Which radiator hose should be hot

I took him back to his hotel for the night. In the morning, I picked up my friend and we got more coolant. I verified that my own car ran halfway up the gauge and that its lower radiator hose was warm, so clearly the thermostat on my car was opening and my gauge and sensor were working correctly.

After we bled his system—which made no difference—I then began swapping cooling system parts with my car. I did the easiest one first—the coolant temperature sensor. I swapped sensors and found no change; my car still read in the middle of the gauge, but his still started low and floated into the red as it warmed up.

Next, I swapped thermostats. I asked my friend about his radiator. He said it had recently been re-cored. Still, it seemed likely that the radiator was the problem.

They asked what we were doing, and I gave them the rundown. And when you undid that radiator cap, it would blow coolant everywhere and burn you. I realized that he was right. After all, when I foolishly undid the temperature sensor from my car earlier, it released pressure and coolant shot out.

Suddenly, swapping the gauge clusters was no longer an academic exercise. My friend removed the cluster from his car, and I yanked the one from mine. We put mine in his, and to my surprise, the temperature read only about a quarter of the way up the gauge. So maybe it was the gauge.

Note to add, the cooling system is under pressure as well to prevent boiling. At the kind of temps I am getting I would at least think my radiator would have a warm bottom hose as well. The thermostat would be well open at that time and with the air going through everything the temps should drop. Just seems to strange to me. Other users report temps of mid 80c during highway use — Booki. Yep, mid 80's is fine Check the top hose carefully!

Remember radiators are specced for extended periods of max load, so must be able to cope with the engine running full throttle. Highway use is very light loads. Yes, mid 80's is what I want. My car is running mid 90's at times with high way driving, unless I start going down hill, the temp swill fall to a good level low to mid 80c, because of the down hill driving I suspect maybe it is a flow issue somewhere.

I updated my original post with additional info, I have swapped the radiator to a genuine one although from a automatic car, but basically the same to me.

This amateur racing site takes a very scientific look at coolant. Worth a read if you want a better idea of how the water-coolant mixture and pressure of the system raises the boiling point. Add a comment. Carguy Carguy 1, 4 4 silver badges 10 10 bronze badges. I wish it was this simple, the car actually has a brand new short block. The coolant always appeared to been have maintained prior replacing the shortblock. JDubya JDubya 1 1 silver badge 8 8 bronze badges.

Thanks for the comment JDubya, I have updated my original post with some more information about the car. I am indeed worried about uneven cooling throughout the car. In my climate Australia , It is our winter at the moment, average max temps are about 12c. Its rare we get any temperatures lower then 0c.

You may be right that there is a issue with a lazy thermostat. From other forums and members I have spoken too, most people seem to get mid to low 80c temps while driving at high way speeds. Stop start normally low 90's. Mine is hitting the stop start tempretures at the high way, its not ideal I would say. While the temps are nothing to really worry about in terms of how the engine was designed to run, I do want to preserve the longevity of the engine and run it ideally around 80c.

Perhaps I will look into a thermostat that opens sooner. Really, Booki, you should not see much change in the temperature on a standard gauge anyway speeding up or slowing down, etc. The speed of the water pump's affect on the temperature is almost minuscule compared to the shear mass of the water.

The only temperature variation that you should see is from the overload or underload caused by speeding up and slowing down and it should be quite small.

If others are seeing 80c temps and the thermostat is designed for 92c open and the weather is cold near 0c then the engine is being operated too cold - so much so that the thermostat is having inconsequential effects - it is closed totally and the engine cannot heat the coolant sufficiently to satisfy heater load and air blowing by.

Detailed information about all U. Posting Quick Reply - Please Wait. Similar Threads air brake hose replacement , Automotive, 2 replies What hose is suppoed to there? Which radiator hose gets hotter? User Name. Remember Me. View detailed profile Advanced or search site with. Search Forums Advanced. Advertisements From what I have read, the radiator hose connected to the thermostat should get hot quickly within a few minute of start-up as the thermostat opens and circulates hot coolant from the engine to the radiator.

Location: U. Quote: Originally Posted by davidt1 Wow, you have answered my question and then some. Location: Blah 4, posts, read 8,, times Reputation: If the readings are correct, the thermostat is probably working properly. An easier, but less exact method is to keep an eye on the temperature gauge inside the vehicle.

If the gauge starts to climb toward the red or HOT portion of the gauge, then you most likely have a coolant flow problem and this should be checked right away. Always make sure there is enough coolant in the system. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere. You can E-mail us at macsworldwide macsw.