How Hot Does Your 456/550 Run? (Revisited)

Hi All:

I started a threat last summer and got some great advice. Had some new info, so thought a new threat was called for. Here's the previous thread.

http://www.ferrarichat.com/forum/456-550-575/379604-how-hot-does-your-456-550-run.html

To recap, my 95 456 GT was seeing coolant temps to almost 215F in traffic, with A/C on and 90F+ ambient. No problem when running at speed. I added two 7" cooling fans and could get to about 210F. Suggestions were radiator, water pump, thermostat, fan, antifreeze, "that's normal", etc.

Changes this spring include a new thermostat, Ferrari # 226484, (apparently a European part, see Cribbj's 456/550/575 Cross Reference thread for discussion and pricing). Anyway, the dimensions were the same as #183758 and I tested the old and new in boiling water. 25mm cold/closed and about 34mm at 212F for both (See WSM pic below). Sooo...it wasn't my stat.

While at it, I changed the antifreeze ratio down to 40/60 water and put in a pint of NoRosion (thinking of increasing the heat carrying capacity of the coolant).

Results.....nominal. It's not yet regularly over 90F here yet, but still see the needle go to about the 2nd mark past 190F, or about 207F. However, it doesn't seem to go any higher than that. So I'm calling it a success. More NoRosion and water would probably get me to my target of 195F.

Still, I continue to think the bypass closure by the thermostat could use some help. Note the WSM shows max extension of the plunger of 35.5mm at 230F. I get about 34mm at 212F. Could those few mm's between 200 and 230 make a difference?

Unfortunately, I forgot to measure the distance from the top of the thermostat housing cover surface to the bypass port (the distance the plunger has to travel to close fully). Damn... I was too busy trying to preserve my old gasket and O-ring (new ones didn't come with the new stat) and forgot all about it! That dimension would have told me at what temp the plunger fully closes on the bypass port. If anyone takes out their thermostat any time soon, Please measure and let me know.

My thought was, if there's still a gap at say 200F, perhaps a stainless steel washer could somehow be welded/mechanically fastened to the plunger and close the bypass at a more desirable temp!

Also, got a look at the inside of my radiator for the first time. A chemical flush wouldn't hurt but tubes had no scale on them for as far as I could see (which admittedly ain't that far).

BTW, I recalled something about the position of the jiggle pin when installing the stat but couldn't remember what it was. Searched here for "jiggle pin" and sure enough Cribbj had advised to place it at 12:00 high. Old one was at 5:00. Thanks John. There's an arrow on the new stat, 180 degrees from the pin, but it doesn't indicate up or down. Chose down???

Regards.....Mark in Houston
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Thank you for sharing Mark.
My car runs at about the same temperature in similar weather conditions.
As long as the traffic is moving the temperature is between 190 and 200 F, if the pace is good, but when stopped at traffic lights or at snail pace the needle goes to 215 F and stays there.
It does not go past 215 F, but I get nervous.
My take is that air flow through the radiator seems to be the problem, or to put it in another way, the radiator does not have enough capacity to offset the reduced air flow when the car is not moving.
The fact that the M has a larger grille opening would seem to support that theory, IMO.
It seems to me that it should be possible to fit a different radiator with more cooling capacity or to replace the stock cooling fans with others, capable of higher air flow.

 

Mark,

that's very similar to my 550's behaviour.
Changing the thermostat did not make any difference for me.
The improvement came from reducing the antifreeze mixture from 50% to 33%.

Stefano

 

Does not seem to be as much a problem on the 575M, which has a higher flow water pump and improved radiator fans. John Cribb has done quite a bit of work in that area.

 

I just sat in line for 20 min waiting for the Fremont bridge to open up (it's a draw bridge) in Seattle, temp stayed at 190F, fan kicking on and off every few minutes. Pics show what the temp gauges read running on the freeway in 65F weather.

2001 456M GT6

Martin
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If your car is running hot, there is probably something wrong. My car was running near 220F on a hot day in traffic and I found several issues with it when I went looking. I found that the connector to the main fan was partially melted, the main fan itself had a broken housing (allowing flow around the fan, not through it), and the radiator was full of crud on the air side.

That last one was probably the biggest part. Heat exchangers get clogged over time with dirt and is a common maintenance item most people don't think about with a radiator. If you look at the 456 radiator, it has the highest fin-per-inch count of any car I've seen. Periodically it will need to be cleaned.

On a related note, it pays to ensure that the bleed hose at the top od the radiator back to the surge tank is clear so it can do it's job. Mine became blocked over time and this created an air pocket at the top of the radiator, reducing it's effectiveness.

In terms of modifications, I would stick with the stock parts for the thermostat, etc. Having said that, my radiator developed a leak that was unrepairable, so I went for the Ron Davis radiator - seems to perform really well so far...

 

Concur Alfredo. See my original thread. I was able to shave about 5F off the temp with two 7 inch cooling fans configured to “push” into the A/C condenser coils. See pic and wiring diagram below. These mounted quite nicely using two of the existing studs on the coils and zip ties on the framing above and below (no change to the original stuff or drilling). Got everything for under $100, IIRC. Also, was concerned that the extra fans might actually block airflow at high speed and keep it from running nice and cool way up there. They don’t.

Stefano, also concur. Think I could shave another 5F off by going to 33 % antifreeze.

Taz, Yes, John and I have corresponded a lot on this and he’s done all the mod’s you mentioned. Last summer he went to pure water and that ultimately fixed it for him. I think he’s now going with a custom rad.

Martin, I hear the M does better and as Alfredo said has a bigger opening. While at first I dismissed this theory, with all the fans I now have, you can actually feel air being forced back out the grill when stopped. So it’s not getting all the airflow possible over the rad from the fans. Conclusion: larger grill might have helped, certainly don’t know for sure. Also, no problem for me at 65F ambient. It’s the 105F on the pavement that drives it past the middle when stopped.

Dean, I've pretty much checked the things you mentioned, including the ¼” hoses, which aren't the “good” ones but were replaced not long ago. Also checked them when doing the ‘stat and found no restrictions. And, I'm mindful my 18 year old rad probably needs attention, although haven’t heard of anyone that’s had them professional cleaned and had cooling improvement. I think most of the problem, not all admittedly, is the radiator size and airflow. And, remember, as someone else said, your hot day is my spring morning. If I were seeing 220F (and some are), I’d be worried too……

At 205-210F, I'm cool with it (pun intended).....

Finally, on mod’g the thermostat. I now have an extra one to fool with, so it would be an interesting project. Again, if anyone has their ‘stat out, please measure the depth to the bypass port.(See last pic.) Still kicking myself for not doing it while I was in there…

Regards….Mark
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Terry, you tickled my curiosity with your comment: if the radiator fans of the 575 are an improved version, would they fit the 456?
Do you have any airflow data for them?

 

Nice work Mark.
Another thought I had was to improve the exit of the hot air from the engine bay.
We have the vents on the hood and tiny openings on the sides, but we also have that pan at the bottom of the engine bay that tends to trap the hot air in, when the car is not moving.
Unfortunately I do not have a lift in my garage to study this avenue in any meaningful way.
About the coolant mixture, I am not too familiar with Houston weather in winter time, but I know it is bloody hot in the summer.
If the winter temperature is not too low, why then not go to just water and anti-scale mixture, rahter than anti-freeze?

 

Alfredo, the 575 fan & motor resembles the "Bosch" or Siemens style fans that are found on the German cars and Volvo's, however the 575 versions are actually made in China, best I can tell. These fans will mount in the same holes on the 550 shroud as the 550's SPAL fans, and actually the shrouds themselves are interchangeable. I have a thread going on another site with more detailed info and pics, but if I post a link here, it'll get xxxx'd out, and I'll probably be booted

I think the "real" improvement in the 575's fan arrangement has been with the shroud, as it fully covers both the radiator & oil cooler cores, unlike the 550 shroud which, IMO is a cr*p design, as it leaves perhaps 15-25% of the cores uncovered, so the fans pull no air through the uncovered areas, and the only airflow is at speed.

As to whether either the fans and/or the shroud would work for the 456, I think it's doubtful, as the 456 models have two different size fans and a completely different shroud than either the 550 or 575, along with a completely different type of radiator (either single or three pass vs the 550/575 radiator which is two pass).

If you can confirm that at least one of your fans is the 16" SPAL, with 10, thin, curved blades that look like skinny scythes, then you could replace this fan with the new style 575 fan, but I doubt that you'd see a significant improvement. I've "subjectively" compared the airflows of the 550 and 575 fans and haven't seen/felt a big difference. Below is a drawing of the 16" SPAL model 30102113 that Ferrari uses for the 550 setup, and might be the same as yours:

2nd pic is what the 456 fan/shroud looks like

3rd pic is a 550 fan/shroud mounted on a 550 radiator

4th is a 575 shroud mounted on a 550 radiator, and you can clearly see the improvement in core coverage over the 550 shroud

5th is a soon-to-be Skunkworks fan/shroud for the 550/575.....oops - can only post 4 pics.
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Thank you John,
Now I have some homework to do.

 

John- You can post more than four attachments. Just do the first four, upload, and start over on the next four.

 

I did check the fans on my car and they are exactly like those you have in the picture, with straight blades.
Switching to curved blades may improve somewhat the air flow and most likely also the noise these things make.

 

Alfredo, I suspect your larger 456 fan is the same, or very similar to, SPAL model 30102120, which is a 16" puller with straight blades. It's slightly smaller than the 30102113 fans used in the 550 and the mounting holes are very close but not quite the same. You might be able to make the 550/575 fans work by slightly enlarging the existing mounting holes in the fans.

BTW, here's a couple pics of the prototype Skunkworks shroud & fans for the 550/575. I'll hopefully be testing this setup this summer if I get my "major" finished in time I'll also be testing them on a new, larger capacity radiator that I've just had designed by a major radiator manufacturer that supplies the Indycar crowd with cooling systems.

The fans shown are slightly larger than the OEM fans for the 550/575, and their Bosch motors are significantly more powerful. They're also 2 speed motors, however I'll probably only use the high speed setting along with external variable speed controllers to avoid having to switch the motors on/off to control the cooling. On/off switching is really tough on the motors, their relays, and the rest of the rather marginal electrical system on the Ferrari.
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John- That is looking really good. If I had an overheating problem, I would be a customer.

 

My car had been running too cool until I recently had a temp sensor, as well as my thermostat, replaced. I'll be stuck in traffic tomorrow with the air temperature about 81 or so and I'll take a snap and post.

 

That is 20* cooler than what john experiences. If you get an overheating problem at 81* you got organic problems.

 

Allan, when you say too cool, you mean below 190? I was looking at Martin's pic (post #5) at 60 mph. Looks too cool to me. Temp should always be 185F+, No? Computer doesn't like cold coolant...

And...Don't tell me you guys in the Arctic are having a cold running problem.... THAT I can fix....

Regards.....Mark from the Tropics....a chilly 93 here today...

 

Alfredo, got to 23F where I live a year or so ago. In 1989, Galveston Bay (salt water), started to freeze over......was 15F where I live.....Texas, even near the coast, can get really cold, every once and a while...

Regards...Mark

 

The straight blades of the 456 fans is also the reason why they are noisy, I am looking to replace at least the large fan with something quieter.

 

This fan is cheap and has curved blades:
Ferrari ACP 12" Universal Pull Radiator Cooling Fan Curved Blades New Unit | eBay

The 550's OEM curved blades are also noisy though....

Stefano

 

Coolant temp had been reading around 160, so I took it in to Craig Nelson (Monza 456) and he ended up replacing both the coolant temp sensor and the sending unit, which was bad.

 

Boy, 81 F is our early morning temperature these days down here.

 

Ok, never mind: I will stay in Florida !!

 

Late afternoon, sitting in traffic, ambient outside temperature 86 degrees
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