Importance of Engine Operating Temperature

[markopolo]

Some of us are using the vehicle engine to provide in coach electricity to power items such as microwave ovens etc. Some of us are using the vehicle engine for heat, cooling or pre-heating & pre-cooling. We're using the engine to charge batteries. I think an Engine Operating Temperature topic could be educational.

I'm hoping the we can separate fact from fiction and come up with some specific information that can lead to some ideas and/or guidelines as to what engine temperatures should we try to attain and how to get to those temperatures. A list of DOs & DON'Ts would be useful.

My assumption is that concerns about Engine Operating Temperature would apply to both low speed operation and idling. I'm also assuming that highway driving does get the engine up to correct operating temperatures.

Post actual data if you can. This topic will need:

1. specific operating temperature recommendations for gas and diesel engines
2. actual temperature data when cold, after idling & after driving.
3. what affect on engine temperature does the load on the engine have - (compressor, alternator)

I'll have to check if the Scangauge in my van can report oil temperature. An infrared thermometer might give some useful data if it can be aimed at the right place.

The following article is not specifically related to Class B vans (the vehicle in the article is a hybrid) but it does illustrate the need to understand one effect caused by not getting the engine up to the required operating temperature: Problem with your hybrid? Burn more gas, Ford tells owner - Newfoundland & Labrador - CBC News

[booster]

I also think this is a good topic, as I have been concerned and testing what happens on our 6.0 Chevy gasser where we can get up to near 300 amps of charging now.

Low speed and idle would seem like the logical place to see a problem, but we haven't to this point. I haven't even seen the water temp come off the thermostat setpoint. Of course it is cool here now, but still surprised. Time in desert will tell us more. The Chevies have a tendency to get hot on long climbs, so I think we may see more issues there with high alternator output. An extra 5-7hp to run the alternator would have about 60% of it going to heat, and that could easily push a marginal climb into the overheat range. The good thing is that most of us can just shut off coach charging easily if going into a big climb, like many will do with the air conditioning.

I can't speak for diesel engines, as we have never had one or even looked much at specs. Back in the day, the engines had 160-180 degree thermostats (summer/winter) and everyone got nervous at 200 degrees water temp. Now most everything has about 190-195 degree thermostats, and we routinely hear that 220 on the water is not an issue, if the pressure cap is good. Personally, I like to stay under 210*.

We always tried to shoot for oil temps of 210-220* degrees back then also, but now I am seeing numbers like 230-250*. The oils are better now, and at high temps especially synthetics, but for a highly loaded van climbing a mountain, I would prefer the lower end of that range.

Our Scangauge doesn't read oil temp. About 5 years ago Scangauge sent me a code to put in to try it, but it didn't work. When I get the RTD thermometer working for the new alternators, I am going to also put a sensor on the oil from radiator line and on the batteries. The thermometer will only have two channels, but I anticipate that once we confirm how hot the alternators run, we would rarely use both, or even on of their sensors. The cables just plug into the meter so I should be able to have any combination of the 4 temperature readings. I am suspect that the oil temp is going to pretty largely influenced by the water temp, like the transmission oil is.

We do get hotter on long climbs, but so far our two 16" add on electric fans have covered it pretty well. IIRC about the highest water temp we have seen was about 205*, with the transmission similar. The oil would probably be a bit higher than that because it's cooling tank is on the hot end of the radiator, so it won't get as much cooling.

Load on the engine will always add more heat to the coolant and oil, at about 60% of how much hp the load uses. I think AC uses about 10hp (enigne) max, which has been stated for a long time, but it will use much less at idle because of the compressor speed being low. So at speed with max AC output and max engine generator output, you could be using 15hp to run things, with double that amount going to heat (water, air, oil, exhaust). At idle, most would probably have 1/2 of that, I think.

[markopolo]

Could it be said that 212 degree F oil temperature (or thereabouts) is the goal for both cold and hot temperature concerns?

[dknightd]

Two separate problems. You do not want the engine to overheat. But you want the oil hot enough to evaporate moisture. But not too hot. RV usage is hard on oil - unless you are driving cross country on a highway. Change engine oil on the taxi schedule

[DCHitt]

Originally Posted by markopolo

Some of us are using the vehicle engine to provide in coach electricity to power items such as microwave ovens etc. Some of us are using the vehicle engine for heat, cooling or pre-heating & pre-cooling. We're using the engine to charge batteries. I think an Engine Operating Temperature topic could be educational.

Thanks for starting this topic. Your description pretty much matches my operation. I have no generator or propane. The engine heats the dash/rear of the van and the water heater. I have worried that maybe the engine, at idle, would not put out enough heat?

All I can measure in my Promaster is the engine temp and it seems to stay nailed on normal. I look forward to following this topic..

[booster]

Originally Posted by markopolo

Could it be said that 212 degree F oil temperature (or thereabouts) is the goal for both cold and hot temperature concerns?

That is a very often asked question, especially on the cold side.

One the cold/evaporate the water side, you don't need to get all the way up to the 212* boiling point of the water. The temp we normally see and talk about is the sump temperature in most cases, unless you have sensor in the return line for an oil cooler. At 180* oil, there will be lots of places in the engine that get hotter than 212* so the oil will be able to flash off the water. That is part of the reason it can take a long drive to get rid of it all the moisture, as all the oil has to be in one of the hot spots long enough in its random circulation. Of course if all the oil, and all the metal in the engine is at 212+*, the water will go away much faster. In the winter it is very, very hard to even get the oil in many vehicles even to 150*, form what I have seen. In the Chevies, or others with a radiator oil cooler, the hottest the oil could get would be radiator temp, for the most part, if the cooler is doing it's job. The oil also is cooled by the water jackets in the engine, as many of them are running cooler than the oil. Our old school V8 Challenger almost always had the oil and water temps within about 5* of each other, which seemed really odd.

On the hot side, the temp optimization is for oiling. Multi weight oils are rated at 212* for viscosity, and I have been told by some folks I knew that took IC engines at the UofM, that well designed modern engines are designed around that rating, and the oil they want to use. The clearances, pump capacity, etc have to match the oil used and temp run to maintain proper film strength, part cooling, oil pressure. We have all seen the move to lighter oils for efficiency, and other things have to change along with the oil change.

In a perfect world, it would be nice to have the water at 195*, oil at 210*, and Tranny at 180* ( if it is a newer one designed for synthetic oil, 160* if not).

[booster]

Originally Posted by DCHitt

Thanks for starting this topic. Your description pretty much matches my operation. I have no generator or propane. The engine heats the dash/rear of the van and the water heater. I have worried that maybe the engine, at idle, would not put out enough heat?

All I can measure in my Promaster is the engine temp and it seems to stay nailed on normal. I look forward to following this topic..

Gas or diesel? Radiator oil cooler? It would be rare to see a gasser run too cold at idle, but diesels surely can, and lots of bad stuff can happen.

[avanti]

I think there is a 2x2 matrix here: gas/diesel x too-hot/too-cool

Gas engines typically come up to proper operating temperature pretty quickly. Diesels, being intrinsically more efficient, not so much. As I said recently in another thread, Sprinter diesels come with elaborate features (Espar aux diesel heater and/or electric air heater) specifically designed to provide adequate cabin heating at idle. There just isn't enough waste heat available to do a proper job without it. This has a significant impact on the effects of idling in cold weather.

As for "too hot", my experience is that no properly-operating modern engine seems to overheat under any reasonable conditions.

[booster]

Originally Posted by avanti

I think there is a 2x2 matrix here: gas/diesel x too-hot/too-cool

Gas engines typically come up to proper operating temperature pretty quickly. Diesels, being intrinsically more efficient, not so much. As I said recently in another thread, Sprinter diesels come with elaborate features (Espar aux diesel heater and/or electric air heater) specifically designed to provide adequate cabin heating at idle. There just isn't enough waste heat available to do a proper job without it. This has a significant impact on the effects of idling in cold weather.

As for "too hot", my experience is that no properly-operating modern engine seems to overheat under any reasonable conditions.

I agree, but there are engine/vehicle combos that will overheat. The Chevy 6.0 in a van is one of them. They are short of radiator and airflow, though, not an engine issue. They seem to fine in the pickups. I know of several Ecoboost pickup that also get hot when towing uphill, both the oil and water. They turn down the boost when the get hot, so you basically become unable to get enough power to pull that heavy anymore and wind up slowing way down or stopping for a while. I haven't seen any modern cars that overheat easily in many, many, years. Cold blooded diesels are a way of life in Minnesota. You see all the diesel trucks, VWs, Audis, etc with the front air blocked off.

[DCHitt]

Originally Posted by booster

Gas or diesel? Radiator oil cooler? It would be rare to see a gasser run too cold at idle, but diesels surely can, and lots of bad stuff can happen.

It is gas and I idle a lot. Don't know about the oil cooler.

[mkguitar]

6.0- I don;t know if original equipment, added by PW or by previous owner- mine has 2 x pusher fans on the radiator which come on from time to time- thermostatically controlled at about 230º
Man they are loud- and I use them as a reminder to turn off the AC if I forget.
Living in Arizona it is routine ( and often signed) to turn off AC on long grades.

on my old '67 GMC I would sometimes have to turn on the heater on a hot day t remove heat from the coolant ( still , I loved that truck).


I figure with modern motors and synthetic oils in a GAS motor ( diesel is different) you want temps to get hot enough to evaporate out any moisture in the crankcase, cool enough to keep parts from over expanding and reducing tolerances.

I figure the 230~240 i have seen is the high range and my vortec GM's seem to pretty much stay 180~190 under most conditions.

I am a 3000 mile changer guy but I have stretched to 5K with 90% highway cruising usage.

as for heat I worry more about the tranny than the motor

I am not a long term idler- but I see cop cars here will pop the hood when idling at a accident scene for example

mike

[dknightd]

Originally Posted by DCHitt

It is gas and I idle a lot. Don't know about the oil cooler.

Follow the taxi regimen for oil change

[dknightd]

Originally Posted by markopolo

Could it be said that 212 degree F oil temperature (or thereabouts) is the goal for both cold and hot temperature concerns?

Yes. ha

[tgregg]

Originally Posted by DCHitt

All I can measure in my Promaster is the engine temp and it seems to stay nailed on normal.

I think the temperature gauge on my gas Promaster is 'highly damped'.

I have a Scan gauge and the water temperature it displays varies from the high 190s to 220 depending on load and the Promaster temp gauge never moves off normal.

[booster]

Originally Posted by mkguitar

6.0- I don;t know if original equipment, added by PW or by previous owner- mine has 2 x pusher fans on the radiator which come on from time to time- thermostatically controlled at about 230º
Man they are loud- and I use them as a reminder to turn off the AC if I forget.
Living in Arizona it is routine ( and often signed) to turn off AC on long grades.

on my old '67 GMC I would sometimes have to turn on the heater on a hot day t remove heat from the coolant ( still , I loved that truck).


I figure with modern motors and synthetic oils in a GAS motor ( diesel is different) you want temps to get hot enough to evaporate out any moisture in the crankcase, cool enough to keep parts from over expanding and reducing tolerances.

I figure the 230~240 i have seen is the high range and my vortec GM's seem to pretty much stay 180~190 under most conditions.

I am a 3000 mile changer guy but I have stretched to 5K with 90% highway cruising usage.

as for heat I worry more about the tranny than the motor

I am not a long term idler- but I see cop cars here will pop the hood when idling at a accident scene for example

mike

I would be nearly certain the fans were added after PW, but you never know. We have two Spal fans that are as big as I could find that still fit and I had confidence in that they would actually make their rated cfm. Lots of exaggerating in that industry. I think were in the 3-4000 cfm and they do sound like an siren. They require a 30 amp fuse apiece, and big wiring, so they are pretty serious items.

[DCHitt]

Originally Posted by dknightd

Follow the taxi regimen for oil change

So far I have been changing the oil when the message pops up on the dash. I do think I will go to synthetic oil. Don't know what a "taxi regimen" would be.

[booster]

Originally Posted by tgregg

I think the temperature gauge on my gas Promaster is 'highly damped'.

I have a Scan gauge and the water temperature it displays varies from the high 190s to 220 depending on load and the Promaster temp gauge never moves off normal.

That would be the getting to be normal "make the customer feel good" gauge that you see too much of these days. They are kind of like an idiot light with a needle.

[bobojay]

Originally Posted by DCHitt

It is gas and I idle a lot. Don't know about the oil cooler.

The 3.6 Chrysler Pentastar engine has an oil cooler located in the V of the block in conjunction with the oil filter housing....

[markopolo]

Thanks for all the great info posted.

I tried this oil temperature Scangauge x-code - Scangauge2 X-gauge Commands - Page 2 - Chevrolet Colorado & GMC Canyon Forum - today for my VPW protocol GM van but it didn't work. That code has the vpw bit at the beginning in place of the cansf bit on the Scangauge website. As I said, it didn't work for me but might be worth a try on newer vans.

I idled the diesel van for 20 minutes today to get some data. Minutes 1 to 10 were at 624 RPM, minutes 10 to 15 were at 1,070 RPM and minutes 15 to 20 were at 1,350 RPM. I upped the RPM (switch controlled) to see if it would help get the temperature up.

Starting temperature: Transmission 46F, Coolant 46F
After 5 minutes: Transmission 60F, Coolant 116F
After 10 minutes: Transmission 73F, Coolant 121F
After 15 minutes: Transmission 84F, Coolant 127F
After 20 minutes: Transmission 96F, Coolant 130F

Then, after probably a 10 minute delay I got the infrared thermometer out and got under the van and pointed it at the bottom of the oil pan which showed 115F. The transmission pan showed 80F. I don't know how accurate the readings were as I forgot to check what setting the thermometer was on.

[booster]

Might be time to block off the radiator on that one!