Wondering if i have a issue in coolant system

[Grantkat]

I just replaced the radiator and heater core about a week ago. Both Nissen parts. Now that it is cold outside I an wondering if I have an issue.
The car warms up seemingly normal. When I started to use the heater I felt like the air could be hotter. Warm air comes out but I feel like it used to be hotter before the change. The upper hose becomes hot once the system is up to temperature, however the lower radiator hose is not warm, its cool to the touch.

any thoughts? what could I do to verify the system is working properly?

[Grantkat]

Additional information:

the car is not over heating even on long 70 MPH runs the Temp guage is where you would expect it to be. When you squeeze the lower radiator hose the coolant in the over flow tank moves up and down.
The upper hose is hot, the heater core tubes are warm, not as hot as the upper hose but noticeably warm.

[scot850]

Did you replace the thermostat? If the

I can't talk to how good the Nissen's heater cores are. I know some aftermarket units are not as large as the originals and may not give out as much heat. Although I have not had the issue myself with the heating system it could be an air lock in the system.

Take the car for a good run to get it hot. When you get home, jack the front up and support it and leave it overnight to see if it burps. Check the fluid in the morning.

Neil.

[Grantkat]

I did not replace the thermostat. However I may have been premature...I just put 2 different temp probes in the vents an both read 118 degrees F. So I may have worried for nothing.... However I may just go ahead and replace the thermostat...
I will jack it up overnight as suggested.....

[454cid]

I assume you're getting similar weather in OH, to what I am in MI. It snowed a few days ago with a drop in temperature, so maybe the heater is just having to overcome colder temps than before you changed parts?

Also, I'd wonder about the thermostat sticking open a bit.

I know you don't have a good reference now, but an IR temp gun is handy to have when chasing temperature related issues. I got mine at Menard's for something like $15.

[Grantkat]

I agree on that point. I have one but my grand son has dropped it a million times making the cats chase the laser. I please to replace it soon. I agree on that point

[abscate]

Cool lower radiator hose doesn’t sound right. I think the engine coolant only drops 10-20 F through the radiator ? Measurements needed!

On edit - missed the heater core replacement. Nissens are great, but did you get a firm, leak free seal of foam between the core and HVAC plastic? A small gap doesnt seem like much, but the gap has much lower impedance than the core, so it will mix cold unheated air from your core. See if you go to recirculate if the performance of the heater improves drastically, then its a heater core air leak. Not too bad to fix.

[Grantkat]

Are you talking about the foam with the adhesive that you place around the core? I can test the recirculate today and see. Reciruclate will change it to be warmer, you are referring to a significant difference?

[Grantkat]

I will also drive it today at lunch and check the lower hose and see what i feel in terms of temp difference. everything done yesterday was in the driveway. Whenever I squeezed the lower hose I got movement in the coolant tank equivalent to squeezing the upper hose. I am assuming that demonstrates that the radiator provides an unimpeded path through that part of the system, correct? In other words there is no blockage etc between lower hose and the tank....
I commuted to work today 35F outside temperature. The temp needle stayed right where you would expect and once it reached operating temp it did not move. 40 minutes travelling at 60 to 75 MPH. Though not definitive, I would think that means coolant is traveling throught the system.

[abscate]

I think your cooling system is fine. Once you go to recirc the cabin air will reach steady state and will be hot.

Then switch to outside air and see what the temp drop is.

Science. It’s a thing