Can a car run too cool?
 

My car normally runs around 180 deg. I have taken it out on a few colder nights (50-60 deg.) and the engine temp was around 125 deg. The engine was running fine unless I hit the gas hard and then it stuttered. I figured the problem might be the car is not running at its normal operating temp so that whole fuel air mixture combo was a problem.

Anyone have a similar situation.

If you see a cobra driving on a cold day with cardboard blocking part of the radiator it might be me. Just kidding!

Running that cool is not cool. :3DSMILE:

It sounds like your thermostat is stuck open (unless your temperature sender is in the radiator return line).

Jams,

I don't know about all the other motors but mine need to run around 210-225 as that is where they make their power. I have seen the NASCAR guys come in and tape off most of their grills on cold days because they couldn't get the motors up past 200. That also helps their downforce. If your fan is running you might try shutting it off and also stopping the oil to the oil cooler to see if that will bring your operating temp. up.:confused:

Jams - You need a certain amount of heat to boil off water condensate in your oil. Your oil/motor will build up sludge if it is too cool, to much. Synthetics help this, but IMHO it is more important to watch your oil temp. As for water temp. the cooler the better by in large unless it's so cool that your oil temp. goes south. And yes your right. the A/F ratio can lean out due to cooling or even iceing on/in your intake manifold. (depends on type of manifold your using) In most engines 180 to 200 degrees coolant temp. is just about right.
cobrashock

The higher temps help evaporate the fuel "atomize ".That is why they use chokes.So enough fuel will be in a burnable state to get ignition . As the temp comes up ,more fuel is evaporated quicker and the choke is needed less. The Warmer the air the more fuel it will entertain but that air charge is less dense.The air charge will have less Oxygen available in that charge to support combustion. If your engine never sees 180°. You'll wash down the cylinder walls ,dillute your oil. When I was searching for a high flow thermostat for my FE ,I was told to stay above 180° . The higher the temp the more power you'll make ,up to a point of deminishing returns.Too much heat and it is hard on engine parts like pistons ,rings and valves.They will only take so much.My thing was keeping temps stable.When temps get too high the coolant boils next to the parts being cooled .Heat removal is deminished. and temperatures start to get out of hand. Cobra replicas don't have the usual cooling systems and make a bunch of heat.It usually works fine ,but when something out of the norm happens temps esculates like mad.Like coming off the highway to stop and go traffic on a hot day, you' behind the curve alllready.How much will your prescious engine take? Also the higher the pressure the higher the boliing point but how much will your system take like coolant pump seals , radiator and hoses and gaskets?It is a dellicate ballance at best.You make your choiches and takes your chances and then pay the price.That temp gauge is there for a reason watch it and take action when it is indicated.

What about the oil temperature ? Water temperature is about 180 - 200 deg. Based on your replies that sounds reasonable. Oil temperature is often below 140. What's the best range for the oil temperature ?

All engines have an optimum operating and coolant temperature range. Since about '72, this has been 180 - 210 deg. Engine clearances are designed to operate in this range. Too high, and the clearances tighten up resulting in accelerated wear. Too low, and clearances are too loose resulting in blow by, sludge formation, water and fuel contamination, and accelerated wear.

Need to keep coolant temp within operating range with correct, and functioning thermostat, and thermostatically controled fan with manual override switch.

The override switch lets you anticipate high coolant load when coming off highway into stop-n-go traffic on a hot day, or stuck in 0 - 10 MPH rush hour traffic.

Walt347- Oil temps usially( this varies) run about 30 degrees more than the coolant temp. I know I am going to ge flamed for this, as I have in the past stated this stuff but here goes. The average car, and that inclues Cobras, does not need a oil cooler. Oil coolers were a 60's performance/racing thing and we have come somewhere since then. Synthetics, aluminum parts everywhere, better designed pans the list goes on and on, all have changed this. A better choice would be to use a racing heat exchanger that cools on the high heat side but also heats up oil when your engine oil is cold on startups and cool conditions.
Gordon Levy used to sell one about a year ago that is made for Cobras, I don't know if he still sells those heat exchangers though. Of course you won't have that "look" in the front of your car of a oil cooler unless like me you use it for a automatic tranny, or as a dummy. Racing supply shops will sell you a oil heat exchanger if you look for them but they are bit salty. I fabracated my own.
cobrashock

Ron, I did'nt know that. I thought an oil cooler is a real must for a Cobra (even with a SB). Thanks.

Walt- I think Ron is refering to an oil to water heat exchanger as opposed to an oil to air exchanger. The oil to water exchanger can be built into the radiator or installed in line with the radiator hose. My oil runs 30 degrees more than the coolant temp on the track and about the same as the water on the street with it. The oil to air cooler kept the oil too cool on the street unless I blocked the air flow to it.

Scott

The solution is easy
 

Use an oil cooler thermostat...that way it only flows thru the cooler if you really need it. Such as a blazing hot afternoon stuck in traffic.

Yes - I was talking about a oil to water setup. Guess I should have clearified that. BIB - A thermostat is ok, but with the oil cooler most cobras have there is no provision to heat your engines oil supply up in cold situations. If you are doing any track work at all or plan on driving your car on cool days there is no substitute. With the aluminum parted crate motor you are planning on using there is no choice in my mind. Time to get "modern" with those updated engines. Another option is to use both if you have them, on really hot days of course. In any rate todays synthetic oils can withstand much more heat and do a much better job of carrying heat away from engine parts. I'll stand firm on my oil cooler statement above. In most cases where engine cooling is not a problem, there is no need for the air to oil coolers that I see on most Cobras.
cobrashock

Jack21 is right on the money.

This reference from an earlier thread:

http://216.239.33.100/search?q=cach...&hl=en&ie=UTF-8

addresses the relationship between coolant temps and engine wear. Yes, I know it's based on tractor engines, but the principle is the same. Cooler engine temps can cause accelerated wear of internal components, as well as decreased power output and increased emissions. Now, most of us don't use our cars as daily drivers, so the slight increase in engine wear may not be as important as it is in the family Saturn. And, given the HiPo nature of the cars, I suspect that most owners aren't overly concerned about elevated levels of emissions. But lower power output??? Blasphemy!!! Proper coolant temperature regulation is best for that.

As to oil temps in cool weather, I confess to doing what several others do. Stuff a rag in front of the oil cooler for those fall rides.

In one of the Ford "How to" books, they presented some info that is in line with what Chopper referenced. I am not sure if they were alluding to coolant temp or oil temp but, in some instances, engine wear increased 80% plus if the temp was not up to snuff. I will try and find it and scan onto this thread.

B in B-
Where in the system do you install the oil temp thermostat? Do all oil coolers provide for the use of a thermostat or do you need to add something extra to the system to use a thermostat?

Thanks in advance,
Mike