Help ID cooling system 99 GMC Suburban

[thebmrust]

I was getting ready to add in a transmission cooler (it's running 200*ish in town at 95*ambient) and found this trio of friends.

Are these:
A) Radiator
B) Air Conditioning
C) Transmission cooler

Is (C) somethjng else? Does my Burb have the trans cooler in the radiator too or is that the oil cooler integrated into the radiator? Tried pulling the radiator shroud off and I can't get my sockets into the lower mount bolts to remove them.

I traced lines (that I could find/ID) and (C) the "trans cooler" has a line going back to the transmission. One line also appears to come from the radiator but I can't get down under/in to find "exactly" where the other line comes from. Several other metal lines throughout the engine bay are also wrapped in wire loom making it harder to trace w/o removing the loom.

I looked deeper and the radiator has 4 metal lines going in/out of each corner. At least one line does end up into the (C) trans cooler.

 

[Hillbilly Heaven]

The external cooler is run in series with the built in trans cooler in the radiator.

 

[CrazyDrei]

You are correct,

A) is radiator, which also has transmission fluid run through it.
B) Air conditioner
C) external transmission cooler.

GM runs transmission line through the radiator because it helps get it up to the right temperature, and the external cooler is to keep the temp down under load like towing and mountain driving.

Have you looked into a dual electric fan conversion, most of the parts just bolt up and you run an aftermarket controller, that will keep the radiator temp down, AC temperature colder and transmission temp lower.

 

[thebmrust]

Have not looked into an electric fan option. Yet.

The trans cooler I was going to install was given to me. Normally I would agree that adding another cooler would be fine. But I'm hesitant now.

 

[Buddha.]

You might try to get between the rad and the AC condenser and see if there's any debris in there like leaves bugs etc. I'd use a garden hose to clean out all you can get to. Those fins act like air filters and in the right environment can become plugged.

Also you could look at trans coolers from big block or diesel trucks and see if they're a simple plug and play upgrade.

 

[NevadaLover]

Get a point and shoot thermometer and check the temp of the water pump compared to the gauge, so many gauges are nowhere near accurate these days and you may find quite a difference difference between the gauge and water pump temp!

 

[thebmrust]

Get a point and shoot thermometer and check the temp of the water pump compared to the gauge, so many gauges are nowhere near accurate these days and you may find quite a difference difference between the gauge and water pump temp!

I am using an OBDII and the OBD Fusion app to monitor vehicle data.

 

[jeep-N-montero]

Also make sure your OEM cooler is flowing properly, when I went to upgrade the stock trans cooler on our Yukon I noticed the inlet was almost completely plugged up. The upgraded cooler is more than 3 times the size as the stock unit and even towing a trailer in 95 degree heat up long hills I am lucky if the trans temp reaches 200.

 

[thebmrust]

Does orientation of the aux trans cooler make any difference?
-cooler barbs up
-cooler barbs left or right
-cooler barbs down

Never mind... found that it does NOT matter the orientation ... (of the tranny cooler).

 

[Hillbilly Heaven]

It does make a difference depending on the type of cooler. Mount it wrong and you trap air in the system.
http://www.pscmotorsports.com/pdf/tech/cooler_mounting.pdf

 

[NevadaLover]

I am using an OBDII and the OBD Fusion app to monitor vehicle data.

The problem with that is it only tells you what the sensor is saying, if the sensor is failing you won't know, that's why a point and shoot thermometer is important, it will tell you what the water pump temp is at that point and will let you know if the water temp is near what the gauge says, it's important to make sure the sensor and gauge are showing what the temp really is, not what a failing gauge or sensor says it is!

 

[rayra]

ABC is correct, HIllbilly is correct, trans cooler is in series with the in-radiator-tank portion (which GM pretty much designed as a transmission warmer). The external trans coolers were typically added as part of factory tow packages.
See the last pages of my build topic in my sig for comments on that and installing a larger aftermarket cooler. IIRC the output from the engine radiator is the lower line. But I might be wrong about that.

And you can get a decent point and shoot thermometer from Harbor Freight for $15-20 depending on sales and coupons. They work nice, mine's held up to casual abuse for a couple years. I use it to shoot brake caliper / rotor / hub temps, suspected bearing failures, the neighbor's cat etc. Well worth the few bucks.