Transmission cooler
Hello all. Just bought a 1984 k5 blazer. All original 72,000 miles on it. Question I’m replacing radiator, and not sure why an axillary cooler is mounted in front. The build sheet said H.D transmission OI. Not sure if any came from factory like this. Don’t look like it. It has a 5.7 7004 trans. Thank you.
Heat is a detriment to an automatic transmission. As such, I'm not sure I share your anxiety on the auxiliary cooler in front of the radiator.
Without a picture of your setup, I also cannot say whether it is a factory arrangement or aftermarket, but I can confirm that if it was equipped with the RPO code Z82, it would have both an engine oil cooler in the driver side radiator tank and an auxiliary transmission oil cooler (air to fluid in front of the radiator) in addition to the standard transmission oil cooler that is in the passenger radiator tank (fluid to fluid). It should also have wiring provisions for a 7-pin plug run to the back of the truck.
RPO code V02 shows up different in my references. I can decipher it two ways... One would be that it would have an auxiliary transmission cooler similar to RPO Z82 without the engine oil cooler & wiring harness. The other description would be that it just is a HD radiator with a HD trans cooler inside the radiator... Weird. So if you can, post a picture of your setup.
Your truck might also have RPO code V01 for the heavy duty radiator as well which is a 4-core radiator.
If the auxiliary cooler is mounted through the radiator, it is not factory. Factory coolers would have their own mounts and would not rely on the plastic zip-tie type mounting methods that the aftermarket darlings adopted for cheapness & ease of installation.
Without a picture of your setup, I also cannot say whether it is a factory arrangement or aftermarket, but I can confirm that if it was equipped with the RPO code Z82, it would have both an engine oil cooler in the driver side radiator tank and an auxiliary transmission oil cooler (air to fluid in front of the radiator) in addition to the standard transmission oil cooler that is in the passenger radiator tank (fluid to fluid). It should also have wiring provisions for a 7-pin plug run to the back of the truck.
RPO code V02 shows up different in my references. I can decipher it two ways... One would be that it would have an auxiliary transmission cooler similar to RPO Z82 without the engine oil cooler & wiring harness. The other description would be that it just is a HD radiator with a HD trans cooler inside the radiator... Weird. So if you can, post a picture of your setup.
Your truck might also have RPO code V01 for the heavy duty radiator as well which is a 4-core radiator.
If the auxiliary cooler is mounted through the radiator, it is not factory. Factory coolers would have their own mounts and would not rely on the plastic zip-tie type mounting methods that the aftermarket darlings adopted for cheapness & ease of installation.
Having an extra trans cooler is great insurance against burning up a transmission and helpingit live long. I installed the largest supplemental cooler I could find to help my Blazer, albeit a baby one compared to yours, with towing my boat.
I believe it was the Hayden 699. A neat feature of it is that it has a built-in thermal bypass valve so it won't overcool in cold weather.
I believe it was the Hayden 699. A neat feature of it is that it has a built-in thermal bypass valve so it won't overcool in cold weather.
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blazerJim1701
2nd Generation S-series (1995-2005) Tech
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Jul 29, 2009 12:54 PM





