I posted this before but couldn't find it again, so here I go. I have two plugs coming out by the grill on the passeneger side of the truck (87 F250 w/ 6.9L) I didn't know which was what but I followed them back and one goes to the engine (the block warmer, I presume) and the other goes in to a red cylinder beside the battery. The cylinder has two 1" heater hoses coming out of it. One hose goes into the firewall and the other goes to the front of the engine. I am not mechanically minded so help! What is the cylinder, do I need to plug it in, how do I test my block warmer to see if it works?

Also, the truck has been "southern engineered" with the glow plugs. I have a push button switch that goes to the battery and to something else behind the breather. Is this common or does anyone foresee a problem with this. I have to hold the button for 25-40 seconds before the truck will start. I know this isn't normal. What would you do? Thanks in advance.
Tommy
:-X11

 

One plug is more than likely the stock block heater, the other is an aftermarket heater used to warm and circulate the coolant so that your heater will be blowin' hot air when you get in. Your block heater also warm the coolant but much of the heat if transfered to the cold metal so your heater will still somewhat cool when you turn it on. The other overcomes that problem.

If it gets cold enough in TX just plug in the one that goes to that cylinder for a couple hours. Start your truck and feel the air comin out or just grab a hold of one of those heater hoses to see if they are warm.

I would check the comdition of the wires prior to plugging them in. Don't go killin' yerself. The only way I know how to check the block heater is by using various electrical tests. Someone else may have a better way than one of my long winded explainations.

As for your glow plugs. I may be wrong but holding it for 25-40 sounds way too long. Should be more like 8-15 prior to starting then cycle them in 4-6 second bursts kinda like the controller would do if you had one. My advice, get a real controller. I don't think all your glow plugs are working. Are you crankin' it while you hold the button or are you holding the button to warm the pre-combustion chambers (6.9L do have 'em don't they? Those weren't DI were they?) THEN cranking it? Well, no matter I believe your glow plugs are shot. I wouldn't hold it that long when you get new ones! You'll burn 'em right up! Good luck those trucks are tanks!

 

Check your block heater cord carefully before using it, especially a 14 year-old one - they can get chafed and burned on the exhaust manifold and have caused some expen$$ive fires. You can test the heater itself with an ohmeter connected across the plug prongs (should read near zero ohms), or by finding a double outlet, plugging a work light into one outlet and the block heater into the other - if the work light dims slightly when the heater is plugged in, the heater is probably OK.

Get rid of the "southern engineering" and get a stock glow plug controller unless you like throwing money down the toilet on burned glow plugs and wiring harnesses.