1979 300SD Starting

[Mergyver]

My 300SD has 92,000 miles over the last 30 years it has only traveled approximately 25,000 miles.

inorder to start it on a hot (90 f) summer day for the first time I need to let the glow plugs warm up first. Is that normal? My experience with other Mercedes diesels(W126&W211) is that you only need glow plugs when the temperature drops into the 30 f range.

What do you guys think? I am worried that it may be a sign that my injectors are clogged from lack of use.

Any advice would be appreciated.

[Alec300SD]

Most likely carbon deposits on valve seats from infrequent use.
This lowers compression and makes the engine more dependent on glowplugs for startup, even in hot weather.

Adjust the valves, they are probably tight.
Afterwards, once the car is warmed up, have a few spirited runs uphill at wide open throttle.
Diesels respond well to being driven hard.

Additionally, you may want to clean your injection pump and injectors with Lubro-Moly Diesel Purge.
Change out your primary and seconday fuel filters after performing the diesel purge cleaning.

A diesel with healthy compression will start quickly without glowplugs.

[Mergyver]

Thanks Alec, I will get to the valves ang get the system cleaned out.