Technical => Engine Tech => Topic started by: Ductape91 on November 17, 2007, 02:31:06 PM
Title: loud roaring sound?
Post by: Ductape91 on November 17, 2007, 02:31:06 PM
about a week ago my car started to make a loud roaring sound while im driving, sounds like a fan kicks on high pushing alot of air. does it hot or cold. i had a mustang that made a similar noise to this and it turned out to be the alternator but i just replaced mine so im trying to hear any other ideas or areas of interest i should check out. im going to pop my old one back in since it tested good anyway. sometimes while on the highway it goes away but not a consitant rate to single out the fan clutch and the trans shifts perfectly. ideas?
Title: loud roaring sound?
Post by: Kitz Kat on November 17, 2007, 03:40:35 PM
Wheel bearing?
Title: loud roaring sound?
Post by: blu84302 on November 17, 2007, 06:01:50 PM
Does your heater work?
Title: loud roaring sound?
Post by: Sick88Tbird on November 17, 2007, 06:08:15 PM
When my fan clutch finally seized, it sounded like an old crop duster coming down the road and the car felt like it was really down on power.
Title: loud roaring sound?
Post by: Ductape91 on November 17, 2007, 10:16:36 PM
Quote from: Sick88Tbird;188276
When my fan clutch finally seized, it sounded like an old crop duster coming down the road and the car felt like it was really down on power.
thats how it kinda sounds and feels right now like its lacking power on the highway. it gets the loudest right before it shifts up to the next gear and as soon as i let off the gas the sound goes away even if its still holding the gear. actually, i got my hand all mangled up in the fan today on accident but couldnt really confirm if its siezed or not as i wasnt trying to test it:hick::flame:
the heater works fine, no smells or leaks as well.
i believe my wheel bearings are in need of replacment but they arent the noise im hearing.
Title: loud roaring sound?
Post by: blu84302 on November 18, 2007, 02:10:06 AM
Rear gears have been known to whine.
Title: loud roaring sound?
Post by: JKATHRE on November 18, 2007, 02:29:37 PM
Good suspicion. I replaced the fan clutch on our '88 TBird here about 6 months ago. Now, the car roars upon startup in the am and then settles down within 15 seconds. Seems like the fan locks up after the engine has been shut down overnight. Puzzling: birdsmily:
Title: loud roaring sound?
Post by: Ductape91 on November 20, 2007, 08:14:45 PM
well, i went and tried to spin the fan by hand this morning while the motor was cold and spun the whole motor practically so i feel it safe to assume the clutch is shot. no big deal just odd how it went so suddenly. anyway, when to my local autohole to get a new one. had them look it up and only 30 bucks so i had the man grab it only to have him put it back and after reading real big on it "made in china":mad: so now ill ask does anyone have any advice on where i should go to get a decent fan clutch? i havent tried the ford dealer as they were closed before i had the time to go there.
Title: loud roaring sound?
Post by: JeremyB on November 20, 2007, 08:19:33 PM
Looks like rockauto.com is out of Motorcraft fan clutches. So it fastpartsnetwork. I'd try the dealer.
From what I've gathered on the A/C forums, the OEM clutches are much better quality than the parts you buy from standard parts stores. This includes Imperial and Hayden.
Title: loud roaring sound?
Post by: Sick88Tbird on November 20, 2007, 10:26:14 PM
I solved my problem with a Flex-A-Lite electric fan kit...lol.
Mine went suddenly as well, after driving for 40 mins, I nailed it coming off a red light and the car was doing the "roaring" you described all through first gear, I laid off and it was fine. It was fine for the 45min ride home that night too, but the next morning...completely seized...I looked and there were little ball-bearings falling out.
Title: loud roaring sound?
Post by: thunderjet302 on November 21, 2007, 01:30:37 PM
Quote from: JKATHRE;188379
Good suspicion. I replaced the fan clutch on our '88 TBird here about 6 months ago. Now, the car roars upon startup in the am and then settles down within 15 seconds. Seems like the fan locks up after the engine has been shut down overnight. Puzzling: birdsmily:
I have a 5.0 Mustang Police Interceptor fan clutch on mine. Does the same thing:hick:
Title: loud roaring sound?
Post by: Ductape91 on November 21, 2007, 09:05:00 PM
went to the ford dealer today to find one, discontinued 3 years ago:mad: i think they wanted $80 for it anyway:burnout: checked rockauto.com and the one they had was like 46 bucks, i never got around to finding out what the shipping would be, plus the whole "dont have a credit card/bank accout/paypal" thing holding me up. rs strauss has thiers for 36 bucks but wouldnt tell me the manufacturer, mightve had something to do with the attitude i had about them asking my personal info so they can look up a part which imo is bs :flip: my next venture will be to carquest and see if they have it, in stock i mean. :angst:
Title: loud roaring sound?
Post by: Ductape91 on November 29, 2007, 08:54:26 PM
replaced the fan clutch with an autohole china made one, no more noise and got some power back, some. took all of 20 minutes to fix but didnt get around to it till today. failed at the bearings from some of the washer jamming in there. im going to hang onto the old one incase i ever need full time cooling:hick:
Title: loud roaring sound?
Post by: Cougar5.0 on November 30, 2007, 12:15:01 AM
Huh, my first instinct was fan-clutch. Well, that or you had a lion under the hood!
Title: loud roaring sound?
Post by: Old_Paint on December 07, 2007, 10:35:09 PM
Locked up fan does not equal full time cooling. Too much air flow through the radiator is nearly as bad as too much coolant flow through the radiator. When the air moves too fast through the radiator, it gets very turbulent, thus, decreasing effective cooling capacity. It's not as bad as the coolant going through too fast, though. The biggest problem is there will be excess wear on the serp belt (if it doesn't break), it will KILL your fuel mileage, and will certainly rob the car of power.
You're right about the discontinued Motorcraft fan at the Ford Stealership, but you can find reman Motorcraft fans in some places. I got one from Advance when mine bit the bullet a few years ago.
Same deal with the roar first thing in the morning when starting, but it calms down in about 15 seconds as stated. The viscous fluid in these things gets very thick when cool, and settles to the bottom of the clutch. You may even notice a little vibration because of the un-even torque with all the viscous fluid in one side of the clutch. Doesn't take long to warm it, though, and all is well again.
Oh yeah, the C3 was a typo on my part when I made the sig. It's a C5. When I get Mrs. Paint a new ride, my '86 will become my project car. I'm debating a 5.0 and AOD swap, and may add a cowl hood to clear an intake for an F-150. OR, perhaps just a Taurus fan setup, and some mild adjustments to the 3.8 to get rid of CFI. CFI is the worst of both carbs and FI. The injectors are on the wrong side of the throttle plates.
I noticed you had an 86 as well. I've had a bizarre problem for a very long time with mine. I get no codes, but under light throttle after it's warm, puttering about in city traffic, it will just nose over like the engine was switched off. If I stick foot in it so that my knee is getting close to the throttle body, it'll take off like a scalded dog (well, a scalded OLD dog). Or, if I let off the throttle slightly, and feather it, it seems to pick back up. It NEVER stalls out completely, and idles as smooth as can be. New fuel pump (about 2 years old), no pressure loss at the throttle body, new TPS about 4 months ago, all new sensors except O2's. You have the 86 too, so I'm sure you're well aware of why the O2's haven't been replaced. I'm not getting O2 codes, and the only way I see getting the 123 side out is to drop the exhaust. (need to do that anyway cause I need a ler).
I'm just curious if you've experienced this problem as well. I'm thinking about trying a reman ECM on it, but I'm stingy about turning loose of the $150 not knowing if that will solve the issue. I've read there were some issues with the capacitors in our vintage ECM, but can't find enough reading material to back up the rumors.
Title: loud roaring sound?
Post by: Carpimp1987 on December 08, 2007, 01:05:40 AM
I was going to say Flowmasters but i just felt like being a Smart@$$ my fan broke so i had to get a Flex-a-lite fan to replace it. Nice to hear it was a easy fix and you can drive without worrying about the noise.
Title: loud roaring sound?
Post by: JeremyB on December 08, 2007, 10:21:07 AM
Quote from: Old_Paint;191631
Locked up fan does not equal full time cooling. Too much air flow through the radiator is nearly as bad as too much coolant flow through the radiator. When the air moves too fast through the radiator, it gets very turbulent, thus, decreasing effective cooling capacity. It's not as bad as the coolant going through too fast, though.
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
Title: loud roaring sound?
Post by: Cougar5.0 on December 08, 2007, 11:31:19 AM
Quote from: JeremyB;191672
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
I agree and have verified that fast moving turbulent air does indeed cool better than a similar speed laminar flow.
The increased coolant flow is a controversial issue since:
1) the benefit is small 2) possible cavitation
I've been using a reduced cavitation (backplate - Flow Kooler) pump and I've seen no benefit to running the pump faster. I actually run it with an underdrive pulley and it cools just fine. I previously ran it with a underdrive (4 3/8") crank pulley with the S/C & cooling was never an issue - even in heavy traffic on a hot summer day. Best I can determine, the biggest benefit aftermarket water pump folks offer is reduced cavitaion. The one company talking about low-flow allowing water to "boil-off" the cylinder must have been smoking angel dust because no OEM pump would flow this slow.
Title: loud roaring sound?
Post by: Ductape91 on December 08, 2007, 12:02:19 PM
the full time cooling comment was actually meant as a joke for when my headgasket goes and i dont feel like changing it:flame: sorry for the confusion
as for the almost stalling thing your having no i dont have that problem with my tbird. im going to take a guess here but when was your last tune up? maybe even a stuck choke. im tired and cant think right now your best bet is to do a search on the site for similar symptoms and see what comes up, or dig thru the archives. replacing the computer from what ive been told is usually a last resort measure for mechanics who cannot solve the problem thru diagnosis(and being an expensive part doesnt help either) you might want to troubleshoot a few things before going that route.
Title: loud roaring sound?
Post by: Sick88Tbird on December 09, 2007, 12:06:41 PM
Quote from: JeremyB;191672
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
I disagree with the increased coolant flow part...coolant flowing through the radiator too quickly(i.e. somebody not running a t-stat) can cause problems with overcooling and overheating....if the coolant flows through the radiator too quickly it doesn't have time to dissapate the heat through the tubes and fins of the radiator efficiently...with increased airflow in this situation, it may help, but idling in traffic it would create issues....I do however agree with the increased airflow/turbulent air point...increased airflow won't hurt.
Title: loud roaring sound?
Post by: Cougar5.0 on December 09, 2007, 01:18:07 PM
Quote
Coolant Flow Rate
Looking at the previous expression, we can see that slowing the coolant down is the wrong way to go. If the heat load is constant, lowering the flow will increase the temperature drop through the radiator, making the bottom tank, or radiator outlet, temperature less than before. If the bottom tank temperature goes down, the top tank temperature must go up to maintain approximately the same average core temperature so that the heat load may be transferred to the cooling air. At the reduced power setting it would rise above 190 degrees F and at 240 hp the engine would be overheating worse than before. In fact, because the lower flow rate results in lower coolant velocity and less “scrubbing action” in the tubes, the average coolant temperature must rise slightly in order to transfer the heat load from the coolant to the cooling air, making matters even worse.
What would happen if we increase the coolant flow? Will it go through the radiator so fast that there won’t be time for cooling to take place? Not at all, from the expression, we can see that if the heat load is constant, increasing the coolant flow rate will reduce the coolant temperature drop through the radiator, resulting in a higher bottom tank temperature. If the bottom tank temperature is increased, the top tank temperature must go down to maintain approximately the same average core temperature. This is what we were hoping to achieve. With the top tank temperature now less that 190 degrees F at the reduced power point, we can expect that the system will be better able to run at 240 hp without overheating, In fact, because the increased coolant flow rate results in a higher coolant flow velocity and better “scrubbing action” in the tubes, the average coolant temperature decreases slightly while transferring the same heat load to the cooling air, further lowering the top tank temperature, resulting in better cooling performance.
From this we see that increasing the coolant flow rate will result in better heat transfer performance. There are some cautions to be observed in increasing coolant flow rate, however. Going too far may result in aeration and foaming of the coolant, possible damage to the radiator by overpressure, cavitation of the pump, due to excessive pressure drop through the radiator, and erosion of the radiator tubes. The ideal coolant flow rate is one that will provide optimum coolant flow velocity through the radiator tubes in the range of 6 to 8 feet per second. Flow velocities above 10 feet per second should be avoided.
Without the thermostat to regulate flow, the issues described above may be observed. I still contend that an OEM design with an anti-cavitation plate has sufficient capacity for a significant increase in OEM horsepower levels.
Quote
Cooling Airflow
Cooling air becomes heated as it passes through the radiator. It enters the radiator at ambient temperature and exits the radiator at some increased temperature. It is the difference between the average core, or coolant temperature and the average of these two cooling air temperatures that creates the ability of the radiator to transfer heat to the air. The slower the air passes through the radiator, the higher will be its exit temperature and the higher will be the average cooling air temperature. The higher the average cooling air temperature, the less heat will be transferred from the coolant to the air. On the contrary, the faster the air flows through the core, the less it will increase in temperature on its way through, making the exit temperature and the average cooling air temperature lower. This increases the differential between the average core temperature and the average air temperature, increasing the heat transfer. Increasing airflow by speeding up the fan, by providing an improved fan, by providing or improving the fan shroud, by reducing air restrictions in the grille or engine compartment, or by providing recirculation shields to prevent air from bypassing the core, will all improve heat transfer and cooling.
Title: loud roaring sound?
Post by: JeremyB on December 09, 2007, 03:43:56 PM
That pretty much sums it up...
Title: loud roaring sound?
Post by: Old_Paint on December 15, 2007, 11:07:02 PM
Quote from: JeremyB;191672
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
I take it then, you've studied a different thermodynamics and heat transfer course than I had to take in college? That was a long time ago, and I'm not sure, but somehow, I don't think the laws of physics have changed that much since then.
If you pass the air too quickly across the cooling tubes, it will not remove/absorb as much heat.
If you pass the coolant through the tubes too quickly, not as much heat will be removed.
Thus, both my statements are very much correct. A radiator is nothing more than a heat exchanger. There is a point at which the radiator becomes inefficient when either flow rate excedes the rating. A locked fan clutch will certainly do that at highway speeds. It ain't roaring because it's having a good time. That's massive amounts of air that it's trying to pull through the radiator. Since the radiator is an obstruction, the only thing it can do is pull it back in the gap between the blades and the shroud, which is what makes the roaring noise. It is rather easy to excede the ratings for flow on a radiator. Not havig a thermostat will do it. A locked fan clutch will do it. Either one will eventually lead to an overheating engine. Been there, done that. When the clutch locked up on mine, I could run 75 for about 15 minutes before the temperature started climbing. Then, I would back down to 65 and watch the temperature drop. Just that 10 MPH made enough difference in air flow through the rad from car speed and fan speed to keep the temperature down. Now, factor in the extra horsepower (heat) being used to rotate the fan, and now we're talking some rather quickly building heat. Oh yeah, it was winter time when this happened, yet the car still overheated because of a locked fan clutch. (not to the point of damaging anything, but certainly to the point of making me back off). Replaced the fan, and temp gauge stays right where it should, regardless of speed.
:flame:
Title: loud roaring sound?
Post by: Old_Paint on December 15, 2007, 11:07:22 PM
Quote from: JeremyB;191672
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
I take it then, you've studied a different thermodynamics and heat transfer course than I had to take in college? That was a long time ago, and I'm not sure, but somehow, I don't think the laws of physics have changed that much since then.
If you pass the air too quickly across the cooling tubes, it will not remove/absorb as much heat.
If you pass the coolant through the tubes too quickly, not as much heat will be removed.
Thus, both my statements are very much correct. A radiator is nothing more than a heat exchanger. There is a point at which the radiator becomes inefficient when either flow rate excedes the rating. A locked fan clutch will certainly do that at highway speeds. It ain't roaring because it's having a good time. That's massive amounts of air that it's trying to pull through the radiator. Since the radiator is an obstruction, the only thing it can do is pull it back in the gap between the blades and the shroud, which is what makes the roaring noise. It is rather easy to excede the ratings for flow on a radiator. Not havig a thermostat will do it. A locked fan clutch will do it. Either one will eventually lead to an overheating engine. Been there, done that. When the clutch locked up on mine, I could run 75 for about 15 minutes before the temperature started climbing. Then, I would back down to 65 and watch the temperature drop. Just that 10 MPH made enough difference in air flow through the rad from car speed and fan speed to keep the temperature down. Now, factor in the extra horsepower (heat) being used to rotate the fan, and now we're talking some rather quickly building heat. Oh yeah, it was winter time when this happened, yet the car still overheated because of a locked fan clutch. (not to the point of damaging anything, but certainly to the point of making me back off). Replaced the fan, and temp gauge stays right where it should, regardless of speed.
:flame:
Title: loud roaring sound?
Post by: Old_Paint on December 15, 2007, 11:18:31 PM
Quote from: Ductape91;191695
the full time cooling comment was actually meant as a joke for when my headgasket goes and i dont feel like changing it:flame: sorry for the confusion
as for the almost stalling thing your having no i dont have that problem with my tbird. im going to take a guess here but when was your last tune up? maybe even a stuck choke. im tired and cant think right now your best bet is to do a search on the site for similar symptoms and see what comes up, or dig thru the archives. replacing the computer from what ive been told is usually a last resort measure for mechanics who cannot solve the problem thru diagnosis(and being an expensive part doesnt help either) you might want to troubleshoot a few things before going that route.
It would probably be better to open this under another thread, but I've tried that, and seem to have been ignored completely. I don't think either of our '86 Birds has a choke. We have CFI sitting on top of our 3.8's. No choke. Fast idle on cold engine is achieved with an ICM (Idle Control Motor), not IAC (Idle Air Control) as is the case with later (S)EFI engines. As for troubleshooting, perhaps you didn't read the parts about it throwing no codes?
Like I said, I'd love to take this to another thread so I don't hijack.
Title: loud roaring sound?
Post by: Old_Paint on December 15, 2007, 11:20:58 PM
Quote from: JeremyB;191672
Both of these statements are incorrect.
Fact - Increased air/coolant flow increases heat transfer Fact - Turbulent air increases heat transfer
I take it then, you've studied a different thermodynamics and heat transfer course than I had to take in college? That was a long time ago, and I'm not sure, but somehow, I don't think the laws of physics have changed that much since then.
If you pass the air too quickly across the cooling tubes, it will not remove/absorb as much heat.
If you pass the coolant through the tubes too quickly, not as much heat will be removed.
Thus, both my statements are very much correct. A radiator is nothing more than a heat exchanger. There is a point at which the radiator becomes inefficient when either flow rate excedes the rating. A locked fan clutch will certainly do that at highway speeds. It ain't roaring because it's having a good time. That's massive amounts of air that it's trying to pull through the radiator. Since the radiator is an obstruction, the only thing it can do is pull it back in the gap between the blades and the shroud, which is what makes the roaring noise. It is rather easy to excede the ratings for flow on a radiator. Not havig a thermostat will do it. A locked fan clutch will do it. Either one will eventually lead to an overheating engine. Been there, done that. When the clutch locked up on mine, I could run 75 for about 15 minutes before the temperature started climbing. Then, I would back down to 65 and watch the temperature drop. Just that 10 MPH made enough difference in air flow through the rad from car speed and fan speed to keep the temperature down. Now, factor in the extra horsepower (heat) being used to rotate the fan, and now we're talking some rather quickly building heat. Oh yeah, it was winter time when this happened, yet the car still overheated because of a locked fan clutch. (not to the point of damaging anything, but certainly to the point of making me back off). Replaced the fan, and temp gauge stays right where it should, regardless of speed.
:flame:
Title: loud roaring sound?
Post by: bhazard on December 16, 2007, 12:36:07 AM
Ida just converted to an electric fan...
Title: loud roaring sound?
Post by: JeremyB on December 16, 2007, 11:34:07 AM
Quote from: Old_Paint;192966
I take it then, you've studied a different thermodynamics and heat transfer course than I had to take in college? That was a long time ago, and I'm not sure, but somehow, I don't think the laws of physics have changed that much since then.
If you pass the air too quickly across the cooling tubes, it will not remove/absorb as much heat.
If you pass the coolant through the tubes too quickly, not as much heat will be removed.
Your assumptions were incorrect when you went to college, when I went to college, and are still wrong. If you have any equations that show your points, feel free to post them.
From a pure heat transfer perspective, added increased mass flow (m-dot) - be it air or water - increases the bulk heat transfer (Q-dot) of the system. Physical effects such as pump cavitation ends up decreasing m-dot, and thus would worsen heat transfer.
Quote
Fast idle on cold engine is achieved with an ICM (Idle Control Motor), not IAC (Idle Air Control) as is the case with later (S)EFI engines.
IAC is a generic term for computer controlled idle. The CFI 3.8's throttle plate actuator and the later 3.8's bypass valve servo motors both are forms if IAC.