So, I need to pose this question to our various Rover V8 guru's..... I have some valve noise that happens intermittently with my Disco. I have the 4.0 V8. ODO claims 107,000 miles, but actual engine/trans/chassis mileage is unknown. I got it with about 80k on the ODO, and up until now the engine has been running like a top, smooth as silk, aside from the massive oil leak. It leaks oil from the valve covers badly, and I think it is leaking around the intake manifold as well, but I am not sure. Too much grease and junk on the outside of the motor to be sure. Anyway, on to more details about the sounds it makes.
On cold start I get some light tapping, which is normal considering at startup you have no oil pressure; these are hydraulic lifters right? After a few moments the low oil pressure light on the dash goes out and the tapping sound quickly disappears. Warm starts do not exibit this as much, but there is a lot more oil in the upper portions of the motor on warm starts. In town driving at normal operating tempature does not produce any tapping, however after about 10 minutes on the highway at 65mph I begin to get tapping, which will slowly get worse the longer I drive at speed. If I pull off the highway and go back to surface streets the tapping will almost disappear again. On very hot days, sometimes I get the oil light blinking a little if I come off the highway and stop at the bottom of the ramp. In late summer the oil light will sometimes blink at idle while city driving as well, but it has never come on if the engine is over 800rpm, it will only blink at 750rpm or lower. I can hold the light off if I apply just enough pressure to the accelerator to pull the engine RPM up just a bit. To me, this sounds like the oil pump is not holding pressure while being driven at speed, or the oil is getting too hot, thinning out too much, and the pump just can't keep up.
Any thoughts? I hope to get at least one more year out of this truck before anything major happens, and I can reduce it's driving down to just to/from work if I have to, but it would be very difficult as the eclipse is just too small for the whole family.
Yes, I have checked the oil level and it is full.
I am concered that I may have damaged the oil pump or the components that drive the pump last december when it was very cold. I had a couple mornings where it was 16F and I had to start the thing, and it made weird sounds, like the oil was extreamly thick and the pump was having trouble moving it. I don't know if Rovers use a high pressure low volume or a low pressure high volume oiling system. My old Ford truck is a low pressure high volume system, so I generally don't get more than 6 PSI of oil system pressure in that truck when it is warm, but that's OK (but not great, could be a bit higher) because of how the system works. My engine knowlage is limited to older Ford and Chevy engines, which generally have a hex shaft that drives the oil pump off the bottom of the distributor, however my Rover doesn't have a distributor so I do not know how the oil pump is driven.
I have reason to suspect that my flame trap may be fully clogged and not venting the engine properly, but I don't think that all of this is related to that, but I can't be sure. I plan to do the PCV valve conversion as soon as I can, but that has not been completed yet. I was going to combine valve cover gaskets and the PCV conversion into one project since I will have one cover off anyway.
Would installing a different or additional, oil cooler help this? I don't really have the time or funding for an engine rebuild, but I could, fairly easily, install an additional oil cooler using some cast off parts from one of my uncles race cars. I am fairly sure that the oil cooler is built into the radiator, so the oil would never be any cooler than the water temp, which is about 180F. I could completly bypass the stock cooler and install a new one below the transmission cooler infront of the radiator, or cut the cooler lines after the radiator cooler and add the secondary cooler, which should keep the oil at a lower temp than it is now, resulting in a bit more viscosity, which may help the engine maintain pressure........
