Unusual coolant leak on 1993 7.3 IDI factory turbo

[jj339629]

I have a 1993, 7.3 IDI factory turbo. It’s winter here in Wyoming and I only drive my truck on the weekends.

I noticed that midweek and midday when I’m not driving my truck it has started to drip coolant from above the starter. I can’t tell where it’s coming from. One guess I have is the block heater. Any other idea or places I should look?

 

[jj339629]

No leak when hot, no leak at the peak of cold like middle of the night. It only happens when it’s cold and the day warms up some and the truck is not being driven.

 

[ihc1470]

Best bet would be to put a cooling system pressure tester on the radiator and pump it up to 15 pounds and start looking. Might be able to borrow one from a parts store if you do not want to buy one.

Yes it could be the block heater. There are some soft plugs in that area also along with the block drain. Could also be running down from higher up on the engine maybe from head gasket.

 

[FrozenMerc]

It is probably leaking from the back corner where the intake manifold mates to the cylinder head. There is a coolant port that is blocked off by the intake manifold and gasket. However, the manifold is kind of cantilevered out in that area, and there is only one bolt providing the clamping, and it is susceptible to leaking. When a leak occurs, the coolant runs into the valley pan, out the back of the motor and down past the starter. Check up top, and work your way down.

 

[jj339629]

It is probably leaking from the back corner where the intake manifold mates to the cylinder head. There is a coolant port that is blocked off by the intake manifold and gasket. However, the manifold is kind of cantilevered out in that area, and there is only one bolt providing the clamping, and it is susceptible to leaking. When a leak occurs, the coolant runs into the valley pan, out the back of the motor and down past the starter. Check up top, and work your way down.

I’ll post some pictures today. Is that a head gasket job?

 

[KansasIDI]

It is probably leaking from the back corner where the intake manifold mates to the cylinder head. There is a coolant port that is blocked off by the intake manifold and gasket. However, the manifold is kind of cantilevered out in that area, and there is only one bolt providing the clamping, and it is susceptible to leaking. When a leak occurs, the coolant runs into the valley pan, out the back of the motor and down past the starter. Check up top, and work your way down.

That is only on 6.9 engines. 7.3 engines have steel plugs that block off coolant from ever reaching the intake manifold. Unless one of those plugs was missing, this couldn’t be possible. My bet is external headgasket leak, somewhat common on 7.3s.

 

[IDIBRONCO]

Is that a head gasket job?

No it isn't. You'd have to remove the injector pump, the intake manifold, and then the valley pan. Of course, it would be more complicated for since you have a turbo. That's why you'll have to determine where it's leaking from first.

 

[jj339629]

Update with a few pictures from today: any better leads from this or any idea how I can try and track it down better?

You must be registered for see images attach

 

[jj339629]

It only does it when I’m not driving and the day begins to get warm and the sunlight warms the truck up.

 

[KansasIDI]

No it isn't. You'd have to remove the injector pump, the intake manifold, and then the valley pan. Of course, it would be more complicated for since you have a turbo. That's why you'll have to determine where it's leaking from first.

I did all that today, to replace lifters. Had to remove my intake hat and turbo drain tube, on my Hypermax equipped 7.3. No other turbo parts had to be removed.

 

[Black dawg]

Have you looked at where the heater hose goes to the left head?

 

[Black dawg]

I mean right head............

 

[jj339629]

Yes. Bone dry there.

How do I track a coolant leak from top down?

 

[ihc1470]

If I was doing the looking the first thing I would do is hose off the engine. Let it dry and then pressure test without running so the fan would not be blowing anything around.

If nothing shows up given a reasonable length of time then I would plug in the block heater so you get a temp change within the cooling system.

Starting with the engine dry you should be able to detect where the leak is coming from.

 

[IDIBRONCO]

How do I track a coolant leak from top down?

They also make a dye that you can put in your cooling system to help find leaks. You will have to run the engine and then shine a UV light all over to see where the leak is at. There's more to it than what I said, but it's the short version.