This is the link in that thread:

Engine Heater Oil Pan Tank Heater 125 Watt 2.25x4 110V:eBay Motors (item 370110049532 end time Jan-02-10 19:50:56 PST)

We have 15 quarts of oil in there.

 

that looks like the one I put on my tractor size wise. I know mine gets hot enuff you don't want to touch it with bare hands. really not sure how it would do with 4 times the oil, tractor only holds 4 qts, but it only takes 20 minutes to get oil warm enough to hit glo plugs and fire right up.

 

My Freightliner came stock with an 850 Watt coolant heater and an "internal" 150 Watt oil heater and my total coolant capacity is 36 qts and my total oil capacity is 33 qts.

An "internal" heater element provides a more efficient transfer of heat energy to the oil but as stated above the easier to install "stick on" pad heater appears to work ok as well.

A 125 Watt "stick on" pad heater produces... (0.125)(2,655,224)=331,903 ft-lbf ...of heat energy for each hour that it's plugged in and a PSD pan contains about a 30-lbm mass of oil so for each hour the 125 Watt oil pan heater is plugged in the temperature of the oil increases by about... (331,903)/{(333)(30)}=33*F. For a 4-qt pan the temperature of the oil increases by about (15/4)(33)=124*F for each hour the 125 Watt oil pan heater is plugged in.

Since you need to have the coolant heater plugged in for several hours anyway the heating capacity of a 125 Watt "stick on" pad heater for the oil pan is a good match for the existing coolant heater and you can splice the oil pan heater into the existing plug for the coolant heater element and both heaters can be safely handled by a single extension cord!

 

Good to know. I thought you only needed to plug in your block heater for a couple of hours?

 

I plug my truck in at night before i go to bed so unless I get a good timer I dont think I would want the pan heater plugged in for that long.

 

Both of my trucks smoke a little on cold mornings. I run synthetic in both. My 97 is my work truck, and I will add 1 quart at about 10,000 miles. I do the extended drain intervals with oil analysis. Last year my 97 got new injectors and o-rings obviously, and oil consumption practically disappeared. 1quart in 10,000 miles is darn good. Truck has over 265,000 miles on it too.

 

I don't know where the synthetic oil goes when I have it in my motor. I did develop a very small leak when running synthetic oil. It seems to have stopped or has significantly slowed because I haven't lost a drop since switching back to dino.

 

I have heard that about synthetic oil, but I have not experienced it.

 

As long as the ambient temperature is less than say 60*F I don't see any problem at all with having both the oil and coolant heaters plugged in continuously because as indicated in the graph below the temperature of both the oil and the coolant will reach a maximum value and stabilize at this steady state temperature for an indefinite time until you're ready to start the engine!



On another thread I explained that the above calculation is a "simplified" approach which corresponds to the "red line" in the above graph and that this "simplified" approach only gives the correct answer for the first several hours. The above quote wasn't intended to imply that the temperature continues to increases by 33*F for each additional hour after the initial several hour period.

The rate of heat loss to the atmosphere is proportional to the difference between the pan temperature and the ambient temperature and eventually this temperature difference is large enough so that all of the heat energy generated by the heater is lost to the atmosphere and then the pan temperature stabilizes at some maximum value. It's difficult to calculate this maximum steady state temperature but my guess is that a 125 Watt oil pan heater won't heat the 15 qts of oil in a PSD pan to a temperature of more than about 120*F above ambient temperature.

 

Our customer rescheduled us for later this afternoon instead of 10am. I plugged the truck in at 7am and just started it. It started great w/o any haze. It's 13*F out there.

 

Never even thought of the blanket for oil pan. May have to look not that. Even though here inNJ it does not get to negative degrees. Usually teens is the coldest and if I plug her in and cycle plugs twice she is usually ok. If I don;t she is not starting. No way no how. Maybe Ill get the blanket to be safe.

 

Thanks for the info on this Eugene. I may look into one of the 125w heaters.

 

The downside is that you HAVE to be around a plug to benefit from the pan heater. If you run syn, it isn't an issue at all, even down into the negative temps. I'd just run syn (and I do).