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Oil leak from cylinder head gasket


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Hi All,

I have noticed a slight weep of oil from the cylinder head gasket of my TR5. It is on the left had side of the engine on the same side as the engine number pad. If I clean the area and run the engine statically the leak doesn't appear but after a 100 mile or so run there is oil present along the length of the joint. It is not possible to see where the oil initially emerges as it runs along the joint. I have found a number of posts about this for the TR5 and TR6, so it seems to be a common problem. There are a number of solutions offered but at this stage I don't want to remove the cylinder head. The engine was rebuilt about 22 years ago and 15,000 miles has been driven. I don't think that the head has been disturbed.

My question is, do you think that retightening the cylinder head nuts is likely to have any benefit? I would do this in the correct tightening sequence, loosening each nut slightly first, then retightening to 70 ft lbs. The thing I don't want to do is to make the leak any worse!

Regards,

Denis

Edited by DenisMc
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Before blaming the head gasket, I would trace the  source by dusting the top of the engine with flour.    Yes, flour! Self raising, strong, wholemeal, it really doesn't matter!

This will reveal where the oil comes from by forming a stained track, which may be washed off afterwards.     The engine is mounted with a slight rearwards tilt, so that a leak from anywhere forwards will accumulate at the back, where you find it.     Personally, I suspect some oil may be escaping from the filler cap!

Good luck!

John

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If it appears to be the head gasket, as you have read in other posts, and you do not want to remove the head, you could try to “seal” it by putting silicone gasket sealant across the entire gap, after thoroughly cleaning. A friend did this last year, and still has no leaks.

Worth a try.

Cheers,
Waldi

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There is a common Oil Leakage problem on the Triumph 4 & 6 Cylinder Engines at the rear left/nearside corner, the Oil feed to the Rocker shaft rises up from the scroll on the Camshaft via the Block and head to feed the rockers.

If the leak isn't to bad I wouldn't worry about it, I don't think a re-torque will solve the problem but it may be worth a try.

If the leak is bad its head off, a new Head Gasket and you need to smear a small amount of Blue Hylomar in a continuous circle around the oil feed hole between head/block on both sides of the gasket, only a small amount as you don't want to block the oil feed to the rockers?

Gary

 

 

Edited by Gary Flinn
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If the leak is coming from the places mentioned, I'd recommend Hylomar to try and seal....after all its what Rolls Royce developed it to seal up their engines.   I've used it on the outside around the timing cover and it sealed things up well.  It stays pliable and isn't affected by oil or gas so stays tacky and holds up over the long term.

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Thank you all for your great suggestions. The oil is definitely not coming from the rocker cover area, which has a cast aluminium alloy cover.  I have fitted the silicone reusable gasket, a new seal in the cap and Dowty seals under the fixing nuts. It is a very slight leak but have noticed an annoying oily smell in the car after 50 miles or so as the oil start to heat up on the joint. I'm inclined to try sealing it externally as has been suggested and perhaps retighten the head when I next adjust the tappet clearances. I have some black RTV sealant left over from securing the rocker cover gasket to the cover, which might work well.

Thanks again,

Denis

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  • 1 month later...

They commonly weep on the linear side. This side of the head outside the rocker shafts often doesn't seal well as it is outside the area clamped by the head studs.

Next time you have the head off, smear a little RTV silicone sealant on both sides of the gasket in this area only to take up imperfections and make a good seal.

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Thanks. I am trying to avoid lifting the head but if I have to this is useful, along with the suggestions I have received from other TR Register members 

Thanks,

Denis

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I found a much better looking gasket than the other suppliers offer, at Bastuck with more silicone beads on the gasket, will have to search for a part number.    Its     MD6TR6

John

IMG_3439 (4).JPG

Edited by John L
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