Do I really need to use the glow plug reamer tool?
 

As the title states, is the reamer really necessary?


How much soot has come out in your experience?

Has anyone cleaned the holes but NOT replace the glow plugs after? Did u notice any improvement?


I just really don't feel like spending $35 on a reamer... Not to mention shipping and SALE TAX (I live in the same state as Kent's company so I have to pay sale tax) which makes this 50 dollar tool....

Sooooo do I really need it?

If so,what size reamer is it? (Kent won't give out that info for less than $5.95)

And lastly, if I do can I just buy a reamer from the hardware store and use a pair of vise grips to hold it rather than the wrench method?


My car is a 1980 300d non turbo with around 230k miles and as far as I can tell all maintenance was done and on time at the dealership up until 120k, so maybe they have been cleaned before. I'm sure maintenance was done after that but that's just when the oil change booklet ended, this was a one owner car


Please help me get an answer to my question before the MBZ Source rant ensues. Thank you.

"Has anyone cleaned the holes but NOT replace the glow plugs after? Did u notice any improvement?"

It will not start if you don't replace the glow plugs.

I have changed MANY GP's and never owned a reamer until a few months ago (one was given to me). I actually pulled the four GP's from my 240 yesterday to test them (wanted to put power to them to see how long each one took to glow), and they all tested perfect. Forgetting that I had a reamer (until just now when I say your poll), I put them back in. I don't remember ever having had a problem getting a plug out or in. My vote would be no, but I am not saying it is not a good idea to use one if you have one on hand. If I would have remembered that I had one, I probably would have used it.....Rich

EDIT: I have heard of folks using a drill bit. I imagine one would work if only twisted with your fingers, and gradually increasing in size until you can't turn the bit with your fingers. Realistically the size should be a few thousandths larger than the part of the GP that extends into the prechamber.

In a perfect world, yes. I live in an imperfect world so I just use a drill bit with a bit of Vaseline if I have easy access to the hole. If not I don't bother.

One can get away without doing many recommended things until the day you can't. Trying to remove a glow plug that is coated with a thick jacket of carbon build-up is no walk in the park.

Reaming glow plug holes is not very difficult and if you don't want to pay Kent's somewhat inflated prices I'm sure you can find something similar on ebay or in the hardware store. Buy a tee-handle chuck with it and you are in business. I do it every Fall and test the plugs as ROLLGUY suggests. Make sure they glow quickly and AT THE TIP not just on the shank.

Kent's main product is step-by-step instructions and special tools for novice maintainers. For those, I think his products are worth the cost.

You may want to check the tool rental program here. As stated earlier you may be able to change your GPs W/O reaming but while you are in there a few more minutes is all it takes. I will also check my tool box I may have one, not sure if I sent it out for free when I sold my valve adjustment wrenches. If I still have it you can use it. I will let you know.
PS do not purchase Autolite brand GPs shortest life ever and at the same price as Bosch.

X2 on Kents instructions. Simple to follow along with the small bristle brush that come in very handy also.

i obviously mean just taking out your working glow plugs cleaning the holes and then putting them back in...........

Have you ever tried to replace GP on OM60x engines without removing the intake manifold? So reaming is not on my schedule. I have gotten away with it on 6 cars in 10 years. Recommended procedures are just recommendations.

ok i think ill get one from my cnc machine tool shop. they have many high quality reamers for good prices.

can someone tell me what size reamer is used to do this??


and yes if anyone has an extra they would be will to part with i will pay shipping. thanks

If it is not broken, do not worry about fixing it. I am sure some will chime in about why change motor oil, etc.

The only (or should I say best) way to know if they are "broken" is to pull them and test with 12v. A plug can ohm out fine, but the "acid" test is to power them up and see how long it takes for the tip to get red hot (comparing them against themselves). I thought the no-start condition on my 240 might be GP related, so I pulled them to test so I could rule that out. Testing with a multimeter is not the most accurate way in my opinion.

When I reamed the holes on my 84 300SD and had trouble getting the reamer in. It had 250K on the engine and I have no idea if previous owners had ever cleaned the holes. I bought a reamer and I'll run it in the holes every time I pull the glow plugs.

Imo, you're rolling the dice by not reaming those holes. If you care for your injector system properly renting a reamer from a member here may be the right way for you to go. I have no idea how often reaming holes needs to be done. I just know that I'm never going to have issues getting plugs out or putting them back in.

Roger Clemson. I give mine the lightest taste of anti-seize on the threads also. A reamer and tee handle are too cheap to bother renting.

I actually just put all new Bosch glow plugs in my 84 300sd last week. I didn't spend the money on Kent's reaming tool. I used my gun cleaning kit with the copper brushes and some penetrating oil to spray in the glow plug holes and that took care of most all of the carbon in my car. It made a huge difference in starting the car especially when cold outside. When I first bought the car it needed glow plugs and I put in glow plugs made by Autolite and I did not ream the holes and the car struggled to start even with the new plugs. I left it this way for months starting was very difficult at times and ruined the starter so I finally bit the bullet and bought much better plugs, new starter and cleaned the holes with my gun cleaning brushes. Cold start problem solved.