Cleaning out a cast iron block

Big Katuna wrote:
You can add a coolant filter too.. Change it often until it's clean.

I'm showing my ignorance. Does someone make a coolant filter for the 454?
Or, do you adapt a filter for a diesel to the gas 454?

Big Katuna wrote:
You can add a coolant filter too.. Change it often until it's clean.

X2

FIRE UP wrote:
TurboJimmy,
Long, long ago in a far away place, (Star Wars stuff, remember?) I used to rebuild engines for side job. When I pulled them and put them on stand to perform surgery on them, I'd take them all the way down to a gain as much access to any portion of the block I could get my little hands on.

Every single time, I'd pull every freeze plug and drain plug. You'd be surprised on how much SAND I'd find in there, big chunks of black carbon, solid chunks of pure rust etc. I'd have to pry much of it out and or, use a chisel and break much of it up to be able to remove it through the freeze plug holes. Once all the debris, sand and other big stuff was removed, then I'd hit with special, long nosed nozzle that I had for my garden hose. You'd still be surprised at what came out as a result of using that nozzle.

That was then, (from about '65 to, oh around '90 is when I quit that non-sense) and this is now. Unless it's an old hot rod, i.e. '60s Chevy etc., I won't even think about pulling an engine in a motor home. But, back to your issue. Yep, pulling the freeze plugs is the least you can do to get the closest inspection at the cheapest cost. Freeze plugs are cheap.

If you have one or, have access to one, you can use an "Inspection camera" to get into many tight places, inside the water jackets of that block. You know, the kind that Home Depot, Lowes, and other tool places sell. I got mine from Costco quite a while back and, it's not the best but, it sure works for getting into very tight places and seeing what's in there. Good luck.
Scott

Thanks! I'll start with the drain plugs, assuming I can free them up. If it looks bad, I'll start pulling freeze plugs. I'm hoping that the problem was the clogged radiator and not clogged coolant passages - maybe the gunk made its way through the block and accumulated at the radiator inlet. The rad shop told me that the stock high efficiency radiator is made of many smaller tubes rather than some smaller amount of larger tubes. Smaller tubes clog easier. Dunno.

Yanking the engine out isn't really that bad. On the '84 there's not a lot to unhook. The 454 comes out the door easily without the exhaust manifolds on it. Everything is easy to get at. Not that I want to do it again, but far better than replacing the TCC solenoid on a FWD Northstar Cadillac, for example (top of the list of things I will never do again).

turbojimmy wrote:
This is my second season with my '84 Allegro. Bought it with a blown engine. Put a Craigslist-found 454 in it (truck spec GM Performance crate engine). When I got the engine home, put it on a stand and turned it upside down a bunch of rusty water came out of it. An alarming amount actually.

With the water pump off of it I ran water through it until it came out clean. Last year was the first camping season with it. It ran great, though on the warm side.

This year, on my last trip out, it overheated pretty bad. I could not get it to cool down.

Yanked the radiator and brought it to a local shop to be rebuilt. For a significant sum of money, I'm getting an all-new radiator custom built. The rad shop called me today and said my problem was that there was a baseball-sized chunk of rust clogging the inlet side of the radiator. The radiator was toast anyway, but they advised me to figure out why this happened otherwise the new radiator will meet the same fate.

So - I need to clean the block out some how. On the one hand I'd like to think the many heat cycles have dislodged most of the rust in there. Upon removing the radiator the lower hose drained clean. I took the thermostat housing off and hosed out the engine - came out clean too. But how can I be sure?

The radiator guy suggested yanking out the drain plugs and seeing whats in there. He suggested pulling out the freeze plugs too.

So....does anyone have any advice that's different than this? Ideas would be appreciated.

TurboJimmy,
Long, long ago in a far away place, (Star Wars stuff, remember?) I used to rebuild engines for side job. When I pulled them and put them on stand to perform surgery on them, I'd take them all the way down to a gain as much access to any portion of the block I could get my little hands on.

Every single time, I'd pull every freeze plug and drain plug. You'd be surprised on how much SAND I'd find in there, big chunks of black carbon, solid chunks of pure rust etc. I'd have to pry much of it out and or, use a chisel and break much of it up to be able to remove it through the freeze plug holes. Once all the debris, sand and other big stuff was removed, then I'd hit with special, long nosed nozzle that I had for my garden hose. You'd still be surprised at what came out as a result of using that nozzle.

That was then, (from about '65 to, oh around '90 is when I quit that non-sense) and this is now. Unless it's an old hot rod, i.e. '60s Chevy etc., I won't even think about pulling an engine in a motor home. But, back to your issue. Yep, pulling the freeze plugs is the least you can do to get the closest inspection at the cheapest cost. Freeze plugs are cheap.

If you have one or, have access to one, you can use an "Inspection camera" to get into many tight places, inside the water jackets of that block. You know, the kind that Home Depot, Lowes, and other tool places sell. I got mine from Costco quite a while back and, it's not the best but, it sure works for getting into very tight places and seeing what's in there. Good luck.
Scott

They make chemicals that will dissolve rust and flush it out of the block. Water, no matter how much, will not dissolve the rust that is caked in the passages of the block.

Tachdriver wrote:
I'm not sure if pulling the freeze plugs out will reveal any more than what you have. It is too bad this was not all checked before you installed it. So what if you installed the radiator and ran it a year and did a flush? Keep an eye on the coolant color in the mean time as a tell tale.

If the coolant does change due to rust in the engine then you know what to do.

That's what's weird. The coolant that came out of the block and radiator was squeaky clean. I pulled the thermostat housing off to look inside and it looked clean.

But...I turned the radiator upside down to completely drain it and THEN the black icky stuff came out the upper fitting (the inlet). I guess it was plugged solid.

The engine had 20k miles on it. I pulled the valve covers and oil pan (replaced the rear seal) and it looked brand new inside. At the time the rust coming out of it didn't concern me - I thought a good flush would do it.

I guess I'll pull the drain plugs first to see what I'm up against. If it looks bad and/or I can't flush it properly I'll take it out again over the winter and have it redone.

My next trip is in October, on a route that got it hot this time last year. A long climb into the Poconos (okay, so not real mountains but still some work for the old girl).

I'm DEFINITELY going to look into a coolant filter. Ironically I just came inside from mowing and got talking to a neighbor that works on diesel cranes. He suggested the same thing.

I'm not sure if pulling the freeze plugs out will reveal any more than what you have. It is too bad this was not all checked before you installed it. So what if you installed the radiator and ran it a year and did a flush? Keep an eye on the coolant color in the mean time as a tell tale.

If the coolant does change due to rust in the engine then you know what to do.

You can add a coolant filter too.. Change it often until it's clean.

Craigslist-found 454 ..............

What you should have done when you had it on the engine stand and all that rusty water coming out was a complete tear down

NOW you have it installed......drain plugs/freeze plugs will allow some access for more flushing but until you pull heads and mechanically clean up cooling passages you will continue to have overheating issues.