Ford 3.8 V6 Timing Cover Coolant Leak and Why You Should Always Prime the Oil Pump!

This Thunderbird has had a coolant leak ever since I bought it 15 years ago. I smelled coolant then and pretty much ever since. It has always had a coolant leak. No matter how many leaks I fixed, there was always one more. I think I finally found the one that never goes away.

When they made this engine, they made a mistake. Somebody thought it would be a good idea to drill the threads for the timing cover studs into the water jacket. This creates a leakage path through the threads. It also makes the studs rust.

So here's how this repair went wrong.

I got all the bolts and studs out except for the one that wouldn't turn. I put two nuts together and ran my little Makita impact driver on it to loosen it. That didn't work, so I got out the big impact wrench. I figured that'll do it. It quickly broke the stud off, flush with the timing cover.

I figured I could pry the timing cover off. I got a big crow bar and pried too hard and broke the timing cover, but exposed more of the stud, shown below.

This gave me the opportunity to waste a week soaking it with penetrating oil while attempting to unscrew it. Every try to turn the stud using tightened double nuts was a failure.

I started pulling on it. Then I wedged screw drivers in and pushed on the opposite side. Then I got out the 12 pound sledge hammer and started whacking the opposite side, trying to pry it off. My neighbor Brent came over, kind of concerned, and asked what I was doing. 

I knew he was right when he suggested just getting out the air hammer and chiseling down the timing cover to expose the stud. This thing's coming out in pieces!

After this, I was able to pry it off. 

Re-Assembly

Here's my solution to stop the eternal coolant leak. I put RTV on the threads of the new stud and installed it. I let it cure before installing the new timing cover. (It's the only stud installed in this picture.)

When aligning the camshaft position sensor, you need to set the crankshaft at 26 degrees after TDC. That's right at the edge of this slot that I'm pointing to with a ball point pen.  

My original timing cover had a much better pointer for reading timing than my new cover has. Compare the pointer in this picture to the one in the next picture.

The replacement cover just has an arrow on the surface. I'm feeling short-changed. 

I aligned the crankshaft to 26 degrees after TDC by lining up the slot with the timing mark. I installed and aligned the camshaft position sensor so that the half circle was towards the engine and the edges of the half circle were aligned in the middle of the sensor. Sorry I didn't get a picture of that. 

Why You Should ALWAYS Prime a New Oil Pump

After re-assembling everything, I started up the engine. After every oil change, there's that pause before you get oil pressure. This time, the pause didn't stop. I kept waiting for the oil pressure to build and nothing. The gauge was at zero. I took off the oil filter and started the engine. Nothing came out. 

I removed the oil pump and everything looked ok except there was no oil in it. I learned something there. Without oil in the pump, it will not create sufficient vacuum to draw the oil up from the oil pan. It will just spin and the air will blow past the vanes. You need oil to fill the gaps and create a seal. 

I figured grease would work even better, so I put grease in the oil pump and spun it to make sure everything in there was coated. 

After re-installing the oil pump, I started the engine. This time I heard a ticking noise for a second

until it got oil pressure.

This reminded me of my idea of a bypass electric oil pump. It would be nice to have an electric oil pump run to build up oil pressure before the starter is allowed to turn. 

Was everything good after I got it all back together? Of course not. The water pump went bad and I had to replace it too.