Over Heating?

[Guest charlie boy]

Hi to all, hope there is someone out there who can help.

I have a 98 1.9tdi galaxy and recently noticed that when i go on a long journey i.e motorway the tempreture gauge shoots up to red and the red light starts flashing which would indicate overheating althought when i lifted the bonnet there was no steam or bubbling from expansion tank, i noticed i lost all heat from the heater but carried on driving and then the heat came back and tempreture went down.

I have changed the filler cap on expansion tank because i noticed water coming out of the bottle and dripping into the battery tray but still the same, and i have to keep topping up water.

Checked for signs of head gasket problems but found none.

Around town and in traffic it is fine, fan works fine, so know i'm thinking thermostat or water pump?

If anyone has any insight to this problem it would be very helpful.

[Topbloke]

sounds like a sticking thermostat to me :(

[Guest nimrod]

and i have to keep topping up water.

Try adding some anti freeze as well as just water! it wont solve your problem but it will help stop the corrosion of the head

[seatkid]

Sounds like water pump. Some VAG models, the impeller (sometimes plastic) fails (detaches from shaft). That would expain cold heater and overheating engine. The boiling would occur in the block/head and the water outside eg expansion bottle be a lot cooler. Water loss due to excessive pressure from overheating in the block.

[charles]

also think that it is the pump, when the thermostat fails, it's allmost allways stuck open (long time to warm up, but no overheating)

[Guest charlie boy]

Thanks guys i'll change the thermostat first and if no joy do the waterpump.

Not done either of these jobs on a galaxy before how difficult is it and are there any hidden surprises?

[seatkid]

IMO unlikely to be thermostat - your heater is unaffected by this component. If you drain coolant (which you will) you will need to replace with new coolant. If your car has G11 (green stuff) then you will need to completely drain down and replace with G12+ (make sure its the plus version!) which is pink. G11 is no longer available.

 

Take care when releasing coolant that it doesnt go on cambelt or drivebelts as it can attack them and cause premature failure.

 

Full instructions are on the Ford TIS CD.

Edited June 27, 2004 by seatkid

[Topbloke]

so thats were i have been going wrong with all those over heated car's on the hard shoulder . The stats can fail either way and is far easier to change than a pump not only that if they use the plastic housings that they us on the later vee dubs then the plastic breaks internally allowing the pin to move and not the two stage stat causeing over heating. my petol galaxy did fail open i grant you, cos it took ages to get to working temp, and they are realy easy to change on the 2.3 engine

[seatkid]

sarcasm always impresses me....

 

I have edited my previous post to bow to your expertise.

[Topbloke]

so glad that you are impessed its very difficult to diagnose via foroms and it was a general direction to go trouble is dont very often get any feedback

[charles]

when the engine is on temperature and you turn on the heating, it must become hot inside very quickly, if not it is probably the waterpump.

[Guest JIMSTDI]

be carefull not to get any airlocks in the cooling system when you refill!!!

 

hope it all goes well :lol:

[Guest charlie boy]

Well i did it, i replaced the pump and the thermo just to be safe and so far so good.

I took it on a long run and would you belive it, no overheating, the temp gauge stayed in the middle and it was fine.

But what i did notice was while doing a school run a couple of days ago the temp light started flashing although temp was fine, so had a look and again saw that some water had come out fo the expansion tank and trickled down onto the water level sensor connector and into the battery tray which is what is was doing before, now i can assume that the flashing light is due to a short caused by the water but why do i still get water coming out of the expansion tank?

I see that there is what seems to be an overflow hole in the ex tank but still a bit puzzled, any idea's.......

[seatkid]

Make sure you don't overfill the expansion tank - my experience of VAG models is any thing much above the MIN mark and the coolant is released until it level reaches just above MIN. (Don't know why, but it happened on my Passat, Golf, Alhambra)

[charles]

Are you sure you didn't overfill the expension tank. Normally it's half full (between min and max markings)

[Guest adpmijs1]

I'm having exactly the same problem on my 1.9TDI. Have had it for a year running up and down the M5 every weekend between Devon and the midlands with no probs, then all of a sudden, the temp light flashes and engine overheats virtually on every trip now.

 

It's been into 2 different garages who both insisted that there was nothing wrong with the car at all.. :ph34r: ...having been stuck on the side of the M5 (usually at night with a car full of kids) several times now, and having to have put at least 1litre of water in every time....I insisted that there was a problem, but to no avail. The AA even had it in one of their centres running virtually all day, both in the garage and on the road with no overheating or flashing warning lights! :lol:

 

If it is the heat pump, could it be intermittent, as some time the heaters do blow hot, yet other times they only blow cold while the gauge is well into the red....??

 

Have also found that you can do long runs if you sit between 55-65 mph with no problems...anything around 70+ does cause the temp to rise though...

 

Have also noticed that sometimes (more often than not) the top hose between the rad and the engine was cold...pumping it manually by squeezing it did induce some heat into it eventually...so sound like water pump to me?? Maybe..I dunno..ask me about computers and I'm right at home....but engines....way out of my field!

 

Anyone know how much it'll be to change the waterpump??

 

Thanks,

 

Andy

[Ivor_E_Tower]

Heat rises - if the top hose was cold and you'd been driving for "a while" I would suspect that the thermostat is jammed closed - if it were open, the hot water in the block would have warmed the water in the top hose, even if the waterpump was not working - unless the waterpump is near to the theromstat and has jammed in such a way that it is blocking the waterways - most unlikely I would have thought. I would expect that changing the thermostat is a simple and cheap job - I once changed the one on my old Rover 820 and didn't lose more than a cupful of water IIRC.