HT4100 4.1, 4.5, 4.9 Discussion, Cooling Problems in Cadillac Engine Technical Discussion; bbobynski;
Thanks for the tips. I think my cooling problem was a false full level in the radiator. This car ...
Thanks for the tips. I think my cooling problem was a false full level in the radiator. This car needs two people to top off the radiator - One to pour coolant while another revs the engine to 1500 rpm. Will know for sure this summer in Houston.
Next problem - it doesn't pass emissions inspection. First it failed for hydrocarbons and NOX. I put on a catalytic converter. Now it fails only NOX. O2 sensor shows proper voltage on the computer readout. I banged on the EGR valve with a hammer (like it says in the manual) and plugged the vacuum line from the air cleaner into it - it killed the engine immediately - so I don't think it is stuck. Can't reach the bolts to take it out - need a double-jointed knuckle wrench.
I can't detect a vacuum coming from the EGR vacuum solenoid switch. This switch is a $150 item. I checked it after the engine was heated up, many times. Never pulled a vacuum. The vacuum line between the switch and the EGR valve did have splits in it, I replaced the line, but I would feel more confident if I knew the switch was doing its job.
I tried the "Guaranteed to Pass" additive - it failed.
Might need a tune-up, but it runs real smooth. What is the trick to getting to that back row of spark plugs on the sideways engine?