Howdy.

I have a 93 GMC 3500 van with the 6.2L in it. Late last winter, it seems that the block heater went. At first, I thought it was just the plug, so I replaced it this summer and paid no attention to it.

Recently it has dipped into the single digits here in S.E. WI, so I've had it plugged in. However, I have noticed that it seems to not be working. Cranking time is extremely long (just put new glow-plugs in this last fall) and the engine (and oil pan) are dead cold.

Right now I've started driving my gas van until I can get a new block heater. Just wondering if anyone had suggestions on what a decent replacement is and what's involved in replacing.

I'm fairly mechanically inclined and have appropriate tools/facilities, so I'm not worried, but I'm curious to know if there's anything special involved or to watch out for.

Thanks.

-Jeff

i just installed one on my 82 gmc pickup it was not hard, all you have to do is remove a freeze plug or in your case the old heater and replace it with a new one. drain all radiator fluid first.

When you install the new block heater, pay particular attention to the tightening torque on the center screw. don't overtighten it! I did that on one or two of them back in the '70s and early '80s. Driving down the road and the t-strap (retainer) broke, the cooling system pressure blew out the block heater. Huge cloud of steam, embarrasment, etc. Cooled it down and drove it off the hiway for a roadside block heater replacement. Not fun. Happened another time to a customer after I had installed a GM 5.7D in a Delta 88. That one wasn't fun either! His wife wasn't very understanding?!?

Thanks for the tip Fred.

Yesterday I tried to start the beast so I could go ice racing, but even with new batteries, she wouldn't catch in the 8deg weather.

I looked to see what type of heater it was, and it goes back to the block, so it appears to be heating the cooling system vice the engine oil (I guess I'll find out for sure in a couple days).

I ordered up a new one this morning which will be in tomorrow. $22.00 for the full thing, including new cord, etc. Not bad...

In my brief investigation of it yesterday though, it does not appear obvious as to how to remove it. I guess I'll have to get a better look.

Fred, if you have any insight as to what I have to do here, it'd be appreciated. I'm assuming I'll have to drain some or all of the coolant, but I'm not sure. Figured I'd play it by ear and see what comes spilling out LOL...

Thanks much!

So to wrap up my experience...

I headed out to the garage this morning with my new heater in hand ready to take it on.

I looked briefly for the coolant petcock and didn't find it. Having worked (extensively) on motorcycles for the last 5 years (liquid cooled inline 4 cyl's), I figured I'd chance it and hope that there would be enough vacuum to hold most of the coolant in the radiator and just drain what was around the block via the heater.

That would have worked, but my radiator cap was sucking air back into the system, so I was pretty much screwed into draining all of it. Oh well.

Once I got the old heater out, it was obvious why it wasn't working. One of the prongs from the heater that attaches to the AC cord had corroded and broken off.

A quick wipe down of the area, a ring of grease around the gasket and I popped the new one in. Tightened it up snugly but not too tight, filled up with fresh coolant and I'm back in business!

It was pretty simple all in all, and cheap too...

Now, the only question I have is if it will do any harm other than sucking electricity if I leave it plugged in whenever I'm not running it in the winter (sometimes several days)?

Fred,
Thanks for the advice about over tightening the screw. Just put a new block heater in the other day while the engine was out. I felt the screw get tighter and then looser as I tightened the screw. Was kind of unsure about that, but guessed it would be ok.. After reading your post, now I know I over tightened it and bent or broke the retainer strap.
Thanks, you probably save me a on the road breakdown!

Glad to help. If I saved you some time, great! If I saved you the embarassment I've suffered from being stuck on the road, even better!!

I hate stuff breaking on the road, it never does it unless I'm in the center lane or have just passed the exit!! Everybody shares a "Hee Haw" on me!

Seriously, that's what attracted me to this site. The helpful attitude of the writers. Thanks guys and Happy New Year!

I have used my block heater only one time in the last 20 years. I thought the heater was just like a freeze plug (core plug), i.e., it is pried out and the new one is tapped into the block with sealant on the flange, but the posts indicate the heater is screwed into the block. Is that the case? And do you screw it out with a socket?

The center screw is usually a dual pattern head. Usually a Phillips #2 or a 1/4 hex socket head. I say "usually" because it differs depending on Mfgrs. I've used a 1/4" ratchet and 1/4" 6pt. socket with success. Sometimes I've been lucky enought to loosen it with a short Phillips screwdriver. It Depends on how much space you have in your chassis. Once you have the screw loose, wedge a screwdriver into the outside edge (lip) and pry it out.

Clean the hole, scrape excess paint, sealer, etc. The new heater will have an o-ring seal that seals against the side of the softplug hole so it must be clean. I use Permatex-LocTite Gold RTV just for insurance.

Don't overtighten the center screw! (See above posts) Good Luck, Fred