1.4TDI overheating - air lock maybe?

T

Turzyx

Member
Just changed the water pump on my 1.4tdi (amf), along with other things. Now car progressively gets hotter during driving (went up to 110 before I could find a safe place to stop).

Water bottle level is correct
Bottom rad hose is cold
Bled through the screw near the top right of the rad (as you look from front)

On the driveway it initially felt like I was getting warm air through the vents, so I let it cool, topped it up and went for a blast.

Am I missing a bleed screw somewhere?

Cheers
 
I had problems on my own TDi removing all the air locks, if youv webasto fitted theres one on the top hose and after releasing all the air from hear while the engine was running i cured my airlocks, bassically i left the engine running with a brick on the throttle pedal so it was at about 1200rpm while undoing the screw removing air with the interior heater on max heat and fan on fastest speed, I kept repeating the process, losen until no air just coolant then tighten slightly and leave for a few minutes and undone again releasing more air, after 3 or 4 goes and 20 minutes later it finally removed all the air from the cooling system and the fan was blowing nice and hot and sitting at a steady 90 on the temp gauge.

a2 webasto.JPG
The webasto heater is located on the driverside inner wing

-Gary
 
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Turzyx said:
Just changed the water pump on my 1.4tdi (amf), along with other things. Now car progressively gets hotter during driving (went up to 110 before I could find a safe place to stop).

Water bottle level is correct
Bottom rad hose is cold
Bled through the screw near the top right of the rad (as you look from front)

On the driveway it initially felt like I was getting warm air through the vents, so I let it cool, topped it up and went for a blast.

Am I missing a bleed screw somewhere?

Cheers
Click to expand...


Did you follow the recomended procedure of leaving the car running wuth the coolant cap left off?

As mentioned the webasto (if you have one) can sometimes be a source of air locks, but letting the car run with the cap off has always worked for me.

Steve B
 
EDIT: Never mind, I am dumb. I think I know what the problem is. I will post back here when it is fixed.
 
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Okay it wasn't what I thought.

I changed the thermostat + oring, no difference (I also tested the new thermostat before fitting).

I bled the system by the book, completely emptied (including the oil cooler pipes which were a PITA), filled slowly from the bottle till it ran clear from the bleed screw, tightened, topped to max, ran @ 2k rpm for 2 minutes with cap off while squeezing hoses. Fit cap and let idle for ages. It sat at 90c for quite a while, front pipe never got hot, fan never came on but I let it cool after about 10 minutes then re-squeezed the hoses at topped it up ~100ml an hour later.

Took it for a drive anyway, it got up 90c about about 5 minutes, then sat there for a few miles, thought I'd fixed it (I was so happy!), then it started to creep up, 95, 100, 110. Kept the revs low ~1.5k and it cooled to ~100, as soon as engine speed/load increases it gets hot(ter) again. Got home, front pipe still cold. Still no heat from the heater although the feed pipe is hot.

What now? Is the (new) water pump ****ed? I checked the receipt, I have no doubt it is the correct one.
 
I had a problem with my heater matrix on my TDI as it was blocked with gunge and had to use a preasure washer to clear it , i disconected inlet and outlet hoses near the gearbox and pushed the lance of the preasure washer into the hoses and blasted away until all the rusty gunk worked its way through , i also did the engine block the same until the water ran clear and used just the garden hose on the main radiator until that ran clear too and that solved my problem with no heat from interior heater... ive never seen my temp gauge go above 90 so 110 sounds very high to me, it may be worth checking the fan is actually getting power or even works, after i was happy everything was working how it should i drained the system and filled up with anti freeze and a conditioner tonic (FORTE COOLING SYSTEM CONDITIONER) to stop the problem coming back.
 
I'm assuming if you see a stream of water into the header tank when running and this stream increases/decreases in flow with revs then the pump is fine, that it how I check mine.
 
mrbroons said:
I'm assuming if you see a stream of water into the header tank when running and this stream increases/decreases in flow with revs then the pump is fine, that it how I check mine.
Click to expand...

How obvious is the stream and does it flow all the time (e.g. when cold?)

I haven't noticed anything. In fact the only time any liquid went through it was when I was getting air out of the top hose and squeezed it.
 
Are you sure it's overheating, could it simply be that the temperature sensor is just reading too high?

When it does get too hot, is there any other evidence apart from the reading on the gauge, if it's getting to 110[SUP]o[/SUP] then there should be other symptoms such as leakage from the header tank, and if you remove the filler cap (safely and very carefully) when it's hot then there should be a lot of water lost as it will boil when the pressure is released. Please don't do this unless you know what to expect.

Often the gauge under-reads, but I suppose it could, in theory over-read.

Steve
 
Sounds all rather familiar although my replacement water pump and thermostat hasn't helped. In fact getting worse as wasn't overheating on guage months ago but has started now and heater sometimes never getting hot. Thinking must be clogged matrix but currently don't use car more than a few miles a day so rarely heats up enough to see what's going wrong. Will be interested to see how you get on. Good luck!
 
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