Boro Posted January 22, 2012 Share Posted January 22, 2012 My 1971 rangerover is fitted with a 4.2 v8 from an lse, it appears to be leaking oil from the valley gasket (oil sat on the gasket and dripping down the front of the engine) as well as losing coolant from somewhere around the manifold as theres coolant on the valley gasket as well, i have been putting this job off for a number of reasons the main one being jobs like this normally spiral (i could find i need to replace the tappets and cam whilst im in there) but realy need to sort it out now, theres two types of end seals listed for the clamps that hold down the valley gasket how do i tell which my engine needs? is the composite valley gasket better than the pressed tin one? neither the oil temp or oil pressure gauges work which may be a result of missing senders or wiring im not sure but where should the two senders be located on the engine? would be nice to get these working so i can keep an eye on things, do the v8 engines have a drain plus for the coolant? the coolant loss seems strange its not losing a lot of coolant and if you take the cap of several days after last running the engine the system still has pressure or maybe its vacuum due to the leak, im going to replace the thermostat and housing gasket whilst im in there along with changing the oil and filter and coolant but is there anything else i should be doing at the same time? Quote Link to comment Share on other sites More sharing options...
g&t Posted January 22, 2012 Share Posted January 22, 2012 I'm not a mechanic but, based on my own past experience, the 'pressure still present when removing cap after a long stand' senerio sounds like head gasket. Sorry I can't be of more help. Quote Link to comment Share on other sites More sharing options...
stuck Posted January 22, 2012 Share Posted January 22, 2012 If you run the engine with the coolant expansion tank cap off do you see bubbles? (try it at tick over and whilst revving the engine) Does the engine overheat or has it ever done so? Quote Link to comment Share on other sites More sharing options...
Boro Posted January 22, 2012 Author Share Posted January 22, 2012 No the engine doesnt overheat temp gauge needle sits where it should, did a 50 mile trip last week and the coolant level didnt drop, it had crossed my mind that a head gasket could be suspect but if it is its very early stages, may see if i can grab a block test kit and test it Quote Link to comment Share on other sites More sharing options...
stuck Posted January 22, 2012 Share Posted January 22, 2012 Was trying to rule out the HG as in MHO it would blow the coolant out of the expansion tank and not pool on the valley gasket as yours appears to be doing. I guess the thermostat housing you have mentioned is a good a place as any to start. I've never found a coolant drain point on a v8, I've always just undone the bottom hose. Quote Link to comment Share on other sites More sharing options...
Boro Posted January 23, 2012 Author Share Posted January 23, 2012 I have been giving the coolant some more thought, the coolant leak wasnt apparent until after i tightened the coolant reservoir cap as i noticed it was loose and was hissing (not losing coolant from the cap though), only had this vehicle a few months so dont really know the history, could be the previous owner left the cap a little loose knowing that when done up tight the coolant would leak... test kits on ebay are £43, i know i shouldnt but if it is headgasket and the heads need to come off (see no point doing just one for the effort in stripping etc) what aftermarket head and cam options are there for the 4.2 Quote Link to comment Share on other sites More sharing options...
SteveRK Posted January 24, 2012 Share Posted January 24, 2012 I think you will find that what you think is 'pressure' in the cooling system is in fact vacuum. When the water is hot pressure will increase, when it cools down it will reduce. what you can have is coolant leaking into or out of the engine when its hot and under positive pressure and then as it cools the leak stops but you now have reduced coolant in the system with a sealed cap that only vents under positive pressure, hence a partial vacuum. Quote Link to comment Share on other sites More sharing options...
bobtail84 Posted January 27, 2012 Share Posted January 27, 2012 neither the oil temp or oil pressure gauges work which may be a result of missing senders or wiring im not sure but where should the two senders be located on the engine? would be nice to get these working so i can keep an eye on things, The oil pressure and temp senders are fitted to the oil pump housing. You might find brass nuts blanking the holes. Here is a link for a temp sender. http://www.rimmerbros.co.uk/Item--i-DRC2479A Oil temp senders are a bit spendy and you don't really need it. If the oil temp is to high the pressure will drop. HTH Jeff Quote Link to comment Share on other sites More sharing options...
iomlt Posted February 10, 2012 Share Posted February 10, 2012 My 3.9 did this that i put into the challenge truck. loss little bit of oil onto the valley gasket. thought hmmm must change that but needed the truck for an event, so i just tighterned all the inlet manifold bolts surprising how loose some where.. check it everytime i use the truck and i have even bought a new genuine valley gasket but its stopped leaking and that was 9 months ago... touch wood tighterning the bolts have sorted it. Quote Link to comment Share on other sites More sharing options...
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