Question about Coolant Flow

[KicknAsphlt]

Has anyone ever measured (whether Toyota, or some industrious individual) the actual flow of the coolant system? This is one of the things I plan to do in the process of troubleshooting my cooling issues, and it'd be nice to have a baseline to reference, if it exists. Thanks!

 

[Bru]

Flow depends on how fast the water pump is turning. If you're having cooling issues, look at the front of the radiator for road dirt, leaves, etc. that may have been sucked up there blocking proper airflow. Also, when the car is cool, take off the radiator cap and look to see if the cores are plugged up. Back flush as necessary. Remove your thermostat and make sure it's opening at the proper temperature and all the way using hot water on the stove. Harbor Freight has a nice laser temperature measuring tool. When the car is cold, give a fan blade a quick push. It should move less than a 3rd of a turn. Otherwise, the clutch could be slipping.

 

[KicknAsphlt]

Flow depends on how fast the water pump is turning. If you're having cooling issues, look at the front of the radiator for road dirt, leaves, etc. that may have been sucked up there blocking proper airflow. Also, when the car is cool, take off the radiator cap and look to see if the cores are plugged up. Back flush as necessary. Remove your thermostat and make sure it's opening at the proper temperature and all the way using hot water on the stove. Harbor Freight has a nice laser temperature measuring tool. When the car is cold, give a fan blade a quick push. It should move less than a 3rd of a turn. Otherwise, the clutch could be slipping.

I've been down this road when I started troubleshooting it. It's a brand-new (at least when I bought it from someone on here) Fluidyne radiator; water pump was good when I built the motor, and I tested the T-stat on the stove, which was good. I think I installed another brand-new Toyota unit anyway, just to cover my bases. And I have electric fans. I also used the exhaust gas leak checker on the system, thinking maybe exhaust gases were getting in the coolant, but that test came up negative. I even damn-near put the car vertical trying to burp it...lol. My old posts may still be in here, if they weren't lost in the crash.

My next step is to see if I'm getting flow, and how much - but I'd like to know what is considered normal. The car will idle all day long without overheating, it's only when you start putting a load on it that the temps climb, and the other issue the car has is when it starts going into boost (only running the stock 7psi, due to it being a new motor), it dumps fuel and pegs the wideband to the floor. I feel like the two are related, but I want to rule out the mechanical issues with the coolant system.

 

[Asterix]

Ah, electric fans. Which ones? Maybe you should put the stock fan and shroud back on and see if your cooling problems go away.

Do you have an engine undercover? That also helps quite a bit.

 

[KicknAsphlt]

Ah, electric fans. Which ones? Maybe you should put the stock fan and shroud back on and see if your cooling problems go away.

Do you have an engine undercover? That also helps quite a bit.

IIRC, I have the Flex-A-Lite dual fans, and I've mounted/sealed them to the radiator so there are no errant airflow leaks. The fans move a LOT of air. And no, no undercover - my car never had one, at least as long as I've owned it. Car never had cooling problems before the rebuild.

 

[Asterix]

FWIW, I've never had a problem with air getting trapped in the system. I usually disconnect the highest hose that goes to the throttle body, then squish the top hose to swish around the coolant until it comes out that hose. That gets out most of the air and the rest works it way out over the next 2 or 3 temperature cycles.

You've checked everything else, but how about the radiator cap? I can't imagine anything clogging the system reducing flow.

Does your thermostat have the jiggle valve in the right place?

Definitely make sure there's no debris between the A/C condenser and radiator. This car loves to suck up leaves and store them there because there's a big gap at the bottom of the condenser. And, how full of crud is your condenser?

 

[KicknAsphlt]

FWIW, I've never had a problem with air getting trapped in the system. I usually disconnect the highest hose that goes to the throttle body, then squish the top hose to swish around the coolant until it comes out that hose. That gets out most of the air and the rest works it way out over the next 2 or 3 temperature cycles.

You've checked everything else, but how about the radiator cap? I can't imagine anything clogging the system reducing flow.

Does your thermostat have the jiggle valve in the right place?

Definitely make sure there's no debris between the A/C condenser and radiator. This car loves to suck up leaves and store them there because there's a big gap at the bottom of the condenser. And, how full of crud is your condenser?

It's been 11 years since i installed the T-stat, but I'm sure I installed it with the hole at/near 12:00, and I might have removed the jiggle valve from the hole. As far as the cap, it's the one that came with the Fluidyne radiator, though there is a sticker on it that I've thought about removing - I can't remember if that cap has a pressure relief or not, but I can't imagine a sticker covering it being good, if there is one.

I can double-check for debris, but everything was clean when I dropped the motor in, and the radiator went in after that.