Seat Cordoba 1.4tdi poor cabin heater

yamaha4life

Hey all,

I recently acquired a 05 seat cordoba 1.4 tdi AMF engine code.

I noticed the day after I bought it the heater matrix was looped out and sure enough when i joined it back up it leaked quite impressively when i turned the fan on it showered the windscreen with coolant!

Anyway i fitted a new matrix all good no leaks, pipes going into it are very hot. Im Not 100% if the feed and return are correct but it wouldn't look correct if they were switched around.

cabin heat is poor it has manual controls and the flap looks operational from the outside. When the front vents are selected the air is sufficiently hot not scalding but acceptable, but every other setting it's lukewarm.

There is no pollen filter fitted i guess the previous owner removed it. Also the fan resistor is faulty so fan only works on highest speed setting.

I fitted a new thermostat also just incase old one was faulty but this had no effect on it.its full of coolant g12 no apparent airlock i burped it with cap off. gauge warms up to 90c eventually its slow even with new stat.

Any VAG heads point me in the right direction ive posted on a vag forum but not inundated with replys sadly and google hasn't proved much help either!

BlakeS94

yamaha4life wrote: »

Hey all,

I recently acquired a 05 seat cordoba 1.4 tdi AMF engine code.

I noticed the day after I bought it the heater matrix was looped out and sure enough when i joined it back up it leaked quite impressively when i turned the fan on it showered the windscreen with coolant!

Anyway i fitted a new matrix all good no leaks, pipes going into it are very hot. Im Not 100% if the feed and return are correct but it wouldn't look correct if they were switched around.

cabin heat is poor it has manual controls and the flap looks operational from the outside. When the front vents are selected the air is sufficiently hot not scalding but acceptable, but every other setting it's lukewarm.

There is no pollen filter fitted i guess the previous owner removed it. Also the fan resistor is faulty so fan only works on highest speed setting.

I fitted a new thermostat also just incase old one was faulty but this had no effect on it.its full of coolant g12 no apparent airlock i burped it with cap off. gauge warms up to 90c eventually its slow even with new stat.

Any VAG heads point me in the right direction ive posted on a vag forum but not inundated with replys sadly and google hasn't proved much help either!

Did you have the heat on full when you burped the system so that coolant can push the air out of heater matrix, it can be difficult to fully bleed air out of there, that would contribute to poor temperature, I'd suggest bleeding again with the cap off and have the front of the car higher than the back i.e on a slope or front end on jack stands or ramps, and give it some revs to 3000-3500rpm a few times during the process, be cautious that coolant may spill out if you don't have any kind of funnel on the filler neck.

Dilbert75

First thought was airlock. Second thought was water pump. There were (are?) VAG cars with plastic impellers press-fitted onto pump shafts where, over time, the impeller splits and spins on the shafts. So shafts turns, impeller doesn't. Eventually engine cooks when convection of coolant is not adequate to keep the engine cool. Might explain slow heating up too....

yamaha4life

I tried this morning to bleed it cap off on a slope took forever to get up to temp! Held a high idle 1500rpm and also a few higher revs, it got a bit hotter during the drive after it got to 90C on gauge.

I also replaced the coolant temp sensor and tank cap this morning to for a known good ones, so it's definitely getting hot at that area.

The feed and return pipes im unsure if i have them correct i didn't loop it off so i just guessed, they are both hot and also the area where the matrix sits it hot can feel it through the plastic box.

Waterpumps are a bit notorious in vag for slipping impeller but i have decent return flow to coolant tank.

Final note is the rad hose to the thermostat is ice cold. top hose is hot. The fingers to hold the thermostat on are broken but ive seen many YouTube videos where the flange fingers broke but they just put the thermostat and it works fine.

Should i switch the matrix hoses around? I dont think they are wrong but I've no point of reference as i didnt loop them off in the first place

BlakeS94

yamaha4life wrote: »

I tried this morning to bleed it cap off on a slope took forever to get up to temp! Held a high idle 1500rpm and also a few higher revs, it got a bit hotter during the drive after it got to 90C on gauge.

I also replaced the coolant temp sensor and tank cap this morning to for a known good ones, so it's definitely getting hot at that area.

The feed and return pipes im unsure if i have them correct i didn't loop it off so i just guessed, they are both hot and also the area where the matrix sits it hot can feel it through the plastic box.

Waterpumps are a bit notorious in vag for slipping impeller but i have decent return flow to coolant tank.

Final note is the rad hose to the thermostat is ice cold. top hose is hot. The fingers to hold the thermostat on are broken but ive seen many YouTube videos where the flange fingers broke but they just put the thermostat and it works fine.

Should i switch the matrix hoses around? I dont think they are wrong but I've no point of reference as i didnt loop them off in the first place

There's usually some sort of heater control valve further back on the inlet hose going into the firewall, the outlet hose has nothing else on the hose, that should tell you which hose is which, as for which port is inlet and outlet, I don't know for sure, but on my own car they are over and under each other, I believe top hose is inlet and bottom is outlet, take them off and switch them to see if there's an improvement.

I presume your thermostat is at the bottom rad hose if you're saying the top is hot. The bottom is cold because the thermostat hasn't opened allowing coolant to flow through. Until car reaches temp the thermostat won't open and then the bottom hose should feel warm, not as hot as top hose but still warm. Take it for a good drive getting up to temp, if bottom hose is still cold then there's another issue, maybe a blockage in radiator and the flap of coolant is being restricted, or could be low on coolant but you've bled the system and topped it off so probably not that

yamaha4life

There doesn't seem to be any control valve on the system, there is a manual flap inside the ventilation system for the matrix which appears to be functioning as i have some heat just not the correct amount.

Going off this diagram i have the feed and return correct, abeit i think the diagram has an extra pipe for an egr cooler? which my car doesn't have.

Feed to right hand exchanger pipe with the small outlet on it to the flange on cylinder head, return to metal pipe that goes around gearbox to front of engine to thermostat location.

http://www.oemepc.com/seat/part_single/catalog/se/markt/E/modell/CO/year/2005/drive_standart/401/hg_ug/121/subcategory/121045/part_id/0/lang/e#sec_28

Not low on coolant anyway the bottle is full i topped it off after the test run, the system is pressuring properly with new cap, i drove the back side off it and the lower hose (thermostat hose) remained cold as if thermostat didnt open but im sure it should have.

I have fitted a febi thermostat 17888 with an O.E reference 044 121 113. Which i was told is correct for my car. It should open at 87C.

Im at a bit of a loss.

Possible suspects in my head
New thermostat faulty
Waterpump failing
Radiator blocked or flow issue.

BlakeS94

yamaha4life wrote: »

There doesn't seem to be any control valve on the system, there is a manual flap inside the ventilation system for the matrix which appears to be functioning as i have some heat just not the correct amount.

Going off this diagram i have the feed and return correct, abeit i think the diagram has an extra pipe for an egr cooler? which my car doesn't have.

Feed to right hand exchanger pipe with the small outlet on it to the flange on cylinder head, return to metal pipe that goes around gearbox to front of engine to thermostat location.

http://www.oemepc.com/seat/part_single/catalog/se/markt/E/modell/CO/year/2005/drive_standart/401/hg_ug/121/subcategory/121045/part_id/0/lang/e#sec_28

Not low on coolant anyway the bottle is full i topped it off after the test run, the system is pressuring properly with new cap, i drove the back side off it and the lower hose (thermostat hose) remained cold as if thermostat didnt open but im sure it should have.

I have fitted a febi thermostat 17888 with an O.E reference 044 121 113. Which i was told is correct for my car. It should open at 87C.

Im at a bit of a loss.

Possible suspects in my head
New thermostat faulty
Waterpump failing
Radiator blocked or flow issue.

The bottom hose will stay cold if the thermostat remains closed, and the thermostat stays closed until the engine reaches a certain temperature. I'd say maybe faulty new thermostat, does car temp go over the midline on the gauge after 15mins or so

yamaha4life

The gauge stays bang on 90 once it gets there takes ages to get there but i wouldn't take the gauge as gospel though. Its never strayed past the 90c mark.

yamaha4life

I ordered a new resistor for the fan speed control, im hoping it will help get the heat out a bit better, i have been reading up and the seals around the mixing flaps commonly wears off and leaves cold air past when closed, its a proper dash out job id imagine. So fingers crossed its something small!

BlakeS94

yamaha4life wrote: »

I ordered a new resistor for the fan speed control, im hoping it will help get the heat out a bit better, i have been reading up and the seals around the mixing flaps commonly wears off and leaves cold air past when closed, its a proper dash out job id imagine. So fingers crossed its something small!

On some cars its not too bad a job and doesn't require the entire dash be removed, may be able to access through the side panels on the footwells in the front. I don't think the resistor will sort the heat issue but if its not working, replace it anyway. I would try remove the lower radiator hose where it connects to the radiator and see is the coolant pouring out freely or is there a blockage in the radiator,while the hose is off pour some coolant or D.I water through the top and if it doesn't have a steady stream out the bottom there's a blockage

yamaha4life

Yeah its not working on 1 2 3 speed so i needs doing, it will help only slightly as on maximum setting it will pull more cold air with it so lower setting maybe slightly warmer if you get me (wishful thinking maybe)

I haven't done anything with it since just charging up the battery as its a touch weak should be fully charged tomorrow and ill be taking it on a 30 min each way trip so ill see how the heater fairs out on longer journey maybe it was just airlock fingers crossed!

If its still poor ill try flushing the radiator, although i had an audi with a failing water pump and had similar symptoms so might be prudent to do the timing belt and waterpump if the radiator is fine.

Dilbert75

If you don't know the age of the tb and wp, and you care about keeping the car running, it'd be wise to change them.

yamaha4life

Just an update, i fitted the resistor bit fiddly but it has helped i can get a bit better heat now on 1 and 2 plus putting recirculating setting on but windscreen will fog up after a while.

It definitely feels like its getting too much fresh cold air on the hot setting and also takes too long to get hot even though new thermostat fitted. The missing pollen filter is probably to blame so i will get a housing and filter soon.

Going from the vag forum this is actually common on these small engine diesels to take ages to heat up though so apparently nothing to worry about there.

My timing belt was done at 123k and has 188k now so its due to be fair, i took the cambelt cover off and it looks in good shape no cracking or teeth showing through the back so I should be ok for a month until i sort out the parts.