back to the head...

[Billy-No-Money]

Hi y'all. Firstly, as a newbie I gotta say all that the feedback and help on my previous threads has been fantastic. Not only guiding me in the right direction, but also in putting my mind at rest from 'surf paranoia'.
So, following advice on an oil leak from round the head, I have isolated it. The engine has just had a thorough chemical cleaning and I can now see quite clearly where the blow is coming from. There is a pressure leak from the head gasket on the front left hand side, above the last few digits of the engine number, just forward of the head bolt at the front of the inlet manifold assembly. The edge of the head gasket is clearly visible here and the leak can be seen coming from both above and below the gasket. Its only a pin-prick leak, reducing to almost nothing as the engine warms up. I was wondering if it could be remidied by re-torquing the head bolt but Im concerned about it snapping if I try. So, should I now make the decision to have the head off to replace the head gasket and be prepared to replace the head if its found to be cracked, or should I just keep running it until it either becomes seriously worse and I get oil/water transfer?
Cheers.

[plumb bob]

I think I would try re-torqueing it, you'll find the figures in the manual, or do a search for the info on here.

You will have to do all the bolts in the correct sequence, the should'nt shear off, as you will be using a torque wrench ste to the correct value.

Maybe TonyN would be able to give more deffo advice on retorqing procedure.

You've got nothing to lose I'd say.

[Morr]

The cylinder head bolts are stretch bolts and so should not be reused or retorqued.
Its up to you if you can live with the oil leak, if not a new gasket and bolts will be required, but as you say be prepared if you discover the head is currently cracked even if its not exibiting any symptoms.

[plumb bob]

Theres always someone who knows more about technical stuff. he he.

A very good point, but if the bolts have not been torqued correctly in the first place woud it not be worth checking?

[Billy-No-Money]

Cheers Guys. I can live with the leak, as i said its not pouring out. My only concern is that if it is the head gasket and not the head then I dont want to make the problem worse by ignoring it.
Ill give all the options consideration. Its due in for timing belt change tomorrow, so Ill get a compression test done while its in. Maybe that will tell me a little more before I have to make a choice.
thanks again, your all diamond geezers.

[BUSHWHACKER]

Cheers Guys. I can live with the leak, as i said its not pouring out. My only concern is that if it is the head gasket and not the head then I dont want to make the problem worse by ignoring it.
Ill give all the options consideration. Its due in for timing belt change tomorrow, so Ill get a compression test done while its in. Maybe that will tell me a little more before I have to make a choice.
thanks again, your all diamond geezers.

How old is your engine oil?
Maybe worth changing if it's old and thin.

[Billy-No-Money]

oils been in for about 5000 miles, but it is lookin abit ropey. I put an additive in a coupla weeks ago that was supposed to help reduce smoking by reducing oil escape as I thought perhaps that the valve oil seals were hardened and innefective. Didint make any difference though, I should have just changed the glowies! Its due an oil change, but been holdin off till I decided what to do with the head. ( actually, the oils a bit of a mix cos its had the occasional top up with a spare can that my lad bought for his peugeot 205 but didnt use because it turned out to be the wrong one)

[BUSHWHACKER]

oils been in for about 5000 miles, but it is lookin abit ropey. I put an additive in a coupla weeks ago that was supposed to help reduce smoking by reducing oil escape as I thought perhaps that the valve oil seals were hardened and innefective. Didint make any difference though, I should have just changed the glowies! Its due an oil change, but been holdin off till I decided what to do with the head. ( actually, the oils a bit of a mix cos its had the occasional top up with a spare can that my lad bought for his peugeot 205 but didnt use because it turned out to be the wrong one)

It's well over due an oil change then!
You'll probably find that the oil leak will subside with fresh, more viscous oil in the engine.

[Morr]

Theres always someone who knows more about technical stuff. he he.

A very good point, but if the bolts have not been torqued correctly in the first place woud it not be worth checking?

There is no reliable way of checking the existing torque as they should have been tightened using a combination of tightening sequences, the last of which are angle torques, ie tighten the bolt by turning a specified number of degrees, so no actual numerical figure is available for the final torque.
Plus if they had been done correctly they will have stretched so any subsequent re-torquing would introduce additional stretching which could weaken the bolt with the possibility of shearing one. Such shearing often occurs at the top of the threads, requiring much effort to then remove the broken remainder from the bottom of the threaded hole in the block, not worth taking a chance with.

[MattF]

It's well over due an oil change then!
You'll probably find that the oil leak will subside with fresh, more viscous oil in the engine.

Beaten me to it. That oil, (and filter), is gagging to be changed.

On a side note whilst you're about Morr, you fitted one of those sump drain plugs, didn't you? Is the oil sump bolt a M12?

[Billy-No-Money]

Thanks again for pointers guys. Decision made then. I appreciate the point about the oil viscosity, but i reckon for it to show as small air bubbles as it blows out of the side if the head there has to be compression leak. The fact that the bubbles are present both above and below the gasket makes me lean more towards gasket failure, as if it was the head leaking i would imagine that the compression/fluid leak would be more prevailant on the head side of the gasket and I would have running probs other than a bit of smoke (most of which now seems to be clearing with the new plugs in). So, Im gonna book three days off work, take the head off so I can get the correct ident from the head gasket, nip to Milners (20 minutes away) for a new gasket and some head bolts and put it all together properly. If I find the head is cracked, well so be it. Its as well to find it now as wait for total and sudden failure. Sound like a plan?

[MattF]

You already have your mind set as to which route your taking. I'd still see to everything basic first and just pressure test, but have fun with the gasket change.

[BUSHWHACKER]

Don't forget to pick up a timing belt and tensioner while your there.

[Billy-No-Money]

Fair point matt. Tell the truth , I'm not too keen on doing it but theres no way i could afford a garage bill for a gasket or head change. An oil/ filter change could well reduce the appearance of the leak, but surley it would still be there? Please bear in mind this is my first ever deisel vehicle, so are you saying that if it is the gasket causingthe compression leak and its only small, its nothing unusual or worth taking on that level of work to rectify?

[MattF]

As I mentioned somewhere around the first time you asked in another thread, , no, I wouldn't go to that excess unless necessary. In all truth, most of our engines are that caked in oil and gunge at the bottom end that a leak that small wouldn't be noticed by most, and I doubt there's many on here who don't have a phantom leak of some fluid somewhere. If you had to start putting half a pint of oil in per fortnight/month, or some other such top up where one of the fluids was mysteriously disappearing, then I'd say yes. If you're using oil that's so far past its best and not having to top up at the moment, I'd say you're worrying over a small concern.