Do popped freeze plugs mean your block is spent?

[Mike McGuire]

I have an overheating issue on a 68 Newport.
I've done lots.. burped, flushed, tested for hydrocarbons (negative) new shroud, radiator, water pump, fuel pump, checked timing, etc.
My latest trick was to finally replace/yank the 2 "temporary plugs", 1 from each side, thinking this might inhibit flow.
[ FYI - this stank since they were deformed/mushroomed a bit, and I had to push them into the block and trim off (circumcise) the inside ring in order to get them out.

I'm curious if losing the plugs (that I think were there as part of the lost sand process, and maybe not for preventing block frozen crack-age, but I don't know), means that the block is damaged.... trying to figure this out..

Thanks in advance.

 

[67Monaco]

Nope just replace them with the proper plugs and you should be fine. Use some shellac for sealer around the edge prior to installation, some will argue this. Use your best judgement based on the condition of the hole. Looks rough that's why I'm suggesting it.

Pick your poison;

Advance Auto Parts - Down for Maintenance

Shellac;
https://www.napaonline.com/en/p/BK_7651229

 

[traintech55]

Now is a good time to get in the block with a hose and flush out each side. Sometimes I have seen the passage close up with sediment. This is something you can see with the plug out.

 

[Duncan]

Now is a good time to get in the block with a hose and flush out each side. Sometimes I have seen the passage close up with sediment. This is something you can see with the plug out.

Yes, I had to get the freeze plugs replaced because they had basically rusted away/through. Once inside they found a good inch of rust that had to be cleaned out. I figured that proved my engine had never been opened before in all of its 50 years. And its still going strong.

 

[traintech55]

Yes, I had to get the freeze plugs replaced because they had basically rusted away/through. Once inside they found a good inch of rust that had to be cleaned out. I figured that proved my engine had never been opened before in all of its 50 years. And its still going strong.

Also a sign the cooling system has never been flushed the correct way.

 

[1970FuryConv]

I have an overheating issue on a 68 Newport.
My latest trick was to finally replace/yank the 2 "temporary plugs", 1 from each side, thinking this might inhibit flow.
[ FYI - this stank since they were deformed/mushroomed a bit, and I had to push them into the block and trim off (circumcise) the inside ring in order to get them out. I'm curious if losing the plugs (that I think were there as part of the lost sand process, and maybe not for preventing block frozen crack-age, but I don't know), means that the block is damaged.... trying to figure this out..Thanks in advance.

I used the same temp plugs. Used them to replace leaking factory freeze plugs. Bought the temps at Advance. Never completely sealed. Had the same trouble getting them out of my 318.

Proper sanding to clean mounting surface, metal freeze plugs, Permatex 2 Form-A-Gasket Sealant, and a good mounting tool sealed the deal for me. No more antifreeze leaks.

 

[Mike McGuire]

Now is a good time to get in the block with a hose and flush out each side. Sometimes I have seen the passage close up with sediment. This is something you can see with the plug out.

Thanks! I have a cheapie yet goodie endoscopic camera. I'll fish around in there looking for some crud. Is there a particular location to look for build up? I heard someone recently mention to yank the intake and look at the coolant passages. I suppose after a good flushing and if the over-heating still persists, I'll try that.
There is also a drain plug on each side of the block. I've never removed these before, but will attempt this as well.

 

[traintech55]

Those drain plugs have probably been in there for over 45 years, not going to come out easily. With the freeze plugs out you do not need to remove them anyway, (and you don't want to break one off in the block).

 

[BillGrissom]

Remove the block drain plugs, since the holes are usually crud'ed up and need a screwdriver to get them to flow. There is often stuff left over from original manufacture, like steel wires, inside. Best to reseal those "core holes", even temp, and run the engine for a few hours w/ pure water plus ~1 lb citric acid, then flush well. I bought 5 lb citric on ebay. The latest Prestone flushes seem wimpier. I run Evans Waterless Coolant in all my cars now (1964 thru 2002), some for several years w/ no overheating issues. Neatest thing is you can open the radiator cap when hot and no appreciable pressure build-up.

 

[Mike McGuire]

Well, sad to say, nothing worked. After a MILD 7 mile drive, relatively flat from a relatively cold start the temperature went up to 230+ with angry boil-over.

Here's what I think might be the culprit....
When the freeze plugs popped, I think something may have happened (damage) to the water pump, where it fails at faster engine speeds. (It is relativley new, but installed before the freeze plugs popped) I didn't have this problem before then, and it still moves water at idle and low engine speeds, but I suspect it fails to pump adequately at faster engine speeds.

It's about the only explanation I can dream up that fits the evidence....

No crack in block, the hydrocarbon blue liquid test is negative, new shroud, radiator, fan, fuel pump, burped, no thermostat, timed well, I mean WTF?... it can't be something small... pretty sure.

I have a brand new water pump in the barn anyway. So, that's next. Stay tuned....

 

[67Monaco]

Plugged radiator. Bad radiator cap.

Or Stan's favorite, the thermostat is stuck. Unless you've changed head gaskets recently.

 

[67Monaco]

There's my reading xonprecompreh again... Reread. Maybe the cap or put a thermostat in.

 

[67Monaco]

Oh, and check timing.

 

[Mike McGuire]

Plugged radiator. Bad radiator cap.

Or Stan's favorite, the thermostat is stuck. Unless you've changed head gaskets recently.

no thermostat, new cap, newer radiator, don't think it is plugged, but will check that out too, thanks.

 

[Mike McGuire]

Oh, and check timing.

already did, and verified last week, perfect.
I'll search for the "xonprecompreh" thread.

thanks
Mike

 

[Wildaugust]

If it's a big block there won't be any coolant passages in the intake manifold. I've even found foreign objects in cooling systems, lids, liners from antifreeze jugs, etc.

 

[swisherred]

What about the exhaust hear riser.....

 

[70bigblockdodge]

Run with water and a dozen or so packs of unsweeted Kool aidcitric flavors are best. Flush with some clean water.

 

[Ripinator]

no thermostat, new cap, newer radiator, don't think it is plugged, but will check that out too, thanks.

Am I to understand you are running with NO thermostat? If so. you really shouldn't do that. Generally, without a thermostat, the coolant won't stay in the radiator long enough to be cooled, and will just keep re-circulating through the block getting hotter and hotter. Also, it sounds like your block coolant passages could be pretty clogged up requiring a pretty aggressive remedy.

 

[Big_John]

Before everyone wastes more time on this thread, the OP hasn't been around for a couple months. Don't try to solve a problem for someone that's not here...