Hi all, greetings from Ireland. I have an A15 in an 1986 Nissan Vanette that my father in law gave to me about 5 years ago and I'm now trying to fix here up as they are rare over here these days. The van was parked up for about 4 years but started on the second attempt the other day but I found oil in the rad. The head gasket was done just before he gave it to me but now after its long lay up its acting up again.


I stripped the head to have a better look and the head seems fine, no cracks etc. I found a bit of carbon build up on one of the gasket rings though. I dont think the head was skimmed the last time it was done but I'm hoping you could advise me on where to go from here.

I'm wondering if there is another way these engines can let the water & oil mix. I know very little about engines but would I be right in saying that there is only one way oil can get up into the cam area and thats through one hole in the centre of the head, pic below. and that if the gasket failed here the water & oil could mix?










The gasket didnt look as if it has broken anywhere so I'm guessing the last guy who was a handy man that done the head didnt do it right?








Last picture turned out bad, it was getting dark. Any ideas or opinions are welcome.

Thanks, Rob.

Hi Rob, welcome.

Yes, the cam is lubricated by that hole.

That is the only gasket where oil and water both pass (the head gasket).

Nissan recommends re-torquing the head gasket bolts ever twenty-four months (every two years) -- of normal driving -- so that may be the problem. It may not have been torqued correctly.

A-series cylinder heads rarely if ever need skimming. The specification is up to 0.004 " from flat and it won't leak. You can measure this with a straight edge.

Hi Rob, these are a cam in block push-rod engine so that oil hole you have illustrated is to supply the rocker assembly up top with lubrication.

The cam is lubricated elsewhere along the circuit, I'm pretty sure it's secondary to the feed from the crankshaft.

I'm not too sure how else you could get oil in the coolant apart from it being a gasket issue, I'll have a think about it some more (bit early!) and get back to you. I would insist it were a gasket failure though, do you have some clearer photos to try and see if there was indeed a gasket failure?

Is the van an auto or a manual? if its an auto The heat transfer section in the radiator could have split allowing trans fluid into the radiator mixing with the coolant giving the appearance of a head problem.... I have seen this a few times before
was just a thought.
Cheers.
Adam.

Thanks guys, I'll see if I can sort a better picture of the gasket in the morning, off to bed for me, big time difference between us

Hi Adam, its a manual... thanks anyway.

"firstly check head for warpage"; then my suggestion would be take the head to a engine reconditioner, get it fully serviced & pressure tested.
it appears to be a bit of a oil burner by pics, maybe give the bores a hone and put a set of rings & bearing in it as well( y apart).would last forever then.
oil in water occurs when; cracked head/blown head gasket(head warpage)/crack in bore(highly unlikely)or if auto trans (radiator my be cracked). cheers ernie, welcome to the site.

Better picture of the gasket.....

it appears blown between 2 & 3, is head warped.if this is the second time its happened, its telling you that the head surface or block has a problem,head may appear straight(but still may have low spots were blown)don't risk it,not much cost for a light mill(surface grind).cheers

Yes it looks blown between 2 & 3. Does not mean the head is warped. I've changed A-series blown gaskets without planing the head and they were fine. (First check for warpage). Block prep is the key: get it clean, no oil on the faces, and tighten the correct pattern, 3-steps, correct torque for the '13' bolts. If you have the original bolts, replace them with a good used set of newer bolts. Re-torque every two years per the Datsun schedule. She'll last forever.

If you are trying to win a race, you may wish to blueprint the engine closer than the Datsun spec of 0.004 allowable warpage.

Wont be winning any races with this.............. Worth more in sentimental value to us, I might customise it a bit if I dont much engine problems.




I cleaned the gasket off the head lastnight but there is a lot left on the block, getting it off is no problem but will i do any harm if bits fall into the chambers or galleries?