I have a 1991 MB 350SD. Does this vehicle have the after glow functionality that my 1996 E300D has. I also have retrofitted my W116 with afterglow functionality that was offerred in a updated Bosch relay.

I read the Service Manual and it appears that some 602 and 603.96 engines did. Mine is a 603.970.

Could anyone offer assistance.

Thanks,
Richard

Bisric,

My 1990 W124 - 300TD turbo has the afterglow functionality so
why should a 1991 - 350SD not have this ?
I agree I am not 100% shure but I would be surprised if your car
didn't.
After a cold start on a cold morning (say 10° C and lower) you can hear a difference in the sound produced by the engine after about 60 sec : the "Diesel" sound becomes more pronounced, it's turning a fraction more roughly and as the current draw by the glow plugs stops, you can actually hear the reaction of the engine
- still turning on idle - when the idle rpm is corrected.
I hope this will help you to find out what GP relais is in your car.

Greetings, Danny

I checked it this morning with a volt meter. It appears that I have a 15 second afterglow. This matches up with documentation that I saw in the service manual. I was considering replacing the glow relay with a unit that has a 60 second glow.

When the 15 seconds passes - the poor girl runs rough until she is driven. In the extreme cold she also smokes alot until I drive her down the block. Then she is like gold.

I will be checking tomorrow morning as well. My initial take was that the voltmeter jumped higher when she was started. I know the glow plugs are new - perhaps the battery is getting weak.

I will check the glow plugs in the cold tomorrow before and after starting her. That will give me more info. Perhaps they are not getting as hot as quickly.

Thanks,
Richard

PS - The service manual also indicates that some 603.96 engines do not have afterglow while other 603.96 engines do.

Thanks
Richard