'94 coolant leak at oil cooler line.

[name]

Hi Guys,

I just replaced my antifreeze and thermostat at the the beginning of the winter and now I am noticing a coolant leak in the area of the upper radiator hose / oil line area on the radiator. How common of a problem is this and would replacing the new thermostat without the little valve in it cause this ? ( the old thermostat had one )

I can not see any cracks in the radiator but the coolant looked like it was coming from above the stamped nut on the upper oil line fitting. Is this oil line fitting a common point of coolant leaking and if this is my problem can it be fixed. ( I took the stamped nut off thinking there would be a rubber o-ring or something behind it, but there was nothing )

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[Caman96]

Original radiator? Might just be that time to replace.

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[Schurkey]

I see evidence of leakage from the cooler fitting. I don't see evidence of leakage from the radiator hose flange.

You "could" take the radiator to a radiator shop and have them inspect, clean, and repair. Radiator shops are getting hard-to-find. Cheap-junk Chinese radiators have killed-off a lot of their business.

Or...think about how many miles/years are on that rad, and maybe choose to replace it.

Or...spin that stamped nut back on the cooler fitting tighter than it was when you took it off, and see what happens.

WHAT ENGINE IS THIS, and are you sure you installed the correct thermostat? Sounds to me like you got the wrong one. No, that would not cause a leak at the cooler port.

 

[GoToGuy]

In the second photo, it looks like the residue trail, the white outline, originates from the upper fitting. Either a cracked hose fitting or loose hose clamp. If you could not identify exactly which was leaking, I would have cleaned both then drove a normal period to identify.
Good luck.

 

[name]

I see evidence of leakage from the cooler fitting. I don't see evidence of leakage from the radiator hose flange.

You "could" take the radiator to a radiator shop and have them inspect, clean, and repair. Radiator shops are getting hard-to-find. Cheap-junk Chinese radiators have killed-off a lot of their business.

Or...think about how many miles/years are on that rad, and maybe choose to replace it.

Or...spin that stamped nut back on the cooler fitting tighter than it was when you took it off, and see what happens.

WHAT ENGINE IS THIS, and are you sure you installed the correct thermostat? Sounds to me like you got the wrong one. No, that would not cause a leak at the cooler port.

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Old thermostat on left with valve , new thermostat on right. The new thermostat part number is 15359 from Auto Zone, this is what they said fit it but they could be wrong.

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We are dealing with a 1994 K 1500 GMC Suburban with the 5.7L , The radiator looks original as best as I can tell, the Suburban has 160,000 original miles, there are no longer any radiator shops left in my area.


I pulled the vaccum can so I could get a small pipe wrench on that stamped nut and tightend it to the point where I dare not go any further, I also but some black RTV sealer around the radiator hose neck and rotated the hose clamp to where it would tighten down in a different area. I also replaced the black rubber o-ring on the oil line with a #8 o-ring
( not sure if this is the correct size ) and left it sit for 18 hrs.

I then ran the Suburban at idle for 45 min. and so far it did not leak , I will try to get it on a short road trip to see if it Holds up to normal driving. At this point I am not 100% sure where the leak was actually coming from but " Go To Guy " is probably correct with it being the oil cooler line.

If it keeps on leaking and I can confirm it is from the oil cooler line , would I gain anything by trying a rubber o-ring behind the stamped nut ?

 

[Schurkey]

No. The O-ring would be on the wrong side of the actual coolant leakage which is internal to the rad tank. Probably just get squeezed-out since there's no groove to retain it.

Does a '94 use a rubber seal on the thermostat, or the usual, old-fashioned gasket?

 

[Hipster]

I ended up replacing my rad for something similar. It was leaking where the cooler line protrudes through the tank. Whatever seals the fitting to the inside of the tank let loose and was letting coolant weep out.

 

[udidwht]

https://irontite.com/p/8197-all-weather-seal-pint/v/8197

 

[name]

Does a '94 use a rubber seal on the thermostat, or the usual, old-fashioned gasket?

I put the thermostat in last fall so I am not 100% sure, But I think I did use the rubber gasket.

 

[name]

https://irontite.com/p/8197-all-weather-seal-pint/v/8197

How does this product compair to Bars stop leak, have never see it before .