GT TDI 115 Coolant Loss

[jordelver]

Hi,
I've just bought a GT TDI 115 (2000) and am slightly worried I've bought a lemon. I'm not that technical, so bear with me

I've had the coolant light come on the dash. Checked the coolant, and there was hardly any in the header tank. Filled up with water
and have been monitoring it since. It has dropped a tiny bit since, but I didn't know if that could be because of a air blockage or something after topping up, and I haven't driven that far.

I'm worried about the possibility of a head gasket failure or worse. There was a slight orange dirty sludge in the header tank, but not a great deal. I've read this could be caused by a mixing of coolants? I don't know what was in there before.

There are signs of a water dribbling down the header tank, as there is a white residue on the side, but I don't think that is new. I can't see any thing obvious leaking from any pipes etc. But, when filling up the header tank with water, the cap didn't seem like it wasn't quite done up correctly.

There doesn't seem to be any usual smoke from the exhaust. It looks ok to me.

The temperature gauge on the dash slowly rises to 90, and stays there.

The heat blower in the cabin fluctuates between hold and cold. Not rapidly, but it does go from hot to cold and back again. I don't know if this is connected or not?

What's the best plan of action? At the moment, I'm just monitoring the coolant level when cold in the mornings. My plan was to flush out the old coolant, and replace the lot with G12 this weekend if the coolant level remains ok, and also do an oil change as that was found to be a it low. (once I figure out how to do that .

Many thanks,
Jordan

[chris.fulton]

Firstly, welcome to the forum.

I believe that white residue on the side of the header tank is a sign that coolant has been leaking from the cap, antifreeze leaves the white residue if the coolant leaks and the water evaporates. This could be the problem however the other signs are a bit concerning too.

Once the engine has warmed up (temp gauge sits at 90) then the car heater shouldn't really go cold unless you stop the engine. The colour of the coolant could just be from the water going through the coolant chambers in the engine especially if it hasn't been regularly changed. If the oil and water mixed it would actually look like oil and water mixed. Easiest thing to do is replace the coolant and keep an eye on the colour of it after that.

Some of the signs point to possible headgasket failure however it could be other things like a sticking thermostat or possibly even a faulty water pump.

My advice to you is drive the car a bit now that the coolant has been topped up and establish is it definitely still losing coolant from somewhere (keep a bottle of water in the car with you just in case). Also replace the coolant and flush the system while you're at it. Keep an eye for any other signs of headgasket failure such as difficult to start engine, mayonaise like substance around the oil filler cap, steam/white smoke coming out of the exhaust, and the oil and water mixing in the cooling system. We can make a better prediction of whats wrong once this has been done

[jordelver]

Thanks for the reply Chris. I thought that I would get that sort of reply. Really too early to tell for sure. I'll definitely change the coolant this weekend, and take it from there.

Do you think it's worth changing the thermostat whilst changing the coolant in order to rule it out. They seem relatively inexpensive, and it's got to come out to drain the coolant hasn't it? Please excuse my ignorance

Also, do you know of any guides for changing coolant? I think I know what I'm doing, but would be nice to see something to confirm.

Thanks again.
Jordan

[chris.fulton]

I'm not sure the thermostat has to come out when changing the coolant although I have never done this on the Golf before so could be wrong. You may as well change it while you're at it and as you say they're not very expensive. I'll have a look at the Haynes manual when I get home from work tonight and will write up their guide to changing the coolant and the thermostat.

[jordelver]

You may as well change it while you're at it and as you say they're not very expensive.

I think I will. Thanks.

I'll have a look at the Haynes manual when I get home from work tonight and will write up their guide to changing the coolant and the thermostat.

Much appreciated I've actually looked for a Haynes manual to cover my car. I almost bought it and then noticed that it says it doesn't cover the PD engines. Not sure how much stuff would be different though.

Where do you stand on genuine parts? Does a genuine part really make the difference on something like an oil filter or is it something that shouldn't really be scrimped on? The price difference on somewhere like vagparts.co.uk is pretty small.

Sorry for all the questions. Thanks for your help Chris.

Cheers,
Jordan

[chris.fulton]

Click on the link, this is the Haynes manual that I have and it covers my car which I believe is the same as yours (GT TDI 115bhp 6 Speed PD engine)
http://www.haynes.co.uk/webapp/wcs/s...0103&langId=-1

My personal opinion on genuine parts is try to get them as much as possible but with small things like oil filters I usually go for a non-genuine part. Bigger/more critical to the cars running things like the MAF for example I would always buy genuine parts. Some genuine parts make more of a difference than others but generally the genuine parts are of slightly better quality all round.

Sorry for all the questions. Thanks for your help Chris.

No worries, that's what the forum is here for

[chris.fulton]

Right here goes. All this is taken directly from the Haynes manual.

How to drain the coolant

1) Ensure that the engine is cold before starting. Unscrew the expansion tank cap.
2) Ensure the handbrake is firmly applied and jack up the front of the vehicle. Remove the undershield to gain access to the underside of the engine.
3) Place a suitable container beneath the coolant drain outlet which is found on the coolant bottom hose end fitting. Loosen the drain plug (you don't need to remove it completely) and allow coolant to drain into container. If no drain outlet is fitted to the hose end fitting, remove the retaining clip and disconnect the bottom hose from the radiator to drain the coolant.
4) To fully drain the system, also disconnect one of the coolant hoses from the oil cooler which is located at the front of the cylinder block.
5) Once the coolant is drained then re-tighten the radiator drain plug or reconnect the bottom hose to the radiator. Also reconnect the coolant hose to the oil cooler and secure in position with the retaining clip. Refit the undershield.


How to flush the radiator

1) The radiator should be flushed seperately from the engine to avoid contamination.
2) Ensure the radiator drain plug is tightened
3) Disconnect the top and bottom hoses and any other relevant hoses from the radiator
4) Insert a garden hose into the radiator top inlet. Direct a flow of clean water through the radiator and continue this until clean water emerges from the radiator bottom outlet.
5) If water does not run clear after a reasonable period of time, consider using a good radiator cleaning agent and follow the manufacturers instructions.


How to flush the engine

1) Firstly remove the thermostat.
2) With the bottom hose disconnected from the radiator, insert a garden hose into the coolant housing. Direct a flow of clean water through the engine and continue until clear water emerges from the radiator bottom hose.
3) When flushing is complete, refit the thermostat and refit the hoses.


Refilling the cooling system

1) Firstly ensure the radiator drain plug is securely closed and all hoses are connected and securely retained by their clips.
2) Remove the expansion tank filler cap and slowly fill the system with coolant (ensuring correct antifreeze is used). Continue to fill the cooling system until bubbles stop appearing in the expansion tank. Help to bleed the air from the system by repeatedly squeezing the radiator bottom hose.
3) When no more bubbles appear, top the coolant up to the MAX level mark then securely refit the cap to the expansion tank.
4) Run the engine at fast idle until the cooling fan cuts in. Wait for the fan to stop then switch off the engine and allow the engine to cool.
5) When the engine has cooled, check the coolant level and top-up if necessary. Ensure expansion tank cap is securely refitted.

[jordelver]

Nice one. Doesn't look too tricky (we'll wait and see ).
I'll be doing this at the weekend. Thanks for spending to time to type this out.

I took the car out for a good run tonight. Temperature gage still remained constant at 90, but the heat in the cabin did fluctuate a bit a first and then seemed to get better.

I'll check the levels in the morning and see what I get.

I'll report back. Thanks again.

[jordelver]

Well, it's definitely loosing coolant. I drove about 40 miles last night, mixture of motorway and smaller roads. Temp stayed at 90. No smoke or anything unusual (that I saw) from the exhaust. The oil level is the same and looks ok. I topped the coolant this morning to replace about 100-200mls of water lost

Is it still worth doing the coolant change if I'm going to loose it all again? :-|

[chris.fulton]

In that case there's no point in changing the coolant until we can establish where the leak is. If you leave the car parked is there is any sign of water leaking out below the car or puddles of coolant on the ground?