Heating issues.

[Ewan kettles]

Hi guys once again I need some help/advice.
My pd170 Heater doesn’t want to heat up the car. At best I get only half warm air into the cab and thts when engine temp gauge is in mid position. Iv noticed it also seems to take an age to warm up to around 75deg after tht it seems to be fine but still very little heat in the cab.

Any help or advice here would be greatly appreciated.

Thanks once again.


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[LEE69]

Sounds normal tbh, diesels don't heat up like petrol cars, and it you only use part throttle will take an age in this weather

 

[Ewan kettles]

Thanks for the reply bud. The heat inside the cab should be hot tho it’s literally only above cool on the high setting it never gets to be even remotely warm.


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[ch1z64]

Worth given the car a scan to see if it throws up any fault codes and take it from there .

 

[SootySport]

As said, DERV's do take longer to warm up as they are a cooler running engine.
Couple of things to try though- change thermostat and make sure the coolant level is between the max and and min levels.

 

[Ewan kettles]

I was thinking thermostat also it’s on my to do list. just looking to see if there has been any issues like this in past that maybe Is an easy fix or overlooked issue that I may not have thought of. Thanks again for the help.


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[andyb616]

Had a similar issue with a Corsa I had. Ended up disconnecting the hoses to the heater matrix and sticking in a hosepipe and blasting water through, the amount of gunk that came out no wonder it wasn't circulating hot water correctly

 

[Nessy]

As has already been said, diesels do take longer to warm up but once up to operating temperature the gauge should get to 90 and stay there, any sign of the needle wavering once the engine is warm is a sign of either a dodgy coolant temperature sensor or a bad thermostat.
My money is on a lazy thermostat (ie one that is stuck open) if the engine is only getting to 75 degrees C, so not surprised heat output is poor.
Many years ago the first sign of a bad thermostat on my car (80 TDI) was the poor heat output from the dash vents one cold night , I replaced the thermostat and the heat output increased enormously.

 

[T8DPR]

I could be missing something here.... I'm seeing the OP's problem isn't the engine temp, but the cabin heaters not blowing very warm despite the engine temp being at 90, regardless of it taking long enough to get to 90 (which is especially normal at this time of year

Wouldn't he be expecting the heaters to be decently blowing hot if the engine temp is at 90??

 

[Nessy]

The OP implies the normal temp is 75....?
Even if the running temperature is 90 if it’s taking ages to get there then to me it’s an indicator of a dodgy thermostat.
It’s my understanding that a thermostat is constantly opening and closing to maintain a constant coolant temperature of around 90 (most diesel Audi thermostats I’ve encountered have been marked 87C) so if the heater output is poor then this could be due to a thermostat perpetually stuck open.
Sure, it could be a heater matrix problem, but coupled with it taking a long time to warm up leads me to suspect the thermostat.

 

[T8DPR]

He first stated that his gauge was in "mid-position", I interpreted that to mean 90 as it's half way up the gauge, before he went on to state it takes a while to get to 75, should his interior heating be better when its at 90? And if it wasn't, what would be the reason?

 

[Nessy]

It’s my understanding that a thermostat is continually opening/closing to maintain a steady coolant temperature of around 90 degrees in the entire cooling circuit.
If a ‘stat is stuck open then the engine is going to take a longer time to heat up and may never reach 90 degrees C as the large radiator and unrestricted flow of coolant through the (stuck open) thermostat will over-cool things.
This will lead to a poor output of heat from the dash vents if the coolant going through the matrix is only 75 and not the correct 90.

 

[T8DPR]

so if it was reading 90 on the dash, his heaters should blow a decent warmth?

 

[SootySport]

He never said the gauge was reaching 90deg. Only to 75deg.

 

[T8DPR]

He never said the gauge was reaching 90deg. Only to 75deg.

He initially stated "mid-point" which is quite non-specific, whether it means half way up the gauge or half way between cold and "normal"

I was still asking because I still would like to know if the heaters should be blowing hot when the temp IS on 90, or whether something else can make them blow lukewarm even if the engine temp shows 90

 

[tcardio]

time to change the thermostat and since you are already in there, change out any hoses and those pesky plastic connectors depending on the mileage of your whip. Might as well clean out the heater core and give it a good reconditioning. This stuff happens all the time. It hardly matters what the temps are or if the op has a diesel as the car just doesn't heat up anymore when I assume it did before. Something is wrong and its likely the thermostat or the heater core. my humble 0.02