Overheating 40 (1 Viewer)

[efmb15cmb]

My 1979 40 runs perfect temper on surface streets for hours. But after a few miles on the freeway at 50 to 55 the temp gage goes all to hot. I get off and take surface streets again it cools down and runs at normal temp again. I have replaced the radiator, thermostat, water pump,fan clutch, and flushed the system. Any other suggestions?

 

[Pura Vida]

Head gasket? Idk. Weird issue

 

[LandCrusher'70]

Sounds like it is getting hot at higher RPMs, yes?
Maybe you are running lean?

 

[Living in the Past]

Are you running the stock 2F engine?

Did you do all these things after you started having overheating problem?

Did make sure all the air is out of the system?

Is the problem now that worse since the temperature have hit a hundred degrees in Phoenix? I avoid my home in the valley once the temperatures get close to hundred.

 

[1911]

Also make sure the vacuum advance on your distributor is working. Retarded timing will make an engine heat up fast.

 

[efmb15cmb]

Are you running the stock 2F engine?

Did you do all these things after you started having overheating problem?

Did make sure all the air is out of the system?

Is the problem now that worse since the temperature have hit a hundred degrees in Phoenix? I avoid my home in the valley once the temperatures get close to hundred.

Yes vehicle is stock, did all this prior to getting it on the road, yes burped the system, act the same at 100 or 70 degrees.

 

[efmb15cmb]

Also make sure the vacuum advance on your distributor is working. Retarded timing will make an engine heat up

Also make sure the vacuum advance on your distributor is working. Retarded timing will make an engine heat up fast.

Do you know which tube on the carburetor the vacuum advance goes on? Also running an electric distributor

 

[1911]

Do you know which tube on the carburetor the vacuum advance goes on? Also running an electric distributor

Here is a page from the 1979 emissions manual that shows which one for a '79 (look in the corner that I circled in red). In any event, it will be one of the lowest ones at the base of the carb.

The stock Toyota electronic distributors are all vacuum advance. Frequently, the vacuum advance units become corroded/rusted from ozone generated by the dizzy and cease functioning; hence the reason I said to check your vacuum advance for proper function as per the factory service manual in the tune-up section near the front of the book.

 

[KimoTheBJ40]

I actually have the same problem with my 79 BJ40. Except I have not replaced anything. When mine does it I find my overflow tank full and coolant has sprayed about in the engine bay. Got a new radiator cap on order

 

[efmb15cmb]

I will look tonight to see if I have a hose going to the distributor. Thanks for the reply

 

[kurtnkegger]

I had very similar problems with mine. When I replaced my airfilter, it started behaving...

 

[Clifton Bennett]

I had very similar problems with mine. When I replaced my airfilter, it started behaving...

Wish it was that easy.

 

[igotta40]

My 1979 40 runs perfect temper on surface streets for hours. But after a few miles on the freeway at 50 to 55 the temp gage goes all to hot. I get off and take surface streets again it cools down and runs at normal temp again. I have replaced the radiator, thermostat, water pump,fan clutch, and flushed the system. Any other suggestions?

I’m dealing with the same thing right now. I found a very small tear in the lower radiator hose. Barely leaking any water, but apparently enough to cause the problem. I’m just guessing, but maybe the leak is letting the pressure escape?

 

[Mark W]

Based on these symptoms, a failing (clogged) catalytic converter is high on the list of probabilities. #1 spot in my mind right at the moment.

Mark...