sotal Posted November 28, 2009 Share Posted November 28, 2009 I've now got my p38 on the drive, and have spent a couple of hours playing with it and many hours reading up about it on the internet, and on the RAVE disc. As I posted before I've bought this Range Rover with problems. Looking at the documentation the Range Rover was taken off the road nearly a year ago when one of the coolant pipes burst and the vehicle overheated. The car was recovered back, the PO didn't know much about cars so a friend came to have a quick look. They started the car for just a few seconds to check the compression, they did this for the front two cylinders (which they said were low - no idea how low - no idea what they should be), After doing the front two cyclinders they it would no longer start up - it turned over but wouldn't actually fire. At this point they took the head off on the offside, to have a look for damage. His friend then told him it must be the piston rings letting compression past (no idea how he came to that conclusion). It has then sat there like that for nearly a year. I now have it like that. The head, rocker cover, manifold valley cover, alternator etc is all in the boot. I don't have the old head gasket to examine. I've now had a proper look over the parts as best as I can to the best of my knowledge. The liners all look fine and don't look to have slipped at all. The pistons all look fine but the front one is cleaner than the others. The head looks ok, checked for warping and it doesn't look to have warped out of tolerance, but would like to check it over a bit better. It looks like it was blowing between the two middle cylinders. The only other problem is that with head being off the vehicle for months the PO has managed to scratch a small section of the head surface. We put a 24mm socket on the front nut and turned it a little with a breaker bar the pistons moved up and down freely - didn't move it far as the other head is still on. - Just moved it back and forth a little. I'm just not sure where to go from here. My thoughts at the moment are to do one of the following options: Option 1: Get a cheap composite head gasket @£10, and put it back together using the old bolts and gaskets as a temporary measure so that I can test the compression and see if it's got sparks and fuel and to help the diagnosis a little. If it runs and compression seems OK then strip down and put both sides back together with new bolts, and new gaskets and seals all round @£60 Option 2: Get the full gasket and seal and bolt set @£60, build the one side up with the new bits - test as above and then build up the other side? Option 3: Strip the other side off then rebuild with kit @60 and cross my fingers Not sure if I should get the head skimmed to get rid of the scratch? If I skim one head should I do both so they match? Or is the amount so small that it wouldn't matter? Not sure but I think the gaskets that were on were composite as there was a bit of black left on the block. Is there anything else I should check whilst the head is off. Would pictures help? If so please say what to take pictures of. Thanks in advance Quote Link to comment Share on other sites More sharing options...
VOUGE50 Posted November 28, 2009 Share Posted November 28, 2009 Hi if you would like to give me a ring on 01805 624290 i can advise Regards VOUGE50 Quote Link to comment Share on other sites More sharing options...
sotal Posted November 28, 2009 Author Share Posted November 28, 2009 Thanks very much for the offer but if you could post details on here it would help others in the future too, or if you want a bit of a discussion about it then the private messages can be used to have a conversation. Many thanks Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted November 29, 2009 Share Posted November 29, 2009 As far as I know all 4.6s had composite gaskets from the factory. They also have stretch head bolts, so reusing them is asking for a sheared bolt - I'd take a gamble and buy the bits to rebuild properly, but just do that side to start with (ie. option 2). I don't know know enough to advise on the scratch - other than I would have thought it's a bad idea to skim only one side. Hopefully a grown up will be along soon. They might need some more detail on the damage though. Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 Thanks for the reply I'll try and get a photo of the damage and a few photos of what I'm facing. I didn't know they came with composite gaskets - I thought they were tin from the factory. I forgot to mention that the radiator looks knackered the bottom has corroded away a fair bit so that could have caused the overheat? Luckily the PO had purchased a new radiator which is in the back of the car. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted November 29, 2009 Share Posted November 29, 2009 Right ……. Lets go back to basics with the brief history that was passed to you…. The car overheated due to a split hose (I would assume the top hose) ……… then a compression check was done and two cylinders were reading low……… OK …… The above makes some sense and gives me some comfort that it was more then likely a headgasket failure, however, it could have been a chain reaction with a liner fault causing pressure build and the head gasket gave in when it got hot …….. but I don’t think so ……..note, I said ‘liner fault’ ……. The issue is generally a crack behind the liner and then gases are forced between the liner / block and into the cooling system on each compression / firing stoke ……. On the other strokes the cooling system fights back and releases some of the pressure as coolant / steam into the cylinder. The term slipped liner is often not evident and often not the true cause. The fact that the front piston is cleaner then the others is that the water jacket is also at the front and this is a common point for H/gasket failure …………..have a look at the inside of the plenum & rocker covers and see it there is evidence of mayo ? I guess in your position I would want to get the engine running as quickly and economically as possible to evaluate the rest of the engine and car. It looks like you have already checked the head ………. I assume that you placed a known ground straight edge diagonally (corner to corner) across the head in two directions and then checked for any gaps with a feeler ……… If the head is OK, then at this stage I would be inclined to just rebuild it with a new H/gasket (yes, 10 bolt Compo) , new valley gasket / rubber seals, and new exhaust manifold gaskets. Also use new headbolts ...... they are cheap. Fill cooling system with 50/50 mix of coolant ……. Start engine then hold your bowls and pray to the lord ………. You have a PM….. Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 Right ……. Lets go back to basics with the brief history that was passed to you…. The car overheated due to a split hose (I would assume the top hose) ……… then a compression check was done and two cylinders were reading low……… He said it was the hose on the drivers side towards the rear of the engine. The compression check was only done on two cylinders - so I don't know what the others are like OK …… The above makes some sense and gives me some comfort that it was more then likely a headgasket failure, however, it could have been a chain reaction with a liner fault causing pressure build and the head gasket gave in when it got hot …….. but I don’t think so ……..note, I said ‘liner fault’ ……. The issue is generally a crack behind the liner and then gases are forced between the liner / block and into the cooling system on each compression / firing stoke ……. On the other strokes the cooling system fights back and releases some of the pressure as coolant / steam into the cylinder. The term slipped liner is often not evident and often not the true cause. The fact that the front piston is cleaner then the others is that the water jacket is also at the front and this is a common point for H/gasket failure …………..have a look at the inside of the plenum & rocker covers and see it there is evidence of mayo ? No Mayo, but I don't know how much it has been cleaned up I guess in your position I would want to get the engine running as quickly and economically as possible to evaluate the rest of the engine and car. It looks like you have already checked the head ………. I assume that you placed a known ground straight edge diagonally (corner to corner) across the head in two directions and then checked for any gaps with a feeler ……… Yes I put a straight edge across in every direction possible and used the feeler which was the same as the overhaul manual specified as being the max warp (can't remember now which one) I tried to push the feeler under all the way down the straight edge but couldn't fit it under at all. I have a better straight edge at work though so will retest when I get home tomorrow night as a double check. If the head is OK, then at this stage I would be inclined to just rebuild it with a new H/gasket (yes, 10 bolt Compo) , new valley gasket / rubber seals, and new exhaust manifold gaskets. Also use new headbolts ...... they are cheap. Fill cooling system with 50/50 mix of coolant ……. Start engine then hold your bowls and pray to the lord ………. So would you just do the one gasket? Or would you strip the other side as well? The kit also comes with valve stem seals so should I do them etc whilst apart? I'll probably order the composite gasket set from island 4x4 they're about £56 inc p&p and include both gaskets, all the bolts and all the other seals and gaskets required. So I may as well then do the other side as well? You have a PM….. Cheers mate will reply in a second Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted November 29, 2009 Share Posted November 29, 2009 Yes, it wouldn’t hurt to do both sides ……….. I would leave the hoodies (valve stem seals) as they are neoprene and last well………… Go here for parts and download the Rover pdf ……… http://www.realsteel.co.uk/ They have excellent service with good technical backup…………. Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 This image shows the head, you can the one on the right is cleaner Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 This image shows the scratch Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 This image shows the scratch from another angle plus also shows a bit of light surface marking where the PO has cleaned off the gasket - is that OK? Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 This image shows the only evidence I could see of it blowing between at all: Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted November 29, 2009 Share Posted November 29, 2009 That is only a light mark .......... it will be OK........ The evidence of blowing is not strong without seeing the head gasket ......... Quote Link to comment Share on other sites More sharing options...
sotal Posted November 29, 2009 Author Share Posted November 29, 2009 unfortunately I don't have the gasket I think the mark does stick up ever so slightly should I rub it down at all? Do you think I should change the waterpump and thermostat whilst I'm at it? - I have a new radiator to go on Do you know if Geoff is right that they had composite gaskets from the factory? Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted November 29, 2009 Share Posted November 29, 2009 Yes, composite gaskets are standard on 4.6 engines & late 4.0 engines W/pump should be OK ………. They are simple enough to change if not, but they go on for a long time. Yes, fit a new 88 deg thermostat……..you will need a housing gasket. Just gently take the raised edges of the mark ………. I would carefully do this with a scraper (or Stanley blade). Quote Link to comment Share on other sites More sharing options...
sotal Posted November 30, 2009 Author Share Posted November 30, 2009 Thanks, I just thought the water pump might be easier now and as it's part of the cooling system etc etc. With the thermostat is that the thermostat itself + gasket? The ones I was looking at include the housing etc do they still need a gasket? I'll try a stanley knife blade on the head to see if it removes the burr from the scratch if it does I'll try and assess how deep the scratches are. Quote Link to comment Share on other sites More sharing options...
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