Transmission Cooler
#1
02-18-2012, 01:20 AM
Transmission Cooler
Hey folks.
I bought my 2007 H3 about 2 weeks ago (58,000 miles). The very day after I got it, it was pouring out coolant. Turns out the radiator was cracked. Fortunately, the dealer (not GM) has agreed to pay to replace it. However, after doing some browsing on this forum, I discovered that the radiator also houses the transmission cooler. Furthermore, there is a risk that if the radiator is damaged, there is a chance that the fluids will mix and ruin both the radiator and transmission. Unfortunately, I did not know about this risk before I took the truck in and got the radiator replaced. It would have been really nice to look for the tranny fluid inside the coolant overflow and know whether or not the fluids have mixed. The next step is to take it in to get the tranny flushed and new fluids added ... which needs to be done anyway. If it is damaged, then hopefully my 3 month powertrain warranty will pick up the costs.
To avoid this problem all together, other members have recommended installing an external transmission cooler and bypass the one in the radiator. So, the questions:
1. Is the trans fluid / coolant issue something I should worry about?
(No warranty after 3 months)
2. Any suggestion on brand, size, mounting?
(I could only find this example)
3. Would I need an external thermal bypass?
(Live in VA, gets below 30 every now and then. Very light driving 10k/yr.)
Any advice would be greatly appreciated.
I bought my 2007 H3 about 2 weeks ago (58,000 miles). The very day after I got it, it was pouring out coolant. Turns out the radiator was cracked. Fortunately, the dealer (not GM) has agreed to pay to replace it. However, after doing some browsing on this forum, I discovered that the radiator also houses the transmission cooler. Furthermore, there is a risk that if the radiator is damaged, there is a chance that the fluids will mix and ruin both the radiator and transmission. Unfortunately, I did not know about this risk before I took the truck in and got the radiator replaced. It would have been really nice to look for the tranny fluid inside the coolant overflow and know whether or not the fluids have mixed. The next step is to take it in to get the tranny flushed and new fluids added ... which needs to be done anyway. If it is damaged, then hopefully my 3 month powertrain warranty will pick up the costs.
To avoid this problem all together, other members have recommended installing an external transmission cooler and bypass the one in the radiator. So, the questions:
1. Is the trans fluid / coolant issue something I should worry about?
(No warranty after 3 months)
2. Any suggestion on brand, size, mounting?
(I could only find this example)
3. Would I need an external thermal bypass?
(Live in VA, gets below 30 every now and then. Very light driving 10k/yr.)
Any advice would be greatly appreciated.
#2
02-18-2012, 06:32 AM
on this subject,some say the oem rad is the best.
you can find lots of coolers on the web.
gotta wonder how a tranny would like it to be running in -10 weather WITHOUT the rad heat? a tranny cooler might keep it too cold as you suggest huh?
they do put coolers in series with the rad in some tow packages but i never saw a van without the rad hookup.
good question, i tend to stick with stock stuff if i dont know positively.
you can find lots of coolers on the web.
gotta wonder how a tranny would like it to be running in -10 weather WITHOUT the rad heat? a tranny cooler might keep it too cold as you suggest huh?
they do put coolers in series with the rad in some tow packages but i never saw a van without the rad hookup.
good question, i tend to stick with stock stuff if i dont know positively.
#3
02-18-2012, 07:48 AM
I bypassed my stock tranny cooler when I replaced the radiator. Here's my setup. In cold weather (15 F), the engine heats up slightly faster and it takes about a 1/2 mile longer for the torque converter to lockup with this tranny cooler. I forget what the H3 torque converter lockup transmission oil temperature (TOT) setting is, but it can be 85 -100 F. My cooler is the plate style which tends to naturally bypass some of the cooling plates until the fluid heats up some. Just another data point for your search.
The stock radiator has a transmission cooler in the lower cap. During a cold startup with the stock setup, it takes a little longer for the engine coolant to reach temperature because you are heating up the tranny fluid too. Then the opposite happens when you are hot - the radiator has to cool both the engine coolant and tranny fluid which can make both run hot.
The stock radiator has a transmission cooler in the lower cap. During a cold startup with the stock setup, it takes a little longer for the engine coolant to reach temperature because you are heating up the tranny fluid too. Then the opposite happens when you are hot - the radiator has to cool both the engine coolant and tranny fluid which can make both run hot.
#4
02-18-2012, 08:15 AM
good stuff
which can make both run hot.
im thinking thats why the rad cooler equalizes the whole chunk of eng/tran/t case,with the t case less needy of heat.
the 195 thermostat kinda says it wants everything hot,less sludge,varnish buildup.
#6
02-18-2012, 11:40 AM
I bypassed my stock tranny cooler when I replaced the radiator. Here's my setup. In cold weather (15 F), the engine heats up slightly faster and it takes about a 1/2 mile longer for the torque converter to lockup with this tranny cooler. I forget what the H3 torque converter lockup transmission oil temperature (TOT) setting is, but it can be 85 -100 F. My cooler is the plate style which tends to naturally bypass some of the cooling plates until the fluid heats up some. Just another data point for your search.
The stock radiator has a transmission cooler in the lower cap. During a cold startup with the stock setup, it takes a little longer for the engine coolant to reach temperature because you are heating up the tranny fluid too. Then the opposite happens when you are hot - the radiator has to cool both the engine coolant and tranny fluid which can make both run hot.
The stock radiator has a transmission cooler in the lower cap. During a cold startup with the stock setup, it takes a little longer for the engine coolant to reach temperature because you are heating up the tranny fluid too. Then the opposite happens when you are hot - the radiator has to cool both the engine coolant and tranny fluid which can make both run hot.
#8
02-18-2012, 01:11 PM
and my understanding is that within limits,everything is /runs better hot.
im thinking thats why the rad cooler equalizes the whole chunk of eng/tran/t case,with the t case less needy of heat.
the 195 thermostat kinda says it wants everything hot,less sludge,varnish buildup.
im thinking thats why the rad cooler equalizes the whole chunk of eng/tran/t case,with the t case less needy of heat.
the 195 thermostat kinda says it wants everything hot,less sludge,varnish buildup.
#9
02-18-2012, 01:14 PM
Do some more research and make sure it is right for you. There may only be a few of us that bypassed the stock tranny cooler. We really don't have a significant statistical base to show there are no side effects.
#10
02-18-2012, 11:28 PM
I think one question is: what is the real benefit of this besides using the one intregated in the radiator? Better performance, cheaper repair down the road? and how long do you plan on keeping your H3? because any upgrades/new parts are going to last a while. I have 65k on mine and the only thing I've replaced is all the fluids everywhere and the vehicle is totally different. Smoother, less vibration it feels like. I guess it's all in the eyes of the beholder.... good luck