Radiator makes engine run too cold

[Matthew Jeschke]

I've seen this in a couple radiator reviews. The radiator made the engine run too cold, it never got up to operating temperature. It wasn't a stuck thermostat but rather a radiator that was "unplugged" it didn't restrict enough flow on the boil line back to the revivor or something to that effect.

I'm trying to find a factory fitment radiator that runs COLDER. I cannot find that radiator again though other than the "Frostbite" radiator linked below. However, I'm recalling a radiator with plastic reservoirs that wasn't so expensive.

Anybody have a radiator that ran too cold? I'd be interested in knowing what the make and model was. Thanks!

Pardon Our Interruption

 

[buckwild27]

Aluminum dissipates heat more efficiently. My trucks run at 183-189° all the time.

 

[RST Dana]

Drive faster?

 

[buckwild27]

Also reviews are not a solid thing to base your decision off of. You naturally assume that the person writing the review knows what they're doing. This is not always the case. They may not have had a stuck thermostat but they also possibly failed to mention that the thermostat is a 160° thermostat. Or when they switched out the temp sensor they went cheap and didn't get a gm replacement sensor.

 

[justirv]

Unless one is "tuned" to take advantage of a 160° or 180° t-stat, there is no reason to be that low. I prefer my street vehicles to target 200°, +/- 3°. Adding a restrictive orifice should work for you. I recall someone may have used a spent bullet casing, possibly a 45 ACP, but I'm not sure.

 

[Marky Dissod]

I recall someone may have used a spent bullet casing, possibly a 45 ACP, but I'm not sure.

Any links to any of those radiators that needed a spent bullet casing to run hotter?

 

[Matthew Jeschke]

Aluminum dissipates heat more efficiently. My trucks run at 183-189° all the time.

Thanks, do you know what brand the radiator is you're using? Is it factory?

Drive faster?

That would be the logical solution. However, I'm on old mining roads climbing mountains in desert sometimes at 115F. Last time I let it rip on front of a range, not in mountains, I banana'd my alignment cams, and ripped chunks out of my K02 tires. Had to buy a whole new set.

Also reviews are not a solid thing to base your decision off of. You naturally assume that the person writing the review knows what they're doing. This is not always the case. They may not have had a stuck thermostat but they also possibly failed to mention that the thermostat is a 160° thermostat. Or when they switched out the temp sensor they went cheap and didn't get a gm replacement sensor.

Understood... The boiler (reservoir) line does play a lesser known role though and I cannot seem to find any marketing w/ spec's on it other than people complaining of the radiator running too cold.

Unless one is "tuned" to take advantage of a 160° or 180° t-stat, there is no reason to be that low. I prefer my street vehicles to target 200°, +/- 3°. Adding a restrictive orifice should work for you. I recall someone may have used a spent bullet casing, possibly a 45 ACP, but I'm not sure.

I agree, however, truck won't run right in 100+F temps going off-road where I can only manage 20 MPH tops. The truck starts to overheat. I need a different than factory spec / designed radiator. The triple row radiators are silly expensive so I'm trying to find one with a slightly different configuration on the boiler line... or something to tune it for a bit lower temp, 180F is the target temp I'm interested in.

Do you have links to any of those radiators? I think that's exactly what I'm looking for.

 

[homesick]

This goes back a way, but I've seen temp gages indicate low because the coolant level was down a little, exposing the thermocouple to air, rather than being submerged in coolant.

joe

 

[buckwild27]

Have you flushed everything out and changed the coolant? It's a necessary maintenance thing since they switched to the orange coolant.

 

[buckwild27]

Thanks, do you know what brand of radiator you're using? Is it factory.

All my radiators are factory. My trucks spend a fair amount of time slow driving and idling. With no over heating issues

 

[Fless]

Think about buying a radiator of your choice and drilling out the restrictor port that goes to the surge tank. Then put an adjustable valve in the surge tank hose so the flow can be adjusted at will. Problem solved.

 

[Matthew Jeschke]

Think about buying a radiator of your choice and drilling out the restrictor port that goes to the surge tank. Then put an adjustable valve in the surge tank hose so the flow can be adjusted at will. Problem solved.

That's pretty much exactly what I had in mind... A friend and I thought to pinch the hose but your idea is even better, with a adjustable valve!

Maybe I just drill mine out? I don't know what the radiator looks like behind the surge port (boil port?) inside the plastic reservoir... Anybody take one of these radiators apart before?

 

[Fless]

@adventurenali92 posted a pic of one in this post:

07 Tahoe engine hot ac turned off

So this problem has been happening for a while and I can't figure out why. First I changed the thermostat and it still happens. I changed the temperature sensor on the engine, and it still happens. I changed the wire going to the temp sensor and it still happens. Weird thing is that when I...

www.tahoeyukonforum.com

 

[Matthew Jeschke]

@Fless that's it! Thanks!!!!! Exactly what I was looking for... I think they tune that hole as a sort of built in tstat that holds ~190F

Have you flushed everything out and changed the coolant? It's a necessary maintenance thing since they switched to the orange coolant.

All my radiators are factory. My trucks spend a fair amount of time slow driving and idling. With no over heating issues

I have a new surge tank and have flushed the engine a couple times since I built the engine a few years ago HERE. The coolant system itself has no faults, I'm pushing the limits of what the factory system can do. I'm climbing on steep grades going 15 to 20 mph for 30+ minutes in well over 100F temps. My current loop is 1000ft gain HERE Prior I used this loop HERE which ascends 2600ft the engine is almost guaranteed to overheat if I run AC in 100+F weather. If I had the stock configuration, possibly even with a stock 6.0L, there'd likely be no issue. However, the engine I built creates more power than the factory 6.0L, the water pump and or radiator is not keeping up in the desert heat here when crawling on trails.

I should say, my truck is very much custom build. It's not much of a factory machine anymore. I'm really trying to identify the radiators with a ported (enlarged) surge tank / boil line. I believe that reduces strain on the radiator by separating the hottest coolant off the top so it can condense and cool separate from the radiator in the surge tank before returning into the cooling system plumbing. I think the factory spec'd radiators designed for ~190F temps. I am looking to bring that down to 180F to give me some headroom when climbing trails in mountains.

 

[buckwild27]

@Fless that's it! Thanks!!!!! Exactly what I was looking for... I think they tune that hole as a sort of built in tstat that holds ~190F



I have a new surge tank and have flushed the engine a couple times since I built the engine a few years ago HERE. The coolant system itself has no faults, I'm pushing the limits of what the factory system can do. I'm climbing on steep grades going 15 to 20 mph for 30+ minutes in well over 100F temps. My current loop is 1000ft gain HERE Prior I used this loop HERE which ascends 2600ft the engine is almost guaranteed to overheat if I run AC in 100+F weather. If I had the stock configuration, possibly even with a stock 6.0L, there'd likely be no issue. However, the engine I built creates more power than the factory 6.0L, the water pump and or radiator is not keeping up in the desert heat here when crawling on trails.

I should say, my truck is very much custom build. It's not much of a factory machine anymore. I'm really trying to identify the radiators with a ported (enlarged) surge tank / boil line. I believe that reduces strain on the radiator by separating the hottest coolant off the top so it can condense and cool separate from the radiator in the surge tank before returning into the cooling system plumbing. I think the factory spec'd radiators designed for ~190F temps. I am looking to bring that down to 180F to give me some headroom when climbing trails in mountains.

I run 180° thermostats. If you're overheating that bad try running without a thermostat or program the fans to come on fully at a lower temperature.

 

[Blackcar]

Any links to any of those radiators that needed a spent bullet casing to run hotter?

Under heating problem

05 Tahoe 5.3 4x4 260k So I recently blew a plastic core radiator and overheated a bit about 3/4 on the gauge. Replaced with a 4 row aluminum radiator and new water pump with tstat amd housing. (Replaced 2 thermostats since, thinking they were faulty) My problem is after I put the new parts...

www.tahoeyukonforum.com

Post #17

 

[Matthew Jeschke]

I run 180° thermostats. If you're overheating that bad try running without a thermostat or program the fans to come on fully at a lower temperature.

Good tips, I had these same thoughts and tested them. I'm really apposed to spending money so tested these things first... It had little effect on where the radiator seemed to settle out. The fans did help but relied heavily on the high speed fan, which is IMO intended for short bursts / a couple minutes of runtime. It was running continuously for months of driving and fried the relays.

Original tune turned on LSF at 185F. The HSF was somewhere in the 190F range (I'd have to lookup the tune). I think these settings are ideal but the radiator simply couldn't get rid of heat that fast. Truck really likes to operate around 180F ECT.

I need to write a post on all the stuff I've tried. It seems I have a knack for finding the weak links in the factory design lol

 

[buckwild27]

If your tune timing is off it will cause it to over heat too.

 

[buckwild27]

Radiator Aluminum Gas 3 Row Desert Cooler, 2 Oil Cooler | Radiator Express

Item has 34 inch fin(core) material length. Overall of radiator will be more like 40-42.<br><br>For Gas Engines. <br><br>Fits auto or manual with or without Engine oil cooler. 34 inch core (42 overall) If you do not need extra cooler = ignore the ports and install. No need to plug.<br><br>Item...

www.radiatorexpress.com

 

[Matthew Jeschke]

Thanks! That's about the best deal I've seen on a triple row radiator, outside of eBay no-name stuff.

I'm going to carefully try to open up that orifice on my radiator and see if my hack does the trick. If not I think I need to buy a triple row. That link will come in handy!

Pics below are from yesterday's test run... Drove up there, walked for about an hour, and then drove back to my house.

Not sure if link below will share? I threw up a video on my Instagram. The current test canyon:

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This is my other place for testing the limits of the truck. I've had my engine overheat there, transmission overheat, and even brakes (way down) ~ so hot the rims were cooking the tires. With help of forum, I redid the brakes (GMT900) upgrade and now they can handle the road in video below: