David85: you didn't mention whether it was a new WAP088 or an old one. Two things can cause the sheath to swell up. !. is moisture getting into the alumina insulation used to insulate the heating coil from the sheath so the heating coil of nichrome wire can work properly. The 2nd reason is simply overheating which melts the alumina (somewhere over 2300 deg F) also weakening the sheath allowing it to swell under the pressure or simply melting the whole mess and allowing it to drip out. Anyway the 12G GP was designed to fit the GM6.2. It will fit the 6.9 Navistar and the 7.3 Navistar. The terminals are different, but they are the same length from the seat, same diameter heater sheath and the same thread. Any GP that crosses to the 12G should work. As I've said before, when I buy a different Manufacturers's product, I would invest $10.00 to get one and verify that it is temperature limiting.

 

It was a brand new plug, but theres no telling how old it really was. The tip simply started to swell up after about 10 seconds and after 23 seconds I heard a pppssssstt, and it was dead, the tip swelled to 1/4". I still have it some where lying around.

I also heard that there may have been a bad batch, but I have completely lost my patience with wellmans after a later incident that forced me to rebuilt my engine earlier than I wanted to.

 

Is this the one?

NAPAONLINE®

 

The 1109 are what I have in my 6.9L they are physically identical to the ZD1A. They seem to be working fine so far. I tested each prior to installation using heavy guage jumper cables and they all passed the test. The OE replacements are 6v and the 1109 are 11.5v according to the autolite specs, other than that I didn't see much difference.

I need a set for the 7.3L... this time I bid $25 (+$7 shipping) on a set of International #1819649C1. I hope they ship them soon.

 

How long did you run them for?

 

I am still running them. I bought a set of ZD1A when they were $2.99 planning to replace them.. but I never bothered to swap them out... put in more than a year and a half ago.

 

I meant how long was the test run before putting them in. I'm thinking that this is a good practice for myself. If what Marianna says is true, than in theory any glow plug could be susceptible to this condition.

 

Well, David85 proved my point for me. If you don't want to burn out another set of glow plugs again, just try a 12G or 1109 Autolite. It will cost you about $10.00 to prove what I have been saying. They are the same thread and extension to the sealing seat so they will work in both the 6.2 GM ( which they were designed for a military application) and the 6.9 & 7.3 IDI Navistar engines. If you insist on using what the engineers and marketing people at GM, FORD,and Navistar tell you,think about the guys that have had failures that required pulling the heads off to remove the swelled up plugs. Then like David85 did, he had to buy another controller ~ $100 Bucks aset of GPs and he lucked out because the failured Berus didn't swell. If they had, the bill could reach about $700 to $800. A nice piece of change for the service department don't you think? The system the engineers designed works great as long as every piece in it works as designed. Reality is that nothing lasts forever. At least if the controller fails with temperature limiting GPs the bill does not include removing the heads, Heck you should never have to replace the GPs.

 

I forgot to mention that the terminals will have to be changed to use Either the AC 12G or the Autolite 1109s. Trust memthe effort will be worth it!

 

I was one of those guys that had to pull the heads. Ended up overhauling the whole thing since I had to replace at least one piston anyway (WAP 080 glow plugs) What sells be on Beru plugs is that I have seen first hand that they will stay in tact even after a 40 second run that ends in a burn out (failed controller).

So just to double check, is this the glow plug you are talking about?

NAPAONLINE®

 

As far as I know, the AC 12G and any GP that crosses to it are the only ones that are dual coil. They only come with a flat spade terminal. You didn't mention how long you left the power connected to the 1109 GP.

 

I tried WAP 080 and 088, bosch, and beru so far beru is easily the best. But if i can get a AC 12G at my local Napa shop I will be very tempted to pick one up and test it. We do have a GMC 6.5 TD in the family that is due for glow plugs.........

 

Yes that's the one AC 12G. Do yourself a favor and buy one. Hook it up like Misnomer did. Realize that if it fails, take it back and get a new one because it must have absorbed moisture into the alumina insulating material. To be safe, let it heat until it barely starts to glow and let it cooloff. this will drive the moisture out without destroying the GP. GPs are made by using a nichrome wire coil embedded in alumina insulating material inside an inconel sheath. Ine end of the coil is welded to the sheath at the tip and the other end is welded to the rod sticking out of the shreath. There is a rubber seal where the rod comes out to seal it. This seal is not perfect. If the GPs are stored in a high moisture environment. If the sheath swells the alumina will not conduct the heat from the coil to the sheath causeing an internal break. GPs are like a minature cal rod that is used in electric hot water heaters. At extreme temperatures, the alumina itself will expand causing the sheath to bulge. At anyrate, if your GP won't take heating in free air outside of the engine, It will not work in your engine either. I know what you guys are saying about BERUs not swelling. Once the dual coil units get past the infant failure they will not swell since they cannot get hot enough to melt the alumnia insulation in the sheath. I only mention this since I purchased a set of Autolite 1109 GPs and when I did my test run with my battery charger 7 out of 8 of them blew out the sheath before they stabilized. I would have been in deep trouble if I had installed them and heated them in the engine for the first time. Autolite warranteed them and the next two sets I bought worked fine. One set in my 85 F250, the other set on the shelf for my current project 92 F350. Both sets are working fine. By the way glow plugs should last the life of the engine. Failure means something went wrong.

 

Now that you mention the moister thing. I remember that WAP 088 that I tested was packaged in a cardboard box and was stored near a concrete floor. Beru plugs are sealed in an air tight bag at the factory, makes me wonder....

I think I will get an single AC delco plug and see what it can do.

 

According to NAPAONLINE® the 6.5 takes a AC60G GP. It is the same thread as the AC12G the sheath appears to be the same length. Check it out at the store toverify that they will fit.