Chevrolet Repair: 4.3L 1991 C1500 Oil leak above the oil filter, mid line, oil leak


Question
There is an oil leak from a housing that the oil filter attaches to. This housing attaches to the engine block by a couple of bolts between the block and the oil filter. What is this housing called and is it repairable (it looks like it leaks from some sort of plug)? Can this housing be taken off and the oil filter attached directly to the engine block?

Answer
Hi Dennis,

This is the oil cooler lines.  I have never removed this housing, but I have dealt with this type of leak.  You have to decide if you want to eliminate this system or repair it.  The rest of this answer is cut and paste from another I answered prior.  That is why it may read oddly.

To eliminate, you must disconnect the line from the radiator.  Easy.  Then from the motor.  Holy-Moly.  This is bad especially if you have to move one to access the other.  You will only get an 1/8 turn at a time, and the fitting will fight the whole way out.  Then you have to disconnect a hold down at the frame, right where you can barely see the screw…forget accessing it.  Once this is all out, you now will fight the fitting to start to thread at the motor.  Once it does, you will fight it all the way in…1/8 turn at a time.  Sometimes, this is easiest if you are able to lift the motor a bit.  Not always.

Now for my advice.  ELIMINATE IT!  Do you know what this line is for?  It is to keep the oil cool in extreme conditions.  Most trucks don’t have this line.  If the oil gets too hot, it will break down and be like water.  Extreme conditions are heavy-heavy trailering or hauling, often.  Off-road driving or mud bogging.  Mostly uphill driving, like mountains, over 45 degree angle, often.  Lets just say, most people don’t need to worry about this cooler line.  

To keep the line:  If the leak is mid-line, you can cut the line at the motor and the radiator, leaving a 2” or so extension.  Then buy a rubber hose and some clamps.  Slip the hose over the extensions and clamp them in place.  Then return the new line.  This is not high pressure.  40 psi most cases.  Use wire ties (the zip kind) to attach the new hose to the old one, to hold it in place.  

To Eliminate the line:  
You can cut the lines at the motor, put a socket over the fittings and remove them.  Then replace them with pipe plugs.  Probably metric, take the old fittings to size them up.  That is it.  

Or you can cut the lines leaving the 2” extensions, then attach a hose, connecting them together.  This could leak eventually.  

Hope this helps.

C J S