5.3 LS swap: cooling issue (formerly a kinked upper hose) (4 Viewers)

[Vandy321]

Here’s a good diagram of LS water flow:

View attachment 2113024

Your upper hose. Is it at any point higher than the top tank of the rad?

Not really...pic attached hose lays across top of radiator

It is a cold day...but that lower hose was 84 degrees...fan was running. I'm lost. Truck wont overheat, but will get hot

 

[Vandy321]

Mine is swapped, even in AZ I never get over 1/2 gauge on the Toyota cluster . They run about about 195 consistent which is just under half on the cluster.

I would make sure you don’t have a air bubble they are hard to purge if you didn’t add a surge tank that back fill is. I have swapped two and that was a issue in the first one.

Take the heater line off the valve on the firewall and see if it dumps coolant if not back fill it through there .

Heater work like a champ and I can feel warm coolant in both lines near the fire wall. Can it still he a air lock if heater lines are full and hot?

 

[SUMMIT CRUISERS]

If while hot upper radiator is 134 and lower is 84 that sounds like an air pocket in the system. Thermostat won’t ever open until 180 or hotter.

 

[Vandy321]

Im starting to think that as well...other than some random guy on youtube...Anybody have a link an easy way to burp the system?

Am slowly learning cars, apologize for the ignorance. I fly airplanes for a living, but mechanical stuff has never been my forte...time to learn. I do have the Haynes repair manual for the 5.3 but the burping instructions dont match to the cruiser overflow bottle with no pressurized cap.

 

[SUMMIT CRUISERS]

It also looks like the radiator cap ought to be on the drivers side to properly remove the air from the system the way that upper radiator hose routes back to the passenger side.

 

[cruisermatt]

Dude, quit fooling around with the IR gun that tells you nothing and get an actual temperature measurement with the water temp sender. The others gave you good advice with the various apps you can download.

Or better yet, spend $100 on a Scanguage and mount it to your dash.

Until you know an actual temperate you're wasting your time

 

[SUMMIT CRUISERS]

Highest point must the cap when filling. I back my trucks down into a bar ditch at an angle with cap at the highest point. I then fill and run with the cap off until water circulates then continue to fill. This can also be done by lifting truck with a jack on the corner with the cap.
As mentioned though, you will always have an air pocket the way the upper hose is laid out according to the cap.

 

[cruisermatt]

Highest point must the cap when filling. I back my trucks down into a bar ditch at an angle with cap at the highest point. I then fill and run with the cap off until water circulates then continue to fill. This can also be done by lifting truck with a jack on the corner with the cap.
As mentioned though, you will always have an air pocket the way the upper hose is laid out according to the cap.

Have you worked on one of these motors before? they don't trap air like old school engines. I don't think his upper radiator hose is trapping air either, my layout is virtually the same.

 

[Mark3406e]

Heater work like a champ and I can feel warm coolant in both lines near the fire wall. Can it still he a air lock if heater lines are full and hot?

Yes it can still be air locked. If you look at the way a stock LS gets filled up it will make more sense. They have a T that’s tied into the back port of the water pump and up to one of the heater lines. Granted you could use that to supply whatever you wanted in theory .
It doesn’t like to just be filled through the lower rad hose which is how it’s being done unless you added a T with a surge tank.

I will agree with the other guys as well get s cheap OBD scanner so you can see what the PCM is reading.

 

[Vandy321]

Thanks fellas...ordered a OBD II bluetooth for the torque app. Will be here Wednesday. Will try to burp the system tomorrow as well. May have easily gotten some air in when I replaced the upper hose to remove the kink.

Assuming lower hose was cold tonight after 25 minutes of city driving as temps were in high 30s and maybe it never got hot enough to kick t-stat on?

Will update after I get a true temp, let ya'll know if bleeding the system worked. Thanks all for the help/suggestions and your time.

 

[Vandy321]

Burped it today, not much air came out. Still unsure of temps. Seems to warm up to 50% extremely quick from cold...by the time I hit the freeway, I get this 3/4 guage...it'll sit there all day, may go up about 1-2 needle width hotter but wont hit red.

Is this potentially just a

calibration issue? We did throw a new PCM in it and it should be the original toyota sensor and guage.

 

[Red Merle]

My temp gauge with the original motor runs at just a smidge above the half way point on the stock gauge. You are talking about a 1/8" higher on the gauge but it doesn't go into the red zone. I guess I would just roll with it for now and double check your temps when you get the scan gauge dialed in so you can see what your temps actually are.

Unless you are seeing obvious signs of over heating, I wouldn't freak out.

 

[Vandy321]

Main reason for concern is previous owner swears up and down it runs exactly at 50%, never higher.

 

[Red Merle]

Main reason for concern is previous owner swears up and down it runs exactly at 50%, never higher.

But that would be a little cooler than what is normal. My motor is tight. I rebuilt the entire top end and it doesn't use oil or do anything odd.

Not saying he's a liar, but I wouldn't hang my hat on that if he was trying to sell you the truck when he told you that.

Obviously, you have a new power plant in there and you are relying on an old gauge that was designed for a different motor and wiring assembly, but if you aren't running into trouble elsewhere with the swap, I think the stock gauge is telling you that as far as it's concerned, you are doing alright. I don't think it's a particularly exact gauge, but you would know you are having a problem if it starts running into the red, which it's not.

 

[goranvolvo]

Do any of those bluetooth OBD II sensors work with torque? Just on amazon they range from $15 to $100...you mind sharing what you picked up?

just get this UltraGauge OBDII Scan tool and Information Center and you can see everything

 

[goranvolvo]

Not really...pic attached hose lays across top of radiator

It is a cold day...but that lower hose was 84 degrees...fan was running. I'm lost. Truck wont overheat, but will get hotView attachment 2113069

that hose is one gipsy setup big time if you went 90 degree from throttle body and 45 degree it will match perfectly to air box
and you can use GM OEM coolant hose with no problems i have apsolutnu no clearance problems
<a href="https://ibb.co/gTsBSG6">

 

[aktundra]

@Vandy321 do you have a mechanical or electric fan ? I would not go overboard till you get a real OBDII reading

As long as temp stabilizes, that’s something.

My swap with electric fans did the same thing when the fan controller, failed. It was before I got my OBDII reader so I don’t know the actual temp. But I was running with essentially no fan. And around town, highway, needle was at about 2:30.

 

[thatcabledude]

that hose is one gipsy setup big time if you went 90 degree from throttle body and 45 degree it will match perfectly to air box
and you can use GM OEM coolant hose with no problems i have apsolutnu no clearance problems
<a href="https://ibb.co/gTsBSG6">

That won’t work with mech fan. Looks like that’s what he is running.

 

[Vandy321]

That won’t work with mech fan. Looks like that’s what he is running.

The hose is fine, yes, mechanical fan. it was the only solution with that geometry. Sure the metal fitting looks wonky, but it had seemingly better flow than the PVC elbows I found. Brass would be ideal, but in a rush, all I found was 1".

Reader comes in today. But I'm confident it's a overheat. AC works normal as gauge sits at 50%...as truck gets up to and past 3/4...AC no longer works and blows very hot.

Gonna swap the t-stat and flush out the coolant, check for clogs when I'm at it. T-stat never visibly cycled yesterday when burping...only thing that's confusing me is why it never truly overheats and boils coolant. Will swap those and report some temps on here later.

 

[thatcabledude]

The hose is fine, yes, mechanical fan. it was the only solution with that geometry. Sure the metal fitting looks wonky, but it had seemingly better flow than the PVC elbows I found. Brass would be ideal, but in a rush, all I found was 1".

Reader comes in today. But I'm confident it's a overheat. AC works normal as gauge sits at 50%...as truck gets up to and past 3/4...AC no longer works and blows very hot.

Gonna swap the t-stat and flush out the coolant, check for clogs when I'm at it. T-stat never visibly cycled yesterday when burping...only thing that's confusing me is why it never truly overheats and boils coolant. Will swap those and report some temps on here later.

I’d run the gauge and see what it says before you do anything changes. Just so you know what’s going on.