Discussion Forum - Northstar Chevelle Club

4-door Chevelle · Super Poster

Cooling Issue.

seagrams72 · Active Member

John D wrote:
The proven method is to run the transmission's output line to the radiator (fluid to fluid) cooler first, then routed to an auxiliary (air to air) cooler, then back to the transmission. A fluid to fluid cooler is MUCH more efficient at transferring heat. The radiator & coolant has about 10x the area to dissapate the heat (in comparison to the add-on trans cooler).

Huh, I was told the opposite of this by a guy who has built racing/ street trannys for years.

Any other changes? (Exhaust near tranny, rerouting of tranny lines, etc.)

I just looked at your cooler, I have never used that kind and always used the flat (mini radiator style) RV/ truck ones from CarQuest and mounted in front of the radiator. It does have fins, but the cooler may not be mounted efficiently.

Fins are more effective in cross flow. I.E. the air flow runs down the length of the fin (like in a radiator) vs. directly at it. This is drudging up equations from my heat transfer course last semester. How is the cooler mounted? I always thought the cylinder style was more of a rail mount or something where the air is flowing down the length and not against the cylinder?

-- Edited by seagrams72 on Saturday 5th of May 2012 09:19:01 AM

-- Edited by seagrams72 on Saturday 5th of May 2012 09:20:33 AM

4-door Chevelle · Super Poster

My concern and the reason for the change this year is strictly to attempt to get less restriction of air flow to the radiator. In the middle of summer the coolant will run about 210 at 70mph with both fans blowing.

-- Edited by 4-door Chevelle on Saturday 5th of May 2012 10:57:12 AM

Tim H · Mega Poster

Move it to in front of the radiator so it gets better air flow . Off to the side won't get you the best cooling. Your radiator has more arir flow through it. If you don't have a fan shroud get one. It makes a huge difference. Where's those hood hinges?

John D · 2K+ Club

My own experience, and the advise of the trans guys I know has proven to me that running a "air to air" cooler alone will not get the job done. Think about this...

- Unless your radiator is fully shrouded, the fan is only pulling air through a circle the diameter of the fan. The other area of the radiator is relying on forced air from forward motion. Sitting parked or in traffic the fan is only pulling air through 1/4 of the radiator area.
- At idle, or low driving speeds you only have "convection" removing heat from the trans cooler - and especially in your case where the aux cooler is sandwiched between two already hot air sources. (The air for your trans cooler is already HOT....)

The proven method is to run the transmission's output line to the radiator (fluid to fluid) cooler first, then routed to an auxiliary (air to air) cooler, then back to the transmission. A fluid to fluid cooler is MUCH more efficient at transferring heat. The radiator & coolant has about 10x the area to dissapate the heat (in comparison to the add-on trans cooler).

Don't believe it??? Think about this...
You're grinding/welding/drilling something and it gets HOT!! What do you do?? Let it sit on the bench for 10 minutes before you can touch it, or dunk it in a bucket of water and go back to work in 30 seconds...

The truth is that the radiator cooler will strip off the bulk of the heat quickly, stabilizing it to an average temp (albeit warmer than most hot rodders want) on it's short trip through. Then the aux cooler will further lower it and send it back to the pan (where it immediately starts getting hot again).

Yes, the additional heat from the transmission will raise the engine coolant temperature - but a properly sized radiator, the correct 50/50 coolant mix, a 180 deg 'stat, a good pressure cap, and efficient fan(s)/shrouding will keep the coolant temp around 200 deg's. average. (Yes, it will spike/climb after a run, or sitting in traffic, or if it's 100 deg's outside - but on average the system will work properly).

4-door Chevelle · Super Poster

The new cooler is just behind the grill so it is well in front of the condensor and radiator.

I am running dual electric Windstar fans so there is no shroud but this thing fit quite well. The first fan is on a controller and kicks on at about 190 degrees. The second fan is on a switch and I typically only need to use it when it is hot outside.

I am using the 3-core radiator that came with my AC car. The coolant is good to -30 so should be about 50/50. The thermostat is a 180 with 2 small holes in it as well.

I do hear you about using the radiator though. The radiator cap is very old but I don't quite understand how it effects cooling.

Maybe I should replace the thermostat as it is a few years old and may not be functioning properly.

I can easily route the output line from the tranny through the radiator cooler again like I had it last year and take her out for a spin today.

John D · 2K+ Club

Sounds like your cooling system is "up to snuff".

The radiator pressure cap is an integral part of the system, equally important as any other part. It is not just a "cork" to plug the hole. Fluid under pressure has a higher boiling point.

How things work

You can easily test/verify your t-stat on the stove with a meat thermometer, a pot, and water. Dunk the t-stat in the pot of water, and turn on the stove. Watch the thermometer and the t-stat while the temp climbs. It should start to open at the rated temp, and be fully open when the water boils.

4-door Chevelle · Super Poster

I have not made any other changes than the ones I highlighted. When I searched about these coolers they were indicated more as a rail cooler which lends itself the the idea that air would travel the length of the unit. I may consider putting the old flat style cooler back in but put it just behind the grill rather than inbetween the condensor and radiator.

Enganeer · Mega Poster

Why not run it like the setup you had before and add the rail cooler as an additional cooler on the return.

Chris R · 2K+ Club

That little cooler you have wont do nearly as well as an actual finned cooler. What you need is a nice cooler like a B&M super cooler or equivelant.

4-door Chevelle · Super Poster

The jury is still out on plumbing through the radiator but I think I need to put the nice cooler back in but mount it in front of the condensor.

4-door Chevelle · Super Poster

There is a metal hose in front of the condensor ... arggggg

John D · 2K+ Club

Huh, I was told the opposite of this by a guy who has built racing/ street trannys for years.

I'll still go back to the heat transfer example - what transfers heat from one object to another more efficiently... water/fluid or air??

4-door Chevelle · Super Poster

There is just no room for a rail cooler and a aux cooler. I picked up some material to make a mount and put the aux cooler about an inch ahead of the condensor. I'll test that then if needed add in the radiator cooler. As a side note the radiator collant is still running almost 200 so my little experiment went bad anyway?!?

John D · 2K+ Club

200 isn't out of line... It won't run at the t-stat rating of 180 (unless you swap in a Kenworth-sized radiator). Where is the probe for your temp guage located, manifold or head?

FYI - The LT-1's I'm running are factory set for cooling fans to come on at 230!

frank · Active Member

i was always told that those tranny rail coolers did little to nothing. also told when mounting stuff to radiator go no more than the thickness of a piece of cardboard away otherwise you create a dead zone. put in a shroud and your troubles are over. on my 37 chev with the 454 i don.t run over 175-180 with a shroud. my radiator is only 12 inches wide.

SShink · 3K+ Club

The 200-4R trans I have has the cooling going through the radiator and nothing else. Master Transmission assured me that is fine. But I don't have a trans temp gauge or run on the track as much as you do Darren.

4-door Chevelle · Super Poster

I mounted the aux cooler about an inch behind the grill on the drivers side. It just fits between the top of the bumper and the bottom of the hood so there is good air exposure. My temp sensor is in the manifold Chris. You are probably right on all counts Frank, if I go back to a clutch fan I will also put the shroud back in.

Enganeer · Mega Poster

He is running a Windstar electric fan setup, so there is a shroud built in. If he goes back to a clutch fan, then he will put a shroud for the clutch fan back also.

I would return to your setup you had before that was running 180 temp trans temp and then add the rail cooler on the return line on the frame rail for added cooling.

frank · Active Member

does electric fan shroud cover 100 percent of radiator, how much cfm of fan doe you have? does it run cool on highway?

-- Edited by frank on Sunday 6th of May 2012 12:52:15 PM

4-door Chevelle · Super Poster

There just isn't room anywhere to properly mount that rail cooler. I took it out for a bit last night, 5 minutes on the freeway then about 10 minutes around Hopkins. Coolant = 200, trans =160. It was cooler last night and moisture may have helped. I am going to hook up the camper and and spend more time on the road with it today but this may be the ticket. 5 days to racing!

seagrams72 · Active Member

It may be because I am running higher line pressure than most, but what I have always been told when running a secondary cooler the radiator cooler is not needed. I also run hard line from the tranny up by the cooler and about 6" of rubber tranny line from there to the cooler. I use 2 "fuel injection" clamps per connection to keep it from leaking.

Anyways, Darren if you want a cheap and quick solution to try I always run the Car Quest (Hayes brand?) coolers, they have them for RV and truck through their catalog. I want to say I was into mine about $30-$40. It comes with or you can get the zip ties that attach the cooler to the radiator from the same source in the same catalog. I hate the zip tie method so I made a bracket on my core support.

Overal thought that rail style cooler may be the source of your problem and the setup you had last year worked just fine.

4-door Chevelle · Super Poster

It pretty much does cover the radiator and is about an inch away from it. I forget what these Windstar fans move though. No, it isn't any better on the freeway.

Test drive today - coolant = 200 and trans = 170. I was out for about a half hour ride of some freeway and mostly Mainstreet pulling the camper!

Rail cooler for sale cheap.

Bowtieman427 · Active Member

What is a good easy to hook up tranny fluid temp gauge ? Would like to add one with the new stall to see if I need a bigger cooler. I do have a TCI finned pan with a trany fliud drain plug.

4-door Chevelle · Super Poster

You can pick up a manifold with 3 fittings in it or have a bung welded on to your tranny pan. I have done both but prefer the bung for less hoses and leaks. If you do the manifold (big T-fitting) and put it on the feed line you get to watch how emotional your tranny really is.

John D · 2K+ Club

What is a good easy to hook up tranny fluid temp gauge ? Would like to add one with the new stall to see if I need a bigger cooler. I do have a TCI finned pan with a trany fliud drain plug.
You can pick up a manifold with 3 fittings in it or have a bung welded on to your tranny pan. I have done both but prefer the bung for less hoses and leaks. If you do the manifold (big T-fitting) and put it on the feed line you get to watch how emotional your tranny really is

Just another reason to not install guages... worry worry worry leak dang it's up 2 degrees worry worry...

4-door Chevelle · Super Poster

I am one with my tranny ...

Pushrod · Active Member

Keep in mind the pan temp is much cooler than the actual temp in the trans and t/c

Bungy L-76 · Active Member

Pushrod wrote:
Keep in mind the pan temp is much cooler than the actual temp in the trans and t/c

Agreed. The best place for the trans temp gauge is in the "out" line going to the cooler. You can get a T fitting with compression fittings on both ends and a threaded fitting in the middle for the temp sender. Probably the easiest way to do it. Or a little more work is to get the T fitting with inverted flare fittings on both ends.

4-door Chevelle · Super Poster

After a trip to Brainerd and a warm weekend here are the stats:

70mph - 3000rpm - coolant = 215 with 1 fan on and 205 with 2 fans on - tranny = 160!

In fact, I could barely get it off 140 before each run down the track. I am now thinking about including the radiator again to warm up the trans fluid and moderate with the coolant?!?

John D · 2K+ Club

Back up to my original comments...

Hydraulic devices don't like cold/thick fluid, nor hot/thin fluids. They're designed to operate within a specific temperature range. As long as the device (trans) is running within the desired temp range there's nothing to worry about.

That said, because of the "duty" your machine is operating under - definition would be "severe/extreme" (racing application) - the service intervals of the fluid & filter should probably be bumped up to every season. That in mind, you'd be changing about 1/3 of the total fluid volume (replenishing the additives), putting in a fresh filter, and being able to give the pan an inspection for clutch dust/wear.