Does it matter what kind of anti-seize I use for glow plugs?
 

Does it matter what kind of anti-seize I used for glow plug threads? Perhaps it doesn't matter...I was going to use copper...all my heads are aluminum.

Interesting that FSM for the CDI doesn't recommend using anti-seize. Wonder if using it affects the torque value.

And then there's the question of whether some plugs have anti-seize pre-applied. I'll be using Beru.

If it says none that is what I would do. The heat might cause it to bake solid...?

x2. You rarely read of glow plug threads sticking. It's usually deposits on the business end that cause problems which antisieze won't prevent.

Maybe the best you can do is clean the threads before installing then soak the dickens out of them before removing.

Sixto
98 E320s sedan and wagon

I agree with Sixto. However, I did use anti-seize. Permatex is the brand I used; I chose it among two or three brands because it is the brand I recognized. The second time (after anti-seize) five of the six glow plugs came our very easily on my '98 e300.


I had problems with the no.1 gp both times. The problem was not the threads but "the business end." I used PB Blaster to free it, which took a while. I unscrewed the gp until I got resistance (less than a quarter turn) and squirt in some PB Blaster and then work the gp back and forth and then unscrew it a bit more, repeating the process until the gp was freed.

For your CDI (and for the om606), the threads are not the part that seizes. It's the shaft that gets carboned up and stuck. The european mechanics give the shaft a generous coat of hylomar to prevent carbon seizing. Don't get it on the tip.

I don't know what kind of steel the glow plugs are made of, but if it's stainless steel, even mild stainless, you absolutely do not want to use copper anti seize. Copper anti seize causes stainless steel to become brittle and *more* likely to break.

For steel to aluminum contact (steel glow plug into aluminum head), aluminum anti-seize is the best choice. But again, it isn't the threads that cause seized plugs on these engines.

FSM recommends dry threads, so yes using any kind of product on them will absolutely affect the torque. Its an aluminum head, you do not want to strip those threads out.

I typically put a thin layer of nickel hi temp anti seize on the business end.

Nickel anti seize works very well, but is recognized as a category 2 carcinogen. Nasty stuff, it should never be handled by bare skin. OSHA classifies it as a Hazmat for this reason. I don't use it in my garage.

Nickel is really only needed for stainless steel or titanium parts, or for temperatures that you'll never see on a passenger car ( > 1800 F ).

I made a little info graphic to help articulate what products and where to apply them. I hope someone finds this useful.

http://www.peachparts.com/shopforum/...s-glowplug.jpg

Shouldn't see in a passenger car. Raising boost with insufficient fuel will result in 1800*F EGTs :eek:

Closer to topic, don't glow plug tips get that hot?

Sixto
98 E320s sedan and wagon

Tip hits right about 1800 F, yes. But there shouldn't be any anti-seize product on the tip, nickel or otherwise.

I notice my local auto parts store carries copper type instead of the silver type of permatex grease.

I wonder which is better.

I use the stuff on all kinds of bolts. And my GP. I'm not only worried about seizing but also galling when I install them since I have an OM617 with an iron head. I was told after an embarrassing incident galling some high end tech equipment together that similar metals are more likely to gall. The active elements in the copper and silver grease are supposed to stop this perhaps (I cannot recall) because of their high electrochemical potential. it stops things from spontaneously welding together.

Not that this is happening on glow plugs.

I really got into this stuff after working in the oxygen sensor business. We always used antiseize on the sensor threads.

I now use it on all kinds of stuff. My wrenching buddies think I'm nuts because they say I should use loctite on things like my vacuum pump bolts. I want to be able to get them out again someday...and as long as I torque them properly they haven't needed threadlocker.

Just my 2c. Considering how many times I have to do my jobs twice I really hate using threadlocker and prefer antiseize to make things disassemble fast.

Call me stupid but most of my SD is screwed together with silver grease with the exception on things like the harmonic balancer, engine mounts, air cleaner mounts etc. that are prone to vibrate loose.

As previously noted, it depends entirely on the application.

I'm not aware of any silver based anti-seize, so I assume youre referring to aluminum by its "silver" color? Aluminum as a base material for anti-seize is good for use on stainless steel, but cannot be used on carbon steel, due to the fact that when it comes in contact with an electrolyte it becomes an anode and since this anode is extremely small in volume compared to the large cathode of the steel, it usually deteriorates quickly, leaving no protection at all on the steel surface. Corrosion therefore takes place at a higher rate of speed, as if no anti-seize would have been present. :eek:

Ergo, aluminum anti-seize is the wrong choice for steel glow plugs in a cast iron 617 head - it causes more harm than using nothing at all. For this application, you most definitely want the copper anti-seize instead.

Ok. I thought silver was indeed silver. Makes sense it is aluminum.

Good to know I should be using copper. That's what I have now. My local chain store no longer carries the aluminum stuff.

If it's not the threads but the "business end" that gets stuck, then how will penetrating oil help to free them up? Will it actually get that far down to make a difference?