Now that it is getting cold, so is my motor. Is it a problem?

[Healey Z]

My car is probably a little unique from others here from a cooling perspective.

The car: 1963 Austin Healey 3000 with an L28 with an original (over sized) Austin Healey radiator. I have had it on the road since this past Spring. The temperature sensor is located in the radiator and the sensor and the gauge are original Healey pieces.

I live in Sacramento, where it is scorching hot in the summer. We will see a summer full of 100+ degree days and in the winter it gets down in the 30's in the morning, 50's during the day.

This car is no garage queen, I drive the car a lot. I drove it to a "shine & show" 20 miles away this summer and it was 105 degrees that day. Going up the "mountain", it peaked around 210 degrees. I have an electric pusher fan on the front of the radiator, hooked up to a toggle switch on the dash, when driving around town in stop and go traffic. The normal temp that it would run around town would be 190. I felt the cooling system was put to the test this summer and I think good enough.

Now the temperatures have dipped into the mid 30's in the morning and 50's during the day. When I replaced the motor (the car already had a Z motor), I put a new thermostat in it. It takes its time to warm up, to where it runs decent without the choke 10 minutes perhaps, but it eventually does. Even after driving for 20 minutes, I can't get the temp gauge to go past 125.

How long do you guys with carb'ed motors run with the choke on? Do you think I should look for a way to increase the temp the motor runs at during this colder weather? If so, what could I do to have it run warmer in the winter, yet not impact my ability to have the motor run cool in the heat of the summer?

[Z train]

T-stat is opening early or hanging open

[madkaw]

what he said

[5thhorsemann]

I think the problem, if you want to call it a problem, is the sending unit being located in the radiator. I think you should move it to the stock L28 location for a more accurate temp reading, I think you are reading post cooled water, for lack of a better way of saying it.

[Gary in NJ]

I run the choke for about 30 seconds. Like the others have said, your T-Stat is the problem.

[Zed Head]

I think the problem, if you want to call it a problem, is the sending unit being located in the radiator. I think you should move it to the stock L28 location for a more accurate temp reading, I think you are reading post cooled water, for lack of a better way of saying it.

If 5th is correct, then your engine might be running at the proper temperature, you're just not seeing the true engine temperature on your gauge. You might see if the Healey sensor and the Nissan sensor have the same resistance versus temperature characteristics and adapt the wire to the Nissan sensor, or see if you can adapt the Healey sensor to one of the holes in the Nissan thermostat housing.

[Healey Z]

Thank you for the responses. The Healey temp sensor is located at the top of the radiator, where the exiting water from the block would flow. Earlier in the summer, I borrowed a thermal gun to verify the motor temp to what my gauge was reading and it was pretty accurate. It is easy and cheap enough to change the thermostat, which I could do.

[5thhorsemann]

Is the water level in the rad all the way full?

[Healey Z]

Oh...5thhorseman. That is a very good question. The Healey does not have an overflow tank and the sensor is near the top of the tank. Having just come off the 105 degree days, I guess it is possible that sensor is sitting in air...I will check it.

[Healey Z]

5thhoresemann, you're the man. That was exactly the issue. I filled it up to above the sensor, but below the top, so all should be good.

[5thhorsemann]

Good deal.