Sourcing and Fitting Two-Core Radiators for 2003+ Chevy Vans

[youngnretired]

I don't recollect the specific elevations of any of the mountains we went over. None of it was on a major highway, all 2 lanes, but I do know there were several that were 6-8 miles long. By that time in our trip, I was more concentrating on the trans temp than engine temp since the engine temp never seemed to move much and thus wasn't an item of concern.

You won't really notice a change on the instrument gauge when you turn the heat on, but with a digital readout it's noticeable.

 

[youngnretired]

deleted.....

 

[booster]

So basically, the rad I recently mentioned is a crapshoot?

That radiator looks like it would work fine, and in reality I think it is just a rebadged 454 cid engine Express van unit. You probably have the quick connect lower hose so if you do, you would need to adapt the lower hose. 7

I like that it is all aluminum, but surprised that it is 3 core but only 1.65" thick. That would probably mean 3 half inch wide cores, which is usually not used in aluminum radiators much anymore. The two core ones are over 2", usually 2 3/16" or 2.250" thick.

Not a bad price compared to a #300 plastic tank like the one on Rockauto.

 

[froggman76]

I recently completed a trip from Seattle to San Diego and back in my 2004C190P. At times, ambient temps were 100+, and included 6% mountain ascents and stop and go traffic. At times, ScanGauge 3 revealed transmission temps of 230+! Ouch! On the trip back to Seattle, I better managed to lower transmission temps by judicious down shifting and use of tow mode. As a result, I'm going to go with a better radiator and a high flow water pump like in these links, as well as Dexron VI transmission fluid. I've reviewed all of the posts in this forum and FB, and believe my proposed mods are the easiest and should produce acceptable results. I may also add a dedicated, fan cooled transmission cooler at a later time.

Comments invited.

https://www.alloyworksplus.com/products/4-row-radiator-shroud-for-2004-2016-chevy-express-gmc-savana-2500-3500-4-8l-6-0l?cfb=178fd5e5-226e-4364-a72a-91ddee315c82&ifb=178fd5e5-226e-4364-a72a-91ddee315c82&scm=search.v39.101.11083.103.104&score=0.3333333333333333&ssp=&spm=..search.search_1.3

https://www.summitracing.com/parts/bra-1669/make/chevrolet/model/express-3500/year/2004

 

[booster]

I recently completed a trip from Seattle to San Diego and back in my 2004C190P. At times, ambient temps were 100+, and included 6% mountain ascents and stop and go traffic. At times, ScanGauge 3 revealed transmission temps of 230+! Ouch! On the trip back to Seattle, I better managed to lower transmission temps by judicious down shifting and use of tow mode. As a result, I'm going to go with a better radiator and a high flow water pump like in these links, as well as Dexron VI transmission fluid. I've reviewed all of the posts in this forum and FB, and believe my proposed mods are the easiest and should produce acceptable results. I may also add a dedicated, fan cooled transmission cooler at a later time.

Comments invited.

https://www.alloyworksplus.com/products/4-row-radiator-shroud-for-2004-2016-chevy-express-gmc-savana-2500-3500-4-8l-6-0l?cfb=178fd5e5-226e-4364-a72a-91ddee315c82&ifb=178fd5e5-226e-4364-a72a-91ddee315c82&scm=search.v39.101.11083.103.104&score=0.3333333333333333&ssp=&spm=..search.search_1.3

https://www.summitracing.com/parts/bra-1669/make/chevrolet/model/express-3500/year/2004

If you read all the overheating Chevy content on this forum, you should have seen many instances where big radiators, big trans coolers, added fans etc helped only marginally under the toughest conditions where you can't get the transmission to lock the converter. Low speed, steep, curvy, hills are the worst as you have no way to lock the converter at near full throttle in 2nd gear until you are going 50mph. If the road only allows 35mph you are screwed and will overheat with a stock PCM. All tow/haul does is raise the auto shift points and the lockup points so can be worse in some cases like 2nd gear climbs as you have to 55mph to lock the converter in tow/haul.

The key for us was to reprogram the pcm for different shift and lockup points when in tow haul so the converter can be locked more of the time, as an unlocked converter is what is generating the heat that shows up as overheating the transmission. Lots of information here on doing that, but is not cheap or easy to do form most folks except car and hotrod junkies. The shift and lockup charts in the stock pcm are shown in other discussions as well as the rpm in each gear by speed so you can know how much hp and torque you wil have at those points (different spreadsheet document).

 

[froggman76]

If you read all the overheating Chevy content on this forum, you should have seen many instances where big radiators, big trans coolers, added fans etc helped only marginally under the toughest conditions where you can't get the transmission to lock the converter. Low speed, steep, curvy, hills are the worst as you have no way to lock the converter at near full throttle in 2nd gear until you are going 50mph. If the road only allows 35mph you are screwed and will overheat with a stock PCM. All tow/haul does is raise the auto shift points and the lockup points so can be worse in some cases like 2nd gear climbs as you have to 55mph to lock the converter in tow/haul.

The key for us was to reprogram the pcm for different shift and lockup points when in tow haul so the converter can be locked more of the time, as an unlocked converter is what is generating the heat that shows up as overheating the transmission. Lots of information here on doing that, but is not cheap or easy to do form most folks except car and hotrod junkies. The shift and lockup charts in the stock pcm are shown in other discussions as well as the rpm in each gear by speed so you can know how much hp and torque you wil have at those points (different spreadsheet document).

Booster: I have read most all of the posts, especially yours, with cures for the Chevy Express 3500 6.0L overheating issues. At some point in time I may flash the PCM in the future, but will be content with my proposed mods for the time being.

 

[booster]

Booster: I have read most all of the posts, especially yours, with cures for the Chevy Express 3500 6.0L overheating issues. At some point in time I may flash the PCM in the future, but will be content with my proposed mods for the time being.

Did you make a copy of the shift and lockup speeds charts? IMO, it is a good idea to have them as they are the key to being able to tell if you are going to be locked or not on any given climb and useful for manual gear selection. As mentioned, unless you get into a set of circumstances where you can't go fast enough to lock the converter, you will be OK for heating as long as you choose the right gear to get to the lockup point.

I have not been able to confirm it, or disprove it, but your Scangauge 3 may be able to display gear number you are in and if you are locked or not locked. If so you have a huge advantage over the rest of us (except to the way big Scangauge 3 and finding a good location for it) by seeing those items in real time. The only way I can see them is if I put on my datalogger through the laptop and that is a real pain to do and monitor. You might have to call Scangauge to get programming information if it is available as an addon gauge, but may be there already if it is a standard gauge now. The other Scangauges can't get either of those items, even though the OBD port does report them as I can see them on the logger through the port.

 

[youngnretired]

Scangauge III will display the current gear, but i don't think the torque converter locked status is available for display. I have a screen setup that displays current gear and RPM as part of the data. I only need to look at the instruments to know how fast we're going. After driving for a while, one can tell if the torque converter is locked in 4th or not by looking at the RPM. I've not ever pushed things far enough in 2nd or 3rd to lock the converter to get a sense for the RPMs.

 

[froggman76]

Did you make a copy of the shift and lockup speeds charts? IMO, it is a good idea to have them as they are the key to being able to tell if you are going to be locked or not on any given climb and useful for manual gear selection. As mentioned, unless you get into a set of circumstances where you can't go fast enough to lock the converter, you will be OK for heating as long as you choose the right gear to get to the lockup point.

I have not been able to confirm it, or disprove it, but your Scangauge 3 may be able to display gear number you are in and if you are locked or not locked. If so you have a huge advantage over the rest of us (except to the way big Scangauge 3 and finding a good location for it) by seeing those items in real time. The only way I can see them is if I put on my datalogger through the laptop and that is a real pain to do and monitor. You might have to call Scangauge to get programming information if it is available as an addon gauge, but may be there already if it is a standard gauge now. The other Scangauges can't get either of those items, even though the OBD port does report them as I can see them on the logger through the port.

I have programmed my ScanGauge3 based on your input, but have yet to tweak like the picture from

youngnretired​

 

[booster]

Scangauge III will display the current gear, but i don't think the torque converter locked status is available for display. I have a screen setup that displays current gear and RPM as part of the data. I only need to look at the instruments to know how fast we're going. After driving for a while, one can tell if the torque converter is locked in 4th or not by looking at the RPM. I've not ever pushed things far enough in 2nd or 3rd to lock the converter to get a sense for the RPMs.

View attachment 2486289

It will be interesting to see if the Scangauge updates fast enough so you can see the lockup and unlock vs gear in the rpm reading. If so, that would be not quite as good as displaying it, but usable.

It looks like you have it sitting on the driver side cupholder. Is that where it lives when in motion? I nearly bought a Scangauge 3 a while ago but couldn't figure out where to put it so I wouldn't have to look away from the road that far all the time. Maybe I could get it on the dash at the A pillar without it blocking any visibilty, but it is quite large. I have our Scangauge two on the steering column so very easy to see at a glance but the 3 would block a big chunk of the instrument panel.

 

[youngnretired]

Ours is mounted on the lower left with the backup camera below the mirror. Both are generally out of the way 90% of the time, windy roads being the main issue. No matter where you mount them, you'll work around them. I have an extra unused mount above the scangauge.

 

[Bangorbob]

I don't have a scan guage but I do have an Edge CTS2 monitor. It does basically the same as a scan guage. Mine does depict when the torque converter is locked. I have mine mounted o.n the left side dash

 

[youngnretired]

I was just looking around online and scangauge apparently can display the torque converter locked status (codes TCL/TCC) or RPM slippage of the torque converter (code TCS). My memory has it that I did see the TCS field when programming the screen layout.

Like I said, after watching tge RPMs as you drive, you'll get a real good understanding of when the converter is locked in 4th or not.

 

[booster]

I don't have a scan guage but I do have an Edge CTS2 monitor. It does basically the same as a scan guage. Mine does depict when the torque converter is locked. I have mine mounted o.n the left side dash

Good information, that it fits an Express van. I have looked at them, particularly for their real time tuners that include the monitor, but they didn't then, and still don't list them for the Express vans like ours are. What application was yours purchased as. It also looks like the CTS2 has a built in custom tuner capability?

Looking more closely at them, and them touting very high use in the diesel trucks, I think these are either the Bull Dog ones that were around when I got our HPtuner or very similar. They look nearly identical.

I just went and looked and Edge and Bully Dog are owned by the same parent company and AI says they just serve different markets as separate companies. Mostly Edge for diesel and special tuning and Bully Dog for gassers and canned tunes. Back a ways, Bully Dog did both under one name. I need to read up a bit more, though.

The large size put me to the Scangauge 2 back then, but now Scangauges are just as large so less difference and Bully Dog/Edge seems to have nicer display options.

 

[booster]

I was just looking around online and scangauge apparently can display the torque converter locked status (codes TCL/TCC) or RPM slippage of the torque converter (code TCS). My memory has it that I did see the TCS field when programming the screen layout.

Like I said, after watching tge RPMs as you drive, you'll get a real good understanding of when the converter is locked in 4th or not.

I think that our Scangauge 2 may also have the TCS available on it but will look for sure. I also saw the online mentions of torque converter lockup online, but the website doesn't specifically list it for the Scangauge 3, at least that I found. I put a contact question into them about a week ago and have gotten no reply yet.

 

[youngnretired]

I just changed the scangauge to display torque converter slip. I placed that data where the max daily coolant temp was because that's really an irrelevant number for me. The van doesn't run hot, so that temperature is reached when we stop and from heat soak, nothing else.

I found two "tcc slip" fields under the xgauge category. The first one i picked didn't work (displayed a constant number), but the second one does. It displays positive numbers when pulling a grade and converter unlocked and negative numbers when decending a grade with your foot off the gas.

 

[booster]

I just changed the scangauge to display torque converter slip. I placed that data where the max daily coolant temp was because that's really an irrelevant number for me. The van doesn't run hot, so that temperature is reached when we stop and from heat soak, nothing else.

I found two "tcc slip" fields under the xgauge category. The first one i picked didn't work (displayed a constant number), but the second one does. It displays positive numbers when pulling a grade and converter unlocked and negative numbers when decending a grade with your foot off the gas.

No gauge for coverter lockup? That is a bummer, and Scangauge actually shows that field in one of their display pix for and unknown vehicle.

Does the slip go to zero when the converter is locked?

 

[youngnretired]

There may be a parameter for locked status. I didn't run the rescan feature to see all available options as I did this while my wife was out of the van a couple stops ago. Only drove about 5 miles with it showing RPM difference, but it did display 0 at least once.

 

[booster]

There may be a parameter for locked status. I didn't run the rescan feature to see all available options as I did this while my wife was out of the van a couple stops ago. Only drove about 5 miles with it showing RPM difference, but it did display 0 at least once.

I think the Scangauge website is kind of old as as the X gauge list for GM CANSF hasn't changed in years so hard to tell what might be available. I wish they would answer my submitted questions.

I did stumble on the X gauge codes for lockup and gear number though. They don't say what they apply to for vehicles though.

Lockup codes

Gear number codes

 

[youngnretired]

I don't know if you can input a specific code you want to monitor or not. I only scrolled thru the list if codes for what was available.

I will say that if one pays enough attention to the numbers etc that you see, you will learn whats going on for slippage and lockup etc. As mentioned before, by knowing what RPMs the engine is doing in 4th gear, i know when the torque converter is locked.. At one time tonight while climbing a hill unlocked and in 4th, it was showing 8xx RPM of slippage when the engine was doing 24xx RPM. Thats higher than i would have guessed.

I do find that I spend more time reading the data on my scangauge than I look at the dash. It literally displays all the important data needed to monitor the status of things.