Expansion tank

Now that I've finally sorted out the electrics I'm gradually working through each issue one by one.

Next issue: When I purchased this 300TDi and drove it back up the M1 and the temp needle appeared to go into the red, obviously I stopped to allow it to cool before filling up the expansion tank and setting off. Once back home I had a closer inspection and noticed that the heater matrix was leaking. I replaced this matrix and filled up the expansion tank and blead the system appropriately. Since then (last two months) everything has been fine with no loss of water, although the temp gauged has remained just over halfway (55%) at all times.

However today following the school run, about a 25 min drive, I thought I'd have a quick look at the coolant level. I switched the enging off and went to remove the expansion tank lid. There was not really any hissing, but the coolant did overflow slightly, not whooshing, rather as I was unscrewing the lid there was a minimum amount of coolant run out and the tank appeared full of coolant. At that exact point my Neighbour came running over from his car shouting "hey young man, that's not good, bad news indeed!!! Yup that's your Head Gasket Gone!" Oh joy I thought as he stood there stroking his beard.

But has it really? I've checked the radiator and that appears to be hot all over as it should as does the top hose. I've only recently just flushed the radiator. I assume the thermostat is working as the gauge is just above halfway which is normal.

I've also noticed a very slight noise coming from the water pump, although I think it's the normal noise. I will post a video later.

Any advice?

I forgot to add that the coolant is clear of oil, likewise the oil is clear with no sludge etc.

Personally I think it's airlocks following removing the radiator to flush.

don't open cap when its been running

The expansion tanks are known for cracking at the join. happened to me, All of a sudden had water with anti freeze coming out of the bonnet while driving along.

with a sealed cooling system when things get to temp they expand. If you remove the cap slow you may hear a hisssssssssss the is just pressure from expanding liquids

That's what I thought, I wasn't unduly concerned rather I thought I'd quickly check the levels having driven the old girl for the first time sine removing /refitting the Rad. It was the old chap from next door who's put the fear of god into me.

To be fair I was more concerned with trying to figure out what this load squealing noise is I seem to have developed somewhere in the frontend or below. As it only happens when accelerating and increase with speed (any gear) and stops the miniute I stop accelerating or pop it into neutral, I suspect that it's one of the front UJ's. Initial inspection they appear solid enough but with this sciatica I haven't been able to look properly.

Landyfox said:

That's what I thought, I wasn't unduly concerned rather I thought I'd quickly check the levels having driven the old girl for the first time sine removing /refitting the Rad. It was the old chap from next door who's put the fear of god into me.

To be fair I was more concerned with trying to figure out what this load squealing noise is I seem to have developed somewhere in the frontend or below. As it only happens when accelerating and increase with speed (any gear) and stops the miniute I stop accelerating or pop it into neutral, I suspect that it's one of the front UJ's. Initial inspection they appear solid enough but with this sciatica I haven't been able to look properly.

Click to expand...

UJ'S grease them and check, better now than freezing snow and rain

Once my back is right and I am able to bend, plan was to attempt to replace the UJ's in my front prop. Can this be done simply by using a bench vice or does it require a hydrolic press.?! If it does I might as well buy a new prop.

Landyfox said:

Once my back is right and I am able to bend, plan was to attempt to replace the UJ's in my front prop. Can this be done simply by using a bench vice or does it require a hydrolic press.?! If it does I might as well buy a new prop.

Click to expand...

easy job in a bench vice. just mark up all mating faces and reassemble the same way. A couple of hours at the most.

Another point re the coolant is that it should only expand when it's hot. So if you had a headgasket issue that was pressuring the system, it would be present when you started the engine from cold. That is to say, you would be able to observe pressure build up by removing the cap after a minute or two. You may also even see bubbles in the tank. Ask me how I know!

Landyfox said:

Once my back is right and I am able to bend, plan was to attempt to replace the UJ's in my front prop. Can this be done simply by using a bench vice or does it require a hydrolic press.?! If it does I might as well buy a new prop.

Click to expand...

bench vise to hold drive shaft. But a 20 oz ball pen hammer is all I have ever used with gentle tapping. If the yoke are cleaned up things go together very easy

sp00k said:

Another point re the coolant is that it should only expand when it's hot. So if you had a headgasket issue that was pressuring the system, it would be present when you started the engine from cold. That is to say, you would be able to observe pressure build up by removing the cap after a minute or two. You may also even see bubbles in the tank. Ask me how I know!

Click to expand...

if HGF you could see the coolant surging on compression stroke, it will act like a pump pushing the coolant

Landyfox said:

Once my back is right and I am able to bend, plan was to attempt to replace the UJ's in my front prop. Can this be done simply by using a bench vice or does it require a hydrolic press.?! If it does I might as well buy a new prop.

Click to expand...

vice is best flange yoke can be the most difficult if outer faces arent square so is best to fit uj to it first ,once spider is in yoke and one cap started push it through till it nearly comes out of other side of yoke ,it makes fitting other cap easier and means both caps have needles stated over spide for when you push second cap on and push whole lot back

jamesmartin said:

vice is best flange yoke can be the most difficult if outer faces arent square so is best to fit uj to it first ,once spider is in yoke and one cap started push it through till it nearly comes out of other side of yoke ,it makes fitting other cap easier and means both caps have needles stated over spide for when you push second cap on and push whole lot back

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add a little extra grease with your finger to hold needles in place

Thanks Chaps I really appreciate it!!

Sp00ks....you didn't did you..?

On a side note - James DVD ordered

Landyfox said:

Thanks Chaps I really appreciate it!!

Sp00ks....you didn't did you..?

On a side note - James DVD ordered

Click to expand...

With my last engine I had HGF, then a cracked head, then I replaced the head with a warped one! Great stuff.

I would have said that expansion and slight overflow was normal for most cooling systems when the engine is hot, your lucky it wasn't more & scalded you!

jpfour said:

I would have said that expansion and slight overflow was normal for most cooling systems when the engine is hot, your lucky it wasn't more & scalded you!

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That's what I thought

Coolant always at the half tank line? No hiss when removing the cap? That'll be the expansion tank splitting on the seam, mine did and it was on the side that's tucked under the wing. It was my MOT dude that spotted it. Have your coolant system pressure tested, or just replace the tank. It may come as a blessed relief it's not a HG!