Put my mind at ease please. Super clean E30 engine bay for your time, I have no idea how someone keeps an engine bay this clean.
A little backstory: My sons pathfinder was overheating. I replaced the thermostat. That did not fix the issue.
I was tempted to replace the water pump and the radiator, but after reading around I found that some people merely had to bleed the air out of the system so I tried that to no avail. My son sent it to a mechanic to have it diagnosed and they said it was the radiator.
I decided in my infinite wisdom to replace the radiator and the water pump while we had the radiator out, figured it would be a good time to wash out the condenser really well too.
This is the 3.5L v6 engine with a timing chain run water pump identical to the one in this video. I followed this video pretty closely but when I backed up the crank to loosen the timing chain on the water pump, the chain did not move for a small distance and then it went ‘CLICK’ and it performed just like it did in that video. Timing chain tensioner moved down and chain became tight while timing chain on water pump became slack.
I was able to remove the water pump and replace it with a new one and then move the crank back to almost where it was. I stopped when the chain on the water pump became tight and started to turn the pump.
Now my dilema: Should I be seriously worried about that click? Should I ensure that the crank is at TDC before I even try to start it? Is there anything else I should look for or check before I proceed to fill it with antifreeze and start it? I’ve put it all back together, but I’m willing to tear it all back apart if someone can give me a reason or something to double check.
Update: I turned the crank a few times and it was mostly smooth with a few stiff spots I attributed to odd hand/ratchet placement. I was skeptical but confident in my abilities.
I had my son start the car and it made an AWFUL clacking racket, so I had him immediately shut it off. At this point in time I’m feeling really awful, I knew that I had done something wrong and perhaps now he was going to need the top end rebuilt and hopefully nothing had been damaged in the block.
For whatever reason I decided to check the oil, to which I noticed it was at the add mark... Hmm, added a quart of oil, crossed my fingers and had him start it again. It was not as loud, but still making a light tapping noise. I had him shut it off again.
The noise seemed to be coming from the drivers side engine front from around the water pump or the timing chain sprocket cover. At this point I’m thinking maybe it’s that driver side front valve getting tapped or something.
After talking to a fellow Pathfinder owner at the local Nissan shop, he told me that it could be the timing chain sprocket or timing chain guides making the noise and suggested to buy a stethoscope and see if I could pinpoint the noise better. So I did, and deduced that it was coming from the sprocket area of the timing chain cover. He had mentioned that this was normally not a big deal to keep driving and since the parts were pretty expensive and the repair was basically a timing chain job plus, he had chosen not to do it on his and was still driving it.
TLDR: We started it up and took it for a test drive, it drove fine, My water pump replacment was a success! Although... it’s still overheating.
We are going to make sure we get all the air out of the system this coming weekend before doing any more parts replacements.
Some assorted musings: the old thermostat passed the drop in hot water test.... I’m wondering if the radiator and water pump were fine too and it’s either the water control valve(2nd thermostat) or it’s just got air in the system.