I have seen too many people destroy their beloved Sentra's engine, many without even knowing it. Here are a few tips to know "when to say when".
1. If for any reason, you lose power, and hear the engine pinging away, that means it is HOT! Confirm your suspicions with a look at the temp gauge. Turn it off immediately. Find out why it overheated. Or keep going and destroy your engine. The choice is yours.
2. If you notice the car had developed a miss, or even worse, it sounds like it is knocking when accellerating, again pull off to the side and find out why. This happened to me once. I was driving an '87 B12 hatchback [not a sport coupe]. My E16S started doing what I just described. The key is to recognize the knocking. I knew that this meant my headgasket had blown between two cylinders. Coolant temp was fine, so I pulled over, and yanked one spark plug wire at a time, to find out which two cylinders were not firing. It was #3 and #4. This told me that the knocking noise was from combustion in #3 was bridging the gap to #4 and trying to push piston #4 DOWN, while it was trying to come UP. That's what the knocking sound was from. Simply pull the #3 and #4 spark plug leads off, and leave them off. This prevents the engine from further damage while you are limping it home. If you drive it this way, you must realize that you only have 50% of the 70 hp that you should have. But you can get home without 'fireslotting" the head or block. Another engine saved........
3. Fix those leaky front crank seals and oil pressure sending switches. Or if you live in the salt belt [like I do] your oil pan can actually be rusted through [pinholes, usually above ex. pipe]. If you are one of the people who never bothers to check the oil, this will catch up with you one day. If you are really low on oil, you will notice the oil light flashing on and off, as you go around sharp turns. That's the last warning you'll get, before you weld your crankshaft to your rods.
4. If your E-engine has a valve tap that just keeps getting louder, adjust the valves right away. It might only need a routine valve adjustment. Or, it might be the start of something worse. Like rocker shaft bolts that are loosening up! I have replaced many broken rocker shafts because of this. On each end bolt, of the rocker shaft assy, there should be a little metal locking clip, to make sure the bolts don't back out. I have seen too many of these missing on people's engines. Seems some "mechanics" don't bother to put them back when they're in there doing a head gasket job. Later, the shaft bolts loosen and leave you stranded.
In closing, let me leave you with this pearl of wisdom: If you are on a highway somewhere, miles from an exit, and your engine is overheating, or out of oil, you have two choices.
A. You can shut it off and get a tow, for an inexpensive repair.
B. Keep going to try to "make it" to the next exit, and still end up needing a tow, but have gotten maybe 4 miles further, but have a very expensive engine replacement ahead of you!
I hope this helps save some of our bread and butter E16's!
