Author Topic: Temperature Issue 1.6TD  (Read 687 times)

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Hic

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Temperature Issue 1.6TD
« on: Jan 02, 18, 16:03 »
My 1.6TD's coolant temp on the dash is usually in the middle or half a bar over the middle.

The lower rad hose is almost always cold regardless of how much I drive.

The heat is only warm, not hot (sometimes only luke warm if the outside temps are very low). 

Coolant disappears very slowly and I never see any leak (I have to top off my bottle once every 15,000kms).

When the car is fully warmed up (after 20 minutes of driving or so), the top portion of the rad is hot, it is warm slightly below that and anything below the middle of the rad feels cold.

Is this normal? 

EDIT: The rad fan never kicks on.  I consistently hear it come on when the car sits for a long period without moving, like waiting at the border line up.  This is also the only time when the lower rad hose feels warm/hot. 
« Last Edit: Jan 02, 18, 16:05 by Hic »

Autohau5

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Re: Temperature Issue 1.6TD
« Reply #1 on: Jan 02, 18, 18:18 »
Either your thermostat is sticking closed, or your water pump is weak. Poor heater output leads me to believe the latter. Do both the heater core hoses feel hot after driving for 15 minutes? If you remove the small coolant bleeder line from the top of the reservoir and aim it back into the reservoir, is there a steady (not sporadic or dribbly) stream of coolant at idle? The flow should increase with RPM.

If the heater hoses are both hot after driving for 15 minutes, then I'd suspect you have a blend door issue in the heater box. If only one is hot and the other cool, then you have a plugged heater core.
'01 A6 2.7TT 6MT  |  '81 Rabbit S 16VG60   |  '15 Touareg TDI R-Line   |   '96 YZF750R

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #2 on: Jan 03, 18, 19:07 »
Either your thermostat is sticking closed, or your water pump is weak. Poor heater output leads me to believe the latter. Do both the heater core hoses feel hot after driving for 15 minutes? If you remove the small coolant bleeder line from the top of the reservoir and aim it back into the reservoir, is there a steady (not sporadic or dribbly) stream of coolant at idle? The flow should increase with RPM.

If the heater hoses are both hot after driving for 15 minutes, then I'd suspect you have a blend door issue in the heater box. If only one is hot and the other cool, then you have a plugged heater core.

I drove 30 minutes today and checked the hoses.  Both heater hoses are hot, top radiator hose is hot, bottom radiator hose is cold (not as cold as if the car sat overnight and never turned on, but nowhere near warm either). The top half of the rad is hot, but right at the middle of the rad, it abruptly becomes cold~warm.  Is this normal? 

Thank you for your input!

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #3 on: Jan 03, 18, 19:11 »
Temps after 30 mins driving.

During driving, the coolant temp on the dash was a bit higher (it was between the 3rd and 4th line - when I took this pic, the car idled for about 3 mins and it dropped down to just slightly above 3rd line).

The oil temp sensor is where the oil drain plug is.

Are these temps normal? 
« Last Edit: Jan 03, 18, 19:13 by Hic »

Autohau5

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Re: Temperature Issue 1.6TD
« Reply #4 on: Jan 03, 18, 19:53 »
Both heater hoses hot indicates you have good coolant flow and your heater isn't blocked. Is that oil temp 113F (45C), or 113C? If it's F, then that's a low oil temperature for 30 mins of driving. Very possible your temp gauge sensor (black) is reading high, and your car is colder than you think. If it heats up and the fan comes on when sitting in long traffic as you said, then I'd believe your temp sensor is reading wrong, or the gauge is off. Compare the temp sensor resistance values with this:

'01 A6 2.7TT 6MT  |  '81 Rabbit S 16VG60   |  '15 Touareg TDI R-Line   |   '96 YZF750R

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #5 on: Jan 03, 18, 22:24 »
Both heater hoses hot indicates you have good coolant flow and your heater isn't blocked. Is that oil temp 113F (45C), or 113C? If it's F, then that's a low oil temperature for 30 mins of driving. Very possible your temp gauge sensor (black) is reading high, and your car is colder than you think. If it heats up and the fan comes on when sitting in long traffic as you said, then I'd believe your temp sensor is reading wrong, or the gauge is off. Compare the temp sensor resistance values with this:



It is 113C. Is it abnormal for the rad's upper half to be hot and the bottom half to be cold? I can drive for an hour and the lower rad hose is cold. The heat being weak is probably a separate issue with the blend doors. I'm just stumped about the lower rad hose being cold all the time...it makes me think that the engine is overheating (since the coolant is not circulating through the whole system), in which case the high coolant temps on the stock cluster gauge makes sense. 

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #6 on: Jan 03, 18, 22:31 »
After seeing this pic, I get why it abruptly goes from hot to cold after the middle of the rad. I was feeling the rad fins on the inlet and outlet side (they're on the same side), so a smooth temperature transition should be seen if I moved along horizontally along the rad. Maybe my temps are fine after all...but it still doesn't seem normal that the lower hose is cold after driving for an hour. 

Unless the cooling in these cars are THAT good and/or they don't generate much heat...I'm not sure if the lower rad hose being cold after an hour of driving is common for a 1.6TD.
« Last Edit: Jan 03, 18, 22:33 by Hic »

Hic

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Re: Temperature Issue 1.6TD
« Reply #7 on: Jan 05, 18, 10:10 »
I just did the blend doors, it blows very hot now. Almost all the foam was gone, no wonder the heat wasn't strong. It is so much easier to get to the HVAC system in these cars compared to my MK3...doing the heater core in my MK3 was a nightmare.  :no:

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #8 on: Jan 09, 18, 11:06 »
Just drove from Coquitlam to Pemberton. Lower rad hose cold when I arrived. Coolant temp gauge hovered between the middle bar and the bar after that. Oil temps primarily around 105C-120C, and 120C-128C going uphills.

This isn't normal right?? The lower rad hose shouldn't be cold after a 200km drive I'd think...
« Last Edit: Jan 09, 18, 11:07 by Hic »

Autohau5

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Re: Temperature Issue 1.6TD
« Reply #9 on: Jan 09, 18, 12:13 »
Glad you got The heater working great. Sticking thermostat, cold outside temps, and low diesel heat output equals highly likely the lower hose is cold.
'01 A6 2.7TT 6MT  |  '81 Rabbit S 16VG60   |  '15 Touareg TDI R-Line   |   '96 YZF750R

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #10 on: Jan 09, 18, 12:47 »
Glad you got The heater working great. Sticking thermostat, cold outside temps, and low diesel heat output equals highly likely the lower hose is cold.

Hmm, could this be caused be a clogged radiator?

Autohau5

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Re: Temperature Issue 1.6TD
« Reply #11 on: Jan 09, 18, 14:21 »
Iím betting on a thermostat.
'01 A6 2.7TT 6MT  |  '81 Rabbit S 16VG60   |  '15 Touareg TDI R-Line   |   '96 YZF750R

Hic

  • Posts: 203
Re: Temperature Issue 1.6TD
« Reply #12 on: Jan 10, 18, 23:55 »
Iím betting on a thermostat.

I shall replace it and see how it goes!