The V8 Owners Forum -

Hi

I recently stroked out my Range Rover 4.0 V8 to a 4.6. At the same time I had a top hat lining job done. The veichle is a 2000 P38.

The engine has done nearly a 1000 miles since the rebuild. During the first 500 miles (pre oil change) there was no problem and the fluid levels sorted themselves out over the first 50 miles or so. Over the last 250-300 miles I noticed that the expansion tank needed toping up. The first time it needed approx 3/4 litre fluid to get the level back to level (probably 200 miles since last topped up...).

I had a good look around but couldn't see any leaks anywhere. I kept an eye on the level and it needed another 1/4 - 1/3 litre after another 50 or so miles driving. Feeling something was wrong I had a look at the filler cap and there was the mayo type substance in the cap and showing in the rocker cover.

I stripped both rocker covers off and there was a moderate layer of the mayo on top of the baffle plate and running down the sides of the left hand side rocker cover. (one with the breather pipe that connects to the Bosch plenum. There was nothing but clean oil on the right hand side rocker cover (breather pipe to throttle body....)

I dropped the oil but I couldn't see any traces of coolant in it. I then removed the left hand side head but everything looked normal with an even build up of deposits and no signs of steam cleaning.

I'm a bit stumped at the moment as if one of the sleeves was leaking into the sump surley there would be traces of coolant floating on the oil. Also why is there just a build up of the mayo on the left hand rocker which leads me to think that the problem is down to that bank. Surely if the problem was a leaking liner the mayo would be evident on both sides?

At present I'm thinking of getting the heads pressure tested and if that shows all to be OK then the block will have to come out and I'll look at getting that pressure tested.

One thing I did notice was that the ARP studs/nuts I rebuilt the engine with seemed a lot easier to undo than the stretch bolts used in the original build. I torqued them all up to 75lb. Maybe it's just me and the fact they didn't undo with a crack like the stretch bolts.......

I really don't fancy having to remove/refit the whole engine again unless I'm sure so your thoughts/experiences would be much appreciated.

Worth checking that your heater matrix is not leaking coolant down behind the carpet.
Cheers Denis

Is it steaming in the exhaust?

Is it only doing short runs?
Off so it may not have got hot enough to clear out all the moisturedrom the damp Uk weather

Ian

No steam showing. It does fairly short journeys but always has done. Water is definately leaking to somewhere and with no drips on the drive and the mayo build up in the rocker it has to be getting into the engine......

Check this area:

Disturbing the pipes in the engine bay can lead to the leaks on the heater matrix. Rub you hand on the carpet and then taste your fingers - if its sweet - its antifreeze and leaking seals.

I did the O rings last year. I have checked again recently and everything is dry.......

When my old engine was revving hard the header tank used to to fill up and empty itself through the overflow, i only noticed it when it was on the rolling road.
So i got a pop bottle and ran a tube from header tank into it and when under load it emptied 1/2 a litre into the pop bottle and then when u backed off it sucked it all back into the header tank.
I simply fitted an expansion tank on the header tank and never had another problem with it.
maybe worth a try...

Thanks for the ideas...... Water is definately getting in the block though as the mayo substance in the head is not normal. I've had the rockers off several times in the last couple of years and there has been no trace of the same substance. As this has built up in less than a 1000 miles (since the rebuild) and I've had to top up 1 1/2 litres in the last 300 miles or so I feel the problem is getting progressively worse... I'm going to pressure test the heads first then if nothing is wrong with them I will pull the block and test that.

Get the engine hot, with a cooling system pressure tester hooked up to the expansion tank. When hot, turn engine off and pressurise to 18psi using tester and maintain that pressure until engine is cold.
Pull sump plug and see if any water comes out afterwards - if it does, suspect a failed seal at the bottom of a liner. Seen this a few times on re-linered blocks, barr's leak seal or one of the ceramic treatments will sometimes work.....

Mayo is nothing to worry about. V8's produce a lot of condensation. You want to see how much mine produces !!

But losing water is not a good sign. If a particular cylinder has been leaking, you can usually see as it pretty much steam cleans both the chamber and piston/plug. So it's usually noticable when you take it apart. If it's only a very very small leak, you may not notice this though.

Place a good straight edge along the top of the block and look for dropped liners. it will only be a very small amount so try a 2thou blade under the edge, or shine some light and see if there is a gap.

Head studs should be tight to remove, although maybe not just as bad as equivalent bolts. If they felt loose it isnt a great sign

What head gaskets were you using ?

The block has top hat linings now so no dropped liner syndrome. I used Elring gaskets. The bolts weren't loose just didn't seem as tight as the stretch bolts. They were smoother to undo maybe a better phrase.... No sign of any steam cleaning.

If the liners have been replaced, you can never rule out an issue with their fitting. They shouldnt move if done correctly, but it isnt impossible.

Issues can indeed happen with top-hat linered blocks, I know of two blocks with slipped top-hat liners. One was my own, one a customers, both done by the same engineering shop via Lund Engines (sorry for swearing, one day Steve Lund you and I will meet up... grrrrr!).
The liners had not been clamped down after insertion in the hot block and had "nipped up" before the block was decked. With the heat of a long run or working hard, the compressive force on the gaskets forced the liners down onto their rebates correctly, allowing a hot gas leak across the gasket face. My liners had dropped by 7 thou! Block was re-decked and all was well for ever more, exactly the same issue with the customers engine.
I've been successfully rebuilding these engines for over 20 years and I can assure you that V8 Rover engines are NOT prone to mayo, even when used for relatively short journeys. If there is mayo present, there is a problem. Last engine I stripped wasn't just mayo, it was full of grey yoghurt and that was traced to the lower seal gone on the no.6 liner.