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1993 cadillac deville engine noise


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mike93
User

Mar 17, 2010, 6:11 AM

Post #1 of 27 (8575 views)
1993 cadillac deville engine noise Sign In

Hi everyone it's me again how are you I have a 1993 cadillac deville 4.9 v8 with 103800 miles on it this morning I started it and a loud tapping noise was there for only like 2 minutes then went away car runs great and ran great while it was just tapping very loud but like I said it went away after 2 mins no sludge in the motor oil is nice and clean what can it be please help thanks have a great day


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 17, 2010, 7:17 AM

Post #2 of 27 (8572 views)
Re: 1993 cadillac deville engine noise Sign In

Mike - would like to know your opinion on that noise. Tapping like a typical sticking lifter, or more of a metallic knocking?

Clean oil may not be the indicator of sticky lifters or sludge that you can't see and valve train parts that can make ticking and just go away when warm. Clean oil can also mean it's not very strong detergent and stays clean as the dirt doesn't get collected!

If it's been a while or over 2,000 miles since last oil and filter I would change it for suggested viscosity of synthetic name branded oil and let the then new additives and better flowing oil when cold just do their thing if you feel this is just sticking sounds.

I would avoid additives as they are in quality oils anyway and IMO the additives for oil's properties are the first to wear out,

T



mike93
User

Mar 17, 2010, 7:46 AM

Post #3 of 27 (8569 views)
Re: 1993 cadillac deville engine noise Sign In

It's sound like a sticking lifter not a metallic knocking sound because like i said it only last a minute or two then no tapping the car doesn't burn oil or anything I put seafoam in the gas tank yesterday and very very little through the vacuum line and after i did that yesterday the tapping started today oil was changed 400 miles ago.


mike93
User

Mar 17, 2010, 8:25 AM

Post #4 of 27 (8565 views)
Re: 1993 cadillac deville engine noise Sign In

could it be the main bearings because on my car the 4.9 engine is known for the main bearing thump with the the engine clearance is greater then 0.02 inches could that be what it is because i do have a minor knock at idle but doesn't do it at wide open throttle


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 17, 2010, 9:44 AM

Post #5 of 27 (8562 views)
Re: 1993 cadillac deville engine noise Sign In

It may take an experienced ear to tell what this noise is.

Enough SeaFoam in the oil! Strong stuff, go easy with that product.

Did this noise just appear after the last oil change and what kind of oil and viscosity are you using? Is this noise like that when you first start up and engine with an empty oil filter?

Seems in that it can go away so fast that just tweaking with oil would suffice and not get too excited about it but I'm not there hearing the noise.

In my experience main bearings are a hammer sounding thunk or like marbles. Assorted noises have their tell tale sounds and if this has been cared for right along that older but not a ton of miles for a cared for engine, IMO,

T



mike93
User

Mar 17, 2010, 9:57 AM

Post #6 of 27 (8558 views)
Re: 1993 cadillac deville engine noise Sign In

yeah i didn't put no seafoam in the oil and no this just started this morning yesterday i put the seafoam in the vacuum line and the rest in the gas tank oil change was done last month it really started after putting seafoam in the gas tank and very little in the vacuum line im using 15w40 everyone on cadillac forum told me they put it in there car with no problems yeah only when first start up the engine but haven't tried it with the filter off but i think it might be main bearing clearance not sure


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 17, 2010, 11:13 AM

Post #7 of 27 (8554 views)
Re: 1993 cadillac deville engine noise Sign In

NO! Don't try it with filter off! That was just a noise when you can't fill an oil filter full in doing an oil change. Please never leave the filter off!

I've worked on several of those engines from exactly that vintage and they were fine on Mobil 1 5-30 or 10-30. I should add the forum sponsor is Amsoil which is awesome oil but hard for even me to get (retired) now just for my own.

OK: Still would like a tech in biz to just listen to that if possible. I don't think you have a problem at all and to eliminate a very short term noise would cost a fortune with unknown results IMO and replacing bearings (crankshaft) is invasive surgery and priced at such.

It's my opinion that 15-40 especially conventional oil at less than high temps (meaning Summer) is a bit thick and alone could cause noise! Opposite of your other suggestions for elsewhere.

What you may have is called piston slap. That's a hollow dull bell sound that goes away and really no practical fix that's worth it and can last indefinitely with it.

If main bearings are slightly out of spec you MIGHT notice upon start up that oil pressure is slow to reach high norms when cold if a gauge or if warning light would take longer to go out. Super condition oil pressure (much can be dictated by main bearing wear) will shut off a light or perhaps show normal oil pressure while just cranking before engine has a chance to start.

Side note: Have worked on and witnessed zillions at assorted miles, age and care AND a couple hundred (no joke) of my own vehicles where you get more day to day observations. A few real clunkers could still be helped with trying various oils and viscosities.

Just make sure that this isn't some other noise such as a pulley or accessory bearing as best you can. It's good to pay attention to noises and already said I can't be sure without being there. As you said it quits quickly so if you brought it somewhere it wouldn't be doing it which is impossible to guess at too unless left overnite or the period of time you expect it again.

One more: If it gets worse, don't delay getting it diagnosed so you know what you are dealing with,

T



mike93
User

Mar 17, 2010, 11:21 AM

Post #8 of 27 (8549 views)
Re: 1993 cadillac deville engine noise Sign In

ok yeah thats the only way for them to hear it me leaving it overnight but maybe it won't happen again because this is the first time it ever made that noise and i had the car a year already but should i just use 10w30 high mileage?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 17, 2010, 1:01 PM

Post #9 of 27 (8543 views)
Re: 1993 cadillac deville engine noise Sign In

You gotta take the claims on oils with a pill! I've never paid much attention except the SAE ratings and whether synthetic or not. I suggest the viscosity of whatever was suggested new as I don't think 100+ K on a V8 is all that much miles. Taken many to 250K and didn't have to play oil games.

Stuff can happen no matter what you do and if you don't know the car from new. I've seen neglected cars do well and cared for ones be a pain but odds are care pays off.

If it's consuming oil just sticking with the same quality grade of choice seems to help and fix any leaks of course.

For some mystical reason changing oil types seems to use some oil even if it didn't before!? I think different detergents take one round to settle in and then it would be more regular,

T



mike93
User

Mar 17, 2010, 4:36 PM

Post #10 of 27 (8536 views)
Re: 1993 cadillac deville engine noise Sign In

yeah it don't leak or burn no oil the car runs great and the oil reason i don't put 10w30 like it says on the oil cap is because everyone says it quiets the knocking and better lubrication for the distributor but I called a mechanic earlier and told me I should try 20w50 and also did my neighbor upstairs who is a master technician who had cadillacs before with the 4.9??


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 17, 2010, 4:57 PM

Post #11 of 27 (8534 views)
Re: 1993 cadillac deville engine noise Sign In

Again - I'm not hearing this noise so hard to say. The higher the #s on oil the thicker it is and 20w-50 is WAY too much for a decent engine. That would be so thick on a cool/cold day the engine wouldn't get lubed for LONGER upon start up not quicker. What are your overnite temps? Here in New England in Winters a car left outside wouldn't start with that oil or be real hard.

That would be an oil I'd suggest for a real oil burner POS on its last legs and that's about it. Go for suggested oil is still my recommendation,

T



mike93
User

Mar 17, 2010, 5:13 PM

Post #12 of 27 (8530 views)
Re: 1993 cadillac deville engine noise Sign In

temps over here are in the 30's rite now 20's in the winter at night 50 80 right now in the morning and afternoon and 80's 90's in the summer I live in pennsylvania so I should just go back to 10w30 right and yeah thats what I thought it's way to thick and like I said car runs great also should I use high mileage?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 17, 2010, 5:32 PM

Post #13 of 27 (8527 views)
Re: 1993 cadillac deville engine noise Sign In

">> I said car runs great also should I use high mileage?<<"

If you want but of the right viscosity. Lots of those claims are gimmickry, IMO. What's so high mileage about 104K on a V8? It should be labeled high abuse or not instead of miles,

T



mike93
User

Mar 17, 2010, 5:38 PM

Post #14 of 27 (8524 views)
Re: 1993 cadillac deville engine noise Sign In

Ok im switching back to 10w30 tomorrow and in a lil my neighbor is gonna check see if it's the main bearing if not im probably gonna change all of the main bearings


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 17, 2010, 7:16 PM

Post #15 of 27 (8522 views)
Re: 1993 cadillac deville engine noise Sign In

See how it goes and think hard about doing main bearings as that requires machining the crankshaft with a high failure rate or perhaps shorten the life of the thing depending totally on what exactly this noise is. Remember you said it just goes away within a couple minutes of it warming up - which is both getting more oil to where it belongs and warmer = a bit thinner so it moves better.

Think hard about the crank bearings. You could buy a whole car that doesn't have the noise for what that will cost. At the moment I/we don't have a definite diagnosis of a serious problem yet if at all??

T



mike93
User

Mar 18, 2010, 5:31 AM

Post #16 of 27 (8514 views)
Re: 1993 cadillac deville engine noise Sign In

Yeah I know I was just gonna change the main bearings with the engine in the car i know this one huys who said he changed all 5 of them and know the car is nice and quiet


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 18, 2010, 6:48 AM

Post #17 of 27 (8511 views)
Re: 1993 cadillac deville engine noise Sign In

So you know if you didn't,

The bearing look like this in most any engine..........



If exact OE replacement you would still need to know they are going to fit exactly as engines are "line" bored when new and the machine bit that makes that perfect (well perfect for engines) line hole wears and is checked for tolerances even when making engines new such that there can be a range of normal when new.

You would check that clearance with "Plastigage" and have a strong clue as to how much (exactly) bearing crush would be expected to hold them in place. Too little they spin and back to square one! Too much and they might burn in and work but make noise stillCrazy

Those bearings are designed to be softer metal than the crank and caps that hold them. That so they can "impregnate" particles of debris and keep on working. If caps or crankshaft are off the engine's life if it does work isn't as good as good originals, or even close to good originals IMO so would reserve that for a last resort.

Note: These are lubed by a layer of oil not rolling bearing like for a wheel. They are first or at least early to get oil pressure from the pump and can make noise till that pressure is within spec. They have a "metered" leak rate that is splitting hairs such that extra oil under pressure then can go on to all other oil lubed parts of the engine. The oil that gets slung off of these is to lube other parts passively as a foggy mist.

In short - this is so critical to get right for it to last it's scary. Know that doom for the engine would result if not tended to or don't with these things as they are the life of the lower end of engines. Doing it wrong, even when all testing and measuring checks out makes the engine block a good mooring (anchor) for a small boat!

T



mike93
User

Mar 19, 2010, 6:52 PM

Post #18 of 27 (8498 views)
Re: 1993 cadillac deville engine noise Sign In

Thanks im going to automotive school I went and visited yesterday and they told me If i buy a motor from a junk yard they will teach me how to rebuild it and I can swap that motor in my car thats what im gonna do


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 20, 2010, 2:31 AM

Post #19 of 27 (8492 views)
Re: 1993 cadillac deville engine noise Sign In

OK: You are in school for automotives and should know how to rebuild various and all parts of an engine. For your own you haven't even diagnosed it needing much or anything so I'd sooner see you and school get a donated "core" to practice with that is so popular it could be sold off covering all costs,

T



mike93
User

Mar 20, 2010, 5:03 PM

Post #20 of 27 (8481 views)
Re: 1993 cadillac deville engine noise Sign In

ok yeah to just now my car started leaking antifreeze the water pump is not wet or anything it's like behind the alternator im thinking hoses?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 21, 2010, 1:16 AM

Post #21 of 27 (8478 views)
Re: 1993 cadillac deville engine noise Sign In

Anything that contains coolant could leak. Water pumps and others can be elusive. Pressure testing can help pin it down. Some leaks will hold pressure. Do check for water pump at vent hole and for any wobble in its bearings. That could make noise also!

T



mike93
User

Mar 21, 2010, 12:38 PM

Post #22 of 27 (8467 views)
Re: 1993 cadillac deville engine noise Sign In

ok noise is gone leak is gone the lower radiator hose clamp was loose now no leak we found out it was the lower raditor hose clamp by pressure testing it water pump is a year old no looks so hopefully were good now


mike93
User

Mar 21, 2010, 3:53 PM

Post #23 of 27 (8462 views)
Re: 1993 cadillac deville engine noise Sign In

I Think im just gonna buy re ring kit for my engine instead of a master engine rebuild kit because the engine is in really good condition just wanna freshen up the motor


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Mar 21, 2010, 3:54 PM

Post #24 of 27 (8462 views)
Re: 1993 cadillac deville engine noise Sign In

Glad to hear it! More glad you didn't toss that engine over a hose clamp,

T



mike93
User

Mar 21, 2010, 4:00 PM

Post #25 of 27 (8458 views)
Re: 1993 cadillac deville engine noise Sign In

Thanks is that a good idea a re ring kit?






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