Got an odd one here. My engine "phtt phtt"s under load, sounds just like my old CJ7 V8. But if I"m under load down-hill or slip it into neutral and rev it, the old 4.0 sounds beautifully smooth with no noise at all..... (can an exhaust leak only be pronounced under load)?

It is a tapping sound, but does not sound like a pre-ignition or slipped liner.

I'm going to try the hose check and see if I can discover an exhaust leak...I've heard it could be a worn cam or head gasket (but my coolant level is just fine and the cooolant does not appear to be contaminated)

Any thoughts on what else I should look for? Could it be a clogged cat? I don't detect any rattling.

I'm planning a Moab trip first week in June, so hopefully the Disco can make it...

 

I had this issue as well. I discovered the gasket in between the exhaust manifold and "Y" pipe was totally shot(passenger side), looked like someone had taken a bite out of it.
From AB: Land Rover Exhaust Gasket (Part # ETC4524) - Land Rover Engine Parts
make sure you get new studs as well. I soaked the old ones in PB blaster for 30 minutes. The most difficult part of the job is that you have to come at it from underneath. You will need a long socket extension (18" minimum) to get at them. Have an extra set of hands to pull down on the pipe will also be very helpful.

 

I've no experience with this issue on our Rover 4.0 engines, but what you describe sounds like the typical exhaust manifold gasket leak.

 

I just had this happen to my passenger side. Not sure how long it was going on, but it killed my Cat, so check it out sooner as opposed to later.

 

Thanks everyone, I'll take a look tonight and report back.

What is the easiest way to detect which gasket is bad? Did you guys use the hose method? While the engine was cold and I first started it up, I ran my hand around the pipe but couldn't feel anything, but then again, it is kind of quiet (small/leak) at idle.

Could you see the gasket damage before taking everything apart?

 

While I was driving I could hear a tick under the floor of the passenger seat. mostly under load. I tried the feather trick and blowing air up the tail pipe. Living in Chicago and not having a garage, it was windy of course, so I could feel air, but it may have been the wind, the feather was useless for me.

I felt underneath the manifold and around the Y-Pipe and the bolt was broken so that made the diagnosis easy. Also, upon start up I could feel air leaking, but I have an electric fan not the clutch fan. With the clutch fan spinning I can't imagine you'd be able to feel anything.

It's tough, because when it is cold it leaks the least and when hot it is no fun sticking your hand in there.

 

A buddy of mine was helping me do some other work on my car and he noticed some unusual discoloration where the manifold meets the Y pipe. We pulled it apart the following weekend when I had the parts. I also noticed that the bottom bolt on the exhaust manifold(closest to the firewall) had the head sheared off. Did not have the parts to deal with it, so we went ahead with the Y pipe gasket. As I said before, one side was blown out, making it look like a pretzel with a bite out of it. PB blaster was critical in this job, so was a second pair of hands pulling from underneath on the pipe so I could get the gasket and studs in place.

 

Thanks everyone!

I had my rover in for state safety inspection and the inspector actually tracked my noise to the Y-pipe manifold gasket. Mine isn't as bad as other's have had yet....the inspector needed to use smoke to find it, so that saved me a bit of a headache in diagnosis.

So I'm looking at Atlantic British and Rovers North, finding the gasket is easy, so is finding the nuts, but where does one find the studs and how hard are they to get out?

I'm planning on using Kroil and soak it during the week while I wait for parts and then hope for the best.

 

Just as info my old 96 D1 had what I would have bet money was a exhaust manifold leak, turned out it was the head gasket. When I took the head off there was a line from the cylinder to the outside that looked about like someone drew it with a sharp pencil. It was amazing how much of a racket it made.

 

Most auto parts places have the studs but the ones that come up on their computer are too small. I just get a bag of each (usually three) and one of them works. I wish I was organized enough to wrote down he specs... I have done that maybe three times and have a bunch of studs I can't use (but they are cheap).