Squeaky Belt on Cold Start, Worse After Shop Visit [FIXED - tightened belt]

[Alibireason]

The story goes I had a shop replace my knock sensor on a 1998 Pathfinder. I told front desk as well as mechanic that I had a very short squeak from drive belt (not sure which one) but only on a cold start, she noted it for the mechanic in her notes. It never squeaked except for that moment and squeak lasted less than 1 second. When I checked out with the front desk, they were super busy and mechanic seemed indifferent, just gave key to me and left. Note that this shop had replaced timing belt/water pump in late 2019, and were the last to work in that are of engine.
Cut to next morning when I start my car and squeak is still present, but instead of less than a second of squeal that seemed very minor, the squeal lasted 5 or 6 seconds. Next morning I have a friend turn it over 3 times in a row and each time is the loooong squeak but I couldn't determine from which belt or side.

How should I go about handling this situation? They didn't address the problem as I had requested. And the issue I discussed is now significantly worse. Should I go to another shop for a second opinion, or go in and be calm and ask them to inspect? They didn't care in the first place about the squeal that could be from the timing belt work they did. Could it just be a HUGE coincidence? Any info on how to proceed in the best manner is highly appreciated.

Also, they called mid-repair and said they had a hiccup. When they had the upper plenum back on and turned the car on, coolant started leaking from a tiny dark metal tube that is on the plenum directly to the lower left of the EGR valve, (a drip every two seconds). Mechanic said it was already leaking ( it wasn't), and that I would need to find a new upper intake manifold from the junkyard to fix the leak. When I picked up vehicle mechanic said first attempt at sealing it didn't work, and had applied JB weld. The JB weld is currently working but I cant help but wonder that it was an unfortunate accident on their part and were unwilling to admit it. Or is this just the risk of working on a 23 year old vehicle?
Should I just give up this shop and find a new one? If it is their responsibility to address these issues how should I go about it, without being rude.

Thanks for reading....so frustrated trying to find directness and honesty in this industry.

[04pathse]

As far as the squeal, check to make sure the belts are tight if they are loose they will squeal for sure.

They need to be pretty tight with minimal movement I think around 1/8" of up and down movement.

There are also a few youtube videos on youtube

[Alibireason]

04pathse, thanks for the reply.
I've tugged on all of them and all feel tight enough. I watched some videos and found how to loosen and tighten the pulleys for when or if I may need to do that. That is why I specifically asking the shop to check, for I have no reference experience. I read it could be the bearing in the pulleys themselves going out. Having had the timing belt replaced at this shop where the idler and timing pulleys were replaced as well, was hoping shop would double check their work. I never have the squeak except for cold starts, and now it is significantly worse since they did work on it.

[QX4ME]

I had belt squeaking on my two cars years ago, very infrequent. It was just a few seconds after engine started. I applied a little belt dressing just enough to stop the squeak. Many people say belt dressing is a temporary fix, but in my two or three times of experience it was nearly a permanent fix; squeak didn't come back.

[Alibireason]

Such conflicting info about that belt conditioner, even Scotty Kilner saying it could damage surrounding electronics if not careful while applying it. Even cashier at parts store told me it was a bad idea.
Did you know which belt it was before you applied it, or did you spray them all? Will just a dab do me, or should I soak them in it?

[QX4ME]

It’s been so long ago I don’t remember what brand I used. I only applied a little and squeak stopped. I will look for the bottle after work and post it back.

[QX4ME]

Do not soak the belt, it only needs very little.

[QX4ME]

Sorry you asked what belt before I sprayed belt conditioner. At least one time was on the factory original belt.

[Alibireason]

I appreciate the help! I may have fixed it. Last night I loosened the nut on the pully situated behind the radiator fan (passengerish side) by a half turn, and tightened the bolt above it about 3 or 4 full turns, and tightened the pully nut back up. This morning it started with NO squeak whatsoever. I may have gotten lucky, but time will tell. There is only a small amount of give when I pull on the belt.

[QX4ME]

Great to hear you fixed it. After my QX4 had a new belt put on, it had some squeaks. I went back to this mechanic and he tightened the belt a bit. Never had any squeak for about six years till today.