I have had cold start issues for a while, in this thread: Persistent cold start problem - now below -11 C / 12 F

Today I did some checking and rechecking:

1. Redid OHM test with block heater inactive. Four plugs now measure .5-.6, the one that previously gave huge OHM reading now gives infinity.

2. Have power to top right pin in small connector at relay with ignition on.

3. When relay active I have 11.98 volts at all five male pins in relay.

4. HOWEVER, only have 9.75 volts at glowplugs when relay is activated. (I had previously used a test light on the GPs, today I used the multimeter.)

What am I seeing here?

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Save yourself the headache and thinking.....just replace all your glow plugs and forget about the readings. I get 10v at each plug and my car starts fine...my glows all ohmed fine but my car wouldn't start....after i replaced all the glows...it fires right up....

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The plugs were new in October. At this point I have no problem replacing them -- need to change one anyway -- but I would like a solid reason for doing all five rather than thinking that I am throwing parts at the issue (I will have to have a shop do it, I am working outside).

I am leaning more toward the battery as a starting point as the relay shouldn't be showing under 12v, as far as I know.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Did the recess for the glow plugs get reamed when they were replaced?

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'70 F100 shortbed
'82 Diesel Westy
'83 Euro 300TD
Curtlo Viper
Yeti ARC
Surly long haul trucker

Ah. No. I borrowed the tool and when I went to use it, it wasn't the right one. Larger diameter.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

People have come up with some alternative methods to clean the Holes. If you have the pencil type Glow Plugs The actual Reamer end is 7mm.

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84 300D, 82 Volvo 244Gl Diesel

About 10.5 volts at the Glow Plugs is normal. However, cold temps sap your Battery so if it was really cold you would expect the Voltage at the Plugs to be lower.


Try the same test after the Car has be running and it is nice and hot under the Hood and the Battery fully charged and see if the Voltage goes up.
If not it could be likely it is your Battery.


There is at least 2 Members who have said removing the Glow Plugs and reaming or otherwise cleaning the Carbon out of the Holes improved their starting.


As far as replacing all of the Plugs instead of only replacing the bad ones that seems to be a personal choice.


But, you can see the though going on with that. If one is bad speculation is the others could also be close to the end of their life.


New Plugs with the exception of occasional duds are though to be at the beginning of their life and the hope is it will be several years before any of them have issues.

Here in S CA where it would be a reall cold day if it was 48 degrees F I would have no issues only replacing the bad ones.

If I lived someplace where the temps are minus something (617.952 Engine) I would if one Glow Plug was bad and they all had been in there along time I would seriously consider replacing them all because I would hope to make it through the Winter without any further Glow Plug Issues.

On those Engines with Aluminu Heads that is a different story. In the Winter if a Plug is bad replace only the one Plug and hope it does not Break when you try to get it out.
If someone plans to remove the Glow Plugs on Engine with the Aluminum Heads that is better done when it is warm enough to remove the Cylinder head if you had to.

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84 300D, 82 Volvo 244Gl Diesel

Now it's becoming ridiculous.

Both Kerry and I have told you, on two different threads, to change the one bad glowplug and see what it does.

You refuse to do that and come back on here with another irrelevant question and now want to replace the battery.

You know the definition of insanity............right???

Gee, Brian? I REFUSE? Really?

Shall we have you screen posts for what is "irrelevant" on this board? If we use your standard, it will be very quiet around here.

To start, I was advised to replace the battery on the earlier threads.

Yes, you and Kerry told me to change the plug. And I could understand your attitude if I was posting a "OH MY GOD MY CAR WON'T START AGAIN" thread. I was not, though apparently that is how you chose to read it.

I started this thread because I mistakenly thought I should be seeing 10v+ at the plugs, which led me to believe I had found new info on the issue. We ended up rehashing some of the earlier info because I had to answer others' input.

Would you like to know WHY I haven't moved on the advice? We are just coming out of a cold snap of around -20 C + wind chills most of the time, for two weeks here. Last weekend the days were colder than that.

I work outside, no garage. No way work is happening at that temp. I have arthritis. Standing still, bent over a motor, for even 20 minutes isn't an option unless I want to spend a day or two immobile in bed after.

From the start of the cold snap, the weather services kept predicting one or two days of cold... then warming. Then one more day. Then two more days. Initially I didn't expect the bad weather to remain as long as it did.

My wrench is in Florida for two weeks to placate his wifey, who hates the Canadian climate. Back today, I believe.

If I call one of the local euro shops for a job this small, I will probably get booked in... in about 3 weeks. All having gone upmarket, they consider anything that produces an invoice under $300 too small to open the bay door. They would be happy if people like me with these old cars just went away.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

It would be very quiet around here. Because most of the advice you receive is, unfortunately, FACTUALLY INCORRECT and not based upon the data presented. What you typically get is someone who cured a different problem, with different symptoms giving you THEIR SOLUTION. Useless.

One of the best individuals on the board with regard to an accurate diagnosis, Tangofox, left the board .

I know all about cold and the inability to work in it. I've got a Dodge van that is now 60 days on a tuneup that I cannot get done due to my knees and my back. But, if it were me, I would take the path of least possible resistance and I would get that single glow plug changed. I might struggle to do it, but I would get it done and see if it improved my situation until warmer weather arrives.

But, that's just me.

You might prefer to spend hundreds of dollars with a mechanic to replace all kinds of things that don't need replacement (you do know how mechanics function..........correct?).

Or you can come on the board and post multiple threads to get hundreds of responses, most of which won't apply to you.

Your choice.

Hi Zach,
Some of the replies are from owners in warmer climes! In Canada, if I leave my 300D outdoors overnight in winter, it is always hard to start below a certain temperature even with the block heater on. Batteries don't like the cold weather either!

I used to use my 300D as my daily driver. I kept it in an unheated garage overnight usually without block heater. It would sit outdoors at work for 8 hours during the day without a block heater in all Canadian winter conditions. I only once had to call for help!

You have done most of what is needed:
- valves properly adjusted (and good compression)
- New glow plugs
- block heater (make sure it is working!)

I would first jump from a battery on one of your other cars. That should ensure full voltage. If that solves problem, a new battery will no doubt be needed. Nothing like a good battery in a 300D!

I made my own reamer but didn't find much build up. But reaming wouldn't do any harm if you are going to pull the injectors. I wouldn't if they test out - It's a bit of a pain getting by those injector tubes!

If one new glow plug is bad - I would wonder why? Perhaps just a bad connection at plug or at relay? Have you cleaned relay contacts and checked connections? (I have not read complete thread)

Again haven't read complete thread, but some cheap aftermarket glow plugs are apparently prone to failure even when new.

I have not tried this solution, but it looks interesting:
TinyURL.com - shorten that long URL into a tiny URL

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

When was the starter last replaced on the car? Are the battery cables original? If the plugs were just replaced I wouldn't suspect them....

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No idea on the starter. It turns plenty fast for the compression on this car.

I understand where you are going but we're talking about a car that fires on the first crank at around -5 C then basically acts like it has no glow at -10 C. It is getting fuel, you can smell it out the exhaust as it cranks.

I have swapped between two relays along the way as well.

The valves were adjusted in September.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Well guess its time too smash the car....

I would replace the starter, the brushes do ware down and the old grease will get hard and a bad starter will kill the battery....and cause a strain on voltage....but you say no sooooo.....

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I'd begin by just swapping out the one known bad plug and go from there. It's only like 5 minutes to do that.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13