[outinthewoods]

I haven't seen one on any of my Legacys, but there's one on the '02 Forester I'm working on now (I don't recall seeing it on my late '99 Forester, but it might have been there). It's a cylindrical heat exchanger that mounts between the block and the oil filter and circulates coolant from the (otherwise plugged) coolant port just behind the filter to a second port in the thermostat housing via a pipe that runs just below the timing cover (maybe I got the flow direction backwards - doesn't matter).

Nobody over on the Forester forum has offered an argument for the desirability of this thing, but I continue to wonder about it. If I happen to find one on a boneyard engine, should I get it for retrofit onto my Legacy 2.5? That is, is it worth the trouble?

 

[Richard Pare]

Was in common use on our race cars years ago - worked excellently. Came on some Mustang models. If I remember correctly, Modine made them. The Forester one was probably shaped differently, but worked the same.



While it did a decent enough job of cooling the oil, it's bigger benefit was quickly warming the oil up from cold.


No idea if they are still available, unfortunately.

 

[outinthewoods]

We deal with a lot of cold up here. If this thing helps accelerate overall engine warmup when it's -30, it's gotta be a good retrofit. Wonder whether the same assembly fits an EJ22 as well?

 

[Richard Pare]

They will fit any engine as long as there is room around the oil filter, since it is bigger in diameter than the filter. The OEM Sub sandwich cooler is probably what you want, since Sub designed it specifically for their engine - the Modine filter we used was for a larger diameter oil filter, so it may not fit.

 

[Richard Pare]

Here's an Amazon page of Subaru oil coolers:



https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias=aps&field-keywords=subaru+oil+cooler

 

[idosubaru]

That is, is it worth the trouble?

No.

Nobody over on the Forester forum has offered an argument for the desirability of this thing

Because it doesn't matter.

I continue to wonder about it.

Then get one. Since it doesn't matter then you can install one and be done thinking about it. You need the cooler, cooler to block retaining bolt, oil cooler gasket, hoses, clamps for hoses, metal crossover pipe, thermostat housing, and thermostat gasket.

14mm hex to remove block plug and 24mm socket to install oil cooler hold down bolt to block.

 

[outinthewoods]

Just back from the boneyard, where I'd hoped to score one or two while getting other stuff. Came home empty-handed because all they had were '03 Foresters. In that year they redesigned it to tap off of the water pump (on the other side of the thermostat) rather than the thermostat housing as in my '02. A quick+easy retrofit that ain't, since it would mean replacing the water pump. But if I run across another '02 (or earlier - don't know when they started adding them) with the modified thermostat housing, I'll definitely pick it up - I just don't see any downside.

Btw, the reason this came up is that I'm transplanting a new motor into this '02 Forester - the car's (busted) motor came with the cooler and the incoming replacement didn't, so I swapped it over.

 

[Berge56]

I don't think the coolant cross over pipe will clear the 06 style exhaust manifold. Also this is more of a oil heater than a cooler, as other have stated, it will help get the oil to temp faster.

 

[RoughDiamond]

It's a great oil temperature stabilizer, rather than a cooler/heater.

They're not sought-after for the reason you found: it requires a water pump change and additional hardware that can add up to near $100 if bought new from the dealer.

The issue with used units is also the propensity to come from motors with spun rod bearings. These SOBs love to hold bearing material and release it when they feel like it, making for an expensive time bomb for little to no reward.

Additional cooling along with a thermostatic oil filter adapter would be the best of both worlds.

 

[outinthewoods]

The issue with used units is also the propensity to come from motors with spun rod bearings. These SOBs love to hold bearing material and release it when they feel like it, making for an expensive time bomb for little to no reward.

Oh. That doesn't bode well. The blown engine that I'm replacing (and that I'm transplanting this cooler from) is a rod-through-block job.