Kbuskill's 2008 Burb LTZ "MOD" Thread

[kbuskill]

Got the virgin Mobil Delvac Extreme 15w40 oil report back...



Looks to be pretty good oil I guess.

 

[kbuskill]

So I made my own restrictor for the radiator today from the metal valve stem of an old TPMS sensor.

I cut the valve stem off right at the sensor like so...



Then threaded the cut off portion into the nipple on the radiator, valve stem end first.

The bigger threaded portion of the stem, where the nut screws on to hold it to the rim, actually was a snug fit and I was able to thread it into the radiator and have it hold.

I obviously removed the valve stem core before installing this.


I also cut the old radiator apart and measured the restrictor hole.

For anyone curious, it is a 3/32" hole. Pretty dang small.

This valve stem may not have the exact size hole but it is definitely smaller than the original unrestricted hole.

 

[iamdub]

So I made my own restrictor for the radiator today from the metal valve stem of an old TPMS sensor.

I cut the valve stem off right at the sensor like so...

View attachment 267094

Then threaded the cut off portion into the nipple on the radiator, valve stem end first.

The bigger threaded portion of the stem, where the nut screws on to hold it to the rim, actually was a snug fit and I was able to thread it into the radiator and have it hold.

I obviously removed the valve stem core before installing this.


I also cut the old radiator apart and measured the restrictor hole.

For anyone curious, it is a 3/32" hole. Pretty dang small.

This valve stem may not have the exact size hole but it is definitely smaller than the original unrestricted hole.

Genius!

Has yours thrown any "taking too long to warm up" code or you did this proactively? I don't know what your weather is currently.

 

[Rocket Man]

So I made my own restrictor for the radiator today from the metal valve stem of an old TPMS sensor.

I cut the valve stem off right at the sensor like so...

View attachment 267094

Then threaded the cut off portion into the nipple on the radiator, valve stem end first.

The bigger threaded portion of the stem, where the nut screws on to hold it to the rim, actually was a snug fit and I was able to thread it into the radiator and have it hold.

I obviously removed the valve stem core before installing this.


I also cut the old radiator apart and measured the restrictor hole.

For anyone curious, it is a 3/32" hole. Pretty dang small.

This valve stem may not have the exact size hole but it is definitely smaller than the original unrestricted hole.

Wait- you have to restrict the flow because the new radiator works too good? I’m confused. Kinda glad I just went with a new ACDelco OEM when I replaced mine as a maintenance item a few months ago. It works great.

 

[kbuskill]

Genius!

Has yours thrown any "taking too long to warm up" code or you did this proactively? I don't know what your weather is currently.

Yes, kind of... it popped up "Engine Hot, A/C Turned Off" on my way home from church the other night.

No CEL but I had to clear a pending P0128 Thermostat malfunction code in order to get the message to go away and the cooling fans to turn off.

I checked everything and the truck wasn't overheating... coolant level was good and the OBD2 data showed 142°.

Evidently GM, in all of their infinite wisdom, decided that if your vehicle takes too long to get up to operating temperature they will make the DIC tell you that your truck is overheating... lol

After the restrictor install the truck gets up to 192°- 194° just like before and no more issues.

 

[kbuskill]

Wait- you have to restrict the flow because the new radiator works too good? I’m confused. Kinda glad I just went with a new ACDelco OEM when I replaced mine as a maintenance item a few months ago. It works great.

Yes the top port on the passenger side goes to the surge tank. From the surge tank it flows back into the water pump housing BEHIND the thermostat. If there is too much flow through that top port it will actually keep the truck from warming up all the way because it is bypassing the thermostat.

Come to find out the factory radiator has a restrictor built into it and when I cut it open to check the size it is only 3/32" in diameter.

I believe the top port is only meant to allow steam/air pockets to escape the radiator and into the surge tank.

 

[Rocket Man]

Yes the top port on the passenger side goes to the surge tank. From the surge tank it flows back into the water pump housing BEHIND the thermostat. If there is too much flow through that top port it will actually keep the truck from warming up all the way because it is bypassing the thermostat.

Come to find out the factory radiator has a restrictor built into it and when I cut it open to check the size it is only 3/32" in diameter.

I believe the top port is only meant to allow steam/air pockets to escape the radiator and into the surge tank.

Shouldn’t have to f around with a new radiator to make it work imo. Good thing you’re a great troubleshooter. Seems like this company needs to fix their stuff or at least let their customers know there might be an issue. Have you contacted them about this?

 

[kbuskill]

Shouldn’t have to f around with a new radiator to make it work imo. Good thing you’re a great troubleshooter. Seems like this company needs to fix their stuff or at least let their customers know there might be an issue. Have you contacted them about this?

I haven't. It seems to be a somewhat known issue with most all of the aftermarket radiators, at least from what I read.

Not sure if Mishimoto has the same issue or not.

If someone were towing, it would be kinda cool to put a ball valve in that hose so that you could open it more for extra cooling when needed.

 

[Rocket Man]

I haven't. It seems to be a somewhat known issue with most all of the aftermarket radiators, at least from what I read.

Not sure if Mishimoto has the same issue or not.

If someone were towing, it would be kinda cool to put a ball valve in that hose so that you could open it more for extra cooling when needed.

Oh yeah I remember hearing about that but I thought you just had to make sure the new one had a restrictor, and that most of the high quality ones had it. Maybe I’m not remembering right though, I AM getting old af. It surprises me that these companies( who must know about the issue) don’t have the option for the buyer to have a restrictor included or at least put an install note in the box that says you might have to cut a valve stem off an old TPMS sensor and rig it up in the top port of their expensive radiator in order for it to work right in your GM lol.

 

[1BADI5]

Cold Case arrived today...
View attachment 266485

View attachment 266486

View attachment 266488

View attachment 266489
I finally will have the petcock that GM didn't install like they should have.

View attachment 266487
I think Benjamin approves... lol

I just posted that last pic to reference the thickness of the core.

I guess I will be swapping from Dex-cool (orange) coolant over to the old school Green coolant per Cold Case's recommendation.

So gonna have to flush the cooling system thoroughly.

Hopefully there are no issues or surprises with the install. I've read that the upper mounts may have to be trimmed slightly to clear the core support and the cooling fans shroud may have to be trimmed slightly as well.

I also looked at the top port on the passenger side that goes to the surge tank on my stock radiator and it appears to be the same size as the new one... unless the restrictor is further up inside the radiator.

Where did you order this fine piece of Aluminum? I want to grab a bigger rad before I install my blower.