cylinder head bolt retorque (to address coolant seep)

[Peter OSullivan]

My 97 Defender has a tiny weep at the rear of the head. The engine was rebuilt about 95000 km ago - I have been advised to tighten [retighten?] the head bolts by first 'cracking' one loose then torquing it up and using the same procedure on the rest. Since the bolts will not be removed, should I use a torque value - or should I simply go with a degree value? [e.g. 15 or 30 degrees more than where each bolt was]

[hurbie]

bad idea , just replace the headgasket and torque it propperly according to the manual .

[western]

Replace head gasket & torque as per workshop manual sequence 

[Peaklander]

Before you do, just check that the leak really is from the gasket. I had a similar weep but it came from the heater hose spigot outlet at the back of the head but looked as though it was from the head to block joint.

[Sigi_H]

I understand that this is tempting. I would try it too, but without loosening the bolts and tightening them again.
In any case, you should have a new gasket and new bolts ready. there's a good chance that it won't work

[miketomcat]

Assuming it's a 300tdi if you tighten the bolts more than spec you run the risk of the head cracking when it expands due to running heat. I had a head gasket weep (poor quality) about a week after fitting it, I bought another gasket and replaced it.

Mike

[Peter OSullivan]

Thanks all for your help.

[Peter OSullivan]

Coolant weep collects at gasket level, but is also visible on the cylinder head above. Could it involve the item in centre of photo or the fitting in middle top? Thanks for your interest and time. PO

[Eightpot]

It does look like it's leaking from elsewhere as well as the gasket - I wonder if there might have been oil/water left in the bolt holes before the head was torqued down? 

Also a slim possibility the engine fan is blowing the coolant around a bit making it look like its running down. 

Either way, I'd be whipping the head straight off and checking/replacing the gasket. 

[fmmv]

I think you are referring to an injector, ie fitting in middle top. That has to be innocent. The rusty bolt head is a cylinder head bolt, it could conceivably be leaking up that. Or it could be the core plug visible in the left of the bottom picture. Or about 20 other things. As @Eightpot advises it needs the head off and investigating. Or if you want to try to diagnose it first try getting the cooling system pressure tested.

Edited Sunday at 12:26 AM by fmmv

[Peter OSullivan]

Thankyou eightpot and fmmv. Will get a pressure test tool tomorrow and work from there. Thanks again. PO

[Peaklander]

The heater spigot to which I was referring is shown in this pic. Your leak is much bigger than mine but still, just have a look there. It's on the right side at the back of the head.

The rotation bug is back. I can't get the forum to post this pic the correct way round, even though I have offered both orientations. i will try from my iPhone in a minute.

Edit. I used a screenshot of the rotated pic. 

 

Edited Sunday at 08:19 AM by Peaklander

[miketomcat]

If it's leaking from the glow plug or injector there's a high chance the head is cracked, because those go into the combustion chamber. Head gasket could blow up past the head bolt but that would suggest the thread wasn't cleaned out properly and the bolt has hydrauliced before it tightened down on the head (ask me how I know this ). Because the coolant is on the head above the gasket it's unlikely it's leaking from the gasket joint, water doesn't generally run up hill unless forced.

Mike

[Sigi_H]

This leak is to big for any approaches to retighten. New gasket and new bolts!

As mentioned check the head carefully for cracks.