Engine Leaking Antifreeze

[55 Fargo]

Hi all, made a grizzly discovery tonight, my engine is leaking antifreeze out the back, found it leaking out clutch housing vent.

Now either it's a blown rear freeze plug, or a crack or something. Last year I did have antifeeze blow up and onto the back of the engine, some must have went into the clutch housing, but I am sure it must have all leaked out by now. This is either a freeze plug leaking or something, this is all I need now. Does anyone have a photo of the back of the long block engines to show me the location of the freeze plugs. What is the best method to tackle this job, how can I be sure this is the problem.

Any help appreciated............Fred

[greg g]

There are two or three freeze plugs on the rear of the engine. Unfortunately, I believe all of them are behind the the bellhousing. Which means either the engine or trans needs to come out to acces them... Were it not for bad luck....you'd have no luck at all. I guess if you decide to pull the engine then ya might as well pull them all and gieve the block a good flushing do the distribution tube, and change the head gasket.

[Norm's Coupe]

Sorry to hear that Fred. However, you probably just found the reason for your engine running on the warm side. So, there is a bright side to the leaking freeze plugs. Like Greg said, the one in the rear is hard to get to without lifting the engine. Hopefully, it's just a bad freeze plug or two and not a cracked block.

[55 Fargo]

Not sure what to do here, I do own a 1955 Fargo truck engine, it was running up to 2 years ago when it was pulled out of the truck to make way for a SBC. It's condition is not really known to me other than it was "supposed to run well".I can also buy a 265 Industrial engine, from a lincoln welder, its 5 miles from my house, the owner wants $100.00 for it. This would be a good engine to use, providing it is in good condition.

Or I can find out whats leaking on the back of my engine repair it and contiue to use the engine, it must be a fairly slow leak, as the antifreeze has barely gone down, and there isn't a huge amount of leakage, but the leakage is there.

Any shadetree ideas to stop the leak, the trouble is you can't see exactly where it is leaking from. Can the bell housing bottom come off, so I canhave a look for antifreeze sitting in the pan..........Fred

[Norm's Coupe]

Fred,

I realize you may have to lift the engine to get to that real freeze plug. However, if your engine is running good now except for a freeze plug or two, I'd stick with it. Freeze plugs are dirt cheap and easy to replace once you make the access. Would be a lot cheaper and easier to replace the plug than to change the engines.

[55 Fargo]

Thanx Norm, here is my idea of the plan of attack. Remove floor pan, Chrysler pans are huge. remove trans, support rear of engine, lif enough to rmove clutch and bell housing, inspect and find leak, remove flywheel and r and r freeze plugs as necessary, which would be all of them in this case. Does this sound like a sound method..........Fred

[Johnny S]

Fred, have you thought about swapping out the current engine for the other used engine temporarily and then rebuilding the one currently in the car? That way you could still be driving AND getting the other engine up to real snuff.

[Norm's Coupe]

Thanx Norm, here is my idea of the plan of attack. Remove floor pan, Chrysler pans are huge. remove trans, support rear of engine, lif enough to rmove clutch and bell housing, inspect and find leak, remove flywheel and r and r freeze plugs as necessary, which would be all of them in this case. Does this sound like a sound method..........Fred

Fred, sounds like a good plan to me provided you can get to that plug. I'm really not sure if you can, simply because I've never tried it. My engine was out when rebuilding it, and that's when I replaced my plugs. Was a lot easier since the engine was already out anyway. Your plan is worth a try though. Removing the pans would be easier than lifting the engine.

[55 Fargo]

removed floor pan, had a look in clutch housing, sure enough antifreeze in there, suctioned it out, 1/2 hour later still leaking back ever so slightly but leaking none the less. Is this common, would it be cracked.

My plan is to remove trans, support engine on rear bottom, with 2 x 4 cribbing, remove clutch and fix freeze plugs. Does anybody think this will work, the clutch housing is filthy and greasy inside, maybe I should replace rear main seal same time. Any other ideas from the masses........Fred

[55 Fargo]

Norm the floor pan is already out, had a good look in this area. To proceed it is just a matter of removing the driveshaft, the trans, blocking the rear of the engine, lifting bell housing and remove. The back of the engine would be staring me right in the face this way.

Of course I need to drain the antifreeze, remove starter, drop exhaust pipe. I was thinking of making out out of wood, a support to go right under the rear of the oil pan, as mine has an extra 1/4 inch plate steel welded to it. Would this be okay to support the rear of the engines weight as I describe.

I could then pop out the freeze plugs, clean out the holes, re-install freeze plugs and hopefully fix the problem, cause man I have had no shortage of problems with this cooling system...........Fred

[greg g]

So there is another oil pan with the cold rolled steel welded on!!!! I have that feature also. It should be more that adequate to support the weight of the engine. Just be sure to use a full width piece of wood to spread the weight.

With the rear open for plug renewal, it might be wise to pull on of the drives side plugs and muck out those cooling passages while flushing from the rear couple of kiddie pools underneath for catch pans to keep the garage dry.

[Norm's Coupe]

Fred,

Actually, after putting my engine back together in my friends service garage we brought it home. When we lifted it out of the truck we sat it down on the concrete floor of my garage. Sat there for at least a couple of days before I picked it up and put it on the stand. So, as Greg mentioned, you shouldn't have a problem. I don't have that extra piece of steel on my oil pan. Those pans are pretty sturdy as long as you don't drop the engine down on it. Just sit it down gently on the floor, or your 2 x 4, either way.

[55 Fargo]

Greg the sides have been done already, I agree the pan should be supported right acros, I will also loosen the fron mounts so it doesn't wist them either. Will likely dismantle tonight and have a look........Fred

[40phil41]

Hi Fred,

I've been away from my computer for a while and am probably too late but here are a couple of photos of the freeze plugs at the back of my D24 long block. Basically, everything has to come off to get access:(

Phil

[55 Fargo]

Phil is that 3 freeze plugs, or is it just the 2 silver plugs. Is theothera camshaft end plug. This is the way I plan on doing this job, looks like the 2 x 4 is holding up the engine just fine, did you losen up the front engine mounts............Thanx Fred

[40phil41]

Fred,

The 2X4 worked just fine. There seemed to be sufficient flex in the front rubber mount for the small lift required to remove the rear mounts (i.e. I did not loosen the front mount).

Can't really say what the 'brass' coloured plug is. This engine was rebuilt in 1952 (Chrysler remanufactured). I had it apart to change the rear main oil seal, which is currently leaking again :-(.

Phil

[JIPJOBXX]

What would happen if you just put some silverseal in your radiator and see if that would seal up the leak? I have used this stuff to stop heater core leaks and it really works. I know for you purist that this might not be the way to go but why not give it a try and save all that work to pull the back end of the engine apart? Just a thought

[Dodgeb4ya]

Be sure to use brass plugs- they will never corrode.

Bob

[55 Fargo]

I like thoughts like this, but if the freeze plug has rusted through it may be only a matter of time before it disintegrates, or heaven forbid as it would put me over the edge a crack in the block. Or what you have mentioned using silverseal, it might just do the trick. Don't like to sound like a whiner ,but this problem is puttin a real damper on my spirits, it's not that I am lazy to do this repair, but to be honest with a large country yard, full time work in a prison, and 2 litttle ones at home, time is a real premium.......Fred

[greg g]

From the pic I do believe the brass one is related to the camshaft. I lost a plug on my fresh built engine, lukily it was one of the ones on the side of the block. It was amazing how quickly the coolant purges from that size of a hole. I put in one of the rubber temp ones, I think it is becoming semi permanent as it is still in there going on the 3rd year.....

[james curl]

I think that the lower one on the right side is the cam, the location is about right for the valve placement, and low enough for the cam followers (lifters) to fit below the valves.

[greg g]

Yer right Jim, had a mini himerz there.

[55 Fargo]

Okay, I am not a pessimist, but how many have our members experienced a all of a sudden leak from the rear freeze plugs. Has anybody heard of the block cracking in behind here, before my cooling problems were kinda resolved, I did have the engine block go up to about 205, but it always had lots of antifreeze in it. Don't think having the engine run up to the warm side with no real heavy load and for a short time would cause a block crack, in fact the rad never boiled over either.

My other theory is, possibly there was crud in the back end of the engine, maybe after getting better flow, this area may have been disturbed, in fact maybe some crud was washed out of this area, thus a leak did begin.

The first time I noticed antifreeze under the car was after the rad had been boiled out, but I thought it was just a small amount that I had spilled when refilling the system, so I dismissed it, as the rad did not appear to go down, I do notice now the rad level going down, possibly the leak is getting worse, now that it has started...............Fred

[TodFitch]

Okay, I am not a pessimist, but how many have our members experienced a all of a sudden leak from the rear freeze plugs. <snip>..............Fred

I have had two different experiences with sudden failures with core/welsh/freeze plugs: Once on a fairly new rebuild. I attributed that to improper installation. The other time the steel plug had rusted through. Well, not quite through but enough to weaken it and have it pop out when under pressure. (Even in a non-pressurized system you have pressure in the block prior to the thermostat opening up, especially at high RPMs.)

Fortunately for me, neither time did it involve a rear plug. But I don't see why it would be any different for the rear than for any other plug.

[greg g]

Most block cracking is related to coolant freezing in the water jackets, and since the rear of the block casting is much stouter (for bell housing attachment) than the sides so I would seriously doubt that there is a crack in the region. Part of the reason for the plugs is to provide pressure relief if for some reason there is a problem within the coolant passages. Thats why they are sometimes are called freeze plugs, they are supposed to give and prevent cracks in the block.