Weird noise

I have a 1995 bonneville sse with a 156000 miles on it, i recently had the plenum replaced because the egr port went out on it and leaked coolant in, now what im worried about is my oil pressure and this weird squeeking noise when my engine gets hot. before the plenum was changed i always noticed the hotter the engine was the oil pressure dropped a little bit when it was idling, but now it seems to drop a little bit more the light hasnt dinged at me yet, at first i thought it was just because i switched to the synthetic amsoil stuff thats supposed to last 10,000 miles (by the way what do you guys think of this stuff?) but that might not have anything to do with it, ive also noticed that the car squeeks (its weird to explain how it sounds) from the passenger side, im thinking one of the pulleys bearings are bad? it doesnt do it constantly though, it squeeks once like every 20 seconds

I have used Amsoil before, expensive but probably one of the best synthetics out there. It has been out for a lot longer than any of the synthetics now available. As for the squeak check the tensioner pulley for the serpentine belt. If the bearing gets dry they will squeak. Usually you have to replace it to get the noise to go away.

Thanks, we figured it was one of the pulleys ill have to check them, better to be safe then sorry down the road since my plenum just went out and that was a major problem

If all the pulleys check out,check the two o-rings on the PCV/MAP sensor housing. One is around the top of the housing, the other on the PCV valve itself. If one or both are missing, it will cause a vacuum leak that will sound like a whistle or squeak.

Alright so i took the car out of town this weekend and with the oil pressure thing i mentioned earlier the car now drops into the red when the engine gets hot, not deep into the red but enough to set the check gauges light off, im wondering if my oil pump is going bad although when you give it gas it pops right back to 40 which then makes me think it isnt the oil pump. i have that amsoil stuff in and i have heard that switching to synthetic is bad for high mileage cars, also i put 5w-30 in and the cap says 10w-30 i live in minnesota so it gets below 0*F am i supposed to put 10w-30 in? im gonna have the guy down the street look at it tomorrow but i want to know what you guys think because with my last problem you guys were really helpful, i have not yet looked into the pcv thing as i have not had time yet and still wondering what that squeek is im beginning to worry that these two problems have to do with each other and it could be very bad

good call on the pcv valve o-ring, there was one on the top cover but not on the pcv vavle itself which created a vacuum leak. i hope this fixes my oil pressure dropping but it did not so im still stuck with that problem

my 92 bonneville doesnt make a squeeky noise but it sounds like a loud vibration....maybe a tire rub but ive checked and it isnt one. do you think our problems could be connected in a way? reply at my email [email protected]. thanks!

I had the same noise after replacing my intake plenum for the second time,(every 100k miles). My 95 Bonneville SE has 210,000. It was the o-ring that wraps around the PVC when you push into the plenum hole. There is another o-ring that seals the PCV cap. That loud swishing sound at idle drove me nuts. It only occured when the engine was at operating temp. I forgot to install one when I did the intake plenum three weeks ago. Fixed it now, in about 5 minutes. The sound sounded like the torque converter or something deep in the engine oil pan was coming apart or getting ready to seize.

I had the same noise after replacing my intake plenum for the second time,(every 100k miles). My 95 Bonneville SE has 210,000. It was the o-ring that wraps around the PVC when you push into the plenum hole. There is another o-ring that seals the PCV cap. That loud swishing sound at idle drove me nuts. It only occured when the engine was at operating temp. I forgot to install one when I did the intake plenum three weeks ago. Fixed it now, in about 5 minutes. The sound sounded like the torque converter or something deep in the engine oil pan was coming apart or getting ready to seize.
Please look at the age of these threads before replying, this is way too old and dead!!