Mobil 1= more engine noise in my wife's GTP

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Hi new poster here! I've read this forum for quite some time. It's great! Anyway, my wife and I purchased a 2000 Pontiac Grand Prix GTP in July. We took a 2000 mile trip the next weekend. I had no idea when the oil had been changed, so about 3 weeks ago I went ahead and changed it. The car has 41,000 miles on it and it is in great shape and runs awesome!! I have no idea what kind of oil was in the car,but it had an AC PF 47 filter on it. I switched to Mobil 1 10W30 synthetic and a Wix filter based on what I have read here and several other automotive forums such as www.clubgp.com and www.ls1.com My wife has done most of the driving since then. We have gone 500 miles or so since the switch to the M1 syn. I noticed for the first time tonight that the engine noise seemed noticeably louder at idle . It seems the engine was much quieter with whatever was in there before. In my opinion,The engine is clearly more audible inside the car now,and it sounds louder from the outside too. It's not really loud, but it is louder. I asked my wife if she thought it was louder since she drives the car most of the time. She said it sounded exactly the same to her. She does know to watch and listen for trouble, but I think it's changed. Maybe it's just me, but I don't think so. I read that Mobil 1 might do this, but I went ahead and tried it anyway. Once again maybe it's just me,but it does seem louder. It's not a cold slap issue either. It does it when the engine is warm too. I know this doesn't necessarily hurt anything,but it is kind of disapointing. I was going to switch to M1 from Pennzoil synth. in my Formula, but I might not now. 99% of the time we have the stereo on ,so we can't hear the engine anyway.I just happened to hear it yesterday before I turned the radio on. The car still runs fine. Anyone else who has a Grand Prix have this problem with M1?? I hate to sound anal, but this kind of stuff bothers me. I know this site is full of folks just like me too. [Smile] [ September 08, 2003, 03:59 AM: Message edited by: Racerjk ]
 

Patman

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When I had my 97 GTP I ran Trisynthetic M1 in it, both 5w30 and 10w30, and had no problems. I never did oil analysis on it though.
 
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Northern Illinois
Since you say you had not turned on the radio yet when you heard the engine I am wondering if this was cold engine "piston slap" which is very common with GM 6 Cyl engines and usually will disappear in a minute or two.
 
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How long did you listen to engine before you put in the Mobil 1, compared to right now? Nothing has probably changed, its just you are paying more attention to it and looking for something to be wrong. Don't believe everything you read on the net, to much is BS and opinions, both good and bad. [ September 08, 2003, 08:11 AM: Message edited by: Mike ]
 

Patman

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quote:
Originally posted by dickwells: Since you say you had not turned on the radio yet when you heard the engine I am wondering if this was cold engine "piston slap" which is very common with GM 6 Cyl engines and usually will disappear in a minute or two.
When I had my GTP and spent a lot of time on the Grand Prix boards, and hanging out with the Grand Prix club in my area, I never once heard anyone complain about piston slap in the 3.8 engine. I don't believe this engine has any history of that problem whatsoever. The 3.1 versions in the base Grand Prix do, but not the 3.8 version in the GT and GTP. [ September 08, 2003, 08:54 AM: Message edited by: Patman ]
 
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Racer, I thought the same thing in my Audi when comparing M1 0W40 with Amsoil 0W30. The engine seemed noiser with the M1, but the UOA indicated it lubricated just as well. Of course there was no way to measure whether or not it was REALLY noisier and it could be both our imaginations. [Cheers!]
 
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quote:
Originally posted by Racerjk: I noticed for the first time tonight that the engine noise seemed noticeably louder at idle . It seems the engine was much quieter with whatever was in there before.
If this noise only occurs on cold starts, you might try 5w30 instead.
 

MolaKule

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Racerjk, Have you considered that if the noise is greater than before, that the oil might have cleaned out gunk in the engine. Where is the noise coming from. Valve train (top end), bottom end (Pistons and crank). How thick and dirty was the old oil? Switch to Chevron Supreme 10W30 or Mobil 1 0W40 and see if the noise level changes.
 
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To Patman: OOps, I was thinking of the smaller sixes, I concur on the 3.8. I also did not realize that the P apparently stands for "Pressurized", which may make it a different animal than run of the mill. Still interested in hearing how it sounds warm.
 

Racerjk

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quote:
I am wondering if this was cold engine "piston slap"
Nope,we had just come off the interstate and the car was at operating temperature. My wife needed to run into Wally World for just a second. I decided I would wait in the parking lot. I guess I turned the radio down before I parked the car, and I noticed the engine noise seemed louder.
quote:
How long did you listen to engine before you put in the Mobil 1, compared to right now?
When we first bought the car, I listened to the engine,checked the oil and trans fluid etc... We had the car for about a month or so before I changed to M1. After we first bought the car, I would really listen for signs of trouble. Everything seemed to be "cool", so I quit paying as much attention to it as I initially did. The engine was super quiet IMO before.
quote:
I never once heard anyone complain about piston slap in the 3.8 engine. I don't believe this engine has any history of that problem whatsoever. The 3.1 versions in the base Grand Prix do, but not the 3.8 version in the GT and GTP
My mother has a 3.8 GT. There is no slap, but it is noisier than our GTP. My parents got a lifetime free oil change deal from the dealer. I think it is Q/S oil. I noticed it sounded a little noisy a couple of weeks ago. I thought ours was much quieter until now. My mom's old '90 Grand Prix 3.1 liter would hammer on start up in any weather. Everyone of those engines I've heard does that. Our GTP doesn't do the cold slap.
quote:
Have you considered that if the noise is greater than before, that the oil might have cleaned out gunk in the engine. Where is the noise coming from. Valve train (top end), bottom end (Pistons and crank). How thick and dirty was the old oil?
When I changed the oil, I noticed the valvesprings looked a little gunky. The oil was not too thick and it wasn't all that dirty. It looked as good or better than what comes out of our other vehicles IMO. The valves springs were a little gunky for sure though. The noise seems to be coming form the top end. Perhaps the M1 is clearing things out.
quote:
turn the radio up
I guess that's what I'll do until the next oil change. I'm just a little disappointded. [ September 08, 2003, 05:10 PM: Message edited by: Racerjk ]
 

wtd

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My wife drives a 98 Grand Prix GT with the 3800 V-6. I've used 10W-30 Mobil 1 in it for the last 55,000 miles and the engine is pretty quiet and still runs strong with 95,000 miles on it. Wayne
 
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Racerjk, When you purchased the car was the engine oil maybe slightly overfull. The reason I ask is earlier in the year I purchased a 2002 monte carlo. I checked the oil cold and the stick read about a quart and a half over the full mark. I asked the salesman what the deal was with the overfill and he stated " These quys at our service dept probably just made a mistake". When I started the engine it was completely silent. I could not believe my good fortune to find a 3.4 with no piston slap. After the purchase I drove the car like this for three days, each morning it was whisper quite. I changed the oil on the following weekend using 10w-30 Havoline and st filter. The next monday morning when I started the engine I was given the beautiful sound of " tick...tick....tick.....tick" for all of about thirty seconds. That same sound still greets me every morning. Since that first oil change I have wondederd if an overfill would quieten down a noisy engine.
 
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My 3.8 does the same thing. I would not wory about it!I found out this summer that mine realy likes Delvac 15W40 in the summer. I was doing Auto-Rx and flush with 15W40 and 10W30 and found that it prefered 15W40. I know have M1 10W30 and it is alot louder. It does not sound like anything mechanicly wrong it is just louder.
 
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Saratoga, NY
Could it just be the thinness of the Mobil 1 causing the noise? [Confused] Try Pennzoil High Mileage Vehicle in 10W30 and see if that stuff doesn't quiet down the motor a lot. A great oil (synthetic blend) for less than $2 per quart at Wally World. [Wink] --- Bror Jace
 
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My Grand Prix didn't like M1, either. I did a few changes with 10w-30, but I really felt like my motor wasn't enjoying it, so I switched to Royal Purple. I felt the difference almost immediately. IMO, the 3800 just likes thicker oil, and the M1 10-30 is like 5w-30 in any other brand. I would try some other synthetic like Red Line, Royal Purple, or whatever you feel comfortable with, and see if it changes. BTW, has the mod bug bitten you yet? It just bit me, I feel a set of rockers coming on [Big Grin]
 

Al

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Well piston slap in GM sixes is well known especially the 3.1 and 3.4. They pribabky had a 50 wt in it wou wouldn't hear it. the 5W or 10W-30 does not improve it. The Delvac 1 also doesn't cure it although it is better. You may need to go to Redline. Turn the radio up [Frown]
 

Racerjk

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quote:
When you purchased the car was the engine oil maybe slightly overfull
I checked the oil at a gas station and it was right on the money.
quote:
I know have M1 10W30 and it is alot louder. It does not sound like anything mechanicly wrong it is just louder.
I don't think it's mechanical either. It's just aggravating.
quote:
My Grand Prix didn't like M1, either. I did a few changes with 10w-30, but I really felt like my motor wasn't enjoying it, so I switched to Royal Purple. I felt the difference almost immediately. IMO, the 3800 just likes thicker oil, and the M1 10-30 is like 5w-30 in any other brand. I would try some other synthetic like Red Line, Royal Purple, or whatever you feel comfortable with, and see if it changes. BTW, has the mod bug bitten you yet? It just bit me, I feel a set of rockers coming on
I guess it is the thinness of Mobil 1 indeed. Most folks over at LS1.com seem to like M1 10w30,so I went for it. Plus, being available at Wally World for less than 20 bucks a jug is great. I would love to run Royal Purple or Redline, but they are not available here other than mail order that I am aware of. I'm definitely going to give one of them a try next time to see if it changes anything. You guys have really been helpful! I appreciate it! [ September 09, 2003, 04:16 PM: Message edited by: Racerjk ]
 
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Try M1 0w40 instead of 10w30. M1 generally has oils at the thin side of the viscosity spectrum. Plus since yours is supercharged, it would definitely like the 40 weight better no matter what. Do that before switching back to another dino oil or fake synthetic. Jason
 

Racerjk

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Oh, and I would love to do some mods also Guitar Geek. A catback and a K&N for sure,maybe more. My wife tends to leadfoot it from time to time, so I don't want to get too carried away. OW40? Hmmm...
 

Patman

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The best mod you can do on a supercharged 3.8 is changing the stock supercharger pulley to a 3.4" unit. You'l increase the boost level up to about 11psi and get about 25 extra horsepower. By just changing to that pulley and putting on a 9" K&N cone air filter instead of the restrictive factory airbox, I got my 97 GTP to run a 13.78 quarter mile at 100.2 mph! It was so much fun beating new Mustangs with that car. [Smile] And I do agree, 0w40 should work very well in that engine. Or at least a thicker 30wt such as Amsoil 5w30 or Redline 5w30. German 0w30 Syntec would also do well.
 
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