Help! Overheating after a water pump install (1 Viewer)

[Super77]

So, just finished a WP install and started a coolant flush, and upon startup and first drive I’m overheating. Here’s what happened:

- WP bearing seized. Caught it immediately (was in my driveway - whew!) and replaced the WP with an Aisin WPT-029.

- Also changed the thermostat with an Aisin THT-007 and rebuilt the thermostat housing with new sensors and gaskets. Thermostat installed with the spring side facing down (pointy “bridge” facing up). It actually won’t go in any other way.
- changed a couple of hoses
- changed all the belts
- fan clutch works and fan is turning
- the 1.5” hose on top of the thermostat housing is hot, suggesting the thermostat is open and there is flow back to the radiator

I drained about 2.5 gal of coolant before I removed the WP, and currently replaced it with about 3 gal of water + Prestone Flush & Cleaner, so I’m assuming no large air pockets. I cannot get any more into the radiator.

At idle, temp gauge fluctuates between halfway and right up against the red - depending on whether I’m running my heat. Driving 30mph the needle almost reaches red.

In the entire time I’ve owned the truck, the temp needle never went above 1/4. I assumed it was a faulty sender, so that’s why I replaced everything in the thermostat housing.

So, what am I missing? Is it normal to spike like this using water? When I drained, I assumed another 2.5-3 gal of 50/50 mix in the engine, so I’m actually running a very diluted coolant right now for the flush, not straight water.

 

[ChaserFJ60]

Does your temp needle fluctuate quickly/rapidly? Mine spiked at red and it was a faulty gauge. Do you have an IR gun or other way to verify the gauge or sender isn't faulty?

 

[Super77]

Does your temp needle fluctuate quickly/rapidly? Mine spiked at red and it was a faulty gauge. Do you have an IR gun or other way to verify the gauge or sender isn't faulty?

Needle moves up slowly. Takes about 5-10 min to go from 50% to near red, at idle. I have a spot gun, but not sure where on the engine to point it and what reading to look for.

 

[ChaserFJ60]

Needle moves up slowly. Takes about 5-10 min to go from 50% to near red, at idle. I have a spot gun, but not sure where on the engine to point it and what reading to look for.

Point it at the top of the thermostat housing, Passenger side engine head and block, multiple coolant hoses. The temperature will be different everywhere you scan but should stay around the same area. You want to see ~180F, I would expect a +/- of 20F but there are alot of variables in play. You should see a correlation between what you scan and your gauge reading. Dont scan too close to the exhaust.

I would check the basics too like verifying coolant hoses are installed correctly, Manually burping the radiator, Checking to see if radiator is clogged, Condition of temp sender wire.

I recently had an issue where my fan clutch would work fine when the engine was cold but would go completely limp at operating temperature causing my engine to overheat

 

[pithicus]

Could still have air in it. You can try screwing the old sensor back in.

 

[ToyotaMatt]

Needle moves up slowly. Takes about 5-10 min to go from 50% to near red, at idle. I have a spot gun, but not sure where on the engine to point it and what reading to look for.

you have a MAJOR AIR pocket in there .

big time

 

[duncanrm]

Is this a petrol engine? Is the backing plate installed on the water pump?

 

[Godly]

Check if there's still air in it.

 

[OSS]

There’s air in the cooling system. Eventually it’ll purge.

 

[Super77]

Is this a petrol engine? Is the backing plate installed on the water pump?

It’s a 3FE. The WP came as a complete assembly, with backing plate. It spins correctly.

 

[Super77]

There’s air in the cooling system. Eventually it’ll purge.

I’m heading that way with my thinking too. It’s weird, though. I put back around as much liquid as I drained, so wasn’t my first thought. Not aware of any air pocket before, but then again I don’t think the old sensors were working right.

 

[fjc-man]

Have you tried purging air on a decent incline (steep drive, up on jack stands) ?

 

[ro11dice]

I had the same issue after changing a lot of the same components you did. I didn't purge with an incline but used a coolant funnel kit. I ran the engine with the heater on and just watched the bubbles surface up. If you do use a funnel kit make sure the gasket/cap covers the overflow reservoir opening so any top off isn't diverted to the overflow reservoir.

 

[Gretsch]

There’s air in the cooling system. Eventually it’ll purge.

I had the same issue after changing a lot of the same components you did. I didn't purge with an incline but used a coolant funnel kit. I ran the engine with the heater on and just watched the bubbles surface up. If you do use a funnel kit make sure the gasket/cap covers the overflow reservoir opening so any top off isn't diverted to the overflow reservoir.

^^^^ This. There has never been a time when I even had to look at the cooling system on mine that it didn't involve weeks of burping to get the air out and temps back down. It will eventually purge itself out but the quickest way to get you on the road is burp with a funnel on the radiator as suggested above. Lean that nose in the air and run the truck. You will amazed at what you see coming out of the funnel. I didn't think air was the problem either....until it was. GL and HTH.

 

[Super77]

I had the same issue after changing a lot of the same components you did. I didn't purge with an incline but used a coolant funnel kit. I ran the engine with the heater on and just watched the bubbles surface up. If you do use a funnel kit make sure the gasket/cap covers the overflow reservoir opening so any top off isn't diverted to the overflow reservoir.

I don’t have a coolant funnel kit, but here’s what I’m finding today:

- idled for 20 min with the heat on. Temp needle rose to about 80% (1 tick short of the red zone) and stayed there. Has never risen above this point.

- after 20 min, my spot IR measures 165-175F max at the top of the thermostat housing, top drivers side of the rad (return pipe) and the passenger side of the engine head (near the spark plugs)

- with the rad cap off, I got a steady stream of bubbles out of the filler neck. Never a huge “belch” but a trickle that still hasn’t stopped after 20min.

- the liquid visible in the filler neck occasionally “gulps”: it rises up and overflows a little, then drops down to where I can add a trickle.

Given this, are we still thinking air pocket and continue to idle & burp? I’ll try jacking up the front and getting a coolant funnel.

 

[pithicus]

I don't trust your new sensor.

 

[avantcruise]

Did you ever overheat prior to installing a new water pump and thermostat? When you say you overheated after install, how long did it stay in the red and did you notice if the coolant / water boiled? How many miles are on the engine? Has the top end been rebuilt - if so, when?

Letting it idle with full blast heat *while nose of vehicle is raised* should be enough to purge the air in the system enough that you don’t overheat. The funnel kit is $20-30 and worth every penny if you plan on continuing to maintain your own vehicles. I have one and recommend it. That being said, just having the car on an incline should suffice.

 

[Gretsch]

I don't trust your new sensor.

Where is it from?

20 minutes of idling likely wouldn't be near enough to get the bubbles out in my experience. Gotta get the pressures up to make it purge. This is on a 2F so YMMV. All those little bubbles add up to lots of air. I never see huge bubbles come out of mine. Streams of small ones for days. Its weeks of driving, burping, driving, burping before temps get to normal for me. It doesn't seem like it would be possible to have an air pocket in there. But I assure you it is. Maybe squeeze the upper radiator hose while idling to help move things along. Get that funnel as it really allows you to 'see' the bubbles coming out. As @OSS eludes to, you could simply fill your overflow, ignore your gauge, and drive, drive, drive. Air will get out eventually this way.

Having said that I have the original temp sensor in mine and the gauge on mine has never gotten anywhere near the red even if the temp has been a bit higher than normal so it does make me question your sender a little.

Someone set me straight here, but I think the 3FE's have a 'sender' for the dash gauge and a 'sensor' for the ECU in that thermostat housing. I think those are different part numbers. I am not sure on this but I think the plugs are different for each device such that the harness wires only fit one way (meaning one connector for sender, and one connector for ECU sensor). If this is incorrect and the plugs for each are the same, could you have mixed up the sender/sensor bits to make this read incorrectly? @ChaserFJ60 maybe you know if the harness wires are specific to the sender type such that they couldn't be mixed up? Not sure if your 2FE uses the 3FE thermo housing or not.

 

[ChaserFJ60]

Where is it from?

20 minutes of idling likely wouldn't be near enough to get the bubbles out in my experience. Gotta get the pressures up to make it purge. This is on a 2F so YMMV. All those little bubbles add up to lots of air. I never see huge bubbles come out of mine. Streams of small ones for days. Its weeks of driving, burping, driving, burping before temps get to normal for me. It doesn't seem like it would be possible to have an air pocket in there. But I assure you it is. Maybe squeeze the upper radiator hose while idling to help move things along. Get that funnel as it really allows you to 'see' the bubbles coming out. As @OSS eludes to, you could simply fill your overflow, ignore your gauge, and drive, drive, drive. Air will get out eventually this way.

Having said that I have the original temp sensor in mine and the gauge on mine has never gotten anywhere near the red even if the temp has been a bit higher than normal so it does make me question your sender a little.

Someone set me straight here, but I think the 3FE's have a 'sender' for the dash gauge and a 'sensor' for the ECU in that thermostat housing. I think those are different part numbers. I am not sure on this but I think the plugs are different for each device such that the harness wires only fit one way (meaning one connector for sender, and one connector for ECU sensor). If this is incorrect and the plugs for each are the same, could you have mixed up the sender/sensor bits to make this read incorrectly? @ChaserFJ60 maybe you know if the harness wires are specific to the sender type such that they couldn't be mixed up? Not sure if your 2FE uses the 3FE thermo housing or not.

The temp plugs arent interchangable, The dash sender is a single wire. If he's reading 175F on the thermo housing while the needle is reading in or near the red then I'd suspect a faulty gauge or sender. Ive had bad air pockets but if the OP put in the same amount of water he took out then this shouldent be a large issue unless the water is going somewhere else in the engine.

 

[Super77]

Just for clarity, which sensor(s) are we talking about here? I replaced all of them. They came from different mfrs, but I tried to get the highest quality I could.

More succinctly, which one could be throwing off the gauge reading? I can try swapping the old one back in for comparison.