How long is a proper glow for a w123?

[gldncatbiofuels]

Hear is the deal, my 83' 300D is for the most part running pretty solid. I recently had a few bad glow plugs that needed a little attention. About a month ago I replaced glow plugs 1 & 2, the rest of the seemed to read fine on the ohm meter. the first week was a little better, but I have noticed that compared to my partners 300TD, the glow plug light seems to stay on about half the time. (around 4 seconds) his is almost double the time of mine. My question is just a general conscious of the amount of time that the average glow is on this model. I notice that the cold start seems to not have much trouble, where as after the car has reached operating temp, it becomes harder and takes a few good hard cranks to restart. I have noticed quite an increase in the amount of coolant consumed over the past couple of months, I'm guessing some correlation for the extra cranking. Someone has told me that its all in the relay and that it needs to be replaced, but Ive noticed that there are really no posts for this topic. so.. if any can give some feedback it will be greatly appreciated. THanks

[Diesel911]

The relay will stay on longer than the glow plug light. The glow plug light is just sort of a guide. If you want to know how long your relay really stays on have someone else put the hold the ignition swith in the glow plug position while you listen to the golw plug relay. You should hear it click on and click off. If you like you can time it. I have read but not paid attention to this but some people use the inerior light to determine how long the glow plug relay is cycling. When the relay is on the light gets dimer when of brighter.
Since you said your car starts OK with the glow plug relay working as it dose now I would think that you have no problem at this time. I would be more worried about the coolant loss which could damage your engine.
The hard starting after warmed up and coolant loss are different and unrelated problems and you might want to do seperate searches for them.

[tangofox007]

Originally Posted by gldncatbiofuels

My question is just a general conscious of the amount of time that the average glow is on this model.

According to the 617.95 engine manual, 25-40 seconds (approx) would be expected above 0 degrees C. The light should extinguish at four seconds at 20 degrees C, 5-7 seconds at 0 degrees.

Originally Posted by gldncatbiofuels

I have noticed quite an increase in the amount of coolant consumed over the past couple of months, I'm guessing some correlation for the extra cranking.

Coolant is not "consumed" under any normal circumstance.

Originally Posted by gldncatbiofuels

Someone has told me that its all in the relay and that it needs to be replaced, but...

Free advice is often worth exactly what you pay for it.

[Brian Carlton]

Originally Posted by gldncatbiofuels

Hear is the deal, my 83' 300D is for the most part running pretty solid. I recently had a few bad glow plugs that needed a little attention. About a month ago I replaced glow plugs 1 & 2, the rest of the seemed to read fine on the ohm meter. the first week was a little better, but I have noticed that compared to my partners 300TD, the glow plug light seems to stay on about half the time. (around 4 seconds) his is almost double the time of mine. My question is just a general conscious of the amount of time that the average glow is on this model. I notice that the cold start seems to not have much trouble, where as after the car has reached operating temp, it becomes harder and takes a few good hard cranks to restart. I have noticed quite an increase in the amount of coolant consumed over the past couple of months, I'm guessing some correlation for the extra cranking. Someone has told me that its all in the relay and that it needs to be replaced, but Ive noticed that there are really no posts for this topic. so.. if any can give some feedback it will be greatly appreciated. THanks

The length of time on the glow light is variable depending on temperature...........and, apparently, due to production tolerances........variable between specific vehicles as well.

So, for your vehicle, establish the amount of time needed to reliably start..........depending on temperature. My SD gets a five second glow down to 20F. Below 20F, since I don't want to risk a no-start, I give it 20 seconds. If it ever gets down to 0F, I give it the full glow time of 35 seconds. This works for the SD. Your times may vary slightly.

Of greater concern is the consumption of coolant. Get a pressure test and see if it's leaking somewhere. If not, and the engine is consuming the coolant, you've got the typical head gasket issue that these engines typically face near 200K miles. Don't allow this issue to remain indefinitely, otherwise long term damage to the engine will eventually occur. The engine doesn't like coolant in the oil for extended periods. You can confirm the presence of coolant in the oil via the use of an oil analysis. I encourage you to do this.

[AdvisorGuy]

Your problem may be carbon on and around the glow plugs. I replaced mine 2 weeks ago. No starting issues, just a lumpy, shaky, smoky idle for about 20 seconds. I assumed I had a bad glow plug and bought all 5. I used JimmyL's reamer. I checked all 5 with an ohm meter and they checked fine but since I had the new ones, I replaced them anyway. I found 1,2 & 5 glow plug holes so tightly packed with carbon that I could barely get the reamer into them. Reamed all 5 holes, replaced the plugs and it starts & idles like silk, even below 30 degrees and sitting for 2-3 days.