully-open or clamped shut (i.e. defective).  I'm considering the possibility that there's an aftermarket cheapie in there that doesn't open as wide and support as high a flow rate as OEM.  Gotta consider it.

[Numbchux]

1 hour ago, jonathan909 said:

Thermostat:  I'm not talking about opening temp, because by the time it's that hot it's either already fully-open or clamped shut (i.e. defective).  I'm considering the possibility that there's an aftermarket cheapie in there that doesn't open as wide and support as high a flow rate as OEM.  Gotta consider it.

Yep. And the internet will tell you that all aftermarket Subaru stats have a smaller opening and you should only buy OEM. Which is why I said the Aisin one I have is smaller, and Duralast one I have is identical to OEM.

And also why I said I've never had a problem with aftermarket, although I'm the first to admit I don't live in a climate that requires much of a cooling system.

YMMV. There is the argument that higher flow rate isn't better, as it doesn't give the coolant time in the radiator to actually cool off, which is why you never want to run without a thermostat. Obviously I don't have the equipment or knowledge to completely analyze the most efficient flow rate of a Subaru cooling system....just adding my anecdotal experiences.

 

I mentioned opening temperature to point out that even after 250k miles and 17 years, my probably-original one still performs almost perfectly to spec (probably within the accuracy of my thermometer).

[1 Lucky Texan]

I think the larger wax capsule 'may' be part of the 'magic' - perhaps for hysteresis reasons? - given that it hangs out in the wind to some degree(no pun intended).

[jonathan909]

There's wax in there?

[1 Lucky Texan]

evidently,... some special stuff with a high coefficient of thermal expansion. I think there are some greenhouse vents that can automatically open using some similar stuff.

[el_freddo]

6 hours ago, jonathan909 said:

There's wax in there?

Yep, that’s what they work with.

Cheers

Bennie

[jonathan909]

This may be turning out to be less mysterious than I thought.  It's beginning to look like the two overheatings from the two bad rad hoses precipitated an HG leak that is now causing coolant loss and in turn the new overheating (insert frowny face here).

[GeneralDisorder]

Likely. We don't even replace the HG's on the H6's. A replacement JDM engine is too cheap to bother. 

GD

[jonathan909]

We already had that conversation, but noted again.