At anywhere below zero degrees F., older Cat and other make pre-combustion engines generally will not start, even if all mechanical items are perfect. Hell, a lot of direct injection engines won't start either. That when you pull out the ether cans and give them a good snort.
How to start a Cat 651B 67K on a cold dark January morning in Wyoming: This also works in New Jersey, Maryland, Pennsylvania, Kentucky, West Virginia, Illinois, Michigan, Colorado, and Utah and Nevada.
1. Get to jobsite and sit in pickup cursing cold weather for a few minutes.
2. Put coveralls and other cold weather gear on.
3. Curse cold weather some more.
4. Get in toolbox and retrieve two cans of ether.
5. Stuff more ether cans in your pockets.
6. Bang on cab door so it will break loose and open.
7. Have your buddy get in cab and have him jam transmission in reverse.
8. Turn master switch on and start preheating the glowplugs for minimum two minutes, more likely four minutes.
9. Use that time to crawl up the ladder on right side. Be careful, it's slippery you fool!
10. Beat snow off air cleaners. Remove both air cleaner covers.
11. Spray thick pattern of ether on both inner air filters.
12. Have partner jam thottle to floor and start cranking the engine.
13. Shoot more ether on inner air filters.
14. Duck large cloud of soot and ash coming out of muffler.
15. If engine begins to fire off on a couple of cylinders, shoot more ether in. Make sure partner stays on thottle. It has to be on the floor!
16. As engine begins to rev up, give it more ether.
17. As transmission starts to drag engine RPM down, give the engine air filters more ether.
18. When engine tachs out and trans is whining good, reinstall both outer air filters tightly.
19. After engine starts and you have about 60 pounds of air built up, pull the retarder in all the way and keep that engine up at full RPM. This forces the tranny oil to heat up quickly. Let retarder go after oil temp comes up a bit.
20. Motion partner to pull trans into neutral whilst keeping thottle to floor. As the engine starts to torque down, shoot more ether in the precleaner bonnet.
21. When engine is finally idling normally, carefully step down, throw empty ether cans at pickup, and move on to the next one. Remember, you started getting the iron ready at four in the morning for a 7AM production start. One down, nineteen to go..... Then the pushcats, compactors, and graders
22. Call down to the warehouse for more ether or send someone in to town to get a pallet or so.
23. Repeat untill all 20 pans are started. Put production supt off as it's now 7:30AM.
24. Repeat next day.
Remember, just because you got the big bustards started, doesn't mean they are going to move anywhere. The brakes are froze you know.
If the above does not work, leave that machine sit and go on to the next. When you have as many started as possible, start working back thorough the line.
1. Try all the dead ones at least once. Didn't start, huh? Not unusual!
2. While you remove the trans input shaft cover (at rear of trans), have your pard remove the outer air filters again.
3. Hook up a machine that started easily (probably a D9) with a set of double 00 jumper cables to the batteries under the cover on the right front. If you are lucky, use the Cat quick-start jumpers instead, they are far better than any clamp on jumpers, and using them is much less dangerous than jumping straight to the batteries)
4. Start engine, let it run until the coolant guage shows it's up to operating temperature. Shut engine off.
5. Keep trans in reverse all this time.
6. Reinstall trans drive shaft, cover, and retainer bolts.
7. Mash thottle to floor, hold it there.
8. Attempt to start engine again.
9. If it starts, follow steps 18-20 above.
10. Reinstall outer air filters and covers. You did help the engine with more ether didn't you?
11. Remove jumpers and reinstall cover if you took it off. (this is a good time to check and tighten battery terminal clamps and make sure battery cables are snug in their clamps. Make double sure the battery holddowns are in good repair and fastened down tight.
12. Oh crap, you forgot the brakes are frozen to the drums, didn't you?
My crew and I worked from 4AM to noon one Saturday in 1975 trying to get 20 651's started. At noon we had half of them going, but production decided that ten wasn't enough and went home. (bar) MY crew spent the rest of the day getting the other ten going and performing general maintenance. I could tell about many other places this had to be done with the B-series D346 engines and 8-speed transmissions. This method of starting extreme cold weather machines was not only approved by Caterpillar engineers and techs, they came up with the original idea.
Some early 67K's that went to Alaska for Green Construction actually had a dog clutch installed between the torque divider and the transmission input shaft. These didn't work out too well and around 67K65 the idea was discontinued. That's when the factory came up with the plan of placing the trans in reverse. They found out in field tests that the transmission pump, in neutral, tried to build up too much pressure, around 400+ pounds I believe. In reverse, the trans safety valve only spooled up to about 60 pounds and that allowed the engine to keep turning over. As the trans oil began to loosen up and with the engine at full RPM, you could pull the trans into neutral, but you had to stay on it. Once we got the hang of it, starting these beasts became much easier. Those that are familiar with the D-series 60-degree engines know that at less than full RPM, these machines couldn't get out of their own way. At full blast, they were nearly unstoppable.
Surprisingly, we had few engine or transmission failures. We kept two pallets of new batteries in stock and a pallet of starters too. We had a standing order for a pallet of ether every week from NAPA, and sometimes had to buy more.
Ether is a great tool for starting engines, cleaning oil and grease off parts, thowing out frozen door handles and padlocks. Used with care and experience, it will not hurt an engine, or you.