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UNKNOWN ENGINE OR EXHAUST TAPPING SOUND!!!
joyrider147
Member Posts: 69
I drive a cadillac cimmarron. I bought it off the guy who well maintenanced, never abused the car and now recently, not slowly but all of a sudden it now taps. When i start the car, it taps loudly, then quietly taps still even after the oil has flowed through the system and the engine is operating at normal operating temperature. I LET THE CAR WARM UP OR AT LEAST LET THE OIL FLOW THROUGH THE ENGINE BEFORE DRIVING.
Recently, i changed all 6 AC Delco spark Plugs which were set at .042 inch gap with Autolite Spark Plugs set to the recommended spark gap at .045 inches. It may be the spark plugs because the car maintenance manual said it may be the wrong type temperature setting for the spark plugs but I don't know. Would the tapping be extra explosions in the engine cylinders because the spark gap is larger? Because now i'm getting better fuel efficency and more get up and go from the engine from the spark plugs.
At the same time i placed the thermostat back (the elctric fan has also been hotwired to run continously while engine is running) in until 2 weeks ago when i changed the spark plugs. 2 months ago, i changed the oil and accidentally place 5 quarts of 10w-30 oil when my car needed 5w-30. Sometimes after the engine has the oil flowing through, i would need to drive it onto the highway. Normally, the oil would have a high pressure until it flows through the system, then it drops slightly, until the oil is warm and then the oil pressure drops dramatically to lubricate the engine. Would the oil take longer to go through the system or overheating the engine do this?
Months before that, I changed the muffler system and exhaust pipes along with a lockup switch for the transmission, but recently, i think i may have put a hole into the exhaust because of these bumps in the ramp of the parking lot at work has scratched alot of people's chassis lately.
Recently, i changed all 6 AC Delco spark Plugs which were set at .042 inch gap with Autolite Spark Plugs set to the recommended spark gap at .045 inches. It may be the spark plugs because the car maintenance manual said it may be the wrong type temperature setting for the spark plugs but I don't know. Would the tapping be extra explosions in the engine cylinders because the spark gap is larger? Because now i'm getting better fuel efficency and more get up and go from the engine from the spark plugs.
At the same time i placed the thermostat back (the elctric fan has also been hotwired to run continously while engine is running) in until 2 weeks ago when i changed the spark plugs. 2 months ago, i changed the oil and accidentally place 5 quarts of 10w-30 oil when my car needed 5w-30. Sometimes after the engine has the oil flowing through, i would need to drive it onto the highway. Normally, the oil would have a high pressure until it flows through the system, then it drops slightly, until the oil is warm and then the oil pressure drops dramatically to lubricate the engine. Would the oil take longer to go through the system or overheating the engine do this?
Months before that, I changed the muffler system and exhaust pipes along with a lockup switch for the transmission, but recently, i think i may have put a hole into the exhaust because of these bumps in the ramp of the parking lot at work has scratched alot of people's chassis lately.
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what is your mileage? burning any oil? you might have enough miles on the engine for pressure to fall because the crank bearings are worn and/or the oil rings are worn.
if you don't have a real pressure gauge, I would say you need to have one put on for test and get some pressure numbers. low pressure and head noise are a bad combination, they mean you're not lubricating the head, and indicates it's rebuild time for the engine.
I think I'd just drive it until it drops, and if you like the car, go find another one with fewer miles or that had a rebuilt engine.
Rebuilding the engine on this car doesn't sound very cost effective.
If it's running OK then I agree with Shifty - drive it till it drops. But if you want to play with it then take it to a good mechanic and see if he can trace the problem. I've owned several old cars that had noisy valvetrains. On most of them a simple valve lash adjustment (i.e. tightening the nut on the rocker) quieted down the engine dramatically. Get a shop manual to help with the job.
On some of the clunkers I've owned, Auto-RX would have been a Godsend.
I did that once with my wife's Thunderbird Turbo Coupe. The book called for 5w-30 and "just to be on the safe side" I used 10w-40. After that the valve train clattered on start up and this was a very low mileage engine. Went away as soon as I switched back to 5w-30.
So I think when manuals say 5w they mean it. Apparently 10w isn't thin enough at cold engine temps to fully lubricate the top end (and maybe other things too). Newer engines come tighter than they did back in the day.
The best way to clean valve lifters is with a quart of ATF (automatic transmission fluid). However, in keeping with the law of unintended consequences, the ATF may clean out the sludge that's keeping those old seals sealing.
way back when, there was a valve clearance (lash) adjustment that needed tweaking on higher mileage engines. that was before the self-adjusting hydraulic lifters came into use. there used to be a lot more clicking in engines in those days, because it's never dirt cheap to remove the valve covers, diddle the lash until the whacking smoothed out, wipe the sprayed oil off everything, get out a new gasket, and replace the valve covers. 'twas a mess and those days are generally gone.
Can i add some "engine flush" (which thins the oil some and helps clean the engine of particles by putting it into the oil)? Will this help make my engine run good while it is cleaning it out?
Could i use methyl-alcohol in the oil or open the valve covers and clean them with methyl-alcohol or ether or some other powerful alcohol based cleaner to remove the particles and clogs from the engine?
There's a slight chance that your lifters clatter because they're dirty, although I'd be more inclined to think that if only one ticked. If they all tick then they and/or something else in the valve train is worn out. Not the end of the world, but it is a sign the engine is worn.
Is the ticking a sharp tick or is it a duller thump like if you beat an empty oatmeal box like a drum? The former is a top end noise, the latter could be rod knock. Whatever it is, it sounds like you've still got decent oil pressure and that's a pretty good indicator the engine will be good for a while.
If you want to try a product like this the only one I'd trust is Auto-RX.
http://www.auto-rx.com/
When you hit the gas, it sounds like a gear moving on a flywheel that hasn't been lubricated (although that's not what's wrong with the car- most likely the valves).
When I changed the oil, it really did quiet it down for 1 tank of gas. Lately, i see more oil pressure in the car than usual. Do you think i might have broken an oil seal on one of the valves (reduced resistance because seal is broken)? So far, i still have not burned oil yet my car does start to putter through the muffler, exhaust-wise. The exhaust seals aren't broken.
what is rod knock? does that mean my engine cylinders are tapped or that my rod is warped or broken? will that tap the cylinders later on if I continue to drive?
Would a slack timing chain have these symptoms? Joyrider, has the engine started to feel sluggish, especially when you first take off from a stop? Could well be time to replace the chain and gears--it's been my experience that they're good for around 100k.
The ticking at idle, especially when cold, does sound like a lifter, especially if changing to the right oil weight minimized it. However, the noise it makes when revved sounds almost like it could be from a worn accessory bearing, maybe a power steering pump, smog pump, AC compressor or alternator.
A good way to isolate the source of engine sounds is to use a very long screwdriver with a plastic handle as a stethescope. Put the blade end of the screwdriver where you think the noise is coming from and the handle against your ear. The screwdriver magnifies any sounds. Be careful to avoid any moving engine parts.
FWIW it looks like he's got a tight engine for 124k--around 40 psi when warm and no oil consumption.
Where does he live? Can anybody go listen--lol!
but every 30,000 or so miles, the drive plate would take enough of a warp that it would start banging on the bell housing past about 1000 rpm. when it started banging about 800 rpms as I started up from a light or stop sign, or when people started looking around for whatever was making noise, it was time to make an appointment for another plate.
if the drive plate is the culprit, be sure they also check the motor mounts, all of them. failing mounts cause other issues like this.
a Flywheel From Hell can also cause noises like this, or issues like this... they might even find a cracked ring gear.
I don't see the new oil as a connection unless it was really heavy weight stuff. And then it would work all the time anyway, not stop after a week.
But it was amazing the difference going from 10w-40 to 5w-30 made in eliminating top end noise. You'd think it would be the other way around.
I had a broken tooth off a ring gear once that rattled around but it didn't make a bell-like sound.
those of us who live in areas where the 5w-30 doesn't flow out of the can in the winter until it's been warmed up on the manifold know about upper rocker whacking, banging, and don't need to buy CDs of "stomp!" for entertainment. switch to synthetic for its much lower gel temperature and it's an incredible difference.
IMHO, if you have overhead camshafts, run the thinnest oil rated for the temperature, change it often enough that the viscosity modifier doesn't go away on you for hot protection, and if you hear any noise, go synthetic until it warms up again. my Ranger 4-popper really liked being treated like that, and it complained mightily on the first zero-degree evening each year.
it is not a good idea to be scraping up the bottom of your car, take the road differently so you don't hit this hump in the pavement, and get a petition going among your neighbors to hand into the public body that "maintains" your road to get the freakin' thing fixed.
it could be a city, township, county, or state-maintained road.. if it has a federal highway designator on it (US 56) the state still does the "maintenance" but does so to federal guidelines and with federal funding for part of the job.
no excuse for leaving a road blow or heave in a public road.
also, get them to put a "bump" sign and flag in there until the road gets fixed, and hit it slower.
Could i keep changing the oil every 200 miles and still drive the car but not damage the engine any more than i already have or would it breakdown later down the line?