Elusive water leak and pressure build up in rocker cover.

grogers · Oct 19, 2014

Hi all,
could some kind person give me some pointers as to where to look for my elusive water leak (I would say coolant but gave up putting that in, it was getting expensive!!).

I thought initially it was the core plug to the rear of the head as this was where i _thought_ the water was coming from, so removed the head, cleaned it up, relapped the valves, replaced stem seals etc while it was off.

Head refitted, refilled system with water (I know i should use coolant but wanted to check it'd didn't leak first) and it's still losing water from somewhere!!

Core plug on rear of block looks ok, heater hoses are ok ,so where is another source for the leak?? I cannot see any other water related hoses/plugs nearby and can only see that the water is dripping of the bellhousing but not how it's getting there.

On a separate note but probably connected to head removal/replacement, i now seem to have pressure behind the oil filler cap, what could this be caused by?

Cheers

Glenn

jamesmartin · Oct 19, 2014

if you run it long on just water it will be leaking from the block core plugs soon enough, if you hace excessive crank case pressure its most likely from head gasket ,did you rest tappets

grogers · Oct 19, 2014

Cheers,
i've not reset the tappets yet as i wanted to make sure the leak had gone. I may drain the system again loosen the head bolts off and redo the torque setting as i'm not 100% I followed the procedure correctly the first time. (40Nm then 60° then 60° again according to bolt tightening sequence)

How many core plugs are there and where are they? I can see 2 on the head and 3 on the block, I've tried using an inspection camera on the ones i can see and couldn't see any water leaking from them. Wherever the water is leaking from it's a pretty good dribble, whether the engine is running or not.

Cheers

grogers · Oct 20, 2014

Update :

Found the leak with the use of friend with a pressure tester and it turns out it was the core plug at the rear that's nigh on impossible to get at!

Now trying to come up with method of removing the old and fitting the new _without_ removing the engine any one done this?

Cheers

boneheaddread · Oct 21, 2014

Hi keep me updated how you get on as I have a leak in exact same place on my 200 tdi , I was told that the core plug is behind the flywheel hence engine out and separate the engine gearbox to replace a £2 core plug ? is this right ?

jamesmartin · Oct 21, 2014

boneheaddread said:
Hi keep me updated how you get on as I have a leak in exact same place on my 200 tdi , I was told that the core plug is behind the flywheel hence engine out and separate the engine gearbox to replace a £2 core plug ? is this right ?

the rear block core plug (erc4996)is above flywheel housing ,but would need engine out to fit properly as bulkheads in the way

grogers · Oct 21, 2014

Right my possible solution to this problem is something like:

Remove old core plug: I reckon i've just enough space to get the head of my plasma cutter or die grinder onto the old core plug to cut a levering out hole to remove the old plug

Refit new core plug: I notice there's a convinient bracket that holds the starter cables and i'm thinking make a plate with a bolt to use as a forcing screw to allow me to produce enough force to push the new plug home (as obviously there's no hammer swinging room!)

If this works it'll save shed loads of time (and money) and hassle and may be of use to others faced with this predicament!!

Has anyone got a good picture of the rear of a 300tdi block so i can work out the relative locations please?

jamesmartin · Oct 21, 2014

the rear plug is the hardest to remove it wont twist as the others as theres very little room behind it

discool · Oct 21, 2014

Perhaps u should look at the possibility of cutting out an inspection hole in the footwell something that was done in the old days by some with a 3.5 RRC to gain access to the rear core plug, and then fit a plate over with self tapping screws.

grogers · Oct 22, 2014

Yep think that might be plan B, might as well give it a go in situ first not got a lot to lose.

Rather hoping my gadget idea may work though, hoping to try the weekend if weather permits! (Oh for a dry area to work on it lol)

Cheers All

jamesmartin · Oct 22, 2014

discool said:
Perhaps u should look at the possibility of cutting out an inspection hole in the footwell something that was done in the old days by some with a 3.5 RRC to gain access to the rear core plug, and then fit a plate over with self tapping screws.

its not going to help

Elusive water leak and pressure build up in rocker cover.

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