Rubber plug in place of block heater, 10 years later...

[The Warden]

Hello!

If any of you remember when I redid my head gaskets and everything in the summer of 2004, as I was buttoning everything back together, I found that my block heater was leaking. I have a very early 6.9l that does not have the reinforced block, so I never used the block heater, and I was broke at the time...so, instead of installing another block heater for the sole purpose of closing up the hole, I put in an expanding rubber plug. I've always understood that these were meant for temporary use, but it held up surprisingly well!

Fast forward 10 years...I drove my truck a couple of weeks ago and noticed that the coolant level was considerably lower...I used a hand-pump tester to pressurize the cooling system, went around looking for leaks, and found this plug dangerously close to popping out

Thanks again Gary for posting a link to cheap replacement block heaters...I ordered one from Fleabay that day, and finally had a chance to pull the rubber plug and install the block heater today. It got too late by the time I was done, so I decided to let it sit overnight and I'll refill the cooling system tomorrow.

For anyone who might be interested, here's what the rubber plug looks like now

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[gandalf]

Wow. Ten years with a plumber's temporary expansion plug? That's amazing. No wonder your truck was starting to mark it's territory.

That plug was starting to look pretty nasty, wasn't it?

It's good to know there is a tempoperm solution for a bad block heater. I'm surprised it was able to deal with the engine heat.

Thanks for letting us know, Tim.

 

[icanfixall]

Nice post Tim. I'm not sure if you know this but you can install a freeze plug in that hole and thats the only place we can in out engines. All the other 7 freeze plugs have the lip the plugs rst against in our blocks. You sure got all the life out of the temp plug too..

 

[The Warden]

Wow. Ten years with a plumber's temporary expansion plug? That's amazing. No wonder your truck was starting to mark it's territory.

That plug was starting to look pretty nasty, wasn't it?

It's good to know there is a tempoperm solution for a bad block heater. I'm surprised it was able to deal with the engine heat.

Thanks for letting us know, Tim.

When I put the plug in, I figured I'd get maybe a year out of it. I was almost finished with the engine work and was anxious to see how she ran...so I went with the cheapest/quickest option. For the first three years or so, I inspected it regularly (not all that easy with the starter being right there) and was surprised to see it hold up...I finally started to forget about it.

Believe me, I'm as surprised as anyone that it held up so long! I think the rubber wasn't really designed for coolant...but, even still, there's something to be said for it holding up as long as it did.

Nice post Tim. I'm not sure if you know this but you can install a freeze plug in that hole and thats the only place we can in out engines. All the other 7 freeze plugs have the lip the plugs rst against in our blocks. You sure got all the life out of the temp plug too..

Gary, I of course knew about the other 7 holes requiring the special freeze plugs, but I thought you had to use a special freeze plug in this hole also. Didn't realize you could use a "standard" freeze plug in this hole. OTOH, given the block weakness in that area and the fact that I already have a block heater in there, hopefully I'm good to go ...time to go and find out!

 

[jaluhn83]

Good that you caught it - that's pretty close to what caused my first major engine casualty, except mine was an expanding copper plug in one of the real freeze plug holes and it popped out at full throttle pulling tehacapi pass with about 18k.... overheated in about 2.5 seconds!

I honestly would prefer the freeze plug over putting a block heater in - the second major overheat issue I had was a result of the screw on the block heater either coming loose or breaking, can't recall which, but I know she proceeded to **** out all the coolant and get toasty.

 

[The Warden]

Good that you caught it - that's pretty close to what caused my first major engine casualty, except mine was an expanding copper plug in one of the real freeze plug holes and it popped out at full throttle pulling tehacapi pass with about 18k.... overheated in about 2.5 seconds!

That's what did in one of Gary's engines too...I consider myself very fortunate that I caught it before it became a catastrophic failure

I honestly would prefer the freeze plug over putting a block heater in - the second major overheat issue I had was a result of the screw on the block heater either coming loose or breaking, can't recall which, but I know she proceeded to **** out all the coolant and get toasty.

Especially since a block heater's useless to me (nowhere to plug in, and with the early 6.9l I'd be a fool to use it even if I could), I agree with you, and if I had known that I could have used a standard freeze plug in this hole, I would have. The newer block heater's an improved design IIRC, and it's already in...we'll see how long it lasts!

FWIW I got the system filled and drove the truck around today...everything seems fine so far, but we'll see how well it does over the next few days...

 

[jaluhn83]

Have you looked into a coolant level sensor? I have an isspro setup on my rig that has a big read warning light if the level gets more than about 1-1/2" below the top of the tank. It's not cheap ($150-ish IIRC), but it's great for piece of mind - wouldn't have another rig without one. It comes with a solder in bung if you have a brass radiator, or you can drill and tap the al one, though better would be to weld a thicker plate on and drill & tap that.

 

[va350]

The same thing just happened to me. My son is driving one of my trucks to college, about a 2 hour drive away. He came home Friday night for Easter weekend and parked the truck. Saturday morning I went out and saw a puddle of anti-freeze under the truck. It turned out the previous owner had replaced the block heater, cord was still there, with a rubber plug. Thank god it didn't pop out driving down the road. Anyhow I did the same thing, I ordered and installed another block heater to plug the hole.

 

[The Warden]

Have you looked into a coolant level sensor? I have an isspro setup on my rig that has a big read warning light if the level gets more than about 1-1/2" below the top of the tank. It's not cheap ($150-ish IIRC), but it's great for piece of mind - wouldn't have another rig without one. It comes with a solder in bung if you have a brass radiator, or you can drill and tap the al one, though better would be to weld a thicker plate on and drill & tap that.

I've thought about a level sensor, but haven't done anything about it. It's probably a good idea...

The same thing just happened to me. My son is driving one of my trucks to college, about a 2 hour drive away. He came home Friday night for Easter weekend and parked the truck. Saturday morning I went out and saw a puddle of anti-freeze under the truck. It turned out the previous owner had replaced the block heater, cord was still there, with a rubber plug. Thank god it didn't pop out driving down the road. Anyhow I did the same thing, I ordered and installed another block heater to plug the hole.

Yipes!! Good thing you caught it before it popped all the way out. The previous owner should have told you about that...

 

[va350]

I've had the truck for a couple years and never noticed it.

 

[The Warden]

I've had the truck for a couple years and never noticed it.

Makes sense...unless you've pulled the starter or are troubleshooting a problem with the block heater (or looking for a coolant leak in the vicinity), there's no real reason to look up there. I'll be honest...after it held for 3 or 4 years, I got complacent with mine, and was even able to forget that it was there. When I noticed a coolant leak, though, I immediately remembered it and looked there second (after checking the hose clamps), and I'm thankful I did!

BTW, I drove the truck to work today (about 40 miles round-trip), and looks like all's holding up well