: Does external oil cooler lower engine temps?



philistine
06-13-13, 03:59 PM
As the title says...I'm sure somebody has some empirical results. I'm wondering if you have relatively high engine coolant temps (ECT)...say 235F, would an oil cooler affect your ECTs and if so under what conditions?

My thinking is that the oil lubricates and cools the rotating parts so if you are maxed out on radiator cooling, shrouds, exhaust pipes etc. Would an oil cooler bring the ECTs down?

darkman
06-13-13, 05:10 PM
The short answer is yes. All else equal, an oil cooler will result in lower coolant temperatures. When and whether you can see though will depend on a number variables. For example, in some circumstances the extra cooling capacity brought by the oil cooler may delay the temperature that triggers the fans, but you will not necessary detect that by looking at ECT readouts.

philistine
06-13-13, 05:22 PM
The short answer is yes. All else equal, an oil cooler will result in lower coolant temperatures. When and whether you can see though will depend on a number variables. For example, in some circumstances the extra cooling capacity brought by the oil cooler may delay the temperature that triggers the fans, but you will not necessary detect that by looking at ECT readouts.

I understand there are many variables but do you think the oil cooling could reduce ECT by as much as 10-15F highway cruising 70-80mph? I just want to get a sense if there was a reduction in the ECTs would it be significant or negligible.

darkman
06-13-13, 05:35 PM
I understand there are many variables but do you think the oil cooling could reduce ECT by as much as 10-15F highway cruising 70-80mph? I just want to get a sense if there was a reduction in the ECTs would it be significant or negligible.

I don't know how many degrees the coolant temperature reduction would be, but I think it would be much less than 10-15F. The cooling effect is indirect since the oil cools different parts of the engine than the coolant, and the oil capacity is less than the capacity of the coolant. The best way to reduce the ECT is a larger radiator. The second best way is a high capacity water pump.

alradco
06-13-13, 06:07 PM
235F cruising on the freeway? I would check coolant level, thermostat, make sure nothing is blocking radiator (maybe you sucked up a bag), and check water pump. That's where I'd start. What's your oil temp?

AAIIIC
06-13-13, 06:41 PM
^^^ What he said. Cruising on the freeway, even in very high ambient temps with the A/C on full blast, the coolant temp should be sitting at the thermostat setting. The OEMs design the cooling system to easily handle those conditions. If your coolant temp is 235F on the highway, something is wrong.

philistine
06-13-13, 09:48 PM
To be clear...I just wanted to know if the heat balance of the ECT would be affected by an external oil cooler and if so...by how much. I do not have temps of 235F but was only using that temperature as an example - consider FI, driving through the desert 110F dry heat etc haha.

Seriously though, I've been doing some reading on oil coolers and wanted to know the relationship it has with the engine coolant temp - the heat balance.

darkman
06-14-13, 10:19 AM
To be clear...I just wanted to know if the heat balance of the ECT would be affected by an external oil cooler and if so...by how much. I do not have temps of 235F but was only using that temperature as an example - consider FI, driving through the desert 110F dry heat etc haha.

Seriously though, I've been doing some reading on oil coolers and wanted to know the relationship it has with the engine coolant temp - the heat balance.

Assuming that you are talking about high speed driving with high ambient temperatures I think the more likely scenaro is that you find the need for an oil cooler to keep oil temperatures down. This is simply because the cooling capacity for the water-coolant system increases with speed, but the capacity of a cooler-less oil system does not increase with speed to the same extent.

philistine
06-14-13, 02:27 PM
Assuming that you are talking about high speed driving with high ambient temperatures I think the more likely scenaro is that you find the need for an oil cooler to keep oil temperatures down. This is simply because the cooling capacity for the water-coolant system increases with speed, but the capacity of a cooler-less oil system does not increase with speed to the same extent.

One of the things I was thinking about was an oil/water heat exchanger such as the Mocal laminova. The oil would get to operating temperatures faster using the engine coolant then as the water-coolant coolant capacity increases with speed, it also gives a linear cooling rate to the oil.

In my case I have the Alradco radiator and believe it could handle the extra heat and keep the oil temps much lower. I would have to look up oil filter relocation and find a good spot but at this point, just pondering the idea. Could run -10AN lines from a sandwich plate to the filter, to the oil cooler, then return. Of course that means finding somewhere to tap into the coolant lines.

darkman
06-14-13, 02:39 PM
One of the things I was thinking about was an oil/water heat exchanger such as the Mocal laminova. The oil would get to operating temperatures faster using the engine coolant then as the water-coolant coolant capacity increases with speed, it also gives a linear cooling rate to the oil.

In my case I have the Alradco radiator and believe it could handle the extra heat and keep the oil temps much lower. I would have to look up oil filter relocation and find a good spot but at this point, just pondering the idea. Could run -10AN lines from a sandwich plate to the filter, to the oil cooler, then return. Of course that means finding somewhere to tap into the coolant lines.

They make radiators that serve both as a coolant radiator and an oil cooler. From what I have read, they are not all that popular because they do not keep the oil as cool as an independent oil cooler. The oil and coolant do not reach idenitcal temperatures but the oil cooler draws heat from the coolant side, which is larger in terms of voume of liquid. I think where you are going is a similar setup, but with more capacity (volume of liquid) allocated to the oil side.

robojesus
06-14-13, 07:02 PM
Holy shit, that is where my temperatures got with a radiator fan unplugged... you got an issue my dude.

philistine
06-14-13, 07:21 PM
They make radiators that serve both as a coolant radiator and an oil cooler. From what I have read, they are not all that popular because they do not keep the oil as cool as an independent oil cooler. The oil and coolant do not reach idenitcal temperatures but the oil cooler draws heat from the coolant side, which is larger in terms of voume of liquid. I think where you are going is a similar setup, but with more capacity (volume of liquid) allocated to the oil side.


The oil and coolant do not reach idenitcal temperatures but the oil cooler draws heat from the coolant side, which is larger in terms of voume of liquid.

I believe that the ECT ramp up to operating temperatures much faster than oil temps. My experience has been that at normal operating temps the oil temps are higher than ECTs. Therefore, during ramp-ups to operating temperatures, the oil is being warmed faster (with the heat exchanger) then at normal operating temps, the coolant would then cool the oil...oil temp>engine coolant temps.

So the engine coolant system would have to work harder due to the additional heat load brought on by a water/oil heat exchanger. In the case of a larger volume radiator, the additional heat load should not be a problem. I agree with you that an air/oil cooler is more effective at reducing the oil temps but does not help with warming the oil during start-up either. An oil/water heat exchanger would then serve as an all-season component.

LS6Steve
06-20-13, 01:47 PM
May want to do a cooling system flush... Something is wrong. I cruise around town in CA summer heat 100F+ and it never goes above 210-215. 235 would be very alarming to me.

DavidBoren
06-28-13, 08:21 PM
He, the OP, does NOT have engine temps of 235. Post #7 clarifies this for those too lazy to actually read what he is saying.

You already have a nice, aftermarket radiator that will handle all of the water/cooling and then some. Adding a sandwich plate and external/independent oil cooler definitely couldnt hurt. It would add to your oil capacity as well, which would also help keep the overall oil temperature down because there would be more oil to heat up. Lowering the oil temperature, as well as providing an external cooling source to that oil, will undoubtedly help keep the overall engine temperature down.

Whether or not it is by a measurable or tangible amount is impossible to know without someone doing it and monitoring it. If nothing else, it should increase your oil's "life" expectancy.

philistine
06-28-13, 11:35 PM
He, the OP, does NOT have engine temps of 235. Post #7 clarifies this for those too lazy to actually read what he is saying.

You already have a nice, aftermarket radiator that will handle all of the water/cooling and then some. Adding a sandwich plate and external/independent oil cooler definitely couldnt hurt. It would add to your oil capacity as well, which would also help keep the overall oil temperature down because there would be more oil to heat up. Lowering the oil temperature, as well as providing an external cooling source to that oil, will undoubtedly help keep the overall engine temperature down.

Whether or not it is by a measurable or tangible amount is impossible to know without someone doing it and monitoring it. If nothing else, it should increase your oil's "life" expectancy.

Yeah I was hoping for empirical data...like a linear/non-linear curve. Something like for every 10F oil cooling, you get 2F lower ECT until you reach you a breaking point and no matter how much you cool the oil, ECT start to go up after a certain heavy duty cycle.

With a such a powerful radiator, I'm thinking of using a heat exchanger for the oil/engine coolant - and yeah I would have to relocate my oil filter, hmm. Once my thermostat opens, it's a large enough heatsink to handle cooling the engine and should bring the oil temps very close to the ECT. So I could cruise around and have my oil temp around 200F under just about any load. If it's a heat exchanger then I don't have to battle for space to find a good air opening like the oil/air coolers.

Something like the Mocal Laminar Flow Oil to Water Heat Exchanger part no. MOC-A43-330:

http://i1058.photobucket.com/albums/t404/jaysenbaker/2003%20s2k%20-%20Hondata%20conversion/2013-02-16153132_zps48853a6d.jpg (http://s1058.photobucket.com/user/jaysenbaker/media/2003%20s2k%20-%20Hondata%20conversion/2013-02-16153132_zps48853a6d.jpg.html)

AAIIIC
06-29-13, 12:58 PM
If your big, powerful radiator is doing it's job, then ECT will be at the thermostat setting, so you'll never be able to see an improvement in ECT as a result of an external oil cooler. The t-stat will just be open slightly less to maintain that same ECT.

And why would you need to relocate your oil filter to use a Laminova type heat exchanger? :confused: I think the real challenge in using one of those is figuring out where to put it such that you can route the full radiator flow through it. There's not a whole lot of room in the front of the engine bay to fit anything extra.

philistine
06-29-13, 02:42 PM
If your big, powerful radiator is doing it's job, then ECT will be at the thermostat setting, so you'll never be able to see an improvement in ECT as a result of an external oil cooler. The t-stat will just be open slightly less to maintain that same ECT.

And why would you need to relocate your oil filter to use a Laminova type heat exchanger? :confused: I think the real challenge in using one of those is figuring out where to put it such that you can route the full radiator flow through it. There's not a whole lot of room in the front of the engine bay to fit anything extra.

Sandwich plate filter augmentation. Yeah I haven't ripped the nose off to see what I'm dealing with. There's another shop that is gonna grab some data for me. It's to find the heat transfer rate and thermodynamic (heat in motion) study - pure curiosity.

DavidBoren
07-06-13, 01:52 PM
Did that shop ever get back to you with their study results?

philistine
07-06-13, 04:01 PM
No, there has been no follow-up - the data would have come from a Mopar build or Mustang. I slapped this thing in my turbo s2k and the oil temps stay about 5-10F over engine coolant temps. During a spirited drive, mostly 50% throttle, as AAIIIC mentioned the cooling system was doing it's job and kept ECTs right at the T-stat with 185F touching lightly up to 200F during WOT. My oil temps stayed in that range.

The ambient air temps were ~90F.

So the comparison using my datalogs:
No oil cooler
hot idle: 210F
part throttle: 220F
WOT: 240F (260F peek autox)

Laminova oil cooler
hot idle: 185F
part throttle: 190F
WOT: 210F (peek w/autox)

I used -10AN lines and have no pressure drops. All my monitoring was done using PLX devices and digitally fed into the Hondata Kpro ECU to record the additional sensors. Unfortunately I have no idea how this will perform in the CTS-V. It's compact and doesn't compete for air flow since it's water/oil heat exchanger. My only consideration would be for forced induction purposes.

DavidBoren
07-08-13, 07:57 PM
When I put the Alradco CTS-V radiator in my 3.6L CTS, I am going to replace my Hayden external tranny cooler with a liquid/liquid laminar flow (probably Laminova) cooler. I like the way they bring the fluid up to temperature as well as cooling it. I am also going to install an oil cooler of the same design at the same time. Granted, all of this will not be until next summer, but it is definitely on the list. Im not even considering forced induction on my LY7, I just like the thought of having everything regulated to the same temperature.