Glow Plug Install

[78 k5]

I would have posted this in the diesel forum but It doesn't get hit nearly as much as the Garage so here goes.....

I'm a fairly new diesel owner and a complete newb to diesel engine tech. I was having trouble with my 6.2 cold starting, and instead of testing the glow plugs I went out and bought an new redtop and 1 gauge cables. She cranked fine for a week or two and now only cranks during really hot/sunny days, so I figure I have a glow plug problem.
A. I don't really even know where my glow plugs are.
B. No Idea how to test them
C. Couldn't remove or replace one to save my life, but I am an average wrencher and have set up gears etc... so I feel I can tackle this with a little guidance.

Does anyone have an EXTREMELY detailed write up the tools needed and the in's and out's of this process? If so post a link and if not anyone feel like writing one???? PLEASE

 

[tRustyK5]

The glow plugs are where the sprak plugs would be on a small block. They have a single wire going to each with a spade connector. They're so easy to test it's not even funny, and you don't need anything more than a test light and 3 minutes of your time.

Remove the spade connector from the glow plug you want to test. Attach the clip side of your test light to the positive termianl of the battery. Tough the pointy end of the test light to where the spade connector goes on the glow plug. If it lights up it's good. If it doesn't then it is dead.

To replace them it is pretty straight forward...unplug them and unscrew them. Installation is the reverse. The only problem you might run into is if they are the older style of glow plug that 'mushroomed' when over heated. These can be a bear to get out as the tip usually swells to larger than the hole. You can do a search in the diesel forum to find out common solutions to that problem. It takes either a 10mm or 7/16" deep socket for the GP's. I can't recall which offhand.

The glow plugs I'd recomend are "Quick heats" from Kennedy diesel. They run about $10 each. They heat up twice as hot twice as fast and are rated for 'constant duty'. I'll be buying a set of those myself soon. I have 2 dead GP's now and it's getting a little harder to start because of that.

Equally important is cranking speed. By definition a diesel is "Compression ignition". The air is compressed (~20:1 compression ratio) which causes the air to heat up a lot. As the piston hits TDC the fuel is injected and ignited by the super heated air. If the air is compressed slowly (slow cranking speed) it doesn't heat up near enough. To get the air super heated you need the compression to happen quickly. There are a couple of guys running single batteries with 6.2's, but I'd recomend two large identical batteries. I run a pair of 1000 CCA Batt's in my truck.

There are also two styles of starter that were used with the 6.2. The better of the two is the 28MT gear reduction starter.

Rene

 

[78 k5]

Big help....thanks

 

[tRustyK5]

No prob...

Keep us posted.

Rene

 

[steve_kibbe]

Red tops are good, but I hink they are only 800-850 CCA.

I'm going to put some 1000 CCA batteries in my truck when I get there. Makes a big difference. I'm also replacing my cables with these.