How hot does your 456/550 run?

My previous thread “1995 456 Fault Codes 4131 & 1121?” had gotten a little off topic, so I thought I’d start a new thread.

The fault code matter is resolved in that I never found out what caused them, but they haven’t come back.

The temp issue is, however, unresolved (or, is it?).

To recap, I was seeing coolant temps to around 215F, with A/C on, in slow traffic at about 100F ambient. Temp is around 195F at 50mph+, regardless of outside temp. No problem either way when it’s < 85F outside.

Every 456 owner has said this is normal, but two folks who really know these cars say it’s not and there is something wrong with our cooling systems.

Cribbj and I have been going through the mechanical issues and he’s posted what he’s done to his car regarding cooling (almost everything!). And, we both live in Houston. Of course, he has a 550 and I understand the cooling systems are slightly different.

The two Dave’s, Cribbj, Alfredo, FFB, 166&456 and others have given me some ideas and here’s what I’ve done so far (no heavy lifting like John, mind you, as it far too hot in Houston to actually be fixing anything right now):

First, I checked the service records and found the under-the-manifold hoses were replaced by the dealer about 2000 miles ago. They have the white stripes as some say they should, but are not the “best” ones most recommend.

Next, I jacked up the front of the car, raising the front about 1'. Cold, I added about a pint of coolant and checked the bleeder. The coolant came just to the hole for the bleeder screw, so I guess I had the back of the engine down enough to make any air move forward.

With the car elevated, I started the engine, let the thermostat open and squeezed the big radiator hose while holding the expansion tank (which I had unbolted) as high as I could given the amount of slack I had in the 4 hoses attached to the tank. The idea was to make any air trapped in the system rise into and escape through the tank. I think that's what Alfredo(oss117) described. I checked the bleeder while hot, as Ferraridriver Dave described, while elevated and had no air or steam.

I put everything back and took off the grill. I used a mild degreaser and soaked the a/c condenser and what I could get on the radiator. Washed it out with hot water through a spray nozzle. The condenser/radiator wasn't greasy and not really even very dirty, but I figured every little bit helps. My car has 17K miles.

It was, again, about 95F outside and I let the car idle with the a/c ON. I don't think anything I did helped because I got the usual temp, about 215F. (note, there are 3 small marks on my gauge between the large marks, so I'm counting each mark as about 9F, see pic below.)

I also used an IR thermometer to measure the rad inlet and outlet temps. But, the results/variance were suspect. Best guess is a delta-T of about 10F.

Next, I took an ordinary, oscillating, house fan (about 14" D and, according to the labeling, 49 watts, IOW's not a powerhouse of a blower) and positioned it about 1' from my (5" high) grill opening.

The coolant temp dropped a little reaching the 2nd mark after the 190F mark or about 205-210F. It stayed that way for as long as I had the house fan blowing into the grill and went up when removed.

So, I ordered two 7” auxiliary fans to experiment with. First, I tried one fan temporarily attached to the inside of the grill, pulling through the grill toward the rad.

In the real world, (out of my driveway) in full sun and 97F+, I was still getting about 215F, but this was the 1st try with one puny fan, (fan is rated at 80W, but I'm getting <4 amp draw on my DVM).

After trying my <50 watt fan as a "pull" on the grill with marginal results, I put two, reversed to "push", on the a/c condenser coils (see pic below). No objective data, but you can feel the airflow being sucked into the grill, so the fans are definitely moving more air over the radiator.

When I “tested” it for about 20 minutes on the West Loop (I-610), pretty near a dead stop, 100F or better on the pavement, again, very little difference, getting between 2nd and 3rd mark after 190F. Maybe, 2-3 degrees better than my originally posted pic below, which I estimated at about 215F.

Again, marginal results and nowhere near the straight needle some say it should be. But when traffic cleared and I was able to do 60mph, temp dropped to about 195F, as usual.

Okay. Why is my temp 210-215F at idle, even with increased airflow, and 195F at speed in the same ambient?

Here’s my theory:

The thermostat doesn't fully extend (and close the bypass???) until 230F? See WSM below…

Could it be, at speed, the bypass is fully closing with the coolant coming out of the engine at 230F+ but then getting cooled by the radiator to 195F by the time it gets to the temp sensor? But, at idle it's still not getting hot enough to fully close the bypass, resulting in a lower average temp and a higher temp at the sensor? Follow my logic? Not sure where the temp sensor is in the coolant flow.

Finally, if my assumption is right (that the bypass doesn't fully close until 230F and I don't know that for sure) and the 1st OEM fan comes on at about 200F and the 2nd OEM fan at about 215F (See WSM below), the system, as designed, was obviously expecting temps in excess of the ideal 190F. The Ferrari engineers didn’t even provide for additional cooling until the system reaches the 200-215F range?

The claim, that the temp should never, ever go beyond 200F, seems flawed to me.

My next step, (and this will probably wait until next spring when it’s closer to the time for a coolant change), is to take out the thermostat and check its spec’s in boiling water. But, if it performs to spec, does that confirm my theory?… And, what can be done then?

Finally, is there anyone out there with a ’95 456 that hasn’t seen their coolant temp go to 215F in 100+F outside temps in dead-stopped traffic? I got’s to know…….PM me if you prefer, I won’t use your name. Love to hear from the 550 gathering and others as well….

Actually, I’m pretty satisfied with my 2 little, auxiliary fan mod. I may be getting near the same temps as before, but there’s a certain peace of mind knowing there’s enough air flow to prevent an overheat situation if stuck in traffic. I’ve never seen the needle go to the 225F mark and, if my thermostat theory is correct, I don’t think it will. The bypass will close before that happens. Thoughts??????

If anyone wants to see how I wired the fans, just let me know. (I need to make a wiring diagram and save it with my service records, in case I die in my sleep or something.)

Regards….Mark in Houston
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My 95 456 runs exactly where you show in the picture in hot weather. In colder temps it runs at the mid line or lower when its moving. Neither temp will damage the engine. Oil temp is very slow to come up and pegs at the mid line even in hot temp. Water temp never gets into the red even if a prolonged stop. So why are you worried? That temp will not cause an engine meltdown.I had a Maserati that always ran hotter(Mexico). They are Italian cars-enjoy.

 

If you believe your problem may be the thermostat, I would say to remove it and run without it and check the results.

 

Never do this!

With the thermostat removed flow is through the bypass eliminating the radiator from the system. If you have any doubt read the work shop manual pg. B68

 

+1 on what Ferraridriver said. Going w/o the thermostat is not an option. Even just to test.....

Thanks Andrew:

There's some pretty strong opinions about there being something wrong if it runs past the first mark after 190F. Just read my previous thread....

 

these systems are pretty basic. IMO you are too close to the red zone. You need to confirm that those are your temp readings. Then there are only a few areas that cover most of cooling issues, water pump, hoses, t stat, radiator. A 20 year old radiator with under20k miles is just as bad as one with 150k miles but younger. Change the radiator or put a cheap one in from a chevy v8 to use as a test for a hundred bucks. You might be surprised.

 

I had a similar problem a couple of years ago, Mark. It was the thermostat...
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I have had similar problems with the Porsche 944 Turbo, I believe the thermostat is exactly the same.

One trick was to drill a small hole (2 or 3) in the housing of the thermostat.

Buy a new one and try it.

You can gets this for under 8-10 USD.

 

Mark, interesting theory there. I do believe Ferrari's choice of location on the 456 for the thermal sensor for the fans was flawed, as according to your WSM they put it down in the bottom tank of the radiator, which on your car means the coolest area (I believe you have a single pass radiator on the 456 while the 550's have a double pass). If I'm right about the location, your sensor is going to be reading the coolest water temps in the system, rather than the hottest, which makes no sense to me. The coolant sensor for the fans "should" be sensing the hottest point in the system, IMO, as the 550 is setup.

On the 550, the fan control temp sensors are "both" mounted on the water manifolds, under the intake manifolds and before the thermostat, where they're sensing at the hottest point in the system.

The location of the fan temp sensor would support your theory about the water being cooled at idle/low rpm, and it would affect the operation of the fans, however I don't think it would affect the operation of the 'stat itself, because the water coming out of the heads is still going to be really hot.

One thing I'd decided to try is a switch from a 50/50 coolant setup to a pure (RO filtered) water setup, with the addition of the proper corrosion inhibitors and surfactants from No-Rosion. According to the simplified heat transfer equation, this should enable the coolant to carry away 20%-25% more heat from the engine than a 50/50 mix, which should lower the top tank temperature by 10-15 degrees (hopefully), or at least boost the deltaT of the system. As a confirmation of this, Bill K. out in LA contacted me over the weekend and advised his techs had just done this switch to his '98 550, which has similar overheating issues as mine, and in fact it did lower his temps by about 10-15 degrees.

So, as I received my "kit" from No-Rosion on Saturday, I'll be switching my car over to this setup sometime this week.

One caveat with running a pure water system is that it doesn't provide any freeze protection. But for those who are living in a northern climate, you probably don't have overheating issues anyway, so this wouldn't be of interest to you.

 

The flow of coolant through the radiator is possibly too low at idle. Ferrari also had waterpump pulleys on these cars with a lower diameter, which would increase flow at low engine rpm, and added a bypass in the housing; presumably to avoid pump cavitation at higher rpm rates. Have a look at the Eurospares website and you'll see the differences (different housing, pulley and belt).

 

Yes, 50/50 is far too much, the thermal capacity of the coolant is greatly reduced.

Try to go down to 10/25 percent and you will notice a difference.

 

Mark,since it goes to 210 but never higher,just like mine,no matter how long I idle in traffic,perhaps this is how the system is designed. Why would you think that at that temperature there might be engine damage? Now you have me worried.

 

John, could you post the results of the switch after you try it? Very interested in trying it on my car as well.

 

Ive checked with a couple of mechanics that are friends. 212 is a normal running temp for modern cars. No chance of engine damage at that temperature.

 

Thanks Guys…Great theories and advice…….

FBB….I think the temp readings are accurate. Pretty close to what I get with an IR thermometer at the t-stat housing and it “feels” that hot. Also, the t-stat opening/closing temp corresponds with about 180F on the gauge. Still, I don’t have OBDII, so can’t get the temp there. I agree, I have a 17 year old rad and it could have some blockage, but wouldn’t you expect the car to run hot under load? It doesn’t, just idle with a/c on. Also, wouldn’t you expect a better result from adding more fan power, if the rad was compromised? I know you know these things as well as anybody, so I value your opinion…..Thanks.

Barry…When you say you had a similar problem, was it running hot only at idle at high ambient? As long as I can exceed 50 mph or it’s <85F out…no problem…Thanks for the pics….Good idea to label old and new…

360modena….$10 for a t-stat? Here’s the parts and prices I’ve seen: 168200- $325USD; 183758- $150USD…Anybody know of another make that uses the same T-stat? At those prices, it’s worth a test before buying a new one. Also, does anybody know which one is correct for the 456GT (non-M)? I see two part #’s. Vastly different prices.

John…Ferrari did do one thing right on the M2.7. The big fan comes on when you turn the a/c on, whether needed or not. So, it’s always on in my scenario... I know water cools better than coolant but I’d have to be thoroughly convinced that the No-Rosion provided the same protection as coolant before risking it. Sounds like something great for racing….I too am having difficulty with my theory that the fluid coming out of the engine isn’t “hot enough” to fully open the T-stat and close the bypass. It’s just the only thing that I can come up with that fits all the scenarios….Cool at load and hot at idle, regardless of airflow?… And, John, are you going to “scope” your own rad? Love to know what you find…..

166&456…Thanks for the tip on Eurospares… Unfortunately, it looks like it’s several thousand $ for the water pump upgrade. I think John/Cribbj did it, to no avail.

Finally, Andrew….Sorry to alarm. No, I don’t think any damage can be done, just 190F is better for the plastic and wiring than 215F.

So far, every 456 GT owner has said they get temps similar to mine under the conditions described, so I guess the further question is: Has it always been that way???? My service records from 12 years ago say it has.

Even if there is a problem, with my extra fans, I can “play” in Houston traffic without worry and I won’t notice anything in about a month anyway….Mainly, I just want to know if I’m getting as good as I can get…….I’d rather be fooling with my exhaust than my water pump…

Regards to all…….Mark in Houston….

 

Mark, if you're interested in going the new water pump route, Capristo now make a new bolt in cartridge that will fit the 456/550/575 models and all the various housings, plus it includes the upgraded design impeller, and I believe they can provide the undersize pulley to go with the package. Ricambi sell the whole package on their website.

Attached is a little blurb I received about it from Antonio Capristo awhile back.

If the package does not include the undersize pulley, you can often find them on eBay for $150 or less. Search for P/N: 169924, which will be a 93mm pulley, in lieu of the one you probably have, P/N: 166454 which is 102mm.
View attachment Capristo water pump.pdf

 

Dave Helms chimed in on one of these threads and basically said you have a problem. Hot running is not normal and he is a real mechanic. Ferrari does some really dumb stuff but even a high school student can calculate the heat produced add a margin of error and voila that's how much radiator etc is needed. This is really dumb old tech. Under engineering the cooling system is not likely. Look for the fault and fix that. Kluging it is fine but it so much simpler just to fix it. If the t-stat is good, water pump good, hoses good I think you are left with the radiator. Radiators are expendable items you can't clean out since the days of the copper core. Some look at an expensive ferrari radiator and just want to "hope it fixed" any way they can. You can even custom radiators for increased capacity. A custom ron davis might be cheaper than ferrari. Oh...I should say that I'm a stickler for new parts. I often dump parts before thier life is over. I look at a 17 Y/O radiator and think that thing needs to go whether it does or not. But that is just me.

 

hi guys, in response to your question,my car runs just as hot as yours,it gets to the point that it pisses out the overflow, i live in glasgow scotland,so not the tropics, but if i can get her up to 55 to 65 mph then she cools down,mine is a 1995 ,6th jan registered car,it also helps if i put the climate control to max heat,max blower,to help pull some heat from the motor.great site.cheers,les.

 

John, not to disagree or argue with you, but placing the thermo switch for the fans at the bottom of the radiator means that the fans will turn on only after the radiator has done its job and if there is still residual heat to remove.
Placing the switch at the entrance of the radiator would have the fans running all the time.
Going to pure water or to a very minimum amount of antifreeze in it will definitely help.
A.

 

Thanks Lesthom….Welcome…

FBB….I’ll mark your vote as “Radiator.” So far I have:

1 – Radiator

1 – Thermostat

2(?)- Water pump mod

8 – “Mine does that too” (I went all the way back to my first post and counted six 456 owners and two 550 owners. All over the U.S., two in Europe and one in Canada. It’s Winter Downunder, so I guess they’re not worried about this now! At least two F-tech’s used by the previous owner’s have said it’s fine as well.)

FBB, you are correct that Dave Helms and you have always said there’s a problem. DH also posted I was getting ready to waste a lot of time and money (and that’s at the time when I suspected the rad).

The point is, I can replace the rad, t-stat, and mod the water pump. But will that improve anything? At least one 456 owner has replaced the rad, etc., with no results.

I’ve tried to provide as much info about the behavior of my car (and what “kluging” I’ve done to it), to see if anyone knows if I have something that needs fixing. Changing ALL the parts is, I suppose, one way to do it, but I was hoping for something a little less extreme in the way of advice.

Regarding Ferrari’s design, you’ll note the 456 WSM gives a test temp of 230F for T-stat full extension. The 2nd fan kicks in @ 215F. Are you sure they couldn’t have meant for the car to run above 195F, as our new Scotland friend says, in the tropics?

Again, I don’t feel my temps are so high that any harm is being done. If my little fans or John’s pure-water solution helps, I say “kluge” away…

Again, not trying to argue…really appreciate the input….

Regards to all….Mark in Houston…

 

I hear you Alfredo, but if what you say is correct, then why did Ferrari relocate both sensors for the 550 to the water manifolds - which is the absolute hottest point to measure coolant temps?

And on the early 575's one sensor was mounted on the thermostat housing cover, and the other on one water manifold. Then the later 575's had both sensors on the water manifolds.

I think both ways will work, they just require different on/off settings, but for me, I prefer to know how hot the coolant is leaving the engine, not how hot it is leaving the radiator.

I decided to fit some temporary instrumentation to my 550 to measure the temperatures at the radiator inlet & outlet under various driving conditions. I had some K thermocouples lying around, so all I needed was some thermocouple extension wire and a dual channel reader, which I picked up from Amazon for $30. This is a very cool little meter as it'll display both T1 & T2 or T1-T2 (differential), and it'll record T1max and T2max, plus will store 5 sets of data. I stuck one thermocouple on the radiator inlet pipe, and that's measuring T1, while the other thermocouple is stuck to the radiator outlet and is measuring T2.

What I've seen so far after only 15 minutes of testing is a deltaT of 20-25 degrees across the radiator when the car is doing 45-50 mph, and this deltaT drops to 6-8 degrees at idle and in stop & go traffic. Unfortunately we're having a very cool day today in Houston (88 degrees F) so I couldn't see what's happening in stop & go in 105 degree ambient, but I did pull the car into my garage and let it idle there & let the garage fill up with overheated air, and the deltaT dropped to only 2-3 degrees. Since both inlet & outlet were above the thermostat temperature, this condition would soon produce a thermal runaway situation, where the temps would keep climbing, which is exactly what's been happening.

So at the moment, since I get excellent deltaT out of the radiator with the car at speed, and lousy deltaT at idle, I'm still leaning toward the problem being airflow or coolant flow at idle.
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Nice looking throttle cable there

 

Mark,

I don't know. But what I do know is that in the mid 90's when these cars were new there were 100*F ambient temps and these cars were sold to those climates. At the time "when new" I don't remember any issues or owner complaints. What has changed since 1995? I don't think it is global warming... I think there is another physical cause. Of the "8 mine does that too", how old are their radiators? There are a zillion guys with High blood pressure. My blood pressure it high too is not a good excuse for maintaining that status quo. I wish i had more answers. I don't. I got some ideas but they are going to cost money to bare any fruit if any. Like I said I change such parts just because they are old. If I wait until I have a problem I have not been keeping my eye on the ball. My cars always run pretty darn nice as you could imagine.

 

Yeah I like! What where how and why. Is this a MSW project I missed?

 

http://www.ferrarichat.com/forum/showthread.php?t=333406&highlight=bling