ARCHIVE 1FZ-FE coolant flow and planning

[BILT4ME]

This is a good customer. He bought the truck online from California? As soon as he got it he took it to an accessory place and had a lift kit, wheels and tires, backup camera, nav system, new bumpers, etc. installed. Then he only had been driving it a week when he brought it to me for no heat and a couple other minor things. The cooling system was dirty so flushed it.

If the coolant was brown gooey stuff, he needs a new radiator. Also need to flush the block with garden hose.

Not uncommon to have idiots mix red and green coolant and end up with brown Jell-O. If the top of the radiator is starting to turn brown anyway, it's time to change.

Get an OEM radiator if available. Otherwise must search the threads for the latest radiator-of-the-month-club.

Also make sure you replace the thermostat and gasket with OEM. (Aftermarket ones get spit out by these...) and make sure you orient it correctly. Then burp the system. Proper procedure is in here somewhere. Search for "burp" and you should find many.

 

[GENEVAJOE]

If the coolant was brown gooey stuff, he needs a new radiator. Also need to flush the block with garden hose.

Not uncommon to have idiots mix red and green coolant and end up with brown Jell-O. If the top of the radiator is starting to turn brown anyway, it's time to change.

Get an OEM radiator if available. Otherwise must search the threads for the latest radiator-of-the-month-club.

Also make sure you replace the thermostat and gasket with OEM. (Aftermarket ones get spit out by these...) and make sure you orient it correctly. Then burp the system. Proper procedure is in here somewhere. Search for "burp" and you should find many.
[/QUOTE
Thanks for the reply. The coolant wasn't that dirty, and it's definitely clean now, and the radiator isn't restricted as far as I can tell. The truck doesn't overheat, in fact I can't get the thermostat to open unless I hold the RPM to 2500 for about 5-7 minutes. The radiator gets hot, but the lower hose and t-stat housing stay around 150-165 degrees most of the time. We had an issue with air in the system before, but we found and repaired a leak at the lower hose connection. With clear hose connected to heater core, and the core sitting in the engine compartment, we could see air in the system and there was no flow at idle when that happened. After the repair and running 'til t-stat opened, we checked the clear hose for air the next morning and there was none. The core was 198-205 degrees in and slightly cooler out. We put the core back in the unit (without the dash) and got pretty good heat. Put it back together and went for a drive - the heat was gone. If warmed up before driven, the heat will get cooler and cooler the longer it's driven.

 

[BILT4ME]

Is the water pump that has been recently replaced and OEM (Aisin) brand or some crappy aftermarket from O'Reilly's (can you tell based on casting marks)?

 

[GENEVAJOE]

Is the water pump that has been recently replaced and OEM (Aisin) brand or some crappy aftermarket from O'Reilly's (can you tell based on casting marks)?

I don't know. I was looking for a loose impeller, missing impeller blades. It was shiny so I assumed it was newer. Probably aftermarket, tho.

 

[bicycleagent003]

A formed hose from the heater control valve to the PHH location, with the proper ID at each end (are they different?) would be fantastic.
Would there be any issues with heat exposure for a formed hose following that route?

 

[baldilocks]

I don't know. I was looking for a loose impeller, missing impeller blades. It was shiny so I assumed it was newer. Probably aftermarket, tho.

Seems like, if there was low water flow the engine would run hot. After looking at the flow diagram on the first page, it appears that the arrows indicate the water flow improperly and there appears to be water returning into the head through the PHH and also back into the thermostat housing. All hoses and pipes connected to the thermostat housing are directing coolant into that housing. That means that hot water to the heater core must come through the PHH from the driver side of the head. Maybe that port is stopped up? Is the hot water valve opening fully?

 

[NLXTACY]

After looking at the flow diagram on the first page, it appears that the arrows indicate the water flow improperly

It is? I need to go through it again. I based it on an old Toyota drawing I had found.

 

[GENEVAJOE]

Seems like, if there was low water flow the engine would run hot. After looking at the flow diagram on the first page, it appears that the arrows indicate the water flow improperly and there appears to be water returning into the head through the PHH and also back into the thermostat housing. All hoses and pipes connected to the thermostat housing are directing coolant into that housing. That means that hot water to the heater core must come through the PHH from the driver side of the head. Maybe that port is stopped up? Is the hot water valve opening fully?

With a clear hose between the valve and core, I was able to observe coolant flow. It was coming from the back of head flowing toward the core. We were thinking a restriction in the pipe or passage in the head may be causing the problem. Is there a way for coolant to flow inside the head that would circulate in the engine but not thru the core?

 

[baldilocks]

It is? I need to go through it again. I based it on an old Toyota drawing I had found.

Looks like the arrows are directing coolant back to the PHH port.

 

[baldilocks]

With a clear hose between the valve and core, I was able to observe coolant flow. It was coming from the back of head flowing toward the core. We were thinking a restriction in the pipe or passage in the head may be causing the problem. Is there a way for coolant to flow inside the head that would circulate in the engine but not thru the core?

Was the system not drained and flushed during all the work that’s already been done? This would have verified whether or not coolant is flowing at 100% from the head to the heater core.

 

[NLXTACY]

Time to add another one to the list. This is the before and after for the Rear Heater Delete using the OEM "bypass hose" and 1ft of heater hose. Its actually not a bypass hose, its just used on 80 series trucks without a rear heater: 80 Series 1FZ Rear Heater Delete Hose

 

[NLXTACY]

I had a conversation with a customer this morning going over his coolant issue. At the end of it he asks if I knew what the paint marks on the OEM hoses were. Figured I’d draw it up based on what’s in the FSM.
The paint mark specifically is where the clamp is positioned for best operation for access of the tool used to remove the clamp.

Secondarily I THINK that the mark is used as a quick visual identifier to know which side of the hose points AWAY from the engine.
Up to this point this seems to be the case each time so it could be anecdotal so if anyone knows specifically please let me know and I’ll adjust as needed.

 

[flintknapper]

I had a conversation with a customer this morning going over his coolant issue. At the end of it he asks if I knew what the paint marks on the OEM hoses were. Figured I’d draw it up based on what’s in the FSM.
The paint mark specifically is where the clamp is positioned for best operation for access of the tool used to remove the clamp.

Secondarily I THINK that the mark is used as a quick visual identifier to know which side of the hose points AWAY from the engine.
Up to this point this seems to be the case each time so it could be anecdotal so if anyone knows specifically please let me know and I’ll adjust as needed.
View attachment 2326019

This does seem to 'jive' with what I've seen on my engine. (Clamp placement anyway).

 

[SmokingRocks]

So I just wanted to drop this here, the corrected coolant flow diagram

 

[Dubbinchris]

This does seem to 'jive' with what I've seen on my engine. (Clamp placement anyway).

View attachment 2363544

View attachment 2363131View attachment 2363132View attachment 2363135

2nd and 3rd photo I would say no. 4th photo barely.

 

[BillyGoatMTB]

Good stuff! Thanks @NLXTACY for the diagrams.... Fantastic!

I have not brought myself to delete the rear heater.... yet, we super dig it on cold cold days, its super nice.......

 

[BILT4ME]

So I just wanted to drop this here, the corrected coolant flow diagram
View attachment 2891705

@NLXTACY Can you replace the one on the first page with this one in order to clean-up mis-information?

I agree with this coolant flow because the stock heater valve has a flow arrow on it pointing this direction.