95oldsVan Posted March 18, 2006 Report Posted March 18, 2006 My brother in law dropped off his 3.1 Grand prix today and Im going to be working on the car soon.We are not exactly sure what is wrong with the car but apparantly its making a knocking noise when you first start it up when its cold out.After 15 seconds or so,when oil pressure is moving well,the noise goes away and the car runs perfect.No noise after that.Drive it anywhere and its fine. When the car is warmed up and you shut it off,the noise doesnt return at all...just has to sit overnight and does this in the cold mornings. Whats your best idea what may be wrong with the motor? Im going to check the oil they used(drain it into a clean pan),and im leaning towards a possible crank bearing or rod knock. Im also going to see if the oil pump is working properly or not.Any other suggestions before going to work? Quote
95oldsVan Posted March 18, 2006 Author Report Posted March 18, 2006 Ahh,I just read that article about the tranny problem that can cause this noise when cold...Ill check that too.I dont think this car has the 4T60E but the older unit.Ill have to check the applicable years as well. Quote
19Cutlass94 Posted March 18, 2006 Report Posted March 18, 2006 if it has the 3.1 ( not the 3100 ) then it doesnt have the 4T60-E Quote
95oldsVan Posted March 18, 2006 Author Report Posted March 18, 2006 Thanks,its the 3.1 not the 3100 series.However,the web site says its applicable for 91-97 grand prixs.Oh well.just another thing to check. Quote
19Cutlass94 Posted March 18, 2006 Report Posted March 18, 2006 I wouldnt even bother with that. it wont harm anything but your nerves. Check the lifters, if its not that, then it could be the tranny, in which wont be worth it even to investigate that. Quote
95oldsVan Posted March 18, 2006 Author Report Posted March 18, 2006 Wont kill me to do some extra checking stuff out...I enjoy fixing cars when I can and it gives me a hobby to do so.If its the lifters indeed,Ill have some fun tearing shit off the engine to get it done. Quote
19Cutlass94 Posted March 18, 2006 Report Posted March 18, 2006 You have the flat-tappet lifters which is where the noise is. If you had the hydraulic roller, you wouldnt have that noise...... Quote
pitzel Posted March 18, 2006 Report Posted March 18, 2006 Replace the oil with 5W-30 or preferrably 0W-30. And then see if the problem goes away. And yes, they can be very noisy engines at startup, especially if it is quite cold out. Temperature makes a huge difference, but using an oil with better cold-flow properties should help cut down on the initial noise. Quote
95oldsVan Posted March 22, 2006 Author Report Posted March 22, 2006 Well,finally gotten around to checking the car out more today and the noise appears to be coming from the engine...its making the noise all the time instead of just on cold start up. My neighbor who is a mechanic as well listened to everything and feels strongly its a bad rod or crank bearing.The noise is noticeable on the bottm of the engine,not the top.We shall see how it goes. Quote
19Cutlass94 Posted March 22, 2006 Report Posted March 22, 2006 How loud is the noise? If it was a rod or bearing, itd be fairly loud. Lets hope its not one of those, but then again new motor might come into play then! Quote
95oldsVan Posted March 23, 2006 Author Report Posted March 23, 2006 Well,we may have been humbled here! I unbolted the TC from the flywheel tonight just to be sure and the noise has stopped! Transmission was serviced on this car not long ago and the fluid is full and pink.Maybe it has a problem inside somewhere.... The flywheel bolts came off easy..they were not even the correct GM ones and someone put locking star washers on them,of course not equal all around.Some had 3 washers,one had 2 and another only had one...What Im gonna do first is get new(proper) bolts and put it back together and see if the noise is still there or not.I dont know who worked on this car last time but the bolt with 3 washers had rolled threads on it.So they gotta go in the trash! Ill keep you all posted... Quote
Robby1870 Posted March 23, 2006 Report Posted March 23, 2006 Well,we may have been humbled here! I unbolted the TC from the flywheel tonight just to be sure and the noise has stopped! Transmission was serviced on this car not long ago and the fluid is full and pink.Maybe it has a problem inside somewhere.... The flywheel bolts came off easy..they were not even the correct GM ones and someone put locking star washers on them,of course not equal all around.Some had 3 washers,one had 2 and another only had one...What Im gonna do first is get new(proper) bolts and put it back together and see if the noise is still there or not.I dont know who worked on this car last time but the bolt with 3 washers had rolled threads on it.So they gotta go in the trash! Ill keep you all posted... Wow....that is messed up. Quote
jeremy Posted March 23, 2006 Report Posted March 23, 2006 Well,we may have been humbled here! I unbolted the TC from the flywheel tonight just to be sure and the noise has stopped! Transmission was serviced on this car not long ago and the fluid is full and pink.Maybe it has a problem inside somewhere.... The flywheel bolts came off easy..they were not even the correct GM ones and someone put locking star washers on them,of course not equal all around.Some had 3 washers,one had 2 and another only had one...What Im gonna do first is get new(proper) bolts and put it back together and see if the noise is still there or not.I dont know who worked on this car last time but the bolt with 3 washers had rolled threads on it.So they gotta go in the trash! Ill keep you all posted... ..............damn......... Quote
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