Original thread here
So I bought a Mustang about 3 months ago that, as I came to find out, burned about 1 quart/1k miles. This annoyed me so I switched to MaxLife to try to slow down the consumption and ended up turning it into a smoker. It did not smoke at startup, but after taking some video and having my wife drive behind me, we found out that it only smoked when taking off from a light or revving it in neutral after idling for a while, so I guessed (well, more like hoped and prayed) that it was just bad valve seals.
So during the week between Chistmas and New Years, I took the valve covers off and using an overpriced special tool, was able to compress the springs and replace the seals with the cams still on the car. I used a compression tester with a quick-connect on it and my air compressor to hold the valves shut while I worked; this, combined with the fact that I could lock the engine in place by putting it in gear, meant that I didn't have to worry too much about finding TDC for each cylinder, rather I could just rotate the engine until the cam lobes were out of the way, put it in gear, apply air, and proceed.
The hardest part of the whole job was prying out the old seals. The directions I had found online said to use an angled set of needle nose pliers, but there was no room for them on the rear 2 cylinders of each bank. The write-up was for a Town Car, whose engine bay is surely bigger, so that might have worked for them, but not for me. I was able to get them all out by prying on them with different sized screwdrivers, using the head or whatever else I could find for leverage.
Before I started, I bought a bag of 8 extra keepers, but I didn't end up needing any. I was able to get them off very easily with a magnetic pick up tool from Harbor Freight, and put them back on with a combination of a magnetic screwdriver and a tube of red tacky grease.
The seals I took off were very dark brown and had hardened to a consistency closer to plastic than rubber. I could squeeze them with great effort, but they did not return to their original round shape once I did so. No doubt they were not sealing properly.
It's also a good thing I bought new valve cover gaskets before starting the job because they literally fell apart when I removed the valve covers. I knew they were leaking, but didn't know they were that bad.
I started it up for the first time, drove it until it was good and warmed up, then let it idle and revved it and there was absolutely no smoke. I've driven about 500 miles since then, and the oil level has not moved from the full mark on the dipstick. Before, it would have been about halfway down by now. I think I can safely consider this fixed!
As an aside, I read numerous posts about this happening on older (early to mid '90s) 4.6 engines due to a defect, but I thought it had been fixed by 2000. I wonder why mine failed?
So I bought a Mustang about 3 months ago that, as I came to find out, burned about 1 quart/1k miles. This annoyed me so I switched to MaxLife to try to slow down the consumption and ended up turning it into a smoker. It did not smoke at startup, but after taking some video and having my wife drive behind me, we found out that it only smoked when taking off from a light or revving it in neutral after idling for a while, so I guessed (well, more like hoped and prayed) that it was just bad valve seals.
So during the week between Chistmas and New Years, I took the valve covers off and using an overpriced special tool, was able to compress the springs and replace the seals with the cams still on the car. I used a compression tester with a quick-connect on it and my air compressor to hold the valves shut while I worked; this, combined with the fact that I could lock the engine in place by putting it in gear, meant that I didn't have to worry too much about finding TDC for each cylinder, rather I could just rotate the engine until the cam lobes were out of the way, put it in gear, apply air, and proceed.
The hardest part of the whole job was prying out the old seals. The directions I had found online said to use an angled set of needle nose pliers, but there was no room for them on the rear 2 cylinders of each bank. The write-up was for a Town Car, whose engine bay is surely bigger, so that might have worked for them, but not for me. I was able to get them all out by prying on them with different sized screwdrivers, using the head or whatever else I could find for leverage.
Before I started, I bought a bag of 8 extra keepers, but I didn't end up needing any. I was able to get them off very easily with a magnetic pick up tool from Harbor Freight, and put them back on with a combination of a magnetic screwdriver and a tube of red tacky grease.
The seals I took off were very dark brown and had hardened to a consistency closer to plastic than rubber. I could squeeze them with great effort, but they did not return to their original round shape once I did so. No doubt they were not sealing properly.
It's also a good thing I bought new valve cover gaskets before starting the job because they literally fell apart when I removed the valve covers. I knew they were leaking, but didn't know they were that bad.
I started it up for the first time, drove it until it was good and warmed up, then let it idle and revved it and there was absolutely no smoke. I've driven about 500 miles since then, and the oil level has not moved from the full mark on the dipstick. Before, it would have been about halfway down by now. I think I can safely consider this fixed!
As an aside, I read numerous posts about this happening on older (early to mid '90s) 4.6 engines due to a defect, but I thought it had been fixed by 2000. I wonder why mine failed?
