Freeze plug size?

[Sycostang67]

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This is what greeted me when I crawled under the 86 today. Since this truck will be parked in a place where no outlets are to be found, I am just gonna put in an expansion plug instead of another block heater. What size plug will I need?

On a positve note, since the heater fell out I am getting the radiator rodded out since the cooling system is empty. I am also replacing the positive battery cable since I have to remove the starter and disconnect the batteries.

 

[typ4]

inch and one half, a cup type might go in there, or an expando one, not my favorite but does work when installed properly.

 

[icanfixall]

Russ is correct. A cup type 1 1/2 freeze plug fits perfectly. I had one installed in my first shop rebuild along with the other brass plugs that popped out. Those caused my engine to burn down because as soon as you have no coolant seeing the temp senders they wont tell you anything useful. Even my isspro aftermarket gauge was reading around 200 degrees. It was the oil temp that told me something was wrong. It was passing 330 degrees and the lifters began to knock.... Too lake....

 

[dyoung14]

I had the exact same thing happen! i used a rubber freeze plug there, works fine

 

[rhkcommander]

Any reason to choose freeze plug over heater?

Mines screwed so I need a new one to plug it up... Oregon ain't that cold but I do camp and have seen some lows but I've got a 600w heater on my lower rad hose

 

[Brimmstone]

I've fixed them a couple ways. One I use lock-stitch pins to install a steel plug and secure it in position. I've used them on several cracked blocks over the years and they work well. The rubber expando plugs while they do work have a tendency to pop out. When I swapped the engine out in my 87 the first time because of the same exact problem I got a new block heater then after installing the heater I coated the entire thing and about an inch all around except for the dipstick tube with JB-weld. I want to see that come out without some work.

 

[jonathan]

Any reason to choose freeze plug over heater?

Mines screwed so I need a new one to plug it up... Oregon ain't that cold but I do camp and have seen some lows but I've got a 600w heater on my lower rad hose

the 6.9 blocks are known to crack around the block heater. no heater=no block cracks

 

[The Warden]

the 6.9 blocks are known to crack around the block heater. no heater=no block cracks

FWIW that's limited to mid-'85 and older blocks, so unless someone swapped an earlier block into his '86 (which IS possible), he should be okay. Also, IIRC the cracking is more due to stresses related to the nearby engine mount than to the block heater...it's generally believed that using the block heater will exacerbate the cracking issue, but that doesn't mean you're immune from the cracking if you never use the block heater.

Look for the block's serial number (should be stamped in the block on the driver's side near the IP drive gear housing)...the reinforced blocks began with serial #173828.

My block heater started leaking in 2004 (first noticed it when I pressure-tested the cooling system after putting the engine back together), and I replaced it with a rubber expanding freeze plug. Probably not the best solution, but I wasn't in a position to do anything else at the time...I need to replace it someday, but it's still holding up...

 

[OLDBULL8]

Don't let anyone rod out the radiator, the tubes are squiggily, rodding will poke holes in the tubes, you can only boil them out in a hot caustic tank for at least two days, then flush real good with clear water.

 

[RLDSL]

A rubber plug cost darn near as much as a block heater. Why not just replace the block heater and have something in the hole that you know is going to stay put for a VERY long time. it's very rare that the things pop loose and start leaking, but a rubber plug is playing with fire.
And definitely as mentioned, do not have the rad rodded out. Afactory rad will not tolerate it, you will either punch it full of holes or weaken it so bad as to make it worthless

 

[rhkcommander]

I'll check the serial in the morning, all I know is spray n seal was used by the po and its dripping a ton now

I think this isn't the original engine, looks like a junkyard pull to me: passenger valve cover has no sticker but does have chaulk or w/e .

I saw a thread here where someone linked to it I think when they found one on ebay and then cheaper at napa or something? Napa showed part number BK 6053137 for a 1000W non-KAT brand. I looked back to march in my posts and couldn't find anything so sorry for hijacking the thread...

Thanks

 

[Dieselcrawler]

i got a new block heater from IH for 30 bucks. i did have a rubber expandable one in that popped out. also i found my original heater the same place as yours, but everytime i hit the key i had sparks at the starter. so i figured the wires were loose. ended up having the heater arcing when the starter was activated.

 

[dyoung14]

rubber freeze plug costed me 3 bucks

 

[jonathan]

rubber freeze plug costed me 3 bucks

me to

 

[Sycostang67]

I'm gonna rubber plug it for now, if it comes out sometime down the road I will put a heater back in. It's going to be parked in a field when not in use so there will be no place to plug it in anyhow. I picked up a plug and some new hoses today, still need to hit a dealership as I decided to replace the t-stat as well.

I thought only the newer radiators had the spiral tubing. I know the radiator in my 93 did so I replaced it. From what I can tell, the 86 radiator has straight tubes. Even a good boiling though should help it a bunch. The crud I can reach with my fingers comes off with little effort.