My friend complained of poor heat in his '08 Hyundai Sonata. The car is in great shape with only 17x,000 km (so not much over 100K miles).
Checked it out yesterday evening. Lots of hot air pouring out of the vents at present, but it's been hot here. Winter, when you need the heat, is the real test.
In diagnosing poor heat I look at three things:
1. Is the vehicle coming up to temperature? Yes, per the temperature gauge (just a hair under halfway between C and H) and per my ScanGauge (c. 90 C).
2. If so equipped (and the Hyundai is), is the blend air door operating correctly? Yes, it seems to be. The air coming out of the vents goes pretty quickly from hot to ambient when the temperature control is turned from hot to cold, and vice versa.
3. Is there good flow through the heater core? Both hoses to the heater core were hot, indicating that coolant is passing through the core fine. To be sure, we unhooked the hoses at the heater core connections at the firewall, attached a long rubber hose section to each pipe, and flushed both ways with a garden hose. Blew compressed air through to clear the water out. Didn't get much if any sediment out, and the flow was good. (Captured all of the coolant in a big pail, so I don't think we missed any sediment.) Bless Hyundai for good access to the connection points. Don't know if the V6 is as accessible, but the inline-4 was great.
But here's the thing - of course the coolant will come up to temperature in this balmy weather. What we don't know, but suspect, is that the (original) thermostat is weak and is opening prematurely, not allowing the coolant to get hot enough in cold weather conditions. But how does one diagnose that when it's hot out? Yes, one can remove the T-stat and boil it in a glass pot with a thermometer and watch for it open, but at that point why not just replace it? Is there an easy way to test for a weak thermostat in-car when the weather is hot enough that the thermostat will definitely open anyway? Would way rather work on the car now in late summer/early fall than once it's cold out!
Thanks in advance.
Checked it out yesterday evening. Lots of hot air pouring out of the vents at present, but it's been hot here. Winter, when you need the heat, is the real test.
In diagnosing poor heat I look at three things:
1. Is the vehicle coming up to temperature? Yes, per the temperature gauge (just a hair under halfway between C and H) and per my ScanGauge (c. 90 C).
2. If so equipped (and the Hyundai is), is the blend air door operating correctly? Yes, it seems to be. The air coming out of the vents goes pretty quickly from hot to ambient when the temperature control is turned from hot to cold, and vice versa.
3. Is there good flow through the heater core? Both hoses to the heater core were hot, indicating that coolant is passing through the core fine. To be sure, we unhooked the hoses at the heater core connections at the firewall, attached a long rubber hose section to each pipe, and flushed both ways with a garden hose. Blew compressed air through to clear the water out. Didn't get much if any sediment out, and the flow was good. (Captured all of the coolant in a big pail, so I don't think we missed any sediment.) Bless Hyundai for good access to the connection points. Don't know if the V6 is as accessible, but the inline-4 was great.
But here's the thing - of course the coolant will come up to temperature in this balmy weather. What we don't know, but suspect, is that the (original) thermostat is weak and is opening prematurely, not allowing the coolant to get hot enough in cold weather conditions. But how does one diagnose that when it's hot out? Yes, one can remove the T-stat and boil it in a glass pot with a thermometer and watch for it open, but at that point why not just replace it? Is there an easy way to test for a weak thermostat in-car when the weather is hot enough that the thermostat will definitely open anyway? Would way rather work on the car now in late summer/early fall than once it's cold out!
Thanks in advance.