Head Removal

[Ed Hall]

How do I remove the head on the firewall side on my 88 Eldorado w/ 4.5 engine? Can it be removed with the engine in place or does it need to be tilted?

Here's the problem. I bought the car with 170k miles and it had a rough idle. I now have 217k miles and the idle has degraded some (maybe 20%). It has used water in the past but I added more bars leak and it stopped using water for almost a year. It is now using water again. Yes, I did a pressure test and no water is leaking onto the ground. I change the oil regularly and see no evidence of water intrusion. Another thing, if I'm in a traffic jam and I idle the engine for a significant time, I get an intoxicating exhaust smell, once the traffic starts moving again, I get a cloud of white smoke. Also, at idle, I can smell unburned fuel out of the exhaust. Once the engine gets above 800 rpm, it runs smooth again. Oil consumption is 1 qt for every 3k miles. I did try unhooking one spark plug wire at a time and identified the cylinder that is not firing. I removed that spark plug and it is clean. I also checked the gap on that spark plug.

Does it sound like a headgasket leak or a valve?

[KHE]

I recall the guru saying that headgasket failures on the 4.x engines were very rare. The intake gaskets would fail before a head gasket. Maybe the intake gasket has let go on your 4.5???

[Ranger]

A white cloud and an unburnt fuel smell from the exhaust indicated an overly rich fuel condition. I'd do a cylinder pressure test to confirm or rule out head gaskets. It will also confirm or rule out valves.

[Ed Hall]

I bought a compression tester but the threads on the adapter don't extend far enough to screw into the spark plug holes.

[Cadillac Jim]

A good auto parts store will have an extender.

[Ed Hall]

I bought a cylinder leakage tester that had the adapter I needed.

Whew, it was a job getting the compression measurements on that firewall side. I got too tired and did not do the other side. I'll have to wait for another day for that. Here are the results:

125

150

150

150

I added some oil to the cylinder that got 125 and it went up just a hair to maybe 130. When I started the engine, the engine made clicking noises like a bled down lifter. I think it was from the cylinder that I added the oil to. I drove around the block then it went away. It still idles rough though.

Forgot to add: The cylinder that made 125 psi was not the cylinder that I thought was not firing. There are 8 cylinders and it is very hard to tell which one is not firing by performing the remove one spark plug wire at a time test.

[Ranger]

Ed,

A compression test will not tell you if there is a bad head gasket. You have to do a cylinder pressure test by turning the crank to get each cylinder to TDC (compression stroke) then pump air from a compressor into it and watch for bubbles in the coolant tank.

[Ed Hall]

I have some good news. When I was doing the compression test, 2 of the spark plugs were leaking slightly due to undertightening. The engine is now idling just like when I bought it at 170k miles. It is still slightly rough but better than it was. I can't really do anything too major on this car so I'm just going add more bars leak and hope for the best. I really like this car and have yet to drive a car that is as comfortable. Someone let me drive their new Acura MDX. It was nice but not nearly as comfortable to drive as my old Eldorado. The seats were hard, steering overly heavy and the transmission shifted rough from 1st to 2nd gear.