Thread: 300TDI coolant loss

not fully understanding your fix for the T junction, but yes my car does take quite a while to get to temp.

can you explain a bit more on that fix?

might be easier just to fit a new sputnik though I guess, seems like they are not too expensive to get new.


The heater core is not leaking, I have replaced it myself it was bypassed when I bought the car.,

Originally Posted by AK83

Shouldn't be a problem, except like I found out:
In cold temperature it'll take 10 x longer for the engine to get to operating temp due to the design of that sputnik thing.

Got some great advice about it here. On the thermostat hose side of the t junction you insert a small pipe with a tapered end so that it doesn't get pumped through.
The length of that small (internal) pipe should be that it passes the junction where it feeds into the radiator.

This is the bleeder air valve thingy working as it should again.

I doubt it'd cause coolant loss, but my Tdi wouldn't get to it's normal operating temp for at least half an hour or more of freeway driving .. with the fan removed.
It would finally reach it's normal 80-83° but I'd be frozen solid by that time.
I did as was explained, now runs perfectly.

Another point to note about coolant loss, is the wetness/dryness of your front carpets/floor mats.
Could be a heater core coolant loss.
No idea on how easy hard a defer is to get to the heater core.

I know I'd notice the smell of hot/warm coolant inside the passengers compartment.
Sister had a (Ford)Lazer and my ex mother in law had a Sigma, both had that hot coolant smell inside them.
I recommended to both back then to get rid of their respective cars before it cost them to fix it, or the inevitable blown headgasket.

There is another thread on here somewhere if you can search for it.

but quickly:

if you have a t-piece, the natural way for it to fit is to have the straight end going from thermostat hose to reservoir, and the t junction divert to the radiator hose.
What I was recommended was that the straight section of the t piece, you insert a small diameter pipe into it from the thermostat hose end, flare the end of this small pipe so that it doesn't get pushed through to the reservoir tank.
The flare of the pipe should be just big enough so that it still fits within the hose coming from the thermostat, but not into the t-piece. Only the pipe/tube should fit into the t piece.

Tpiece mod should look something like this:

return bleed t-piece.jpg

small red thin part inside is the internal pipe. Note how the pipe extends past the t junction to the radiator(that's the important bit!), and that the other end is flared to stop it pushing through to the reservoir.
I used a small bit of plastic pipe, heated the end and inserted it onto a tapered screw, pushed it while hot to make the flare end.
So far so good, but I have a feeling that if it gets hot, the plastic pipe may soften and push through.

The vent for release is the expansion tank cap.
My cooling system takes 7kms @ 60kph to get upto operating temperature.
A sneaky leak is the weep hole on the waterpump.
Collant can leak but evaporate quickly, leaving green snot hidden by the pulley.

Use a Y piece and you won't have any issues, not sure why you would use a T as it prevents the proper coolant flow.

Well it's been a week and the coolant level hasn't dropped any this week... so it could be a good sign.

I think it may have been leaking at the T that had been installed and it just wasn't noticeable, because all I did was bleed it with the coke bottle method and refit the T piece with mod done.

I used a flared piece of 4mm brake pipe inside the T piece to do the mod mentioned and it does now get up to temperature much quicker (still takes about 5-10 minutes).

So thanks for the help... I'll probably get a proper replacement peice, although seeing as it is a plastic piece that seems to fail maybe my brass T junction is actually more reliable.