Freeze plug replacement on 428 CJ

Anybody know how difficult it is to replace freeze plugs on a '69 XR7 CJ? Seems when my newly purchased car was delivered today, where our low was zero and after being on a car carrier at from -5 to +15 degrees the last few days, one was completely gone and I may have damage to others. Do you have to pull the engine?

You probably will in the end have to pull at least the heads as often exhaust manifold bolts will break. If your motor is somewhat fresh you may be able to get away with just pulling the exhaust manifolds. We just had the coldest weather since 1972 and I do not even want to look under the cover on the boat. It is in the garage and we just never thought about it before!

Thanks much, does WCCC have them? I have been a good customer for several years working on my '68 KR, your power brake proportioning valve rebuild kit and video saved me last year. Also, there was NO (as in zero) anti-freeze in the cooling system. Ice plug in the top of the radiator too, what kind of person does that with a nice car from Iowa?

I tend to be a bit on the paranoid side, but I’d be a little worried. Hopefully you don’t have any bigger problems.

I hope you are right, I have checked most other things and they are fine. When I gave this car a thorough inspection, I never thought to look at the coolant. I checked the oil dipstick, PS dipstick, looked for leaks (there were none the whole three days it sat there at the auction), no smoke or noises on start,all power equipment and A/C worked, etc. It is always the one thing you don’t check I guess, but not sure what I could have done there, except not bid. It is on my lift now, two popped block freeze plugs, one driver’s side rear one that will be a PITA. Oh well, another winter project.

When did you officially take possession of the car? I would assume you signed a disclaimer after the auction. That’s a nice car for that to happen too.

Hard freeze of water in cooling jackets can do bad things. IIRC, Brian (mmeat)'s 427 from the GTE he did had cracks in the water jackets in the lifter valley (trying to give a FE reference for their vulnerabilities). As Al said, hope it is not more than popped plugs, unfortunately, it could be.

Yes, it was as is where is condition when purchased. I have it on the lift in my garage. I see no leaks after thaw out, no oil, no other coolant traces, and no coolant in the oil. I am hoping the freeze plugs did their job. They will be replaced, flush and fill, the hope for the best. You guys prefer brass or steel plugs?

Oh man, that sucks :-/ Hope it all works out for the best. Keep us posted…

Holy cow! That’s really bad… I live in Don’s area and have been tweaking about my 50/50 antifreeze cars…can’t imagine NONE. My CJ Cougar also has a chronically leaking freeze plug, but it’s just from age–and of course it’s one right over the motor mount on the passenger side. Here is a post regarding freeze plug size and replacement I saved from the FE Forum: Let us know how things go.

Always brass, they will never rot out as the steel ones sometimes do. Now, about freeze plugs (and don’t mean to be a pessimist here, I hope all is well with the engine too), they are actually core plugs made so that the core casting sand can be removed after casting. This is why sometimes engines that have gone through hard freeze end up with cracks in the valley, no core plugs there.

At this point, I would say you should replace the plugs, fill with water or 50/50 and see how it goes monitoring the oil for water, etc.

Thanks! I will have to have this done in a shop that has equipment for an engine lift, the driver’s side rear plug is too inaccessible for me to do. It goes in this morning. The car starts and runs great, I didn’t let it run long, just on and off my lift a few hundred feet today. Still no signs of anything amiss other than the plugs. I usually use Zerex G-05 anti-freeze, 50/50, in my old cars, like my KR and the Corvettes. So I guess that is OK for this one too.

On the British show Wheeler Dealer they once used a new Waterless Engine Coolant called Classic Cool 180. No chance of freezing since there is absolutely no water being used.

OK guys, hoped for the best, but after plugs replaced and filled, run for 20 minutes, oil is milky with coolant. So, the engine will be pulled out to see where all it is cracked. I am probably in the market now for a '68 date coded 428 Cobra Jet block, my car was built mid September, 1968. If you know of any, please let me know, even if the date is not close. The engine in there was cast September '69, and no VIN stamp, so it was a replacement anyway. Thanks for any help.

Good attitude… Yes, losing the vin stamped block would be bad. I had to find one a few months ago for a 70, I used “Search Tempest” and found at least 20 between CL, Ebay and the usual sources. Got a standard bore long block for $2800, $300 to ship. I was able to sell the rare pulleys and brackets to recoup some $$$. Was very happy it was so easy and somewhat surprised to get a spot on date code.

Thanks, need to wait and see after disassembly if there is any way to fix the old one first. One other interesting thing, the same Iowa dealer who sold mine, sold two other Cougars (a lime gold '67 SB and a '69 428 Eliminator) and a Marauder X-100. So, be on the lookout for some other cracked blocks if he put water in all them. The trip from KC, any direction, would be through subzero nights.

Condolences Mike, having to pull the engine and do all of this is no fun. If there is a bright side, you will know what exactly you have when you are done. Also, the block didn’t typically have the VIN stamp, it would have been on the back side of the head on the drivers side.

Actually by 1969 even the small blocks were vin stamped.

This one is too early for that, isn’t it?

I am probably in the market now for a '68 date coded 428 Cobra Jet block, my car was built mid September, 1968.

The thing to do is to check the back of the head and look for the VIN.

You also, need to check the front of the passenger head, because sometimes they get swapped if they were off previously.