never mind 1
never mind 1
never mind II
I should just delete the previous posts, but IMHO....
In the core engine coolant circuit, the same one that goes to the interior heater, two oil-water coolers should be used- one for engine oil, and one for trans oil. Both of them are quite happy running at 195-230- which is the typical range for coolant temp. And by keeping separate coolers out- there's more space for even airflow to the radiator.
Just let the water do most of the cooling work. Warms up fast, which will warm up the engine oil and the trans oil fast, and the heat rejection if the big radiator is quite good.
alfadriver said:frenchyd said:Dusterbd13-michael said:Separate coolers. With thermostats.
Wrong!!!!!!!! Cold oil or transmission fluid will arrive at a stable temperature when combined with coolant. Cold oil is thick oil and takes longer to get to critical spaces same with trans fluid.
On race cars they are separated for packaging purposes and carefully brought up to temperature prior to use. Maybe even preheated separately.The radiator stays at ambient temp until the coolant thermostat opens up. Which means the trans is running ambient temp for a very long time- and that is doubly bad at -20 when the T-stat barely opens- so the trans is constantly being cold to -20.
If the trans cooler just used raw engine coolant, that would be better- since the trans likes being 200F.
In the radiator, though, it's whatever it is in the radiator.
I never paid attention much to other manufacturers' TCC strategy, but it became very apparent after installing the 4000rpm stall speed converter that Volvo does not engage the torque converter clutch until the trans fluid comes up to temp.
At least the loose converter ensures that it comes up to temp VERY quickly.
I never paid attention to the cooler topographics, but my S40 was air cooled only for the trans. Oil cooling was via a water heat exchanger bolted to the oil pan, no external oil lines.
A lot of manufacturers are putting the trans cooler on the trans and just routing coolant to it. Your post brings to light that this WILL warm up the trans fluid from cold, since the hoses are generally from the heater circuit.
In reply to Knurled. :
FWIW, it's just an opinion. Not that the company I work for does anything logical like that....
In reply to alfadriver :
Ford did something extremely logical in hindsight for the 6.7 trucks - water cooling for everything, moving the water to the heat exchangers mounted where it was convenient for them, instead of a tangled forest of plumbing and a cooling stack 12 inches thick.
Kind of like when Dodge realized, hey, we can make the radiator 40% smaller if it didn't have a bunch of stuff in front of it, so let's put the radiator here and the condensor and fluid coolers next to it...
MrChaos said:See 2005-2008 nissan xterra/frontier/pathfinders. Many a replaced transmission.
Nissan put in bad radiators those years. You never heard about the 2004 and earlier Xterras constantly having issues mixing the coolant and trans fluid, but they all used a combo engine coolant/transmission fluid radiator..
On the wife's truck, I had external p/s and trans coolers installed with a hitch. Part of the deal I put together. The ONLY issue we've had in 13+ years is when it's idiotically cold (-15 and lower) it takes about 20 minutes for the trans to get warm enough to lock the converter at highway speeds. But I like having them seperate. Blow at trans? No problem replae the cooler.
Something has been nagging me in the back of my head. These look like my radiator actually has an oil cooler in it.
For some reason I'm thinking I plugged them when I pulled the 6.2 and put in the 350.
In reply to Stampie :
They work better with fans. Debate me.
In reply to SVreX :
They work just fine with leaf blowers in the staging lanes. Technically a fan just not mounted on the car.
In reply to Stampie :
Usually the passenger side is the trans cooler and the driver side is the oil cooler, because Hydramatic transmissions have the trans lines on the right side and Chevy engines have the oil filter on the left side.
That said, Buick Grand Nationals had a weird setup where the oil and trans coolers were both on the right side. The trans cooler lines snaked around to a set of fittings on the front of the radiator, requiring some hard to find right angle fittings. And an extremely hard to find radiator, IIRC only Modine made them aftermarket and they got hoovered up by LKQ and their product lines discontinued. An F body radiator physically fits the car, and when you go to a roller cam you can delete the oil cooler.
In reply to Knurled. :
You know I'd agree with you normally except this one has trans lines on the driver's and the RV donor also had oil lines on the passenger. IIRC the junkyard Gen V had oil on the driver's side.
Stampie said:Something has been nagging me in the back of my head. These look like my radiator actually has an oil cooler in it.
For some reason I'm thinking I plugged them when I pulled the 6.2 and put in the 350.
Yup. I almost always get a radiator with the circuit even if it's not used in my application.... unless it's considerably more expensive. Never know if there will be some fluid I want to warm up or cool down.... PS return, oil, blinker fluid.
There were some years of manual GM trucks that had the trans fluid cooler circuit in the radiator with plugs in it just like that. Same exact radiator, just assembled with the tank that has a circuit in it.
Curtis73 said:Stampie said:Something has been nagging me in the back of my head. These look like my radiator actually has an oil cooler in it.
For some reason I'm thinking I plugged them when I pulled the 6.2 and put in the 350.
Yup. I almost always get a radiator with the circuit even if it's not used in my application.... unless it's considerably more expensive. Never know if there will be some fluid I want to warm up or cool down.... PS return, oil, blinker fluid.
There were some years of manual GM trucks that had the trans fluid cooler circuit in the radiator with plugs in it just like that. Same exact radiator, just assembled with the tank that has a circuit in it.
My manual miata's radiator has a integral transmission cooler too.
My wife's FJ radiator has a trans cooler built in as well, but with a manual transmission it's not needed. I'm going to use it to plumb a back country shower one of these days.
In reply to Stampie :
I did say usually 
Generally, aftermarket radiators have the cooler, just to cut down on part numbers. OEMs can shave a couple cents because they know how many of each type the will need.
When I had my 99 4Runner (with an automatic transmission), one of the regular mods was to put in a trans cooler instead of running the combo radiator/trans cooler as the design would allow for a breakdown internally and then you have trans fluid mixing with the radiator fluid. It's fairly prevalent and known as the 'pink milkshake' issue and will kill a transmission super quick. When I bought the truck, I immediately replaced the radiator, but did go OEM and didn't do the separate cooler, just for money purposes at the time.
Curtis73 said:My thoughts...
Oil (either trans or engine) needs to be at the RIGHT temperature. Drivers too often think that cooler is better, but that is not the case. Trans fluid is hydraulic fluid as well as lubricant. The whole transmission is designed to operate best in a certain range of temps. Too hot and things burn. Too cool and the thicker properties of the fluid can't properly operate the hydraulics as they were designed.
Engine oil is the same way. Too cool and it can't flow into the gaps like it should and you aren't lubing properly. If you go way too cool, you risk spiking oil pressure and opening the bypass valve which means you're not filtering. It also wants to be hot enough to evaporate/burn off things like blowby hydrocarbons and condensation. Of course, too hot has drawbacks as well. Oil too thin to properly suspend bearings, lower pressure, and cooking additives and hydrocarbons.
The benefit to having a radiator circuit for the transmission is that it helps get the transmission up to temperature as much as it sheds heat from the transmission. People fight me on this a lot, but I get so irked at people who insist on going crazy with cooling. Drivers like cool. Engines like hot.
I will also say that transmissions don't like complexity. An inline thermostat is a big no-no, especially for some transmissions. Many transmissions (including the one in your K truck) rely on the cooling circuit as part of the lubrication circuit. Simply stopping the flow of fluid can fry that trans in short order. You might be thinking a bypass stat would be better, but it's just an extra failure point waiting to happen. Unless you install a trans temp gauge and monitor it religiously to make sure the temps don't spike (stuck closed) or never get warm enough (stuck open), just skip it.
The real answer here is to get a radiator with a circuit for the trans. If you want additional cooling (and by that I mean only if you NEED additional cooling), then install a secondary cooler. Put it in front of the radiator, oversize it, then send it back through the radiator circuit. Don't fight me on this, I'm right. This has all kinds of benefits. If you just randomly send all the fluid through an external cooler, you have no control over the fluid temps. Did you oversize and it's too cool? Did you undersize it and it's too hot? Not to mention, it will be vastly different temps if you're stop and go, highway, towing, etc. Putting the extra trans cooler FIRST means that you can't oversize it. Let's say you're sending 230 degree fluid from the trans. If you send it through the radiator first, then the external, you are dropping the temps to 200 in the radiator, then randomly dropping them to whatever bulk heat gets shed in the external and sending back a big question mark to the transmission. If you do the external first, you can drop it to whatever you want... 180 maybe? Then sending it back through the radiator will bring it back up to the proper temperature. (and draw some heat out of the coolant as well instead of adding). Always put the known entity last in the circuit... in this case the radiator circuit.
For oil cooling, I would verify that you need it first. Randomly adding cooling can be a bad thing. Install a gauge, hitch a trailer to it, wait for a 90 degree day, and go climb a mountain with your foot to the floor. If the oil temps don't get over 230, you don't need an oil cooler. If they don't get over 250 for synthetic, you don't need an oil cooler. The oil in an engine spends a considerable amount of time on the other side of water jackets. and is pretty good at cooling itself. Ford 460, not so much. B and RB mopars, not so much. Chevys... pretty good.
i really appreciate the engineering type viewpoint here but you're also describing a system where we know berkeley all about the actual temp in the radiator.
lets say youve got an LS but then you put in a bigger aluminum radiator in every dimension. then you do a lower temp tstat. then a high performance water pump, better hoses and larger welded aluminum tank. oh and a heater core bypass valve for good measure...
okay now this system has a cooler in the rad just like stock, but that E36 M3 aint keeping it at stock temps.
I'm looking this info up actually for a maybe cheap way to baby a 4l60 that got way too hot riding around in a truck with a blown headgasket in spite of having... all of the above... lol... and basically trying to source a cooler thats sized as big as possible so I can repurpose it as an oilcooler for my engine oil after I delete the autotragic?
this basically makes sense right? oilcoolers and trans coolers are interchangeable basically, I cant see why changing the application midlife would be any issue lol...
[edit] yes I know Im replying to something ancient but anyone who searches like I did will still read it in order.
sorry for bumping this old topic but, if all the temps are who knows then WTF...
i actually tried to look up the heat output of a supercharged 408 stroker LS via the coolant pipes in BTU (surely this is engineering data that exists) while essentially trying to decide if dual tbird fans on an alu rad will be enough to do standing awd burnouts in 117°f temps but since thats the most idiotic thing I could imaginably ask it to do Id like to go with that lol. Im abusive and irresponsible and boys just wanna have fun right?
anywho, the internet is not forthright with such high resolution data, even with the advent of AI...
[edit2]
its funny to me that on a locost group, anyone at all would be talking about anything on the assumption... that some components of the system might still actually be original equipment 🤣😂🤣
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