1.9 tdi cold radiator and heater

[karl s]

On Sunday my 166000 miles  1.9 tdi  flashed up stop check coolant on start up which I topped up to correct level, now I've noticed the heater or radiator does not get hot the gauge rises to the middle and stays there even after sitting ticking over for 20 mins or more also the fan does not kick in, there's no milky signs on the dip stick or oil cap  the water is a rusty colour in the header tank!

[johnnyroper]

Chances of getting rad hot and fan cutting in are slim on a 1.9tdi due to the engine being very thermally efficient.

First checks to do are make sure impeller on water pump is still connected securely to the pump,plastic ones can detatch from shaft. Take thermostat out and put finger in see if you can spin it.

Also check the restrictor in small return pipe to expansion bottle is not blocked.

Finally do you get excessive pressure in the expansion bottle after it's been run and if left overnight does pressure remain in bottle? (Don't disturb cap after running and check in morning)

[karl s]

I'll check the pressure in the morning

[karl s]

No pressure in expansion bottle when cold this morning  but pressure when hot going to check return restrictor tonight

[insanitybeard]

You mentioned the coolant being a rusty colour in the header tank......... has this become apparent recently or have you not really looked at it before to notice? I'm assuming the heater not working issue has only become apparent since you had the coolant level warning flash up?

[johnnyroper]

How much pressure when hot was it just a slight hiss when releasing  cap or a full on whoosh with gurgling etc and level rising?

Restrictor and pump defo need checking and if they are ok I suspect you are looking at head gasket failed between cylinder and cooling jacket.

[karl s]

Took it for a long run 80mile round trip heater was getting warm then when I got home I undone expansion bottle cap and there was a strong hiss and gurgling like trapped air in the pipes then some coolant spat out but nothing major..
As for the rusty brown coloured water I've never really noticed it before.
Temp gauge stays bang in the middle all journey

[johnnyroper]

My personal opinion is head gasket to cause pressure like that along with poor cabin heat and rusty water.
Chances are restrictor will be blocked as well due to the rust.

80 mile trip and no overheating I think would rule water pump out

[karl s]

Right cleared the restrictor as it was blocked, went for a long test run up and down hills etc heater is back to normal and when I got home I opened the cap on the expansion bottle and there was a hiss with a slight bubble sound and the coolant level stayed the same  a massive improvement on before. hoses seem back to normal temperature wise
I'm going to do a full system flush and get a pressure test done

[karl s]

Also do the head gasket repair additives work?

[insanitybeard]

I'd say not reliably......... this poster didn't think so!

Although it may be behaving better now that you've unblocked the restrictor the question remains.... did it block due to to the head gasket failing and causing a load of rusty deposits to be stirred up, blocking the restrictor and causing the coolant colour to go rusty brown in the header tank? Good chance of it I fear.

There's more discussion about some of the common symptoms in this thread.

[johnnyroper]

I wouldn't waste time and money with pressure and block test on a pd it will not show anything up due to nature in which they fail.


Best bet is flush cooling system so it's clean fresh anti freeze and monitor how it goes. As above I suspect the blockage is a result of the head gasket.

[suffolkadam]

good evening chaps
had to drop in on this one , that is exactly what happened to my galaxy, took her for a trip in the cold weather last year on my way to get the mot done actually and after about 10 or so miles noticed the heater was still cold thought it was a bit strange so belted it down the A14 for a few miles and still no heat, took to the garage for the mot and they pointed out i had some water coming down the n/side around the battery area and when undoing the cap whoosh lots of pressure  and water came rushing back in. well i lived with it for a year I even drove to France and back with it loosing about a litre of water in the process never over heated once always at 90 deg and i tried every single thing possible to not do the head gasket. ie the additives....DO NOT USE.... waste of money all the vids reckon there great etc but i tried K seal ultra first and it just seemed to make things worse so flushed out completely inc removing the stat etc then i tried Steel Seal at first i thought it worked 50/60 miles all seemed good but that was only round town . i then drove down to the airport and was running a little late so pushed her over 80 and when i got to the car park could instantly smell the antifreeze. so back to square one.
after back from holiday i decided to stop wasting all my time and energy and actually do the head gasket. overall not too bad a job but i am a diesel fitter of 26 years so i should have been able to do it . and if you get stuck you've got all the help in the world on this forum..honestly cant put a time on just how many hours i wasted trying all sorts of stuff. what id suggest is that you keep an eye on the pressure in the expansion tank and keep topping up the levels and watch your temp gauge and wait till the better weather now if your gonna do it your self. unless you have a garage that is.on another note the difference in the engine is noticeable cos i completely de-coked the head and the EGR manifold and EGR itself and i even de-coked the turbo. she purr's like a kitten and a noticeable pick up in power so well worth doing and my heater is now better than ever.

[karl s]

Well I have checked the pressure after two 80m round trips and it seems to be behaving itself and this was giving it some, This will have to wait if it's the head gasket  if it gets done at all as I'm in deep with the v6 restoration shell stripped and ready for paint and engine sent away for tuning and rebuild which leaves me no room in the garage lol!

If it fails I think it's time to break the tdi 😥

[insanitybeard]

So you're doing a full strip down and restoration of a Mk2 V6 then? Not exactly a common subject for a full strip down & overhaul! Feel free to post some pictures, I'd be interested to see that!