Anyone else had repeated problems with the preglow relay (OM 617) in extreme cold?
 

On my '85 300d, I have had this occur now with three different preglow relays.... When the temperatures drops to about -20 deg C (- 4 deg F) or below, and the car is parked outside all day where I work (no plug-in), the relay won't engage by itself.

That is to say: I have to open the hood and tap or press on the side of the relay for it to engage. Then it works fine. Sometimes, the action of springing open the hood is sufficient.

I always blamed this on the relays being old. However, this winter I have one in there that has seen maybe 9 months of use - albeit it's a Huoco. The others were Bosch and Hella and of unknown age.

I'm thinking you have a run of bad relays...

perhaps your hood is allowing water to collect on them?

The moisture aspect had occurred to me as well, which was one reason I bought the Huoco relay, which has the correct orientation for a w123 - that is, the harness with the plugs and electrical connector comes up from below, meaning the relay cover should prevent most or all moisture intrusion (the blank end of the cover faces the windshield when installed).

If you use a relay not from a w123, some are oriented to have the harness connect from the other end of the relay, meaning that the open end of the cover is facing up and toward the windshield, where it is vulnerable to moisture.

I know that Clacker, who lives near me, has had the same issue on at least one OM617 relay. I am just curious if it may be a localized issue due to our area's climate, which is moist all year 'round (humidity all summer, lots of freeze-thaw cycles and of course snow in the winter months).

Might be a candidate for a manual glow setup - the classic Ford starter solenoid replacing the electronic glow complexity of the MB unit.

...just a thought. Personally, I'd never go back and the coldest temps we ever see around here is still above freezing.

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http://www.peachparts.com/shopforum/...1&d=1420571561

We've had no issues with my dad's 300SD... or with my 300D. Both were able to start at low temps. The 602 started up in -15F without block heater. The 617 started but wasn't enthusiastic about it as I recall

Perhaps if you take them apart and coat the contacts etc with some dielectric grease it would keep moisture from freezing key points together... just a thought

I've had no glow relay issues in the cold ever on any of our diesels....my 190 has an older Bosch relay and its been doing fine in single digit temps all week. :eek:

If you simply it with a manual circuit... probably no chance of problems the rest of your life... or if there are... the cause will be easy to find and cheap to fix...

Okay, so I am hearing that I'm the Wile E. Coyote of preglow relays? :blink:

I had a Ford solenoid arrangement on my old Coupe. My biggest drawback is that I don't want to mess with the interior of the 300d by installing a switch.

The other option is, of course, one of Funola's modified relays.... Which keeps things closer to stock but still requires a switch somewhere.

Why can't you hide the switch a little up under the dash... OR make it a FOOT SWITCH... like the old starter switches were....

Let me understand this... you would rather have a stationary vehicle... than one with a non stock switch on the dash.... ?

I never said I was stranded from a relay not engaging. The relays all worked, they simply needed a nudge or tap on the body of the unit to engage in extreme cold weather (typically somewhere between 2-5 days during a typical winter around here).

I am not for putting a hole in the dash of a two-owner, 119k mile car to accommodate a momentary switch, if I can avoid it.

Foot switch won't work with my 14 EEE feet and 6 ft 4 ins height. My left foot is resting firmly on the floor most of the time.

You could hang a switch around the steering column just in the winter...on the left side so no one would see it....

True, that is a good idea.

I had also considered putting a switch with a cover into the tray area behind the shifter, somehow. That would give an excuse to use one of the funky 'arm the nuclear warhead' switches with a flip-up safety cover :D.

If you go that route, make sure you get a momentary switch not an on-off switch.