Keeping the Automatic Cool

[rh77]

It certainly is heating up outside, and under the hood.

During Winter, I sometimes set up a grille-block, but I'm hesitant this Summer. The transmission has a cooler line that runs into an isolated corner of the rad. Today, I ended up thinking about airflow over that section and the implications of blocked flow.

With the kickdown cable tightened to activate the TC asap, heat is a consideration.

Has anyone monitored tranny temps with grille blocks on automatics? Once I get a few hours in the garage, I'm thinking of replacing the fluid with Synthetic (if that helps). Should a transmission temp gauge be installed as well?

RH77

[ELF]

Synthetic fluid will help for sure, That is where the synthetic shines, extreme hot or cold. Synthetic tranny fluid will take a lot more heat than dino. Also some claims are made that synthetic oil runs cooler.
I would think having a little air flow over that isolated corner would be helpful.
I say if in doubt open up the grill a little, you wont loose that much FE.

[BMac]

Look in my garage. The Dak has a new tranny cooler but I put it in the airflow. Most of it anyway. Should definitely be a consideration!

Oh crap! It's not installed in those pics. I'll have to load in a more recent one when I get home.

[ffvben]

ford offered a external trans filter with your new rebuilt trans, it was just a external in line filter with some fins on it to help a bit more with cooling the fluid. i'm pretty sure you could use it on any trans with the rubber cooler lines.

[Blue03Civic]

A change to synthetic would definitely help, and opening your grill block a little so that the flow goes over the transmission cooler would be beneficial as well. Have you considered installing a small electric fan on your transmission cooler? Maybe that would help too, maybe a PC case fan?

[rh77]

Originally Posted by Blue03Civic

A change to synthetic would definitely help, and opening your grill block a little so that the flow goes over the transmission cooler would be beneficial as well. Have you considered installing a small electric fan on your transmission cooler? Maybe that would help too, maybe a PC case fan?

I have a box full of PC fans -- great idea! That would draw very little current as well.

-Rick

[brucepick]

Small electric fan, yes.
PC fan, I think that's way too small.

I don't think pc fans will blow enough air to influence a/t fluid temperatures to any significant degree. I think a car moving even 5-10 mph will have faster airflow over the fins as long as the air path is open.

I wouldn't try to create airflow with a fan when there's essentially free airflow from the car's movement. My two cents.

[Bill in Houston]

I agree with what Brucepick said. PC fans seem a little small.

[Raccoonjoe]

Agreed with Brucepick :-)

However, I could certainly see using the PC case fan to exhaust hot air from the engine bay through the...wheel wells, for instance.

rh77 - towards the idea of keeping the tranny cool?? If you're worried, put in a gauge. It's not going to hurt anything, and may help tell when the tranny gets warmed up in the wintertime.

You could also go with an aftermarket tranny cooler. Take the fluid out of that portion of the rad, as it serves to heat the engine coolant while it cools the tranny fluid. They're easy to install, and not too outrageously expensive....

[s2man]

On the trannie cooler: Unless it's thermostatically controlled, I believe you need to install that BEFORE the radiator (I'm dredging stuff up from the hot-rod days here) . The trannie needs to run in a certain temperature range, so running the fluid through the radiator not only cools it, but guarantees it returns to the trans at a decent temp (180-200?). A thermostic cooler will also ensure the trannie fluid is not over cooled.

rh77 - Speaking of trannie coolers, I've got one you can have for free. Just let me know if you're interested.

[rh77]

Originally Posted by s2man

On the trannie cooler: Unless it's thermostatically controlled, I believe you need to install that BEFORE the radiator (I'm dredging stuff up from the hot-rod days here) . The trannie needs to run in a certain temperature range, so running the fluid through the radiator not only cools it, but guarantees it returns to the trans at a decent temp (180-200?). A thermostic cooler will also ensure the trannie fluid is not over cooled.

rh77 - Speaking of trannie coolers, I've got one you can have for free. Just let me know if you're interested.

Thanks for the offer, man. What I'd like to do first is to install a temp sensor/gauge to see what I'm dealing with. BTW, does it install inline with the cooler lines?

The problem I have in the Winter is getting things up to temp for the TC to kick-in. Even with a grille block installed and the block heater, it's hesitant to heat up and lock-up -- would the cooler help regulate temp too, or just bring the temp down?

When I had my Evo, the oil cooler and trans cooler would get caked-up with snow and blocked airflow, so I had to monitor the gauges on the 2 days it snowed here

-Rick

[ffvben]

Originally Posted by Blue03Civic

A change to synthetic would definitely help, and opening your grill block a little so that the flow goes over the transmission cooler would be beneficial as well. Have you considered installing a small electric fan on your transmission cooler? Maybe that would help too, maybe a PC case fan?

I've seen a small factory electric fan on either a BMW or Mercedes (i forgot what one). I had it on a lift and seen it sticking out from all the under car belly pans. I'm guessing its a little boost to keep the air flowing from the trans area. it was about a 5 inch fan pointing to the ground by the trans pan.

[s2man]

Originally Posted by rh77

Thanks for the offer, man. What I'd like to do first is to install a temp sensor/gauge to see what I'm dealing with. BTW, does it install inline with the cooler lines?

You bet. Sounds like a good idea to see what you're working with, before you start making mod's. The cooler is a typical tube and fin, radiator-type, heat exchanger. It is ~11x16in, with two rubber hoses attached on one end. You could cut the metal trannie line going into your radiator, and reconnect the lines with the rubber hoses. But I prefer to unscrew the nut-shaped fitting which holds the line to the radiator. Then I get an identical fitting and 6" of tubing, and attach that to the radiator. This method reverts to stock config much easier.

Originally Posted by rh77

The problem I have in the Winter is getting things up to temp for the TC to kick-in. Even with a grille block installed and the block heater, it's hesitant to heat up and lock-up -- would the cooler help regulate temp too, or just bring the temp down?

It doesn't sound like you'd want any uncontrolled cooling in the winter, then. This cooler has no controls or fans. It has to be mounted where it will get airflow, like in front or behind the radiator. And that's why the fluid needs to go through it before the radiator; to guarantee a minimum oil return temp. Coolers which have thermostats and fans can be mounted after the fluid flows through the radiator, and should be mounted out of the air flow. I think one of these would provide cooling in the summer, if you need it, and yet do little/none in the winter, when you certainly don't want it.

Have fun, and let us know what you find out with that temp gauge.

[n0rt0npr0]

Rick,

I think a cooler is only going to bring temps down in the winter, and thats going to kick out the TC.

Plus Acura is a high end name, I'm sure they tested your car in NYC crazy stop and go and desert heat like in death valley, and if they didn't put a cooler on it stock then my thinking is that its unnecessary. In fact just putting synthetic transmission fluid in should help regulate the temps better along with the stock system that pushes the trans oil thru the radiator....
Especially since you plan on using Amsoil...
~Will

[s2man]

Someone stole your '89 Celebrity?

[ffvben]

don't forget to flare your metal tranny lines if you cut into them or they will blow right off from pressure

[01_fast_ride]

Has anyone experimented with adding a circulation pump in-line with the trans cooler, since for a cooler to truly benefit anyone EOCing fluid has to be flowing?

Here's my idea:
Mount a circulation pump close to the radiator. Connect to the return line, maybe add a 180F thermostat inline to trigger the pump. That way while EOCing you don't even have to think about it.

But I know jack about things, so I don't know if it would require some sort of bypass for when the ICE is running normally. Online I saw pumps around the $200 mark.

[smay665949]

Synthetic tranny fluid will help lower friction, which will lower your transmission temp and help mileage.

http://www.lubedealer.com/T&SMay/

[s1120]

Dig around on the 4wd, or proformance car online parts stores, and you will find a lot of options. They sell a cooler/fan assy that can be mounted anywere. Also I have seen one that is a huge heat sink. Its a few feet long, and about 3" in dia, and has heatsink fins all over it. The hotrod guys mount it on the frame rails.

[mjo]

Originally Posted by ffvben

don't forget to flare your metal tranny lines if you cut into them or they will blow right off from pressure

With the Saturn S-Series transmission (TAAT) it has 1/4" NPT to quick-disconnect adaptors on it that you can take off and install 1/4" NPT hose barbs. I tried it and it works great! If you get a thermostat for the transmission be sure to connect it the right way - otherwise you'll get some nasty pressure buildup that will spray fluid from every transmission crevice.

[Pete]

Car makers fit the trans cooler in the radiator to moderate the temps of both units.

The engine coolant helps get the trans up to operating temp more quickly then it would alone and it also helps limit the upper temps by allowing the trans heat to be taken up by the same radiator coolant.

Normally a thermostat is fitted to protect the trans cooler from excess pressures from cold fluid as much as regulate the temp of the fluid.

Nearly all cars run a ( relatively speaking ) lower pressure area in the wheel wells so fitting a duct to allow air to transit from the higher pressure area ahead of the rad to the lower pressure area in the wheel well will not need a fan.
You may want to consider some sort of flap / louvre arrangement to stop road debris coming into the duct.

Pete.

[kamesama980]

-A PC fan will be dead in days because it is far from weatherproof. oyea, and 15 cfm it'll move is worthless above 1 mph.

-mount the trans cooler before and in line with the factory in-radiator cooler only IF NEEDED. Keep in mind your transmission is fine unless you're doing lots of towing or up steep hills...high load conditions like that and the transmission fluid does need to be around operating coolant temperatures to be at it's best: it's engineered that way.

-if your radiator cooler is set up like mine and runs the trans fluid through a tube in the radiator (helps heat up and keep from overheating) it will be moderated by the coolant. unless your coolant starts overheating massively, the trans fluid won't overheat either. that is unless as stated above, you do lots of up-hill towing or drag racing.

-in-line pump: DON'T. during normal operation (any time not in park) the rotation of the torque converter connected to the engine spins the pump in the transmission. adding another pump in-line will do one of two things: block flow (bad) or cavitate if it's powerful enough. (less bad but wasting the power to spin it) and you'll have a hell of a time matching it to the pump in the transmission (changes with engine rpm. same problem as electric superchargers)

[mjo]

Originally Posted by kamesama980

unless your coolant starts overheating massively, the trans fluid won't overheat either.

In the summertime, the coolant in some cars will routinely peak above 210 degrees in stop & go city driving. The engine usually tolerates this but it will damage an A/T to some degree.

It also depends on where the transmission fluid heat exchanger is placed in the engine cooling circuit.

[mjo]

Originally Posted by Pete

Normally a thermostat is fitted to protect the trans cooler from excess pressures from cold fluid as much as regulate the temp of the fluid.

I didn't know that some cars have thermostats to regulate flow to the trans cooler. Can you give some examples of cars that contain such thermostats? I have a Saturn SL1 and SL2. Both have automatic transmissions and neither come stock with transmission thermostats.


Keeping the engine cool by heating up the transmission is not a benefit to having a transmission fluid/ engine coolant heat exchanger. Engine temperatures vary wildly with speed/throttle position/ ambient temperature. A heat exchanger passing on these wild temperatures to the transmission will cause the transmission fluid to have varying viscosity. This doesn't help the ECU any because it must relearn how fast it should activate the solenoids. When I put an external transmission radiator on my SL2 it caused the transmission shifts to be much more consistant and firm. Before the transmission would tend to be too fast and slam when the engine was hot and too slow when the engine was cold. IMO, reducing the ECU relearning is another factor that should help reduce the transmission wear.

Originally Posted by Pete

You may want to consider some sort of flap / louvre arrangement to stop road debris coming into the duct.

When I installed the external transmission cooler I wrapped the cooler in aluminum screen. The stones and bugs bounce right off of this screen.

[mjo]

Originally Posted by Pete

Normally a thermostat is fitted to protect the trans cooler from excess pressures from cold fluid as much as regulate the temp of the fluid.

I didn't know that some cars have thermostats to regulate flow to the trans cooler. Can you give some examples of cars that contain such thermostats? I have a Saturn SL1 and SL2. Both have automatic transmissions and neither come stock with transmission thermostats.


Keeping the engine cool by heating up the transmission is not a benefit to having a transmission fluid/ engine coolant heat exchanger. Engine temperatures vary wildly with speed/throttle position/ ambient temperature. A heat exchanger passing on these wild temperatures to the transmission will cause the transmission fluid to have varying viscosity. This doesn't help the ECU any because it must relearn how fast it should activate the solenoids. When I put an external transmission radiator on my SL2 it caused the transmission shifts to be much more consistant and firm. Before the transmission would tend to be too fast and slam when the engine was hot and too slow when the engine was cold. IMO, reducing the ECU relearning is another factor that should help reduce the transmission wear.

Originally Posted by Pete

You may want to consider some sort of flap / louvre arrangement to stop road debris coming into the duct.

When I installed the external transmission cooler I wrapped the cooler in aluminum screen. The stones and bugs bounce right off of this screen.

[scdave]

wouldnt a shroud around the trans cooler be helpful to make the cooler more efficient?like sheetmetal pieces to farce more air into the cooler. also, i always thought that the cooler the trans oil,the better.

[kamesama980]

the engine temperature does NOT vary much or quickly with loading. the radiator temps certainly don't. put an aftermarket gauge in the thermostat housing in your engine and after getting the engine up to temp, cruise at a constant speed with a couple peeps in the car with you...then floor it for 15 seconds and watch the temp gauge. it'll slowly go up MAYBE a few degrees... Besides, you guys barely touch the gas in the first place. I've got slightly higher performance parts than a saturn and I drive a lot harder than you guys and my cars fine. hell drifting didn't bother my engine...or trans one bit (WOT or near enough for 5 minutes at a time)

Most trans coolers are placed on the cooler end of the transmission. in my cressida, the radiator flows from top to bottom and the tranny exchanger is in the lower tank....well below operating temps.

As for the engine being heated by the transmission....the amount of heat the transmission generates is insignificant compared to the engine heat and far overshadowed by the size of the radiator and volume of coolant.

[Pete]

Originally Posted by mjo

Can you give some examples of cars that contain such thermostats?

Sorry for the delay ; I lost track of the thread !

Some of the Land Rover / Range Rover vehicles had them but they may have been part of an options kit for low temperature environments.

Many years ago we owned an a Land Rover which was ex Snowy Mountains hydro scheme and it had one fitted.

I recall a friend having trouble getting a suitable temperature range replacement for one fitted to his Land Rover Discovery and I think there were some Jaguar models which had them as well.

Pete.