how hot is too hot

Have you flushed and re-filled your coolant system lately?

 

Have you been bleeding periodically at the radiator just to get a feel for how often you should?

 

I've never seen my oil temp go more than 105C even when the water has boiled over. It does sound like you have a cooling problem. One of the air intakes leads to an oil radiator, and this has a flap to change between winter and summer settings. Perhaps you may want try flipping it and see if the oil temp is reduced? This won't solve your cooling problem, but may help keep oil temps down.
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Hi........

First of all, never add cold water to a hot system. Always let the entire engine cool down before you add any liquid. Might crack the block or heads or "reservoirs" in the system with cold water.

Better to use 50% antifreeze, as that mixture will possess a lower boiling point than a 25% mixture.

Worst case scenario: major decrease in oil pressure due to the high temperature. What are the "normal" positions of the oil pressure and oil temperature gauge needles ??

Good luck with the Texas heat !!

Frank........23005
www.masiarz.net/bb_resource

 

More antifreeze may make for a higher boiling point, but it actually LESSENS the effectiveness of the cooling system's ability to wick away heat and so then your engine would run hotter... MUCH hotter than just using distilled water and water-wetter. A 25% mixture is actually good ratio to use in a high-performance engine like a Ferrari.

 

Without a doubt that's true for the short term...

...but antifreeze is slick (the reason it is banned from race tracks as a spill hazard) for a reason, and that reason is to lubricate your waterpump. Less lubrication for your waterpump can, over time, reduce your water pump's efficiency, or even lead to a water pump failure.

 

It's great to have new fluid in there, but a real coolant system flush under pressure will blow out loose corroded bits of flotsam...something that merely draining the old fluid and adding new fluid can't do.

I don't know about your 308, but I can tell you that the manual for my 348 says that you can't remove the thermostat in these cars; if you do, then the water circulates ONLY through the engine, not through the radiator.

So if your thermostat is defective (or missing!), you'd be seeing the very behavior that you've been describing. A simple 160 degree (i.e. cooler) thermostat for our cars costs all of $5 (Aftermarket). Easy and cheap test.

 

my 348 in traffic , with 90+ temp , was running about 200 on the oil, and 210- 215 water . both arrows were just barely past the 12 o clock position..... i wonder if i installed a small electric helper fan would get that hot air out of the engine bay?

 

Hi.........

Please explain the comment about the effect of higher concentrations of antifreeze: "it actually LESSENS the effectiveness of the cooling system's ability to wick away heat and so then your engine would run hotter..." ?

Does not a greater concentration of solute increase the heat capacity of the fluid ??

Thermodynamics/physical chemistry people out there ?!

Frank.........23005

 

I still find it amazing that some of these little 178 cu in motors run up such high temps. It would be interesting to see how many of us really have the problem. I run 50/50 distilled water and phosphate free antifreeze and have no problems. Run the timing at 7DBTDC and just the other day it was 94 degrees out with 50%+ humidity and on the open road with the A/C on my water temp and oil temp is on the 1st mark on the gage. When I go into bumper to bumper traffic the water temp crawls up to 195 and the fans turn on and it stays there for a few minutes and then I can watch the temp go down. So either the mix it not right or the cats are a contributor or the timing is to far advanced or there is scale build up in the lines or the rad. Oh yeah I bleed the rad. once a week and on the 77 there is no bleeder on the top of the thermostat.

 

That's why you HAVE to have Redline or other brand water-wetter as a surfactant -- it also acts as a lubricant for your waterpump.

 

Glycol (antifreeze) is absolutely necessary in the winter (to lower the freezing point) but it being thicker than water it is not as effecient as a heat carrier. Here's a PDF file that explains some of the technical aspects.

Or, if you want to watch a flash demo of how it works (though it's a bit of a commercial), click here
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No, but it does raise the boiling oint of the coolant mixture considerably.

I.

 

"and on the 77 there is no bleeder on the top of the thermostat."[/QUOTE]




My 1977 308 GTB has a small bleeder valve on the top right of the radiator..
some don't? (Maybe my radiator is aftermarket.....)

Greg

 

Greg you misunderstood. In the later cars they put a bleeder screw on the top of the thermostat housing in the motor where the main hose enters the engine. All raditors have a bleeder screw on the top passenger side. With the thermostat housing bleeder it is easer to bleed the system.

 

Not as much as you might think... at 15psi pressure (and stock 308 cap is only 13psi pressure) it's only an increase of 15 degrees Farenheit (going from 250 degrees F with pure water to 265 degrees F with 50/50 mixture).

 

Water has a specific heat capacity of 1 cal / gm while glycol is at approx. 0.6 cal / gm. A 50-50 mix will give you 0.8 cal / gm. In a properly working cooling system this should work for engine loads of the full BHP of your engine in 100 F ambient temperatures.

If you are not running cool just driving around town then you have a cooling system problem that needs to be brought back up to spec.

The heat generated under racing conditions is around 15 to 20 times that of normal around town driving in what many call "severe" conditions. Ferrari cooling systems are larger than in other cars, they should run cooler unless you are pushing it on the track on a hot day.

Race cars use straight water. The water does not actually even get up to boiling and carries the most heat. Also, in the event of an accident the water does not make the road course slick. It would be very hard to remove.

aehaas

 

Indy (IRP) track event. 90 degrees ambient. Reasonable humidity. Running car hard at the track. 195 water temp. 220 oil temp.

My question: should I upsize the oil cooler or add a fan?

Response from QV London: check the (water) radiator. Water shouldn't run that hot at the track.
Philip

 

My BB512i runs around 90c water and 100c oil even in 90f+ 90% humidity Georgia summer weather unless I'm pushing the car hard. Even then, the water temp only gets to about 95c and the oil temp to around 115c, and when I ease up the temps drop back down quick.

 

195 and 220 doesn't seem crazy for a carb'd 308 (your profile states 77 B). What does your OM say?

 

The oil temp is fine, no problem there.

The water temp is acceptable too I think, but I wouldn't want to see the water temp much higher....it might be time to start thinking about a new radiator.

 

Mark, I agree. The 308s QV London runs at the track run cooler than I am seeing. Running the thing at 100 mph it shouldn't be trying to turn on the fans!

As the water temp comes down, so will the oil.

Franklin, if my high school math is correct, your 90 C = 195 F.

DTV, from memory, it states the max temps at which you should slow down.
Philip