Engine Block Heater for SBC 350

Hello,

As winter approaches, I want to be able to start my truck in less than 30 total seconds of cranking. I live in Wenatchee, WA and last winter got down to about 0 degrees F. I've looked at different engine heater options and I see coolant heaters that get installed in the freeze plug holes, screw in heaters that go in where the coolant temp sensor goes or some other hole, pads that stick to the oil pan, heaters that screw into the oil pan drain plug hole, and dipstick heaters. Do you have any recommendations based on experience with these? I see lots of options but not many that are specific to the SBC 350. Thanks!

Bryson

Most reliable and easiest to install are soft plug heaters. Directions will instruct which one to install it in. Remember GM installed them from the factory.

I live in Spokane, we get comparable weather. Actually any maintained vehicle with a good battery should start decent in 0 degree weather. 30 seconds cranking? Has a problem.

I live in the Yakima area, and have tried a few on my SBCs over the years. The ones that worked the best was the one that tied into one of my heater hoses and circulated warm water through the system, BUT it didn't last, rusted out really fast, and got rust in my radiator. I've also tried the magnetic type that just sticks to the side of the oil pan, and that wasn't bad. I have yet to try the kind that installs into a freeze plug in the block. I'm trying to decide which one to use on my newest 350 as well, so I'll be following this.

I've lived most of my life where it regularly gets -40 for extended periods, and based on my experience from what I have used:
First choice - recirculating coolant heater
Second choice - coolant heater in place of a freeze plug
Last choice - Magnetic oil pan heater.

I haven't tried the other types mentioned.

Normmus said:

First choice - recirculating coolant heater

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I would also recommend a tank type coolant heater. Heat the engine and the cab heater too.



This is one of many Zerostart brand external tank heaters. You don't have to mess with a freeze plug. Pull out the coolant block drain on the passenger side, add the hose fitting. Cut the heater hose and add the "T". You mount it vertical, bottom hose fitting on the heater has a check valve to prevent reverse flow. That is the inlet from the block. Tank heater top hose (next to the cord) goes to the "T".

Zerostart has been around for years, they make all types. The 1500 watt heater pictured only needs to run an hour or 2 before start up. Use a timer.

fast 99 said:

Most reliable and easiest to install are soft plug heaters. Directions will instruct which one to install it in. Remember GM installed them from the factory.

I live in Spokane, we get comparable weather. Actually any maintained vehicle with a good battery should start decent in 0 degree weather. 30 seconds cranking? Has a problem.

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Thanks for your reply. What does the battery have to do with this? And if you think there is a different problem, is there a way I can troubleshoot? One thought I have is that previously I haven't adjusted the electric choke coil on the carb. I should probably do this as it will have a different tension on it in the winter. Otherwise, I'll look into soft plug heaters.

BigT said:

I live in the Yakima area, and have tried a few on my SBCs over the years. The ones that worked the best was the one that tied into one of my heater hoses and circulated warm water through the system, BUT it didn't last, rusted out really fast, and got rust in my radiator. I've also tried the magnetic type that just sticks to the side of the oil pan, and that wasn't bad. I have yet to try the kind that installs into a freeze plug in the block. I'm trying to decide which one to use on my newest 350 as well, so I'll be following this.

Click to expand...

I like the idea of the magnetic ones, but I can't tell with some whether they have adhesive to be stuck to the pan or if they're magnetic pads. I'm thinking of those rectangular orange ones. Could you suggest a brand or send a link? Thanks

Normmus said:

I've lived most of my life where it regularly gets -40 for extended periods, and based on my experience from what I have used:
First choice - recirculating coolant heater
Second choice - coolant heater in place of a freeze plug
Last choice - Magnetic oil pan heater.

I haven't tried the other types mentioned.

Click to expand...

For the freeze plug ones, what's the best way to get a freeze plug out? I've watched a couple videos and in one, the guy drilled a hole in it and used a slide hammer which would be easy but probably drop metal shavings in the engine. And in the other, he tapped one side of the plug with a punch until it turned, but it almost seemed like the whole plug could have fallen into the block. What's your experience with this?

Good battery means adequate amperage to crank fast enough in a cold environment. Shouldn't be using heavy grade oil 10-30 or 10-40 ok, no 20-50.

To remove a freeze plug, use a blunt punch of some kind or even a long 1/2" extension. Hit it towards the outside edge. It may twist in the hole, that's good. Then use a channel lock or other pliers pry it out. Plug may fall down if pushed all the way in but not far enough that it can't be reached with fingers or magnet. Have replaced lots of soft plugs. It's not hard, just a little messy.

Yes some investigation into choke operation might be a good idea.

I've started my wore out carbed 350 in -50F and colder. I daily my square in ND all year round. Good battery and cables and proper choke operation. They can start without the choke too it's just kind of rough on em and a pain in the ass usually.

The soft plug heaters work good and are reliable. Been using em for a long time. Haven't had to replace one. It's not gonna make the coolant all warm and toasty but it is very noticeable when I plug it in, just spins over and starts way better. Heat gets into it way faster after startup.

You could even do dual soft plug heaters! lol

Not necessary for your temps though. One soft plug heater will do just fine. Very easy to do, as said above, try to knock the plug in sideways so it twists, then use a vice grip and rotate it out. If it falls in, it can be fished out pretty easily.

PrairieDrifter said:

I've started my wore out carbed 350 in -50F and colder. I daily my square in ND all year round. Good battery and cables and proper choke operation. They can start without the choke too it's just kind of rough on em and a pain in the ass usually.

The soft plug heaters work good and are reliable. Been using em for a long time. Haven't had to replace one. It's not gonna make the coolant all warm and toasty but it is very noticeable when I plug it in, just spins over and starts way better. Heat gets into it way faster after startup.

You could even do dual soft plug heaters! lol

Not necessary for your temps though. One soft plug heater will do just fine. Very easy to do, as said above, try to knock the plug in sideways so it twists, then use a vice grip and rotate it out. If it falls in, it can be fished out pretty easily.

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Sweet thanks! Sounds like the freeze plug heater is the way to go. Out of curiosity, where does "soft plugs" come from? I guess it just means freeze plug but I haven't heard that before.

Brysonsproject said:

Sweet thanks! Sounds like the freeze plug heater is the way to go. Out of curiosity, where does "soft plugs" come from? I guess it just means freeze plug but I haven't heard that before.

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Freeze plug/soft plug. Same thing. Softer than the engine block lol

I grew up in ND, and freeze plug (or block) heaters were installed on just about every carbureted vehicle. You can put it on a timer for a few hours, or if you aren’t worried about the electric bill you can run it all night. A 1500 watt heater element will never be able to heat the antifreeze too much.

At 20-30 below zero some carbureted vehicles were just about impossible to start if they were not plugged in. It was also great to have near instant warmth from the heater.

Brysonsproject said:

I like the idea of the magnetic ones, but I can't tell with some whether they have adhesive to be stuck to the pan or if they're magnetic pads. I'm thinking of those rectangular orange ones. Could you suggest a brand or send a link? Thanks

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As far as I know, the newer style pads are totally magnetic, high temp silicone. Clean off a spot on your oil pan and stick it, then run your cord and leave it alone, but I have not tried one of those. I the one I had was many years ago was the type pictured below, by Handi-Heat. It worked well, but stuck out a bit and could get knocked off on a rock or something, so I don't know if I would leave it installed like the pad type. They kick ass for tractors and the like, because they are accessible and you can just take it off every day. On a car or truck, not so much.

The freeze plug heater guys have all noted some good experiences, and I suspect that's probably the best overall method long term. But if you don't want to crawl under there and make a mess, then the recirc heater like the Zerostart one Turbo mentioned above is probably a safe bet, and way easier to install. I'm probably going to do that myself.