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Dake

EJ25 block is plugged with calcium – should I bother cleaning it?

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I’m a car nerd and a hobbyist mechanic learning by getting my hands dirty. I picked up a 2003 Forester, Pacifica Blue with ~170k, bone stock, a great body and interior, and one big issue – overheating.

 

After pulling the engine I found that some of the coolant passages were plugged solid. Mystery solved. It’s a bit crude but the attached picture features a flathead screwdriver stuck into the calcification – that’s how dense it is. I have to assume the smaller internal passages are just as bad, though the water pump itself was clean and the passenger's side passages aren't *as* bad.

 

I was told phosphoric acid cleaner would eat away at it, but would it really get it all? I know the most effective way would be to pull everything and have the block hot tanked. I’m worried I’ll jump into a money pit of pistons / rings / bearings if I go that route. The engine ran well, and I can still see factory crosshatching on the cylinder walls. IMO they don't look bad but other people say they do. It might get headers and exhaust some day but it will most likely remain totally stock.

 

I have head / intake / exhaust / oil pan / valve cover gaskets, rear main seal, head bolts, thermostat, timing belt, water pump, and more waiting to go on.

 

I’m pondering my options before the heads go to the machine shop. Because of new circumstances I need this to be my daily driver, so I'm trying to save money. On the other hand, I want to do things properly and reliably the first time. Advice has ranged from “chip away what you can” to “buy a different block” ... what would you do?

 

High-res images here https://imgur.com/a/eGBDm
 

Edit: attached another image - is that oil weeping past the rings?

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Edited by Dake

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First off. All that white stuff is from the Subaru OEM coolant conditioner.

I found this out the hard way on an 09 Subaru Outback that the shop I'm with was adding to the engine after coolant flushes (thinking it was supposed to go in that new of a car) and when I had to pull the heads to do the HGs, all that white build up was in there. Being as we were the only shop that ever touched this 1 owner car. It pointed to the coolant conditioner.

 

As for removal. Honestly, I didn't have a good way to get it out of the block. I ended up getting in with a chisel and slowly got it all out. Taking the cross-over pipe off to allow for flushing of the coolant passages with water. 

I tried brake cleaner, a few different forms of soap, and a few other products. Nothing took it off (at least not in a timely manner)

 

You might be best off just getting as much off as you can, replacing the water pump. And then dealing with the a restricted radiator or heater core when the time comes. 

There's not many small passages for coolant, besides the lines to the throttle body. 

 

IMO, you'll be fine with just getting as much off the block as possible. I didn't do anything about the head ports on the engine I was dealing with, besides the easily accessable spots. 

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Just to update this for anyone Googling in the future. I took a thin screwdriver and carefully chipped away at the buildup, then covered the cylinders with towels, tilted the block at 45 degrees on the stand, used a garden hose to flush water through the crossover pipe inlet, hit it with air, then switched sides, rinse, repeat, etc. I let it sit overnight and did it again, that seemed to free it up more. All in, it took me probably 5 hours and it's *mostly* out - all the chunks are gone but some residue remains. It was caked on the walls over 1mm thick.

 

When I picked up the heads (also dirty and plugged solid at cylinder #4) the first thing the guy said when I walked in was "I had to sweep the whole shop - that crap was everywhere!"

 

Worth it? Yes. Where I live Subie parts are expensive and hard to come by.

Edited by Dake

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Does the conditioner only do this when the vehicle overheats or runs low on coolant?

 

Both instances here suggest that it happened on overheating engines.

 

Hopefully it wasn’t k reheated terribly. A few percent of blocks loose the lower end bearings shortly after a job like this due to the prior overheating. Hopefully the prior owners didn’t limp it around like that too bad/much.

 

You’re right don’t ever sit a Subaru blocks. It’s not worth it and GD says you’ll end up not getting doing it right anyway the first time.

 

The crosshatching is almost always visible on Subaru blocks, it basically doesn’t go away outside of catastrophic issues. Good to see it and know they’re clean but also that’s not where the first isssues, if any, will present.

Edited by idosubaru

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And people wonder why I bad mouth the "coolant conditioner". It's nothing more than stop leak that Subaru decided to use as a bandaid to get cars through the warranty period.

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That white calcium is NOT from Subaru OEM coolant conditioner.

 

It's gotta be some other "fix in a bottle" like Blue devil or something.  It's definately not the green conditioner that subaru puts in. That stuff doesn't cake up like we are seeing here.

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That white calcium is NOT from Subaru OEM coolant conditioner.

 

It's gotta be some other "fix in a bottle" like Blue devil or something.  It's definately not the green conditioner that subaru puts in. That stuff doesn't cake up like we are seeing here.

 

Woah crap - I didn't see the pics.  That's not from running tap water which is evaporating off and calcifying like a distiller does is it? 

Looks to chunky and loose for that?

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