FJ40 Radiator Extension (Reservoir Runs Out of H2O) (1 Viewer)

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Thanks @flx. Yes, you are correct. The Reservoir begins to get full when the engine gets hotter.


Thats Normal

Thermal Expansion , applies pressure on the RAD cap

at 0.9 it is spec's to the spring will release coolant into the overflow


if your getting more coolant then normal coming out and filling a OEM capacity overflow to max and beyond ?

then I KNOW exactly why this is occurring , there is ONLY one possible reason .


is this your exact or close scenario > going on
 
To confirm that @ToyotaMatt knows of what he represents regarding FJ40/60/62 reservoir tanks for 2F engines, the following information is from OEM Toyota microfiche, factory service manuals, and volume measurements I performed on a reservoir "tank" in my possession, that was standard on FJ40's from 7501 - 7706:


Here is the parts fiche:
1626897857359.png



Here is a illustration from the 1975 FJ40 Service manual, available here on 'Mud in the reference section:
Note that the instruction states to fill the reservoir tank up to the "Full" line on the tank, in the cold condition.
1626896971594.png


Here is an illustration of the reservoir tank represented above with measurements I took using a measuring cup graduated in ml:

Reservoir with level markings.jpg


So, based upon sound engineering practice and procedures performed by the engineers at Toyota Motors, the design of the reservoir tank may be deduced, as as follows:

Maximum drawdown from "Full" level is less than 1,000 ml. (Primary purpose of full reservoir is to temper the heat from hot coolant entering reservoir from normal expansion)
Maximum expansion (cold to design operating temperature) from "Full" is less than 700 ml.

Expansion beyond the 700 ml design capacity would be the result of abnormal operating conditions allowing "boilover" situation:
- Radiator not designed for A/C condenser heat load and air flow restrictions (OEM A/C systems had larger radiators than non A/C systems)
- Air trapped in cooling system

Overheating due to:
- water pump fan clipped back to avoid interference with A/C compressor
- faulty radiator cap
- restricted/plugged/damaged radiator (internal and/or external)
- improper coolant
- restricted/plugged/fouled engine water jacket or hoses
- corroded water pump impeller
- loose water pump drive belt
- missing/damaged/altered fan shroud
- high ambient temperatures
 
do u know the exact capacity you need or want ?

i DO have larger options NOT listed online store ?
I'm happy with it, any bigger reservoir would not fit where I put it and would be a hassle to install.
It's only that the expansion goes from "just above low" to the top in normal operation of my engine but the low level stays stable and the reservoir does not lose coolant once stabilized. And this includes the temperature peak my engine likes to do when you shut it down a bit too quickly after pushing it.
You can see the level before expansion on this picture, and also how it fits to the mm between the shroud and the horn, anything larger would touch one.
1626903257553.png


But really I was not commenting here to give an opinion on your product, actually before this post I had not mentioned that I was using your reservoir ;)
And yes it's very possible my engine still have some air in and so expands too much, blurping is a never ending task.

Your experience is contrary to what the auto radiator industry manufacturers say .

Possibly radiator caps in France have special characteristics not available here in the US?
Interesting question, because yes and no x)

Yes, in Europe we had a different radiator cap with a release lever on the top (it's pictured and mentioned in the user manual) but this cap is NLA and partnumber completely unknown from the Internet.

So no I'm running the same OEM cap as everyone here.
Actually I have both model ordered from Toyota with the partnumber :
1) with only 1 gasket and listed for <75 :
1626904160163.png
1626904194374.png


2) with 2 gaskets and listed for >74, the one already pictured by Matt :
1626838283403-png.2737028


All of that to say that I had noted the conception difference between the 2 but was unable to find what it would change. So when I installed the new cap and then the reservoir I have been very vigilant of how it operated and so I stayed personally in front of my engine with 1) fitted to see the coolant expands and then retracts in the radiator without trouble. Maybe it's not "normal" and maybe once the cap a bit rusty it may stop working but for the time it is.

But yes I'm interested in understanding how it should work and if there is a real advantage to use 2) (because let's be honest, 1) looks a lot better under the hood :playful:)


Thanks @flx. Yes, you are correct. The Reservoir begins to get full when the engine gets hotter.
The important question is, is-it stable ? Does the low and high level in your reservoir always the same ? Does your reservoir lose coolant everytime by the overflow tube ?

And as a lot of people are pointing on overheating, do you have any other sign of overheating ? What does the temp meter says ? Does the engine smells hot ? etc.


To confirm that @ToyotaMatt knows of what he represents regarding FJ40/60/62 reservoir tanks for 2F engines, the following information is from OEM Toyota microfiche, factory service manuals, and volume measurements I performed on a reservoir "tank" in my possession, that was standard on FJ40's from 7501 - 7706:


Here is the parts fiche:
View attachment 2737679


Here is a illustration from the 1975 FJ40 Service manual, available here on 'Mud in the reference section:
Note that the instruction states to fill the reservoir tank up to the "Full" line on the tank, in the cold condition.
View attachment 2737654

Here is an illustration of the reservoir tank represented above with measurements I took using a measuring cup graduated in ml:

View attachment 2737672

So, based upon sound engineering practice and procedures performed by the engineers at Toyota Motors, the design of the reservoir tank may be deduced, as as follows:

Maximum drawdown from "Full" level is less than 1,000 ml. (Primary purpose of full reservoir is to temper the heat from hot coolant entering reservoir from normal expansion)
Maximum expansion (cold to design operating temperature) from "Full" is less than 700 ml.

Expansion beyond the 700 ml design capacity would be the result of abnormal operating conditions allowing "boilover" situation:
- Radiator not designed for A/C condenser heat load and air flow restrictions (OEM A/C systems had larger radiators than non A/C systems)
- Air trapped in cooling system

Overheating due to:
- water pump fan clipped back to avoid interference with A/C compressor
- faulty radiator cap
- restricted/plugged/damaged radiator (internal and/or external)
- improper coolant
- restricted/plugged/fouled engine water jacket or hoses
- corroded water pump impeller
- loose water pump drive belt
- missing/damaged/altered fan shroud
- high ambient temperatures
This is very interesting thanks !
Sadly I'm not near my FJ40 currently otherwise I would have measured mine for comparison and I will not try to eyeball a value because I know I would be wrong x)
From this picture I see it quite smaller than the original, particularly in width :
1626905467728.png

And from the picture from FES74 I would guess his reservoir is even smaller.
 
I'm happy with it, any bigger reservoir would not fit where I put it and would be a hassle to install.
It's only that the expansion goes from "just above low" to the top in normal operation of my engine but the low level stays stable and the reservoir does not lose coolant once stabilized. And this includes the temperature peak my engine likes to do when you shut it down a bit too quickly after pushing it.
You can see the level before expansion on this picture, and also how it fits to the mm between the shroud and the horn, anything larger would touch one.
View attachment 2737802

But really I was not commenting here to give an opinion on your product, actually before this post I had not mentioned that I was using your reservoir ;)
And yes it's very possible my engine still have some air in and so expands too much, blurping is a never ending task.


Interesting question, because yes and no x)

Yes, in Europe we had a different radiator cap with a release lever on the top (it's pictured and mentioned in the user manual) but this cap is NLA and partnumber completely unknown from the Internet.

So no I'm running the same OEM cap as everyone here.
Actually I have both model ordered from Toyota with the partnumber :
1) with only 1 gasket and listed for <75 :
View attachment 2737812View attachment 2737813

2) with 2 gaskets and listed for >74, the one already pictured by Matt :
1626838283403-png.2737028


All of that to say that I had noted the conception difference between the 2 but was unable to find what it would change. So when I installed the new cap and then the reservoir I have been very vigilant of how it operated and so I stayed personally in front of my engine with 1) fitted to see the coolant expands and then retracts in the radiator without trouble. Maybe it's not "normal" and maybe once the cap a bit rusty it may stop working but for the time it is.

But yes I'm interested in understanding how it should work and if there is a real advantage to use 2) (because let's be honest, 1) looks a lot better under the hood :playful:)



The important question is, is-it stable ? Does the low and high level in your reservoir always the same ? Does your reservoir lose coolant everytime by the overflow tube ?

And as a lot of people are pointing on overheating, do you have any other sign of overheating ? What does the temp meter says ? Does the engine smells hot ? etc.



This is very interesting thanks !
Sadly I'm not near my FJ40 currently otherwise I would have measured mine for comparison and I will not try to eyeball a value because I know I would be wrong x)
From this picture I see it quite smaller than the original, particularly in width :
View attachment 2737834
And from the picture from FES74 I would guess his reservoir is even smaller.



the LAST photo here is MY coolant overflow i offer same as i outline above , thats my clients BJ in the photo below with my bottle on his Radatior ,,,,,,,,,,,fyi

thanks





1626907642402.png
 
I'm happy with it, any bigger reservoir would not fit where I put it and would be a hassle to install.
It's only that the expansion goes from "just above low" to the top in normal operation of my engine but the low level stays stable and the reservoir does not lose coolant once stabilized. And this includes the temperature peak my engine likes to do when you shut it down a bit too quickly after pushing it.
You can see the level before expansion on this picture, and also how it fits to the mm between the shroud and the horn, anything larger would touch one.
View attachment 2737802

But really I was not commenting here to give an opinion on your product, actually before this post I had not mentioned that I was using your reservoir ;)
And yes it's very possible my engine still have some air in and so expands too much, blurping is a never ending task.


Interesting question, because yes and no x)

Yes, in Europe we had a different radiator cap with a release lever on the top (it's pictured and mentioned in the user manual) but this cap is NLA and partnumber completely unknown from the Internet.

So no I'm running the same OEM cap as everyone here.
Actually I have both model ordered from Toyota with the partnumber :
1) with only 1 gasket and listed for <75 :
View attachment 2737812View attachment 2737813

2) with 2 gaskets and listed for >74, the one already pictured by Matt :
1626838283403-png.2737028


All of that to say that I had noted the conception difference between the 2 but was unable to find what it would change. So when I installed the new cap and then the reservoir I have been very vigilant of how it operated and so I stayed personally in front of my engine with 1) fitted to see the coolant expands and then retracts in the radiator without trouble. Maybe it's not "normal" and maybe once the cap a bit rusty it may stop working but for the time it is.

But yes I'm interested in understanding how it should work and if there is a real advantage to use 2) (because let's be honest, 1) looks a lot better under the hood :playful:)



The important question is, is-it stable ? Does the low and high level in your reservoir always the same ? Does your reservoir lose coolant everytime by the overflow tube ?

And as a lot of people are pointing on overheating, do you have any other sign of overheating ? What does the temp meter says ? Does the engine smells hot ? etc.



This is very interesting thanks !
Sadly I'm not near my FJ40 currently otherwise I would have measured mine for comparison and I will not try to eyeball a value because I know I would be wrong x)
From this picture I see it quite smaller than the original, particularly in width :
View attachment 2737834
And from the picture from FES74 I would guess his reservoir is even smaller.

************************************************

Thanks @flx. Here are my answers to your questions:

The important question is, is-it stable ?
- I don't think so it is.
Does the low and high level in your reservoir always the same ?
- No.
Does your reservoir lose coolant everytime by the overflow tube ?
- It depends on how far I travel. If it is an hour trip, then YES, expect an empty reservoir the following morning when you check it.

And as a lot of people are pointing on overheating, do you have any other sign of overheating ?
- If the traffic is heavy and no movement for 15 minutes or more then i see the temp meter going up. So what i normally do is I try to pre-empt the Rad not to overheat by stopping the engine at the side of the road. But so far i have not seen it overheating yet. Just symptoms of overheating.

What does the temp meter says ?
- Temp meter is consistent at the middle as lonh as it is running the whole time.... meaning w/o heavy traffic on the streets.
Does the engine smells hot ?
- Yes. It is a bit hot. I need to use a cloth rags to touch the hood and open it.

Thanks @flx.

************************************************
 
i have a OEM Radiator cap with a manual arm on it to relive pressure

is this what you refer to above ?

its a NON USA Toyota parts application for a land cruiser , buts that's all i know about this unique radiator cap manual arm on top ?
 
Im sure someone has already said this but just in case I'll mention it. For every 1 pound of pressure in your cooling system, it raises the boiling point 3 degrees (F). So if your system has a 15 pound cap, the boiling point would be 257 degrees F. If you have a cap that wont seal, water will boil near the normal 212 degrees. Replacing the cap is probably the easiest and cheapest way to go to see if it fixes the problem.
 
YOU CANNOT Exceed the 0.9 pressure spec. on the OEM toyota land cruiser cap genuine nippondenso ..........

fyi thats a recipe for a major issue ...

see photo below of the cap ear tab ...........


ALL 5 different style caps below are for Land Cruisers various years applications

big cap pre -4/86

later small cap 5/86 and later

ALL have 0.9 pressure specs in fact i have NEVER seen any Toyota that had a different pressure cooling system spec ..?




1626968246004.png





1626968275534.png




1626968322033.png


1626968341442.png


1626968404323.png
3A82628B-50F0-411A-8096-196984A945EA.jpeg


F315AE54-E406-43D0-8388-23A63158413C.jpeg
 
Last edited:
You shouldn't use a cap with a flip lever on a closed cooling system(reservoir type). They are designed to blow off steam/water when its exceedingly hot b4 opening the rad. They typically wont allow water to be sucked back into the rad during cooling.
 
To confirm that @ToyotaMatt knows of what he represents regarding FJ40/60/62 reservoir tanks for 2F engines, the following information is from OEM Toyota microfiche, factory service manuals, and volume measurements I performed on a reservoir "tank" in my possession, that was standard on FJ40's from 7501 - 7706:


Here is the parts fiche:
View attachment 2737679


Here is a illustration from the 1975 FJ40 Service manual, available here on 'Mud in the reference section:
Note that the instruction states to fill the reservoir tank up to the "Full" line on the tank, in the cold condition.
View attachment 2737654

Here is an illustration of the reservoir tank represented above with measurements I took using a measuring cup graduated in ml:

View attachment 2737672

So, based upon sound engineering practice and procedures performed by the engineers at Toyota Motors, the design of the reservoir tank may be deduced, as as follows:

Maximum drawdown from "Full" level is less than 1,000 ml. (Primary purpose of full reservoir is to temper the heat from hot coolant entering reservoir from normal expansion)
Maximum expansion (cold to design operating temperature) from "Full" is less than 700 ml.

Expansion beyond the 700 ml design capacity would be the result of abnormal operating conditions allowing "boilover" situation:
- Radiator not designed for A/C condenser heat load and air flow restrictions (OEM A/C systems had larger radiators than non A/C systems)
- Air trapped in cooling system

Overheating due to:
- water pump fan clipped back to avoid interference with A/C compressor
- faulty radiator cap
- restricted/plugged/damaged radiator (internal and/or external)
- improper coolant
- restricted/plugged/fouled engine water jacket or hoses
- corroded water pump impeller
- loose water pump drive belt
- missing/damaged/altered fan shroud
- high ambient temperatures


well ?

was i right or ............ 🤔


i have a fj60/62 new overflow coolant bottle

i filled with water and then poured into my compact tall and skinny bottle i offer shown above

same exact capacity ............

it is indeed a optical illusion that it appears small maybe , but that's its true gift to 40 series and 55 folks too

it is approx. the same OD oe thickness as the radiator support frame itself ..........

so its both protected and non interference designed .........

i nicked named it my " KILLER KOOL LITTLE GUY "

and he indeed is just that :cool:
 
@FES74

It's time for you to identify your findings on the cap, the A/C system, radiator and condenser fins, and anything else on the list of issues.

Thanks @73FJ40 . With all the info that I got, I should be able to determine where is the problem of my truck. Thanks again.
 
You shouldn't use a cap with a flip lever on a closed cooling system(reservoir type). They are designed to blow off steam/water when its exceedingly hot b4 opening the rad. They typically wont allow water to be sucked back into the rad during cooling.

Noted @pb4ugo. Thanks
 
Im sure someone has already said this but just in case I'll mention it. For every 1 pound of pressure in your cooling system, it raises the boiling point 3 degrees (F). So if your system has a 15 pound cap, the boiling point would be 257 degrees F. If you have a cap that wont seal, water will boil near the normal 212 degrees. Replacing the cap is probably the easiest and cheapest way to go to see if it fixes the problem.
Noted @Magnum44 . Thanks.
 
i have a OEM Radiator cap with a manual arm on it to relive pressure

is this what you refer to above ?

its a NON USA Toyota parts application for a land cruiser , buts that's all i know about this unique radiator cap manual arm on top ?
Thanks @ToyotaMatt . Yes. I bought that unique cap from Rockauto parts. It is made from Mexico.
 
None yet. I sourced out most of my FJ parts from Rockauto parts, eBay and Partsgeek.


I Offer ALL First Time MUD MEMBER Customers a special 10% off coupon Code ...fyi :cool:

i will send you a PM to further discuss ....


here are the LINKS for both your Needed Genuine NipponDenso Made In JAPAN Land Cruiser Parts .......




 
I Offer ALL First Time MUD MEMBER Customers a special 10% off coupon Code ...fyi :cool:

i will send you a PM to further discuss ....


here are the LINKS for both your Needed Genuine NipponDenso Made In JAPAN Land Cruiser Parts .......




Thanks @ToyotaMatt . Truly appreciate this.
 

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