| Author | Message | ||
| david handa (Davehanda)
Junior Member Username: Davehanda Post Number: 223 Registered: 5-2001 |
Yoshi, I would not run the fans continuously. I don't think the motors are meant for continousy duty, and may wear prematurely. More importantly, if your cooling system is operating properly, it should not be necessary. Replace the switch to start, and fix whatever else is plugged, broke, and not working.....Jumpering the wires will at least tell you your motors and related wiring is okay, but either the switch is broken or you radiator is plugged. | ||
| Richelson (Richelson)
Member Username: Richelson Post Number: 828 Registered: 12-2001 |
The thermal switch is at the bottom of the rad. and it more on the pass. side. It should have 2 connections on it. Just use a jumper connection(on the wires that are coming into the thermal switch) and it should turn both fans on. Takes only a few minutes to do. | ||
| Yoshi Toda (Ytoda928)
Junior Member Username: Ytoda928 Post Number: 65 Registered: 6-2001 |
Thanks, guys for the advices. I will have my radiator checked out. Meanwhile, as for the non-working fans, should I connect two terminals (attached to the thermo sensor or switch locate at the bottom of the radiator on the passenger side) to make those fans work permanently? I have read this tick on some other similar threads.  I know this picture is blurred. Do you think this is the thermo switch/sensor? Can anyone verify it for me? Thanks! | ||
| Richelson (Richelson)
Member Username: Richelson Post Number: 821 Registered: 12-2001 |
You should remove the rad. Have it checked for blockage. Now that your sister over reved it that won't help. | ||
| Dr Tommy Cosgrove (Vwalfa4re)
Member Username: Vwalfa4re Post Number: 299 Registered: 5-2001 |
Sounds like a radiator leak that closes itself up after it warms. I bought my 308QV with a small leak at a weld point. I had it fixed and another popped open. Fixed it and 3 years later another opened up. This was the only thing about my car that REALLY made me mad. Especially when I priced a new one. The last repair is holding so far but every time I get behind a car on the highway that is spraying their windshield and the water hits mine it scares the hell out of me. I can just see another damn leak opening and spraying water thru the hood vents and onto my windshield. My point is pull the radiator and have it psi tested soon even if its the 4th time this year. | ||
| Yoshi Toda (Ytoda928)
Junior Member Username: Ytoda928 Post Number: 64 Registered: 6-2001 |
Oh boy, this is a long thread, but I am very curious about this topic now as I have just noticed the same or similar problem with my 308QV. My symptoms are 1) the temp goes up to close to 250 in a matter of 5 minutes while idling in a garage. Then, from the front hood ventilation above the radiator, a white smoke rises and fogs the front windshield (outside) on the driver's side. The smoke disappears after maybe a couple of minutes or less, and then everything goes back to normal, including the high temp gradually comes down to in a range of 195 ~ 225 after driving it for 5 ~ 10 minutes. I have also noticed that the fans do not seem to kick in at all. I can really use some advices here, my friends. HELP... | ||
| Charles I Claussen (Atlantaman)
New member Username: Atlantaman Post Number: 28 Registered: 3-2002 |
NO-so far there have been 5 cars made--all by different people. I have seen all the others and they are pretty crude to be frank. I had the luxury of having a machine shop and all new CNC equipment. Mine is also an EFI motor. My car is all black and I do keep a spare 308-4v setup handy for backup because all the v-12 horsepower wears out the tranny bearings really fast | ||
| Verell Boaen (Verell)
Member Username: Verell Post Number: 362 Registered: 5-2001 |
Atlantaman, I just picked up on your V-12 comment. Is that the original Goldsmith 308 V-12 conversion you're now driving! | ||
| Ulf Modig (Ulf308qv)
New member Username: Ulf308qv Post Number: 40 Registered: 3-2001 |
Ken, your problem could be a leaking head gasket. Combustion pressure leaking in to the cooling system. If the leak is minor it might not mix oil/water or show low compression. I have experienced this type of symptom on other european cars. Open the radiator cap and check if you can pick up a reading with a CO meter. | ||
| Charles I Claussen (Atlantaman)
New member Username: Atlantaman Post Number: 27 Registered: 3-2002 |
PS--you can also relocate your oil cooler to the front of the car for added cooling. I had to do this---with a 400hp v12 in my car , even the new radiator was not quite enough. | ||
| Charles I Claussen (Atlantaman)
New member Username: Atlantaman Post Number: 26 Registered: 3-2002 |
GUYS-- re-coring the radiator is really not that hard and it works great. The ferrari red has something like 10fins/cm and an modern Honda CRX unit has about 20fins/cm. All you have to do is pull off the tamks on top and bottom and order a new core to the same dimentions then reinstall the tanks and it all looks original.. any good radiator shop can do this for about 2-300 AND IT WORKS!!!! | ||
| Greg Rodgers (Joechristmas)
Member Username: Joechristmas Post Number: 447 Registered: 3-2001 |
I agree. The only time I had air make the cars temp go up was when I had drained the car almost completely. I ran it to warm it up and it was noticeable. It went from less than 1/4 to over 1/2. After 10 secs. it went down. I bled it afterwards. Then that was it. Usually when you have a gradual overheating problem the rad. is partially obstructed. I think air in the system is getting out of hand. Just like I stated in the being of this thread if you do all of these items, wp, rad., therm., fans, 50/50 mix., etc. than it would lead to a headgasket leak of some form. 230 is very high IMO. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 103 Registered: 5-2002 |
No problem bleeding mine either. I did do it twice just to be sure. If you're having trouble with air in the system. I thing I would replace all the 25 year old rubber coolant lines and pump/thermostat gaskets before I went after the head gasket. | ||
| Paul Newman (Newman)
Member Username: Newman Post Number: 458 Registered: 12-2001 |
I had no problems either after the engine job. I used the bleeder at the rad once to verify no air and I havent touched it since. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1908 Registered: 2-2001 |
I don't understand the difficulty everyone is having with air in the systems. After overhauling my entire engine I simply filled the system with 50/50 mixture of coolant and started the engine and waited for the thermostat to open which only took a few minutes and then put the radiator cap on where it has been since then. No problem. If you continually get air I would suggest a head gasket problem. | ||
| James Selevan (Jselevan)
Junior Member Username: Jselevan Post Number: 131 Registered: 6-2002 |
Bleeding the system is problematic. I recently bled my Dino, and air continued to exit the system. The best way is to purchase 20 feet of clear tubing. Press this tubing onto your bleed valve on the front radiator, and run the other end into the expansion tank on the rear. Using this clear tubing, you recapture coolant exiting the bleed valve, and can watch for bubbles. My problem was that when I raised the RPM to 2000, bubbles seemed to reform, suggesting cavitation at the water pump. I could never get the system completely free of bubbles. This is all accomplished at atmospheric pressure, thus the open system may be prone to cavitation while a sealed system is not. Have others seen this? Jim S. | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 248 Registered: 4-2002 |
If you bleed the system every week, will you eventually get all the air out so long as the coolant level in your filler/reservoir is above the hoses when you bleed? | ||
| E.K. (Eulk328)
New member Username: Eulk328 Post Number: 4 Registered: 7-2002 |
From what I've heard it seems that it is difficult to bleed air out of Ferrari cooling systems in general. Perhaps someone has already mentioned this product............. MityVac makes a tool which should ensure that your cooling system is air free when you change coolant. Note that this device CANNOT be used to purge air from a full or partially full system and a small shop air compressor is required. It should be very useful on any mid-engined, front radiator car. I bought one a few months ago. It's very nicely made but I have not yet had a chance to use it on my 328 or Lancia Montecarlo (also mid-engine front radiator). MityVac is a well-established company and I doubt they would put their name on something that does not work as advertised. The best price I found was from Tool Warehouse (when you order on-line, not over the phone). $75.00 seems like a small price to pay when it may save you from overheating an engine, especially a $$$ engine like ours. I'm providing the link below: http://www.thetoolwarehouse.net/shop/MIT-4700.html Erich | ||
| Paul Newman (Newman)
Member Username: Newman Post Number: 453 Registered: 12-2001 |
Im indifferent, cant you tell? | ||
| James Selevan (Jselevan)
Junior Member Username: Jselevan Post Number: 129 Registered: 6-2002 |
Paul, how do you really feel about these discussions? Jim S. | ||
| Mark Eberhardt (Me_k)
Junior Member Username: Me_k Post Number: 102 Registered: 5-2002 |
If your car is overheating and it didn�t do it from the time it was new, the steps are: 1. check coolant level 2. bleed the system 3. check the fans 4. inspect system � hoses, correct parts, air gasket around radiator, shrouds/ducts in place, ect. 5. replace the thermostat 6. boil/recore/replace the radiator 7. inspect/replace pump 8. boil out the block If you get to the bottom of this list and it is still overheating, the assumption that it worked properly when new should be revisited. Also, it looks to me that there is a little everyone is right argument going on here. If you try to spin a water pump too fast, it will cavitate. This will make it pump less water, not more and the engine will get hotter, not because there the water is moving too fast, but because it is not moving fast enough. Laminar or turbulent, I�m pretty sure pumping the water faster is a good thing (up to the point of cavitating the pump)because it increases the average temperature of the radiator and therefore it�s ability to heat the air, which cools the system. The water wetter is still a question in my mind. At the track, were antifreeze/coolant in not allowed, it helps. It lowers the surface tension of the water so the heat transfer is good and proves the necessary corrosion protection. On the street, standard coolant does both of these things for you and raises the boiling point so the system can operate at a higher temperature(without a high pressure cap), which gives you a better safety factor on boiling over, not to mention freezing. If you�re not running the standard 50/50 blend in your coolant, I guess the question would be why? If the car is running too hot on the street under normal conditions, the cooling system is degraded or broken and requires repair. Switching to straight water with wetter is really just a Band-Aid. It will make you feel good because the temp gage is lower, but it real isn�t fixed. JMO | ||
| Matt Morgan (Kermit)
New member Username: Kermit Post Number: 48 Registered: 8-2001 |
Doctor Lawrence, I was unaware of your degree in this area. Had you simply said " I have a PhD in mechanical engineering from Virginia Polytechnic Institute. My dissertation was in the area of heat transfer". I would never had called DR Ted. I would simply have noted that you got your degree with that, it must be true. I assumed that due to the nature of his field of expertise, he might be able to better explained it to me. Quite honestly I had difficulty comprehending your post. I'm, sure that there are others out there who are respected in their diverse fields of expertise who had difficulty as well. I think we can all agree that motors must be kept at an even constant temperature to be most efficient. So whether the water goes thru the block to fast to pick up heat, or for the radiator to fast to get rid of it, really becomes a moot point. I would suggest we get back on the topic of the thread. | ||
| Paul Newman (Newman)
Member Username: Newman Post Number: 446 Registered: 12-2001 |
I guess this all boils down to... just change the f-ing thermostat and see what happens! You dont need to know about fluids slipping over themselves and turbulant vs laminar flow to diagnose an overheat problem. Just use common sense, its probably a simple fix. Im getting a headache listening to this crap about physics and how the molecules interact with each other. | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 245 Registered: 4-2002 |
Well I have to answer this. 1. The purpose of the thermostat is indeed to maintain block temperature. However, if you remove it on some cars, they will overheat. One has to assume that the maintenance of block temperature is a 'given'. 2. Either you have confused what your friend said or your friend misunderstood what you said or your friend is in error. What I typed out is a standard turbulent flow correlation. It is for Reynolds numbers above 2000 which is the generally accepted criterion for the change from laminar to turbulent flow. While I don't have a reference at home I believe it is called the Ditus-Boltzer equation that provides the Nusselt number as a function of Reynolds and Prandtl numbers for conduit flow once the entrance effects subside. 3. For laminar flow, heat transfer is a diffusion mechanism because the flow is merely sliding over itself. The only way heat moves normal to the flow is by diffusion just like it does in solids. There are no break away chunks of fluid that carry heat away a la turbulent flow. I believe that in that case the Nusselt number is a constant, something like 4.34. Your friend or you has it exactly backwards. It is velocity independent for laminar flow. Heat transfer is entirely dependent on the thermal conductivity of the fluid for laminar flow. Velocity doesn't enter the picture. 4. I have a PhD in mechanical engineering from Virginia Polytechnic Institute. My dissertation was in the area of heat transfer. Not that this matters, but since you brought up the pedigree stuff, I feel compelled to reveal mine. 5. What has happened here is why hearsay is not admissible in court. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1896 Registered: 2-2001 |
I think the rocket scientistneeds to stick to rockets because a rocket thermostat does not work the same way a car thermostat does. There are no automotive thermostats that I have ever seen that open above the boiling point of the water or coolant. Also there are most certainly thermostats that direct the coolant to different passages depending on the temperature. | ||
| Matt Morgan (Kermit)
New member Username: Kermit Post Number: 47 Registered: 8-2001 |
Lawrence, I found your post to be very informative. It did however not answer to what I have seen over and over. So I refered your post to an old friend, who retired from the Aerospace Industry, and has a PHD in Physics. My favorite "Rocket Scientist" had a bit of a different view, as follows: 1. Engines have a thermostat, not so that coolant will "go to the right places" but to make sure the engine warms up to proper operating temp. quickly & to provide quick heat to the passengers heater, & defrosters as well. take the stat out & the enging (usually) never gets hot enough to vaporize condensed engine byproducts, runs cool, & forms engine varnish "Goo". 2. The equations that are cited describe what is happening when a condition know as Laminar Flow is present. This is usually the case when liquids (air/water/etc.) flow over a smooth surface below some maximum speed (plane wing & ship propellers are examples). Inside a radiator, it is not smooth so flow is not laminar but really better described as turbulent! Under turbulent conditions, air can come out of solution with the water; cavitation can cause the same affect. If water speeds are increased to a high enough level it is very possible that large bubbles are formed greatly reducing the heat transfer from the engine coolant to the radiator core (air has a lousy specific heat value compared to the coolant). 3. Additives is coolant antifreeze increase the wetting properties of the coolant & are essential. Likewise, thermostats should be set so that the coolant temp can rise above the temp that water boils so as to get rid of it! If oil is getting too hot, that is another problem best solved elsewhere. However, I make sure that oil temps are always above 220 F so as to boil off any condensed water that is present! | ||
| Ron Smith (Designr)
New member Username: Designr Post Number: 2 Registered: 9-2002 |
The 308 service manual specifically says to never run without a thermostat because of the water routing in the engine (like the Mercedes below). You can test your thermostat with a thermometer and a pot of water on a stove...just note when the bimetallic spring moves the valve, and check the temp. Although, after I go to the trouble to pull the t-stat, even at $50 a pop, I would just put in a new one, and see if the problem is fixed, after I checked the timing and pressure tested the cooling system..... | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 239 Registered: 4-2002 |
Pushing water through the radiator too fast reduces heat flow. This is an old wives tale or street skuttlebutt as I would call it. Here is why. This is somewhat technical but it is what I do for a living. When a liquid passes by a solid with the liquid being hotter than the solid, heat is transferred to the solid by something called forced convection. There is a mathematical parameter associated with forced convection called a film coefficient. The larger the film coefficient, the more heat transfer you get. The film coefficient is dependent on many properties of the fluid. They are the density, viscosity, thermal conductivity, and specific heat of the fluid. Lastly, the film coefficient is dependent on the velocity of the fluid. Mathematically, the Nusselt number equals the product of the Reynolds number to a power slightly less than unity times the Prandtl number also to a power less than unity. Thus you have Nu=c*Re**.8 *(Pr**.6), where Nu=h*d/k, Re=rho*v*D/mu, and Pr=mu*cp/k. This is a standard correlation used to design thermal equipment - such as heat exchangers. c=constant h=film coefficient d=measurement of passageway k=thermal conductivity of fluid rho=density of fluid mu=absolute viscosity of fluid cp=specific heat of fluid v=velocity of fluid Nu=Nusselt number Pr=Prandtl number Re=Reynolds number The heat transferred equals the film coefficient times the wetted area times the difference between the bulk fluid temperature and the metal surface temperature. The units are Btu/hour in our English system. Therefore if you increase the velocity, the film coefficient becomes larger because the velocity increases the Reynolds number. If you increase the film coefficient, you increase the heat transfer. Since more fluid is passing by, the temperature change of the fluid will be less. However, more heat is transferred because it passes by more frequently - makes the round trip more frequently. The coolant is merely a conduit that removes heat from the block and carries it to the radiator. The reason why some cars require a thermostat or other obstruction is to force the water to go where it is supposed to go. Mercedes Benz cars are like this. If you remove the thermostat, the coolant will not go where it is supposed to go inside the engine. Therefore you don't cool the engine. It is not because the fluid travels faster through the radiator that it does not cool the engine. | ||
| Matthew J. Morgan (Kermit)
New member Username: Kermit Post Number: 45 Registered: 8-2001 |
Ken, here's a thought. I just found a mismatched pulley situation on a clients 3084V. Someone had added an earlier pump(small bearing) which also had a small upper pulley. With the dampener pulley @5" and the pump @ 3"+, he was overdriving his pump 50 percent. If you push the water too fast thru the rad, it will not have time to lose the heat. Many times I have seen people remove the thermostat, only to find it then overheats. On the track we used to use a restrictor disc in place of the thermostat. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 3084 Registered: 2-2001 |
Jeff makes a good point. If your timing is retarded it can cause the engine to overheat. | ||
| Charles I Claussen (Atlantaman)
New member Username: Atlantaman Post Number: 24 Registered: 3-2002 |
you can always recore the radiator--I took the ferrari core out (removed the end caps) and replaced it with a 4-row Honda crx core that cools A LOT better-- cost about 250 for everything | ||
| billy bob (Fatbillybob)
New member Username: Fatbillybob Post Number: 19 Registered: 8-2002 |
If the T-stat is not bad then the problem can be bad radiator even with what you mentioned because the temp can be right but the flow rate can be bad. Also the new W pump impeller may not be in spec relative to the WP housing. Did you check? It needs to be about 0.5-1mm gap..check the manual | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 211 Registered: 4-2002 |
So the water is coming in at 190 and leaving at 168? Is radiator cross flow? That sounds pretty normal to me. Where are you measuring the temperatures with the heat gun to get the 230? How do you know the heat gun is correct? Can you run the engine without the thermostat in place? On some engines, you cannot do this because the water won't cool the engine without thermostat in place. | ||
| Ken Ross (Kdross)
Junior Member Username: Kdross Post Number: 117 Registered: 2-2002 |
I had readings of 168-190 throughout the radiator. | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 207 Registered: 4-2002 |
What is your temperature drop across the radiator? | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 719 Registered: 1-2001 |
How about a collapsed hose? Haven't we been down that discussion before? -Ben | ||
| Ken Ross (Kdross)
Junior Member Username: Kdross Post Number: 116 Registered: 2-2002 |
My fans are working correctly, the water pump is new and the belt is tight, and we did bleed the block too. The radiator also appears to be working correctly and not clogged. This seems to narrow it down to a bad thermostat. | ||
| Lawrence Coppari (Lawrence)
Junior Member Username: Lawrence Post Number: 206 Registered: 4-2002 |
Water Wetter works. I've used it in my 328 when we used to have car events at Rockingham in June. It is hot as the blazes there. Water Wetter does reduce engine temperatures. The way it works is to reduce the surface tension of the coolant. This limits the size of bubbles during the boiling heat transfer regime. When a hot piece of metal is wetted by water, bubbles form. This creates a vapor shield between the liquid water and metal impeding heat transfer. If the size of the bubbles is reduced and their ability to free themselves from the hot metal is increased, the vapor barrier is less and you get more heat transfer. The lower surface tension causes smaller bubbles to be created and makes it easier for the smaller bubbles to break away from the metal so you get benefits two ways - easier to break away from metal and smaller bubble. As soon as the bubble breaks away, it is replaced by liquid which boils and breaks away. It is the changing of the phase from liquid to vapor which consumes huge amounts of heat. The bubbles that break away come in contact with cooler liquid coolant and recondense. Having said this, it appears to me that you have a problem with your cooling system. Water Wetter would only a symptom reducer, not a cure of the disease. As you have changed the water pump, it sounds like you may have a clog somewhere in your system that is restricting flow. | ||
| Bill V. (Doc)
Junior Member Username: Doc Post Number: 119 Registered: 9-2001 |
Ken--this is not the cure if there is a real problem present but a # of people I've spoken to swear by Red Line Water Wetter. I hear that that alone lowers temps--I emphasize the word " hear" because I haven't tried it myself as yet. I'll probably dump a bottle into my system when i get it back from Wide World. Good luck. | ||
| Greg Rodgers (Joechristmas)
Member Username: Joechristmas Post Number: 440 Registered: 3-2001 |
There are many things it could be. A sticking therm. could cause this. I assume that the rad. is clean. Are the fans kicking on? If so are they rotating the correct way? (blowing) If the car is running extremely lean it can run hotter, worst case would be a headgasket. If so you will see a lose of compression and fluids mix, coolant in the oil, coolant in the cylinders etc. Provided the clearances are correct on the waterpump there isn't a lot left to check. | ||
| jeff ryerson (Atheyg)
New member Username: Atheyg Post Number: 10 Registered: 8-2002 |
I assume he bled the block also I this guy is worth anythng I am sure he has checked : Make sure water pump belt is tight Themostat Flushed radiator remove hoses back flush block if necessary rod out radiator check for plugged hoses You could have nothing wrong with your cooling system and your timing or valves make be off causing overheating | ||
| bruce wellington (Bws88tr)
Member Username: Bws88tr Post Number: 768 Registered: 4-2002 |
ken look at my thread " looking for ben lob, steve man,mike" etc.. look at my problem and the solutions, maybe a help to you.. hope family is ok. regards, bruce | ||
| Ken Ross (Kdross)
Junior Member Username: Kdross Post Number: 115 Registered: 2-2002 |
My 1985 308 QV is still running hot after my mechanic bled the system Friday. There was a lot of air in the system, about 1" worth of air in the radiator proably. Unfortunately, the car is still running hot. The car had a 30K major about six months ago and got a completely new water pump. We also verified that there are not any hot spots on the radiator and a heat gun confirmed that my gauges are registering the correct temps. The anti-freeze is at -10 degrees. The car after about 30 minutes will run at 230 water and 230 oil. This is too hot. Any suggestions? Will a new thermostat correct the problem? |