Engine not reaching operating temperature

[afpj]

There seems to be lots of advice regarding cooling system bleeding on our engines. It's actually not that difficult to understand looking at the hoses under the hood. With our style cooling system the surge tank does all the work. The surge tank is a sealed system with an extra air space hose connected to the radiator that provides a path for escaping air. Essentially there is no special procedure to bleed the cooling system. Just drive the vehicle like normal.

From service manual:

That is from a post by matahoe in another thread with the exact same title. It appears that the upper hose routing which is just the airspace hose, if routed incorrectly and dips below a certain level it could pull in coolant. We actually might have a winner here.

 

[Chiller449]

I took this opportunity to get acquainted with my own 2005 Yukon cooling hoses. The unused hose mounting clip you mentioned holds the hose going to the throttle body on mine. I noticed you have the hose from the radiator to the upper surge tank routed below the engine air intake. Mine is routed over the top of the air intake much the same as another posters photo. Just for the heck of it try rerouting that.

I don't remember you saying where your surge tank fill level is. Just now I noted mine is just slightly higher than the cold fill level mark at the middle of the tank , at what looks like a seam left from manufacture.

You mentioned replacing a fan clutch. My Yukon has none, I have electric fans. I run the Torque Pro app and my normal operating temp is right about 190. I just now let it idle until at full operating temperature[ and observed no fluid flow through the upper surge tank hose. Perhaps that hose is there as you say, as a safety to allow some flow under higher rpms when the thermostat is closed.

View attachment 212132
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I wonder if there’s something screwy with the radiator. Is that bigger radiator a factory option or completely aftermarket? Just thinking out loud. As others have said, with engine warmed up I don’t have flow into the coolant overflow tank on any active basis. It sits at a higher level than when cold but I don’t see coolant churning around, like if you were to look at your power steering reservoir with the engine running.

That is from a post by matahoe in another thread with the exact same title. It appears that the upper hose routing which is just the airspace hose, if routed incorrectly and dips below a certain level it could pull in coolant. We actually might have a winner here.

The radiator is aftermarket. But had great reviews. I think you guys are onto something about the houses not routed correctly. Here in a few hours I'll go out there and rout them correctly. I'll keep you all updated.

 

[Doubeleive]

I still think it could be pressure related also.....i'm not sure how the pressure part works it may only need to build pressure from the top port of the radiator (the capped off line)

 

[Chiller449]

It didn't work guys. I routed the houses like factory and I'm still getting coolant rushing into the surge tank from that top hose. I had the system pressure tested and they did find a leak on the water pump but the new pump fixed that. It still holds tons of pressure and heats up great if I plug that top hose. I embedded a video from YouTube that I made. You can clearly see coolant rushing into the surge tank.

 

[swathdiver]

It didn't work guys. I routed the houses like factory and I'm still getting coolant rushing into the surge tank from that top hose. I had the system pressure tested and they did find a leak on the water pump but the new pump fixed that. It still holds tons of pressure and heats up great if I plug that top hose. I embedded a video from YouTube that I made. You can clearly see coolant rushing into the surge tank.

Still running the green stuff I see. Not good.

 

[Chiller449]

Still running the green stuff I see. Not good.

View attachment 212181

What's wrong with the green stuff? I heard that orange coolant is terrible. It turns to sludge over time. From what I've heard. Anyways I'm almost sure this is it. I'll take that top hose off this weekend and look into the nipple with a flashlight. I bet there is no orifice inside. I'll have to go back to a stock radiator unless they make some kind of adapter I can use.

 

[swathdiver]

What's wrong with the green stuff? I heard that orange coolant is terrible. It turns to sludge over time. From what I've heard. Anyways I'm almost sure this is it. I'll take that top hose off this weekend and look into the nipple with a flashlight. I bet there is no orifice inside. I'll have to go back to a stock radiator unless they make some kind of adapter I can use.

It's not made for these engines or radiators. It only turns to sludge when mixed with Dexcool or when Dexcool is mixed with ethylene glycol. Dexcool has higher operating temperatures and lasts longer. I posted a research article about it earlier this year somewhere on here.

 

[TJ Baker]

What is your cold fill level? You haven't overfilled, have you?Should be down at the seam. On my stock vehicle the hose seems to exit the radiator maybe just a bit higher than the coolant level at the tank.

It's hard to see in your video but the tank is stained a good deal higher than the cold fill mark.

Speculating that the coolant level will be roughly the same throughout the system, in my case the hose to the surge tank exits the radiator above the coolant level as shown by the surge tank level.

Of course, I could be totally grasping at straws here

 

[Chiller449]

It's not made for these engines or radiators. It only turns to sludge when mixed with Dexcool or when Dexcool is mixed with ethylene glycol. Dexcool has higher operating temperatures and lasts longer. I posted a research article about it earlier this year somewhere on here.

Thanks for the info. Not sure if I'll ever switch it back. I've had way too many bad experiences with dexcool. All my chevys and all my friends chevys are running it and no one has reported any problems yet.

What is your cold fill level? You haven't overfilled, have you?Should be down at the seam. On my stock vehicle the hose seems to exit the radiator maybe just a bit higher than the coolant level at the tank.

It's hard to see in your video but the tank is stained a good deal higher than the cold fill mark.

Speculating that the coolant level will be roughly the same throughout the system, in my case the hose to the surge tank exits the radiator above the coolant level as shown by the surge tank level.

Of course, I could be totally grasping at straws here

Cold level is right at the seam on the tank.



Gonna see if I greatly reduce the size of the tube if it will help. If not I'll just get an oem radiator and be done with it.

 

[bottomline2000]

Well one thing I see is the hose that splits off the water pump and runs to the heater core on the firewall is connected to the outlet of the heater core. Mine runs from the water pump to the passenger side connection. Yours is reversed. Not sure that would make a difference or if the heater core is directional or not..

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[Fless]

MIne is just the opposite of yours, @bottomline2000. The heater hose coming off the water pump with the tee goes to the driver's side on mine. I have rear heat, so it tees again as it goes into the heater core.

 

[bottomline2000]

MIne is just the opposite of yours, @bottomline2000. The heater hose coming off the water pump with the tee goes to the driver's side on mine. I have rear heat, so it tees again as it goes into the heater core.

#FAIL ﹰﹰﹰlol..this crazy..I don't have rear heat, but I guess the heater core isn't directional. I didn't see a ﹰT in the OP truck so maybe he doesn't have rear heat..

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[Matahoe]

What's wrong with the green stuff?

Technically there is nothing wrong with running ANY type of coolant in our system so long as the previous coolant is flushed out in whole. Really it all comes down to maintenance interval and characteristics of the coolant you put in.

Green inorganic silicate coolant is fine as long as you change it religiously (~30,000 miles) or else you will start to see galvanic and corrosive effects.. Take a look at this video by Scotty Kilmer. It explains it all pretty much.

 

[Chiller449]

#FAIL ﹰﹰﹰlol..this crazy..I don't have rear heat, but I guess the heater core isn't directional. I didn't see a ﹰT in the OP truck so maybe he doesn't have rear heat..

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Yes i have rear heat. I do have the T its just not pictured. Thanks for the idea though.

Technically there is nothing wrong with running ANY type of coolant in our system so long as the previous coolant is flushed out in whole. Really it all comes down to maintenance interval and characteristics of the coolant you put in.

Green inorganic silicate coolant is fine as long as you change it religiously (~30,000 miles) or else you will start to see galvanic and corrosive effects.. Take a look at this video by Scotty Kilmer. It explains it all pretty much.

Everything was flushed thoroughly before adding the green stuff. Including the heater core and engine block. All of this was done when I put the new radiator in. I found a hose that might work for running from the rad to the surge tank. Im putting it on this weekend. Im really not satisfied with this though and am really thinking about just putting an oem radiator back in it. Anyone know if Gm made a 3 core radiator that will fit in a Tahoe that has that re-stricter plate in it?

 

[swathdiver]

Technically there is nothing wrong with running ANY type of coolant in our system so long as the previous coolant is flushed out in whole.

IAT coolant typically lasts but two years and has a lower operating temperature. It is also much harder on rubber hoses.

James, plug your VIN in over at ACDelco or GMPartsDirect or GMPartsKing and see what was available for yours. If you do not have the built in engine oil cooler, consider the radiator that does as it will usually have bigger tanks and probably a third row.

 

[Chiller449]

IAT coolant typically lasts but two years and has a lower operating temperature. It is also much harder on rubber hoses.

James, plug your VIN in over at ACDelco or GMPartsDirect or GMPartsKing and see what was available for yours. If you do not have the built in engine oil cooler, consider the radiator that does as it will usually have bigger tanks and probably a third row.

Ill do that. Mt Tahoe does not have an oil cooler. So ill try and get a radiator that does. This aluminum one does but I dont think im gonna be able to get it to work.

 

[SnowDrifter]

IAT coolant typically lasts but two years and has a lower operating temperature. It is also much harder on rubber hoses.

James, plug your VIN in over at ACDelco or GMPartsDirect or GMPartsKing and see what was available for yours. If you do not have the built in engine oil cooler, consider the radiator that does as it will usually have bigger tanks and probably a third row.

Wasn't IAT coolant phased out in the early 2000s? i.e. when all the long life coolants came onto market?

 

[SnowDrifter]

Technically there is nothing wrong with running ANY type of coolant in our system so long as the previous coolant is flushed out in whole. Really it all comes down to maintenance interval and characteristics of the coolant you put in.

Green inorganic silicate coolant is fine as long as you change it religiously (~30,000 miles) or else you will start to see galvanic and corrosive effects.. Take a look at this video by Scotty Kilmer. It explains it all pretty much.

Scotty is a friggin' hack. The amount of inaccuracies in his videos about makes me put my head through my desk.

1. New antifreeze is just as poisonous to animals as the old stuff. It's still ethylene glycol based. That's what is toxic.

2. Coolant doesn't have anything conductive in it. What happens is with repeated heat cycles, the pH buffers in it wear out. Without going into chemistry, a pH that is either too acidic or too alkaline will begin to dissolve the metals in your engine - primarily aluminum and iron. With acidic favoring iron, and aluminum being a picky thing dissolving on both ends. These suspended ions are what gives the coolant its conductivity, essentially turning your engine into a battery - internal corrosion. Oh yeah, don't forget that your spinning water pump creates static electricity that helps to feed the whole thing. Anything over .2v, I condemn the coolant.

"But the internet said .3v!!."
Yeah that's a crock of shit. If you're at .3v you're well past any protections the coolant has offered and now you're actively destroying your engine. Why do I choose .2v? More chemistry! The electromotive potential of iron is 1.83v, and aluminum is 1.61v. What's important to note here is the difference between the two. 0.22v. That's your magic number. Anything above that and you've forced a battery.

3. Silicates are no longer needed in coolant to the same degree they once were. They were an old school method of protecting parts as it would form a layer over whatever came in contact with it. Not unlike a wax. Huge tl;dr we can form that protective coating without relying on them now. Why don't you want to use silicates though? Well.. They're incredibly abrasive. Yeah they do a good job of protecting metals but they chew through any soft bits like hoses, water pump gaskets, etc. You'll have some coolants that have a very small amount of silicate, I think HOATs do, but they're not packed full of the stuff and are what I would argue is, generally safe.


Fun fact: OATs are a known plasticizer. They make nylon brittle. Our heater core connectors are plastic. Dexcool is OAT. Make sense why they break now?

 

[Matahoe]

Dude...take a pill. You are kind of just arguing about nothing. The Kilmer video is still very informative.

 

[Matahoe]

Ill do that. Mt Tahoe does not have an oil cooler. So ill try and get a radiator that does. This aluminum one does but I dont think im gonna be able to get it to work.

You don't need an oil cooler unless you have a need for one. I.e. you tow a lot in hot weather. It's more of an oil heater than a cooler.