[Engine Ear]

I am not concerned about driving it home, I'll keep an eye on the gauge. I have a new thermostat to install, and I will check the cap and wiggler for function. I blame them popping out on the plugs themselves. (I could be wrong) Crap design not enough side wall. It appears you need a special tool to set them to the precise depth. I tried to locate the needed size in the traditional cap shape and at O'riley's the counter guy found them on ebay but when I got home, I could not find the same source on e-bay and no one selling them had the specs (Size) posted so I made some. Cummins never got back to Me not a big money maker, I guess..

Need to get a vernier or digital caliper and measure the plug hole diameter. The new plugs should be slightly oversize for a press fit. Not sure, perhaps 5 to 10 thou over. You can measure new ones in the store to confirm fit. Suppose that a proper setting tool has a shoulder to catch the block or head surface to get depth and alignment right. Maybe a big socket could be used to set them. If other undesturbed plugs are accessible, could measure their depth with the caliper depth tail. Wind tape around the socket as a visual depth indication. This should get it close. If you freeze the plugs first as earlier mentioned, they should pop in quite easily.

 

[Raedwulf]

Need to get a vernier or digital caliper and measure the plug hole diameter. The new plugs should be slightly oversize for a press fit. Not sure, perhaps 5 to 10 thou over. You can measure new ones in the store to confirm fit.

I agree and have done that. The only place near Me that had any, had one size in stock and they were not tight enough, so I ordered the next size up which was the correct size but when they came in it was a different design. I have snap gauges and micrometers as well as a 14 1/2-inch South Bend lathe They needed to be 2.257" I will post more about my success or failure around next weekend . I am pretty sure it was just a crappy design on the plugs they sent .

 

[Engine Ear]

I agree and have done that. The only place near Me that had any, had one size in stock and they were not tight enough, so I ordered the next size up which was the correct size but when they came in it was a different design. I have snap gauges and micrometers as well as a 14 1/2-inch South Bend lathe They needed to be 2.257" I will post more about my success or failure around next weekend . I am pretty sure it was just a crappy design on the plugs they sent .

I'd been wondering how you made your own plugs. Did not know that you have the lathe. Maybe with the lathe you can make a setting punch with a shoulder at correct depth for catching the block or head surface. This should get the depth just right and set each plug straight in the hole. The supplier might even send the right plugs yet.

 

[Raedwulf]

I'd been wondering how you made your own plugs. Did not know that you have the lathe. Maybe with the lathe you can make a setting punch with a shoulder at correct depth for catching the block or head surface. This should get the depth just right and set each plug straight in the hole. The supplier might even send the right plugs yet.

These will work and carry me over until I can locate the plugs I want . I am wondering about the aluminum corroding them. the replacement radiator is aluminum and on my 77 the water pump is aluminum .....also in the service manual it specifies anti-freeze with (Alumiguard?) to protect aluminum in the system so I think they will hold up fine. I just don't trust the design of the newone and its thinner metal , probably designed by a bean counter

 

[Engine Ear]

These will work and carry me over until I can locate the plugs I want . I am wondering about the aluminum corroding them. the replacement radiator is aluminum and on my 77 the water pump is aluminum .....also in the service manual it specifies anti-freeze with (Alumiguard?) to protect aluminum in the system so I think they will hold up fine. I just don't trust the design of the newone and its thinner metal , probably designed by a bean counter

The aluminum radiator is not in direct metal to metal contact with the iron engine, so galvanic corrosion is not much of an issue. My radiator is several years old and it too is aluminum. When two dissimilar metals are in close contact within a conductive fluid, they form a galvanic cell like a battery cell. So one plate looses ions while the other gains. With iron ad aluminum, the aluminum will lose material. In marine applications, aluminum is sometimes used as a "sacrificial anode" to prevent wastage of other metals, though zinc is more common. Magnesium anodes are generally used on aluminum structures. Anodes inside water heater tanks can be any one of these three metals. Of course the process is not instant and it could take months or years to see significant wastage. In vehicles in the south, this is not usually a factor for parts exposed to weather. But here in winter road salt laden areas it is very common. I have seen the main alternator bolt of a car corroded in so badly that it required to be well heated by acetylene to remove. The reaction produced a white corrosion product that wedged against the bolt and hole wall. This was all due salty water acting on the steel bolt and white metal alternator over years. I had the same trouble with water pump bolts in an aluminum timing chain cover. I am not sure if the corrosion inhibitors in antifreeze will prevent aluminum to iron galvanic corrosion when the two metals are in close contact. Perhaps I stand to be corrected by a chemist or antifreeze expert. Your aluminum plugs should last for a while, but for how long is difficult to say. If it were my truck, I would err on the side of caution and fit steel plugs sometime within a year, as I do not think that this is an immediate concern. Possible aluminum wastage could take months to become significant.

OK, maybe there is someone out there with better chemistry or antifreeze knowledge than I, but that was galvanic corrosion in a nut shell. Not a chemist, but on the practical side, I do marine work and have replaced anodes and have seen the effects of this sort of damage to metal parts in contact with sea water.

 

[24hrsparkey]

The aluminum radiator is not in direct metal to metal contact with the iron engine, so galvanic corrosion is not much of an issue. My radiator is several years old and it too is aluminum. When two dissimilar metals are in close contact within a conductive fluid, they form a galvanic cell like a battery cell. So one plate looses ions while the other gains. With iron ad aluminum, the aluminum will lose material. In marine applications, aluminum is sometimes used as a "sacrificial anode" to prevent wastage of other metals, though zinc is more common. Magnesium anodes are generally used on aluminum structures. Anodes inside water heater tanks can be any one of these three metals. Of course the process is not instant and it could take months or years to see significant wastage. In vehicles in the south, this is not usually a factor for parts exposed to weather. But here in winter road salt laden areas it is very common. I have seen the main alternator bolt of a car corroded in so badly that it required to be well heated by acetylene to remove. The reaction produced a white corrosion product that wedged against the bolt and hole wall. This was all due salty water acting on the steel bolt and white metal alternator over years. I had the same trouble with water pump bolts in an aluminum timing chain cover. I am not sure if the corrosion inhibitors in antifreeze will prevent aluminum to iron galvanic corrosion when the two metals are in close contact. Perhaps I stand to be corrected by a chemist or antifreeze expert. Your aluminum plugs should last for a while, but for how long is difficult to say. If it were my truck, I would err on the side of caution and fit steel plugs sometime within a year, as I do not think that this is an immediate concern. Possible aluminum wastage could take months to become significant.

OK, maybe there is someone out there with better chemistry or antifreeze knowledge than I, but that was galvanic corrosion in a nut shell. Not a chemist, but on the practical side, I do marine work and have replaced anodes and have seen the effects of this sort of damage to metal parts in contact with sea water.

Ground Strap on the heater core , sometimes gets cast aside by sloppy mechanics .
CAN create galvanic action ( esp if the replacement is cheap aluminum ) and 12v weirdness in coolant .
ALWAYS re connect that ground strap boys and girls.

 

[Engine Ear]

Ground Strap on the heater core , sometimes gets cast aside by sloppy mechanics .
CAN create galvanic action ( esp if the replacement is cheap aluminum ) and 12v weirdness in coolant .
ALWAYS re connect that ground strap boys and girls.

Good point, I had not mentioned the ground strap on the heater core. I don't remember if my radiator has a ground connection, but since grounding is required for the heater core, it follows that one should be needed for the radiator. When I went shopping for a heater core a few weeks ago, all local parts shops could only quote me on an aluminum. The most expensive one on Rock Auto is aluminum. It seems that heater cores with brass tanks and copper cores are a thing of the past. I did not check to see if a rad shop could recore mine, as I wanted to get the job done quickly. Another thing to consider is that aftermarket cores can be bought that have swivel pipe connections. This makes installation possible without removing the plenum. And removing the plenum could extend the job by hours of work, plus cause potential problems by disturbing linkages and wiring. Some guys cut the pipes and splice back with hose and clamps, but that makes opportunity for leaks that could require another dash board dismantle to repair, and who wants coolant leaking inside?

 

[24hrsparkey]

Good point, I had not mentioned the ground strap on the heater core. I don't remember if my radiator has a ground connection, but since grounding is required for the heater core, it follows that one should be needed for the radiator. When I went shopping for a heater core a few weeks ago, all local parts shops could only quote me on an aluminum. The most expensive one on Rock Auto is aluminum. It seems that heater cores with brass tanks and copper cores are a thing of the past. I did not check to see if a rad shop could recore mine, as I wanted to get the job done quickly. Another thing to consider is that aftermarket cores can be bought that have swivel pipe connections. This makes installation possible without removing the plenum. And removing the plenum could extend the job by hours of work, plus cause potential problems by disturbing linkages and wiring. Some guys cut the pipes and splice back with hose and clamps, but that makes opportunity for leaks that could require another dash board dismantle to repair, and who wants coolant leaking inside?

OEM available at places like MoparOverstock.com for about 200$. That was awhile ago for my 2001 24v rust bucket . Gone now. Where ever it is , it has good heat . lol.
Ha Ha no cutting the solid tubes for me , could be trouble .
Ground strap on the HC yes ,, never seen one on any radiator like you. Do not know the reason ground on one and not the other .

I have seen " I Have SPARKS comming off the fan belt " or " my heater core only lasted 2 years " threads . Usually related to no ground strap on the HC or a very very bad alternator . Also saw pics of a multmeter dipped into the coolant showing 13 volts . lol.
I do not want any of that drama , so i put the ground strap on the HC . lol.

 

[GAmes]

Do not know the reason ground on one and not the other .

Could it be that the radiator is bolted to a metal frame which grounds it and the heater core is not?

 

[GAmes]

Another thing to consider is that aftermarket cores can be bought that have swivel pipe connections. This makes installation possible without removing the plenum. And removing the plenum could extend the job by hours of work, plus cause potential problems by disturbing linkages and wiring.

A little bit of search time would reveal that a stock replacement heater core can be installed without removing the HVAC or discharging the A/C. I wouldn't use a swivel pipe connection core for any reason.

 

[Engine Ear]

OEM available at places like MoparOverstock.com for about 200$. That was awhile ago for my 2001 24v rust bucket . Gone now. Where ever it is , it has good heat . lol.
Ha Ha no cutting the solid tubes for me , could be trouble .
Ground strap on the HC yes ,, never seen one on any radiator like you. Do not know the reason ground on one and not the other .

Yea, kind of strange that a heater core would be grounded, but not a radiator. Is there a corrosion engineer on the forum? About the frost plugs. As simple as a metal plug may seem, there should be some engineering in their design. Gotta know how much oversize is required to get a good press fit. Too small and they will fall out, to big and it will be damaged while driving in. Could get distortion and burred edges. Precise size will be a determined by elasticity of the metal. How much oversize can you expect will drive in and make a good sealed press fit? You might find info in a machinist data book on class of fit chart. But this is usually for solid shafts. Typical frost plugs are sheet metal stampings, so proper spec. could be different. Ok, a stray detail, but due to high cost of failure, best to use high quality plugs, perhaps from the engine manufacturer, though I have used aftermarket plugs.

 

[Engine Ear]

Could it be that the radiator is bolted to a metal frame which grounds it and the heater core is not?

I think that you are right. I do not remember details from when I changed mine. But the Chrysler shop manual in section 7-46 shows bolts that secure the rad side brackets to the rad supports. And of course the side brackets are probably soldered to the rad itself. Hence the securing arrangement provides a ground path.

 

[Engine Ear]

A little bit of search time would reveal that a stock replacement heater core can be installed without removing the HVAC or discharging the A/C. I wouldn't use a swivel pipe connection core for any reason.

Great if anyone can wiggle a solid pipe core into the plenum without disconnecting the AC evaporator and removing the plenum. I gave up on removing my old core in one piece. Had to cut the pipes. I had to remove the bolts from the plenum studs to move it a bit, but did not have to remove it from the truck. Maybe I missed something, but sometimes fifth dimensional physics just do not work, and I have to solve a problem in the 3D world. I watched a guy on youtube wiggle a swival core in without disturbing the plenum, but I could not make it work.

 

[GAmes]

Great if anyone can wiggle a solid pipe core into the plenum without disconnecting the AC evaporator and removing the plenum. I gave up on removing my old core in one piece.

the procedure involves removing 4 nuts. It isn't that hard.

 

[Engine Ear]

the procedure involves removing 4 nuts. It isn't that hard.

Yes, the plenum studs have four nuts on the engine side of the fire wall. One is just aft ward of the valve cover, and a little toward the passenger side. The other three are around the computer. And the computer has to be removed to get at some. Inside, there is a nut inside the door post, and one about center below the windshield. Loosening the plenum allows the a core with swival pipes to be removed, and fitted back. But I discovered that a core with solid pipes is trapped. Either need to cut the pipes or remove the plenum. Removing the plenum is not an easy job. Need to disconnect everything from the dash board and move it out. Need to disconnect a lot of harness connectors and linkages and lift the awkward bulky plenum. Then it all has to be fitted back. Swivel pipes avoid a lot of trouble.

 

[GAmes]

You are mistaken. The HVAC will slide rearward enough to easily remove and replace a core without swivel pipes. Been there done that, more than once. When those swivel joints start leaking come back and tell us how they "avoid a lot of trouble".

 

[Engine Ear]

Thanks, if the joints start leaking, I'll have another look at the potential of sliding back the HVAC farther. Perhaps I did not examine the situation well. I concluded that I did not want to gut out the entire dash board and HVAC system. Have you seen the swivel joints leak? I did have to uncouple the evaporator connections to draw back the plenum slightly. With the plenum in its normal position, even the swivel pipes could not be steered past the windshiels and upper plenum surfaces. Not a loss to uncouple the evaporator though, as the refrigerant had leaked out long ago. I was rushed to get the job done, as I work outdoors and weather was beginning to deteriorate. I was just glad to get the job done before winter weather.

 

[GAmes]

A have read a few posts from members who had them leak. Obviously I haven't experienced that myself. I didn't disconnect the A/C couplers either. My evaporator is the original.

 

[Engine Ear]

A have read a few posts from members who had them leak. Obviously I haven't experienced that myself. I didn't disconnect the A/C couplers either. My evaporator is the original.

Thanks again. Hopefully my core will last a few years, and I'll deal with it when it does.

 

[Raedwulf]

So far so good. Drove it home with the cap off, no issues . I now have the cap on and it is working as it should. (Pulling water out of the overflow tank) I have yet to drain it and load it up with antifreeze, so I am running straight water in in. If it starts to freeze, I'll plug it in they a predicting 31 degrees for a couple hours on Sunday, lol. I plan to get to it this weekend.My heater core seems OK was plenty warm, I'll get ahold of cummins for the plugs (for future use). Maybe I'll get some brass and make them. ....The Machinery Handbook is your friend