Overheating Alhambra tdi

[Angarak]

Hello all,

I have a 2001 1.9 Tdi Alhambra that has developed an overheating problem of late.

Originally it overheated when on motorway journeys (usually when I was going uphill), however of late it can overheat on short urban runs.

When the car initially overheated, I put the heating on HIGH with the fans at MAX and this did help to lower the oil/water temps. However lately the heater system blows cold regardless of heat setting. I had to drive to Leeds a couple weeks back and I noticed that when going uphill on the M62 (towards pennine way) the oil/water temps would rise and the heater would go cold (when set to high temp), but when going downhill or on a flat section the oil/water temp would lower and the heater would start producing heat again!?!

I've noticed the car is losing coolant through the overflow on the header tank.

To date I have:

1> Replaced Thermostat (and tested new thermostat in boiling water to ensure it opened at temp)
2> Replaced the OEM water pump (with plastic impeller), the new pump has the brass impeller (and I've just taken it out to ensure its fine).
3> Checked all hoses for splits - none found
4> Checked radiator for leaks - none found
5> Checked oil for signs of water contamination (ie: headgasket failure) - none found
6> Taken it to SEAT and had it diagnosed - no faults logged, and more annoyingly they couldnt get it to overheat on their rolling road. They also believe the head gasket to be 'bullet proof' on these engines and the garage I took it to (Warrington) has never known one to fail.
7> Checked carpets for dampness to indicate heater matrix leak - carpets where bone dry.


I've heard that it could be a failed header tank cap. If its not sealing then it will boil the coolant at a lower temperature than it should, and it would also 'gas out' into the header tank. I've ordered one from SEAT but wont get it for a couple days.

I have also noticed something behind the header tank that is attached to the top heater hose (the one that runs over the top of the engine behind the oil filler neck). If I waggle the wire to this 'device' once I've just turned the engine off, it makes a whinning noise (as if an electrical fan/pump is working) and it releases pressure out of the coolant system (you can hear gurgling)....any ideas what this 'device' is?

Mystery Device:
:: http://mooch.pwp.blueyonder.co.uk/alhambra_mystery_device_1.jpg
:: http://mooch.pwp.blueyonder.co.uk/alhambra_mystery_device_2.jpg

One other thing regarding the head gasket, if it does fail wouldnt you notice a reduction in power? (something I have not noticed).

Any other possible ideas on the overheating?

I will update this this thread once I've tested the new header tank cap later in the week.

Cheers
Simon

PS: Sorry for the long post

 

[Angarak]

Update:

I believe the source of my leak is the front heater matrix *gulp*. Whilst the carpets are bone dry inside the cabin, I noticed what appears to be an overflow/drain pipe in the bulkhead down towards the passenger footwell.

Here is a picture of said pipe:
http://mooch.pwp.blueyonder.co.uk/al..._leak_pipe.jpg

I'm assuming (unless someone can correct me) that the matrix must be leaking and the water is being drained through this pipe into the engine bay. It has left coolant stain so Im pretty sure it is the culprit.

Will now look into the cost of a new matrix and how much hassle is involved (presumably quite a bit!).

Edit
The 'mystery device' appears to be an additional water pump (Part No: 1J0 965 561 A).

 

[Angarak]

Ok, after spending 2 days stripping the dash and scuttle panel out I can confirm it isnt a leak on the Matrix.

Im now thinking the 'leaking pipe' isnt part of the heating system, but maybe a drain pipe for the external moisture on the aircon pipes that enter the bulkhead (to prevent moisture dripping down behind the dash).

So, Im off the investigate the 'additional water pump' behind the header tank, failing that a compression test to see if it really is the head gasket (despite no signs of contamination in the oil or loss of power).

 

[Jochen]

Hello,
Sounds like headgasket too me im afraid or hairline crack in cylinder head.
Had one at dealer where I used to work doing excactly the same. when its under more load, the compression is higher and combustion gases leak into the coolant causing air bubbles to get into the coolant and cause overheating.

 

[peteTDI]

try a new cap on the header tank as it may not be sealing/ making pressure

 

[Angarak]

Update:

Replaced the header tank cap but still had the problem. Had it pressure tested and found a leak around Cylinder #1, so it goes in this week for a new HG.

Thanks to everyone who replied

 

[twindecks]

did you get your car sorted out i have the same prob i have change Thermostat new header tank cap and the fan switch i ahve no leaks but still loseing water

 

[Angarak]

I had the head gasket replaced but only got it back 2 days ago and havent done a long journey - but so far so good.

Oil/Water temps seems fine, the heating system is blowing warm air when it should and the the coolant system doesnt have any excessive pressure.

Cost approx £670 for parts and labour to have the HG done.

 

[twindecks]

did you get that done at main dealers

 

[Angarak]

No mate, the quote from my local SEAT dealers was considerably more!

I had mine done by R.N.A Engineering in St.Helens.

The following work was done:

:: Cylinder head removed, stripped, cleaned and pressure tested for cracks.
:: Surface grinding
:: Valve and Seats vac tested
:: Hydraulic followers adjustment
:: Gasket kits and various other bits such as replacement head bolts.

 

[twindecks]

bummer

 

[Angarak]

I would take it somewhere to get the HG pressure tested, cost me around £80 and confirmed it was the HG.

With hindsight, I should have done that before wasting 2 days taking out my dash to check the heater matrix

 

[twindecks]

ok thanks

 

[twindecks]

ok just one more this i checked the top pipes and they were hot but at the bottom pipe was cold the car temperature was at 90 as is the the radiator

 

[twindecks]

is your car running fine now

 

[sheltonj]

alhambra overheating

hi you said the top pipe on your alhambra was hot but bottom pipe cold ,did you get it fixed and if so what was the fault ,regards jeremy

 

[sheltonj]

hi twindecks just wandering if you can help me .i have an alhambra,and the bottom hose is cold ,when the top pipes are hot could you tell me what the problem was with your alhambra.kind regards jeremy

 

[Graham89]

hi twindecks just wandering if you can help me .i have an alhambra,and the bottom hose is cold ,when the top pipes are hot could you tell me what the problem was with your alhambra.kind regards jeremy

Sounds like a stuck thermostat

 

[sheltonj]

thanks graham will try that,best regards jeremy

 

[orangecruz]

did the guys with cold bottom rad hoses get them sorted if so what was it please