LS Cooling Issue

[72MARIO]

I read thru your post but couldn't find the answer. Where is your tempature sending unit ? And are you using dakota digital sender or the GM in drivers front of block and the BIM-2 interface to display what the pcm is seeing ?

[MotoWells]

Originally Posted by 72MARIO

I read thru your post but couldn't find the answer. Where is your tempature sending unit ? And are you using dakota digital sender or the GM in drivers front of block and the BIM-2 interface to display what the pcm is seeing ?

Yes, I'm using Dakota Digital with the BIM-2 module that plugs into the diagnostic port (ODBII). No sensors, gauges should be getting PCM data.

• I did pickup a code scanner, data reader
  
• New coolant
  
• New thermostat
  
• Manual temp gauge

Will attempt to pull data on cool start this morning to see if numbers are different than Dakota Digital.

[knomadd]

I've been meaning to ask, did you program the DD gauges to use the "BUS F" sensor for the water temp gauge so it will read from the BIM module? If not, you'll need to do that. Otherwise, if you're running the DD water temp sensor, you'll have to program the DD gauges to "DD F" (or use "C" for celcius in place of "F" if you so desire). If you install both the DD sensor and keep the factory sensor you can switch your gauge setting to see if one reads different from the other.

[MotoWells]

Originally Posted by knomadd

I've been meaning to ask, did you program the DD gauges to use the "BUS F" sensor for the water temp gauge so it will read from the BIM module?

Yes sir, configured the gauges to read from BIM.

Good point about being able to switch between sensors to double check readings. Might have to go there.

[MotoWells]

Update for you fellas

Spoiler alert, no fix yet.

Confirmed the gauges are displaying the same data as found on the reader.

Observations:

After running truck and tempurtures started to climb to the 225-230 mark I pulled into driveway. Turned off heater to see what would happen. Temps started to climb. Turned on heater and the temp started to decrease. Only shift 3-5 deg over 3-5 minutes but it was craving more heat dispersion.

Got her up to 45-50 MPH and temp didnt seem to come down in fact it did the opposite. Thinking more validation to pull thermostat.

Next steps:

• Replace thermostat
  
• Replace fans
  
• Pull shroud from fans

Any thoughts on next steps, anything else to try? Should I borrow a pressure tester for radiators?

[72MARIO]

You say new thermostat. What brand are you using ?

[MotoWells]

Originally Posted by 72MARIO

You say new thermostat. What brand are you using ?

The one that's in there now is the OE GM that came with the crate motor. I picked up a new one from Napa the other day. New 180, I thought it was AC Delco but I will confirm.

Is there a better brand?

[mongocanfly]

if you change thermostat don't forget to repeat the engine block fill procedure by filling thru the top hose...
also have you verified the belt routing yet? making sure the pump is rotating in the right direction...I know a guy that had his backwards . .his pump mounted fan was pushing air thru the radiator to the front. .

[MotoWells]

Originally Posted by mongocanfly

...also have you verified the belt routing yet? making sure the pump is rotating in the right direction......

Yes sir, verified that the pump is indeed rotating in the recommended counterclockwise direction.

I also hardwired one of the two fans to come on immediately after fire up to test that theory. I would say that helped a little but not much.

[Hart_Rod]

Originally Posted by MotoWells

Yes sir, verified that the pump is indeed rotating in the recommended counterclockwise direction.

I also hardwired one of the two fans to come on immediately after fire up to test that theory. I would say that helped a little but not much.

You should be able to see the water in the radiator "churning/flowing" once the thermostat opens up (195/200F). If you are not, then you have a restriction in the coolant system, either thermostat or radiator. Personally, I would just pull your current thermostat and leave it out. Restart truck, leave the radiator cap off and let it warm up. If it's still getting hot and you can't see the flow in the radiator, then then you have a radiator restriction. If you do see good flow, it's your thermostat.

[MotoWells]

Originally Posted by Hart_Rod

You should be able to see the water in the radiator "churning/flowing" once the thermostat opens up (195/200F). If you are not, then you have a restriction in the coolant system, either thermostat or radiator. Personally, I would just pull your current thermostat and leave it out. Restart truck, leave the radiator cap off and let it warm up. If it's still getting hot and you can't see the flow in the radiator, then then you have a radiator restriction. If you do see good flow, it's your thermostat.

A most excellent suggestion, I will do this next and report back.

Thank you

[indymachinist]

If you are seeing an improvement in temperature control when you run the heater then the short answer is your system is just not able to keep up with demand.

I am looking at these 2 cute little fans and the flat aluminum shroud and thinking GUILTY.

Unless they are Spal, those fans likely don't move much CFM. From a look at your picture they appear to have 2 wires each. Power and ground. This means that they will not have a high and low speed. (I think I saw you posting about this earlier) They are either on or off. They should each have a relay with a large gage power wire feeding them and the PCM only turning the relay on or off.

How close is the shroud to the back of the actual radiator core? If it is very close at all, you are essentially blocking off what looks to be half or more of your core. This is not good.

I know it is not always the most visually appealing, but a junkyard dual fan with its proper shroud would run circles around your current set up.

[homemade87]

I agree with indy . It does look like the flat alum is right on the core . The fans can not pull air from the rest of the radiator and also when running down the road the forced air can not make it thru because it is dead heading against the flat alum shroud . Regardless if it fixes it or not I would add a 1" spacer or more to the alum shroud and get it away from the radiator ( Dont just add washers , it needs to be sealed around the whole radiator ) . This will allow the use of the whole radiator .

[Trackman101]

The radiator is a true dual pass correct? You should see a welded in baffle between the upper and lower rad hose forcing the water from the passenger side to the driverside and back.
Laser temp guns are a handy tool but can sometimes read inaccurately when pointed at/on shiny objects.

[MotoWells]

I purchased a dual pass radiator, not sure how to confirm. I have attempted to locate the baffles as specified by Trackman101 but haven't been able to locate just yet. I will attempt to probe a bit more deeper tomorrow evening when I have a bit more time.

Good points on the fan(s) and shroud. This radiator should be able to dissipate that heat all day long. I purchased one 16 inch 2500 cfm Syclone fan. My thought was to remove the shroud and replace both fans with this to see if it improves.

Before I do that I was thinking of pulling thermostat and seeing if wide open improves things.

Thank you for the input, lots of things to try. I will attempt these soon and report back findings. Thanks for all your input, really appreciate it.

[mongocanfly]

look at the end of the radiator in this pic..notice between the upper and lower hose connections there's a seem in the end cap..that seperates the radiator into a upper and lower unit..the flow is as in the diagram
I'm thinking they're right about your shroud...the way it is your only cooling right at the fan and blocking off the rest of your flutes..looks like just 4 bolts holding it..stick some 1/2" or 3/4" spacers between shroud and radiator creating a air gap and see what happens

[indymachinist]

Dont pull the thermostat. I'd nearly bet money it is a shroud and/or fan problem.

[MotoWells]

Thanks guys, working all week but should be able to pull shroud and test cooling this weekend. I will be sure to report back findings. Thanks for all your input and sharing of wisdom!

Next steps will now be:

Pull shroud, test cooling

If no success, replace two fans with new 16 inch 2500 cfm

If not, pull thermostat

Thank you guys!

[indymachinist]

If you pull the fan and shroud completely off it should stay cool while driving. Just watch out for overheating as soon as you stop.

[Rich84]

Originally Posted by indymachinist

If you pull the fan and shroud completely off it should stay cool while driving. Just watch out for overheating as soon as you stop.

What he said..
With my truck moving it never budges from 193 -195..The fans only come on at long traffic lights for a very short time.
I have the proper sender for my gauge and it is in the passenger side rear of the head it reads about 230.

[davepl]

Pretty easy way to tell if it's a dual pass: if the intake and outlet are on the same side, it's likely a double with a baffle midway down.

[Hart_Rod]

Updates?

[Trackman101]

......Fixed?
Looking at this again I agree the shroud is to tight to the core.
Adding some shroud flaps might help.

[MotoWells]

Finally was able to get back after it tonight and I found the issue!!!

As I was removing the fan shroud bolts I saw something that should not be sandwiched between the rad and the shroud A PIECE OF CARDBOARD!

I almost passed out with excitement. It was a blockage for sure.

Took it for a test ride and was happy at 210 the whole time, even got cooler as more air went through it.

So happy and grateful for all your help through this total head scratcher.

Now time to break this mill in.

THANK YOU !!

[mongocanfly]

are you freakin kidding me?.....wow....beautiful truck...