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"Normal" engine operating temperature.

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M

Midget78

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"Normal" engine operating temperature.

Hey gang. Up here in North East Ohio we are starting to get some breaks in the weather entering Spring time. Yesterday the day was beautiful with temps into the upper 60's. I had my midget out on the highway for a good 30 minute drive and noticed the temperature gauge running just a little past the middle temperature range. One of my concerns with my Midget is the cooiling system as I have no leaks or anything but that radiator sure looks old. I recall guys putting on oil coolers and things like that because its my understanding these cars can run on the hot side. Is this true? Just looking ahead I am guessing when we get to the summer months around 80 degree days my car will probably get up close to that 3/4 zone on the gauge which in past cars gets me a little concerned. I have no clue what temp range the thermostat is yet I could start there with the lowest temp range that is offered.
 
Re: "Normal" engine operating temperature.

i have trouble gettin mine UP to temp on a cold morning. If you have doubts about your radiator, most radiator shops can flush and check it for you at reasonable $$.

mark
 
Re: "Normal" engine operating temperature.

Other things to check, water pump, hoses if they are old can be closing up inside and look OK outside, thermostat - does the car have one and if so does it work?
Does your heater work? That core may be clogged, or your heater valve may be old & constricting flow. Just think of everywhere that water flows and make sure it does.
 
Re: "Normal" engine operating temperature.

Sweendog,

About the only real way to tell is getting your Spridget out on the expressway for a long 25-30 mile romp at speed and see what the temps do. Bugsy around town will operate below the N mark on the temp gauge. A strong romp at speed will bring temps up proably 2/3rd of the way around the temp gauge. Slowing down on the off ramp I can see temps dropping quickly back to the left side of the N mark. Oil pressure will do the same, 60-65 lbs around town will drop to 55 lbs after 15-20 minutes at speed when engine temps climb. Still within range however. After engine cools down on off ramp, oil pressure quickly rises back to 60-65 warm as well around town.

Make sure coolant is clean, get the radiator and heater core flushed and you should be good. Add a 180 or even go as low as 165 thermostat for the summer and you'll be good. I did change out the 40 y.o. 9 row factory oil cooler last year to a 13 row new oil cooler. Logic saying there has got to be so much crap trapped in there after 40 years. I do now notice slightly cooler radiator temps and oil pressure probably 5 lbs greater at speed after making the change out.
 
Re: "Normal" engine operating temperature.

Down here in sunny Johannesburg.

I to get concerned if the temp approaches the 3/4 mark. After flushing everything in site and checking that there was enough oil (an embarrassing story here) I found as per my travel for the South African spridget tour that the water pump comes in 2 different sizes. Get the larger diameter one. This topic was discussed about 9 -10 months ago, see if you can search for this topic.
 
Re: "Normal" engine operating temperature.

SilentUnicorn said:
i have trouble gettin mine UP to temp on a cold morning. If you have doubts about your radiator, most radiator shops can flush and check it for you at reasonable $$.

mark
Click to expand...

Mark, I had the same problem you are experiencing, and I spent maybe $10 for a new 195 degree thermostat and gasket, and problem is solved.

takes all of 10 minutes to complete the job, I highly recommend you do this for the winter months.

my car would only get to about 1/4 of the range, and with the new thermostat she sits right in the middle of the range.

I will be putting back in the 180 degree thermostat for the summer months.

hope that helps
 
Re: "Normal" engine operating temperature.

Thanks,
I will keep that in mind.

m
 
Re: "Normal" engine operating temperature.

Mine runs 180 in the summertime, but I have trouble getting it up there in the winter. I had a winter front on it last month when I drove it 30 miles on the highway and still could only get it up to 160.
 
Re: "Normal" engine operating temperature.

I've thought about that Joe, but it kinda scares me too. All the overheating stories you hear. I have also thought about rotating a 195 and 180 winter and summer, but nixed that. I don't drive it enough in the winter to warrant that.
 
Re: "Normal" engine operating temperature.

if you're not running the car in the winter, the change isn't worth it.

thermostats are not there to prevent the car from overheating, it's there to raise the temperature of the engine to the desired temperature, and maintain that temperature. if a 180 degree thermostat is unable to raise the temperature of the engine to the desired level say during winter, you run the risk of other problems: oil viscosity, contaminant buildup in the oil, heater not working and greater wear on the engine.

having a higher degree thermostat does not increase the chance of overheating at all, unless you have other problems like a bad water pump, or blocked coolant passages or clogged radiator. then you want the thermostat open as much as possible to keep the coolant flowing as much as possible. but in that case, you probably just want to remove the thermostat or fix the problem.

When an engine runs cold so does its lubricating oil, which means more potential for moisture and acid to form in its oil. At higher temps (both oil and engine) harmful deposits are boiled off. This prevents the slow destruction of bearing material and shortened engine life. When an engine runs too cold, the fuel economy goes down. Wear increases because of two factors. First, the cold engine doesn’t heat the oil sufficiently and harmful deposits, moisture, and acid accumulate rapidly, then eat away at the inside of your engine. it is very important to ensure your engine is at optimal operating temperature to burn off those contaminants.

at least that's what my father told me !!!! he has been know to be wrong before, i'll let others either confirm of contradict what I learned.
 
Re: "Normal" engine operating temperature.

For rare winter running, partially blocking the radiator with a piece of cardboard will warm it right up and hold it there. Finding the nominal size of cardboard to use requires some experimentation. Start large and carry a box cutter.

Jim
 
Re: "Normal" engine operating temperature.

Joe
As far as what you said about the T-stat temp and overheating, you're pretty much on target. The engine has to run up to temp. to be efficient on all fronts, (oil, fuel, wear and tear).

If you are going to run a cardboard plate in front of the rad, Please cut a circular hole in the center. I have seen fan blades come off because the plate covered only the lower half. This causes a change in the air flow top to bottom. The fan pulls harder on the bottom and flexes the blades. In some cases, they will self-destruct. This isn't pretty.

Dave :savewave: JMO! Not trying to scare anyone
 
Re: "Normal" engine operating temperature.

It scares me when the temps approach 190. The electric
fans sensor switches on at 185. I hit the manual over-ride
after 170. It will rise to about 190 on shutdown with the
fan off. Reading these posts have made me feel better about my operating temps. It stays a stable 170 or so when running hard with the fan on. It does have a larger water pump and radiator.
I guess I need to see if the water is circulating and the thermostat is open at those temps.
Should I just let the thing run around 190 and let the auto fan do it's thing? Is this higher temp better for the engine?
How high is too high? What is too low?
 
Re: "Normal" engine operating temperature.

If you have a pressurized system, (you do) then a temp of 190 isn't all that high. The boiling point is likely around 230, so you can see the difference.
The new cars (aka fuel inj.) all run around 195 so that fuel is burned properly. That is one of the ways they meet the emission standards.

Do you have an electric fan on your car, (sorry I came late to this thread
and may have missed that).
If it is automatic, then I would watch it the first couple of times out, but it doesn't sound too bad to me.

Dave :savewave:
 
Re: "Normal" engine operating temperature.

The previous owner put in an electric fan/aluminum
radiator w/ the oversize water pump and removed the belt
driven fan. It does have a 16 row oil cooler.
I think I'll resist the fear next time out and see what happens.
I'll check to be sure the fan switches on too.
I'd like to do what's best for the life of the engine and
not be a nervous ninny.
I don't trust those "low/high" gauges. I like a numbers reading.
Preferably a mechanical one.
My old Land Cruiser had "guessimate" gauges for oil and temp.
They too made me nervous. I installed real gauges and feel much better when I'm beatin' up the beast.
Are the Mk1 gauges electrical? They have real numbers but are they mechanical?
 
Re: "Normal" engine operating temperature.

The MK1-3 Midget/Mk2-4 Sprite has a mechanical gauge. I don't know about the 1500 though.
 
Re: "Normal" engine operating temperature.

1500s had the bourdon-tube water temp gauge right up till 1978.

Which reminds me, if you have the C-N-H gauge, (or even a degree gauge if it's the original 40-year old one!) you'd do well to check its calibration, to see just what temperature "left of N" really is. Uber-simple to do. One person can do it, but it's easier with two. Just take the sensor out of the engine, and immerse it in an insulated mug of boiling water, with a thermometer in it. Look at your gauge, and make a note of where the needle is at 212. Now, take cold water, a little at a time, until you can drop the temp in the mug by 10 degree increments. Each 10 degrees, make another note of where the needle is. If you're picky about such things, a little dot with a sharpie on the bezel can remind you where the divisions are. Quick and easy, and you'll always know just where 185 is on YOUR gauge. It's saved me a lot of needless worry.
 
Re: "Normal" engine operating temperature.

so what was used for after 1978? As opposed to the bourdon-tube water temp guage?
I had a brake in the tube which leaked out the ether. Found out it costs about $175 replace. I notice I can get an electrical temp sender for about $8 but need a gauge that can read an electrical sender. Any idea if there is a dual gauge with a oil pressure / water temp reading that would fit in a 1974 mg midget console?
 
Re: "Normal" engine operating temperature.

I used the wife's digital lazer temp sensor to verify the gauge.
They sell them for hobbyists to check temps on gas R/C cars too but the wife's is for checking roast's temps.
Point and shoot with a digital read out. The Sprite's gauge was spot on.
 
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