02 Galaxy 1.9tdi Overheating

[et19560]

I have an 02 galaxy 1.9tdi milage is 150k, 4 months ago the heater matrix was replaced because it was leaking, there was pressure in the expansion tank before it was replaced, the cylinder head was checked and found to be ok, even after the matrix was replaced there is still pressure build up in the expansion tank.

It has never over heated, even when towing, that was until 2 weeks ago when we were towing the caravan going away on holiday, the temp rose to max after towing for about 20 miles with water coming out of the expansion tank cap, the aa came out and diagnosed a faulty expansion tank cap, saying there was a seal missing from it, the aa recovered us to our destination at Scarborough. When it was looked at by the garage there, they said the cap was ok but that the bottom hose was not getting hot so replaced the thermostat, the bottom hose now gets hot. When coming back off holiday towing the van everything was going great, until, after about 30 miles with no problems the temp went up again, same thing water coming out of the expansion tank cap,

We eventually got home by allowing it to cool, it would work fine for 30 to 40 miles and then the temp would again go up, what I did notice was that the 2 fans in front of the radiator do not appear to be cutting in. The car drives perfect apart from this and is serviced regularly and still does not over heat under normal operating conditions.

Does anyone have any ideas what the problem could be and how to get the fans to work.

[chrispb123456]

Things to check.

 

Engine water pump, suffers from detached impellor, you can check this by removing thermostat.

Also check electric run on pump, switch ignition on without starting then switch off, it should run for 3 minutes then stop

Run engine from cold with cap removed, does the coolant rise and spill over, look for bubbles rising in coolant bottle.

Am guessing your aircon is not working as cooling fans would be running if it was.

 

Do a search on here for overheating it's all been covered so many times

 

You will be surprised how many members have had so called checks/tests for failed head gasket only to find not only was the gasket blown but the cylinder head needed refacing.

[et19560]

Thanks for the information.

I'll check the run on pump later, will I be able to feel the water pump impeller when the thermostat is removed? The air conditioning has not worked for some time, do the fans only work with air con on?

I have run the engine from cold with the cap removed, the coolent doesn't spill over and there is just a constant trickle coming out of the pipe leading into the top of the expansion tank.

Something that I have noticed previously but it doesn't happen always is that when the car has been stood overnight that there is a damp patch under the car almost directly under where the expansion tank sits, not sure of the significance of this. This is when the car is parked on a gentle foreward slope.

The head gasket has been checked by 2 different garages both saying it is ok, it sailed through the emmisions test on the mot in July, I don't know but would a blown head gasket have any effect on the engines emmitions?

Edited September 3, 2012 by et19560

[alan_131]

Just a speculation but if run-on pump doesn't work, possible you're getting localised heat transfer on switch-off, causing localised boilng. bit of water pushed out of the expansion tank... If you squeeze the big hose in the morning with the engine cold, and it's soft, then open the expansion tank cap and it hisses, sounds like you have below atmospheric pressure in the system.... Ditto small leak somewhere can pump out small amounts of water, which over time add up. If it only leaks under pressure, you get the same negative pressure when the system is cold....

 

If you wedge a piece of kitchen towel/tissue in front of the expansion bottle outlet, you'll see if the water under the car is from the bottle or elsewhere....

 

Of course, if the head gasket's gone, then it gets pressurised and looks much the same.

 

My old 90 took about 5 miles to get warm enough to produce useful heater output round town - in other words, when not stressed, the cooling system has a lot of reserve capacity. When it was overheating, did you have heater output? (no water though heater matrix, no output....)

Edited September 4, 2012 by alan_131

[chrispb123456]

Thanks for the information.

I'll check the run on pump later, will I be able to feel the water pump impeller when the thermostat is removed? The air conditioning has not worked for some time, do the fans only work with air con on?

I have run the engine from cold with the cap removed, the coolent doesn't spill over and there is just a constant trickle coming out of the pipe leading into the top of the expansion tank.

Something that I have noticed previously but it doesn't happen always is that when the car has been stood overnight that there is a damp patch under the car almost directly under where the expansion tank sits, not sure of the significance of this. This is when the car is parked on a gentle foreward slope.

The head gasket has been checked by 2 different garages both saying it is ok, it sailed through the emmisions test on the mot in July, I don't know but would a blown head gasket have any effect on the engines emmitions?

Primary purpose of the run on pump is to minimise hot spots around the engine after switch of which could lead to distortion and premature gasket failure, it also aids circulation through rear passenger heater and booster heater.

 

As you have stated coolant is trickling/returning to the bottle then I would say your engine water pump is OK and yes you can feel the impeller through the thermostat housing.

 

In normal circumstances these engines struggle to get to normal operating temperature, 5 + miles this time of year and longer in the winter if boosters not working, in the 8 years of owning a MK2 the cooling fans have never cut in, only with aircon on.

 

So youv'e run engine from cold up to normal operating temperature with cap removed and no significant rise in level.

 

Try this, with the level correct and cap fitted go for a drive motorway speed on return check level of coolant again there should be no significant rise, switch off and leave for 10 minutes, now carefully remove cap, there should be a small amount of pressure released and then a slight rise in level.

 

See how you get on report back.

 

ps how are they testing for head gasket failure?

[et19560]

Hi,

Just to report back on suggestions and to update what I have done.

 

3 days ago I topped up the expansion tank and ran the engine for approx 40 mins without the cap on with the heater and blowers on max and topped up the coolent level has it went down, I needed to put in about 0.75 litre of coolent to bring it to max level. I then allowed it to cool overnight with the cap off.

 

The next day when I checked and replaced the cap the coolent level was still at max.

 

I have checked for the sound coming from the run on pump, there is a sound coming from near the expansion tank but it does not sound as loud has it did before the heater matrix was taken out and replaced, we also had a new expansion tank fitted at the same time.

 

Today after taking the car for a run and allowing to cool, the level was still at max, I released the cap and there was a bit of pressure and water rushed into the expansion tank rising about an 1 inch above the max level but not overflowing out of the tank, I left the cap off and allowed to cool but the level has not dropped back to max, it has been driven again with cap on for approx 5 miles but the coolent level still remains above max level.

 

Could this indicate a possible airlock in the system?

 

As far as the head gasket test goes, I'm not sure what kind of tests were done. I asked the garage who diagnosed and replaced the heater matrix to test the head gasket before I spent out money on having the matrix fitted, they apparently did 2 different types of test both showing no problem with the head gasket.

[NikpV]

well I have had exactly the same symptoms as you - had everything checked finally bit the bullet and had the head gasket replaced and head pressure tested etc head was skimmed as well - now it drives beautifully :-) I have had spent 3 years topping up water - sometimers a lot sometimes hardly any oh and it never has overheated beyond 100 and that only twice until about 2 months ago

[chrispb123456]

Hi,

Just to report back on suggestions and to update what I have done.

 

3 days ago I topped up the expansion tank and ran the engine for approx 40 mins without the cap on with the heater and blowers on max and topped up the coolent level has it went down, I needed to put in about 0.75 litre of coolent to bring it to max level. I then allowed it to cool overnight with the cap off.

 

The next day when I checked and replaced the cap the coolent level was still at max.

 

I have checked for the sound coming from the run on pump, there is a sound coming from near the expansion tank but it does not sound as loud has it did before the heater matrix was taken out and replaced, we also had a new expansion tank fitted at the same time.

 

Today after taking the car for a run and allowing to cool, the level was still at max, I released the cap and there was a bit of pressure and water rushed into the expansion tank rising about an 1 inch above the max level but not overflowing out of the tank, I left the cap off and allowed to cool but the level has not dropped back to max, it has been driven again with cap on for approx 5 miles but the coolent level still remains above max level.

 

Could this indicate a possible airlock in the system?

 

As far as the head gasket test goes, I'm not sure what kind of tests were done. I asked the garage who diagnosed and replaced the heater matrix to test the head gasket before I spent out money on having the matrix fitted, they apparently did 2 different types of test both showing no problem with the head gasket.

After reading the results after the drive you have early stages of gasket failure, am guessing they done all there testing at idle with no load on engine, at the moment your only getting the problem when engine is under load this is why there test shows no fault.

 

As for air lock in the system, combustion gasses being pushed into the system gets trapped until cap removed.

 

Make sure head is checked for warp and cracks, will probably need skimming to be sure.

[et19560]

What is a reasonable price for a head gasket and the head to be skimmed?

 

I don't want to be ripped off again like I was for the replacement of the heater matrix.

[chrispb123456]

I can't help you with garage pricing but would hazard a guess around £400 to £500 get some estimates in your local, if you give a location other members may be able to help that have had similar work done.

 

You said you were ripped off with the heater matrix, do you know what's involved to change this as it's quite time consuming, incidentally the excess pressure from the HGF would be a contributory factor to the failure of the matrix.

[chrispb123456]

well I have had exactly the same symptoms as you - had everything checked finally bit the bullet and had the head gasket replaced and head pressure tested etc head was skimmed as well - now it drives beautifully :-) I have had spent 3 years topping up water - sometimers a lot sometimes hardly any oh and it never has overheated beyond 100 and that only twice until about 2 months ago

Welcome back nik, what's happened to the cat :)

[et19560]

The garage who replaced the heater matrix sent me photos of the job which inolved removal of all the dashboard, so like you say a very time consuming job for which I was charged almost £1000 to get the job done, having talked to other people since, this would appear to be quite expensive.

 

I lost faith with the garage after the drivers side electric window stopped working shortly after having the matrix done, They quoted £475 + vat to replace with new motor and mechanism, Another garage did the work fitting new parts for £320 inculding vat.

 

I live in Northampton so if there is anyone who could advise on reliable garages/workmanship I would like to hear. I will phone around to see what I get quoted.