5W-40 oil will help.

__________________
Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

I had an incident when it got really cold and had problems starting my diesel. I solved that by going outside during my lunch hour, starting up my engine and letting it run to temp. I asked my company contractor to activate the outdoor outlet next to my parking spot so I could plug in but that crackpot told me to buy a gasoline powered car. Really, I should have kicked him.

__________________
1980 300SD (Mr. Sparkles), 1976 450SEL, 1982 300D turbo, 1989 VW Cabriolet morphing into a td cabriolet , 1997 TDI Passat, 1996 piece of Jeep,1993 F150, 1990 F250 7.3L...i think that's it, for now.

those blanket and run engine during lunch break will help too.

during cold days I go out to buy coffee so the car gets a 20 mins run.

__________________

borrow a laser thermometer, click on GP see if all have same temp. Do it when engine is cold or else u cannot see the temp difference.

My old SD had the prob, and I checked it, 2 out of 5 didnt make any temp increase, also you can use voltmeter to check the individual GP.
My 79 SD has individual wiring, it turned out one GP's wiring has no power going to it, I attach a wire from another GP to the dead one.
If worry one wire supplying 2 GP, one can run a relay there.

My last 240D I wire my own relay and hold her for 15 20 secs.
Put 2 off-road lamp relay in it, one can carry limited current.
Good Luck

__________________