fj40 overheat at idle .. every thing checked (2 Viewers)

[shahab]

That's strange then. Are your Air:Fuel ratios in order?

my carb is new ...

 

[shahab]

Avoid sitting at idle in traffic.

If you are forced to idle in traffic do these two things: 1) raise the engine RPM to increase airflow across the radiator for the duration of your traffic. 2) turn off the air conditioning.

There is nothing wrong with the truck other than it was not designed with the possibility of prolonged traffic stoppages a factor of it's design usage.

Consider a newer vehicle designed after such realities became common factors of it's potential usage.

my freind have an fj40 with aftermarket a/c
but he have not this problem ...

if I turn off my a/c in traffic . nothing diffrence

 

[Steamer]

Was the engine block boiled out when the rebuild was done? If not, then you could have some deposit build up in there. Remember when doing a cooling system flush and the rinse water comes out crystal clear it doesn't necessarily mean it's clean in there. It only means there's no more crud left that will come loose.

 

[RAYJON]

You have done all the normal stuff and sounds like you addressed all the normal causes.

my guess.... cracked head??? did you do a combustion gas test on the coolant?? there are little tabs you can put in the antifreeze to test for co2, changes color to indicate blown head gasket or cracked head..


this is a band aid fix but alot of the off road guys run them over here..

What's better than a Ford Taurus fan? A taurus fan from a better application... - Page 4 - Pirate4x4.Com : 4x4 and Off-Road Forum

ford/volvo fans move about 4500cfm on high.

the fan moves a lot of air, just be sure to run a modern alternator that puts out over 30amps at idle...

 

[JohnnyC]

had you burped the system? to me sounds like you got air in there

do you have an overflow tank?

pics of the radiator .... shroud.... engine compartment on the side with coolant lines

 

[Tools R Us]

Are both thermostat gaskets installed? If the upper is overlooked, some coolant will bypass the radiator, causing inconsistent cooling.

 

[shahab]

I taked some picture .. from my engine .

I hope this picture help you to find my problem ...


I was build my engine head 6 month ago ..

and shave a bit of head ... (very very little .)

my temp gauge drop down when I am in highway ..
and will climb up when in idle ..


with out a/c temp gauge climb up to 90c if I still idle for a long time (with out thermostat) in normal weather (about 30 c)

I did remove thermostat and block bypass hose ..

I did block heater hoses to .. (for test)

there is not enough space to use electric fan ( I can find slim electric fan )


if I cant solve problem ..
I will remove a/c condenser and test a engine heat ..


I am so confused ..

I ask him why ?
where is the problem ..

why ?

 

[shahab]

*sorry my temp gauge climb to 100c (long time idle )*

I think my engine temp increment is fast ...

 

[shahab]

had you burped the system? to me sounds like you got air in there

do you have an overflow tank?

pics of the radiator .... shroud.... engine compartment on the side with coolant lines

hi .
how can I burp the system ?

I have an overflow tank .

 

[Jerry D.]

Did the heating problem appear soon after you had the engine rebuilt, or develop after a month or so???

Is it possible the head gasket was installed backwards, and you are not getting any oiling to the top causing the heat issue at idle?

I know one friend went as far as putting in electrical fans trying to fix a heating problem, and later found the head gasket was not in correctly. Changed head gasket, went to stock fan, no problems.


Jerry D.

 

[Output Shaft]

my temp gauge drop down when I am in highway ..
and will climb up when in idle

There is not enough air flowing past the radiator when you are idling and the coolant isn't circulating fast enough. Also all cars' coolant heats up from heat soak after driving fast then suddenly idling. As mentioned previously, idle speed needs to be raised if idling on a hot day in traffic after driving at speed.

Also as mentioned, if air is still trapped somewhere in the head from a recent coolant change, the temp gauge can show hot at idle for up to 2 weeks.

I don't think there is anything "wrong".

 

[Dynosoar]

Look in the 80 series section for info about changing the fan clutch fluid to some super duper keep your truck cool stuff.

Dyno

 

[RAYJON]

That pix looks like a clutch fan,

If it has a clutch fan the fan clutch may just be bad.

 

[sggoat]

hi .
how can I burp the system ?

I have an overflow tank .

You MIGHT have an issue with air in the system, but, if so, you should see overheat at all engine loads, not just at idle(in fact - idle will be down to normal). I would suggest a compression check on all cylinders to make sure the head gasket is ok.

 

[shahab]

Did the heating problem appear soon after you had the engine rebuilt, or develop after a month or so???

Is it possible the head gasket was installed backwards, and you are not getting any oiling to the top causing the heat issue at idle?

I know one friend went as far as putting in electrical fans trying to fix a heating problem, and later found the head gasket was not in correctly. Changed head gasket, went to stock fan, no problems.


Jerry D.

hi
1- I had this problem before rebuild my engine too .
2- head gasket is OK ( I'm sure)

 

[shahab]

There is not enough air flowing past the radiator when you are idling and the coolant isn't circulating fast enough. Also all cars' coolant heats up from heat soak after driving fast then suddenly idling. As mentioned previously, idle speed needs to be raised if idling on a hot day in traffic after driving at speed.

Also as mentioned, if air is still trapped somewhere in the head from a recent coolant change, the temp gauge can show hot at idle for up to 2 weeks.

I don't think there is anything "wrong".

hi .
I know this fact ..
but I think my engine is heater than other cars when in idle ...

my friend car temp is about 70c when idle ..

but me ...

 

[honk]

hi .
I know this fact .. my friend car temp is about 70c when idle .. but me ...

.... Karma.

 

[srgould41]

Like some others have said it seems like not enough air flow at idle. I had that same problem. At idle I could stand in front with my hand in front of the grill and feel no air moving. Try that at idle, can you feel any air flow? If you put your hand in front of the radiator and have someone raise the engine speed can you feel air moving?

It may be the fan clutch, too much gap between the the fan blades and shroud, water pump not pushing enough fluid through at idle, or other causes. A 4 row aluminum radiator may help if you can find one. Running the carb a little more rich could help. You might even need to switch to an electric fan.

 

[sggoat]

There is not enough air flowing past the radiator when you are idling and the coolant isn't circulating fast enough. Also all cars' coolant heats up from heat soak after driving fast then suddenly idling. As mentioned previously, idle speed needs to be raised if idling on a hot day in traffic after driving at speed.

Also as mentioned, if air is still trapped somewhere in the head from a recent coolant change, the temp gauge can show hot at idle for up to 2 weeks.

I don't think there is anything "wrong".

You may be right about this--My 77 has the orig rad(cleaned) It has headers, and a weber carb. It does not have A/C. I can drive the truck for an hour or so at 60 mph,-the temp runs at ~ 195 deg. F. If I slow down for a traffic light and sit at idle for several minutes, the temp drops to ~190 deg. F--it will sit there at this temp pretty much all day, at idle(well maybe not all day-haven't done this) but it will sit for over an hour while the valves are being adjusted, and the temp actually drops down to 185 deg. F. I'm in Fl. and the ambient temp when the adj was made was 89 deg. F.
Seems like this issue may be related to total air flow thru the rad(as others have posted)
As the poster has said the A/C on or off does not seem to make a difference, I would guess the condenser in front of the Rad is causing the reduced airflow, or the fan is not up to moving enough air(the pic of the fan blades indicate they are a little beat--up)
Do the test srgould41 suggests

 

[srgould41]

I remember after installing the electric fan and feeling the air race past my hand versus no flow from the mechanical fan. It was an amazing difference. I am not saying you need an electric fan, but the airflow issue seems very logical.

You may be right about this--My 77 has the orig rad(cleaned) It has headers, and a weber carb. It does not have A/C. I can drive the truck for an hour or so at 60 mph,-the temp runs at ~ 195 deg. F. If I slow down for a traffic light and sit at idle for several minutes, the temp drops to ~190 deg. F--it will sit there at this temp pretty much all day, at idle(well maybe not all day-haven't done this) but it will sit for over an hour while the valves are being adjusted, and the temp actually drops down to 185 deg. F. I'm in Fl. and the ambient temp when the adj was made was 89 deg. F.
Seems like this issue may be related to total air flow thru the rad(as others have posted)
As the poster has said the A/C on or off does not seem to make a difference, I would guess the condenser in front of the Rad is causing the reduced airflow, or the fan is not up to moving enough air(the pic of the fan blades indicate they are a little beat--up)
Do the test srgould41 suggests