Hi,

Sorry for such a long first posting, but this problem is driving me nuts and I have posted on other board with good responses, but nothing that turned out to be the correct problem yet. Hopefully someone here can lend some insight.

I have a 2000 D2 with 128k on it, and over the past few weeks I started noticing a tapping or rapping sound, but only at highway speeds.

It first started at about 70 MPH/2500 RPM and sounded more like a piece of the wheel-well rubbing on a tire and clicking, or possibly something contacting the fan, not a really "metallic" sound it didn't seem.

The sound seems to go away immediately when I let off the gas, but comes back as soon as gas is applied again, so it seemed to be only under load at speed, so I thought perhaps something was rubbing or hitting the fan, but couldn't find anything.

When stationary the noise does not happen and engine sounds fine from idle right up to high RPMs.

Oil is fine. Reads a bit high on dip stick, but has since mile 1 that I have owned it and I always drain well, and fill with amounts spec'd in book. That has never been a problem for 128k now. Just a wierd stick I guess. Diff's and T-Case are all full as well.

Took out plugs and replaced with new champions. Still the same. New Magnecor 8mm wires last summer.

Front driveshaft out...same noise. Viscous fan out...same noise

Had a shop look at it and they thought it might be the flex plate, but scoped it and couldn't tell from that. Said most likely $800 + just to get in and check it. Ouch.

Followed up on the cat idea from another board and driver's side cat had a rattling to it, so I replaced them in the hope it was one of the bisquits in the cat rattling around and then flipping back into place when speed/pressure changed, but that didnt help. At least I have new high flow cats and was going to have to swap cats anyway sooner or later it seemed.

Any ideas? I would hate to pay someone to pull the transmission off to check the flex plate and have that not be it.

It doesn't make sense to me that it would only do it after a certain speed or under a really heavy load, say up a steep hill, at decent speed only. Once it starts now it will do it at pretty low speeds as I slow down but keep load on it, but once I stop I cant hear it anymore to check. But with flex plate, isnt it constantly spinning? Would speed really effect it so much it would go from perfectly normal to a pretty loud banging/tapping sound? Also, no loss of drive from transmission, just lack of power when it gets really loud and starts to bog down.

Deffinetly changes with RPMs. At say 1500-200 after it has started it is a low pitched sound but deffinetly not 1500-2000 times a second. More like only a few. Kind of like a manifold to Y pipe leak sound, but rev it and frequency increases as does pitch of sound. More a rapping sound then, and louder. but again. I could drive 40-50 miles of side roads and it drives fine. Only have I noticed it on highway or going up a very long, steep grade at over 40 MPH. That is more recent. At first it was only on highway.

I did look inside front inspection hole and found the allen screw I have seem mentioned in other posts. It was indeed showing that it had been rubbing something at sometime, but after removal they problem still exists, same as with it in there, so that wasn't it.

I was getting some missfire codes and the p0171, P0174 fuel trim codes after it really does it bad, and do now notice a lack of power when it is happening and then service engine light blinks till I let it coast a bit and then back to normal. Also getting some p03xx missfires here and there and an intermitant "Gear 3 incorrect ratio" code. The p0171, P0174 fuel trim codes I have not seen again since new cats were welded on.

Really driving me nuts now after swapping out cats with that not being the cause, and looking at possibility of pulling transmission off to the same end.

Anyone else have an idea I might try to look into?

Thanks far any help. Seems a tough one to diagnose.

John

 

John,
So when was the last time you flushed out your enine and or checked your oil pressure?
I am thinking your engine may be gunked up and possibl the oil pick up tube is restricted.
As for the codes, your 3rd. gear code usually always shows up when your MAF has started to fail.
Mike

 

Hi Mike,

Well, ever since it turned 100k I have been flushing at every other oil change. Either with some ATF added to oil shortly before draining, or using an actual "flush" product.

I do change my oil very regularly and have been using Mobil 1 from day 1. Was thinking of switching over to Rotella, but not sure yet.

I do have a slight knock at idle from around the pan that I was thinking could be pickup tube, and was going to check it at next oil change, but the noise I am hearing when driving is MUCH louder, and it only happens when I get up to a decent speed first or it hits say a very long, steep grade, and it is much more of a loud, prominent rapping.

I have not checked oil pressure, simply becaus eI dont really know how to be honest, but was thinking of having it read on a test book because I have heard sometimes the oil pressure switch can get stuck open.

John

 

John.
You need to get a mechanical oil pressure guage and hook it into the engine down by the oil filter, that is the only true test. Then you check it cold at idle and then at 2000 RPM's and then retest it when hot at idle and at 2000RPM's.
You really need to pull the oil pan and do a up close inspection for extra parts in the bottom of the pan and also verify the pick up tube is not plugged. If you decide to pull the pan, drain out the old oil and put 6 qts of ATF in for a 20 minute idle, then drain and drop the pan.
Mike

 

Thanks for the info Mike,

I will try that when I have some time to do it all one shot.

I talked with a rover tech that suggested I might want to check the pickup as well. Possible at certain RPM or temps that oil is not getting to bearing and causing it, or bearing is worn and pushing rod/piston up to contact head.

Not sure when I am going to be able to get to it, but at least I am not driving it on highways right now. Seems to be ok locally.

Will let you know what I Find when I check the pickup, and pressure.

Thanks,

John

 

Hi Mike,

I am hoping that this weekend I can do a flush and take off the pan to have a look.

I had a couple questions about the flush.

Just to make sure. You are saying use 6 qts of straight ATF, no oil at all right? Just seemed very thin to me if there is an issue with a rod bearing or something. Is the 10w or whatever the weight of ATF is going to be ok on it all for 20 mins?

Should I be aware of any strange sounds or running symtoms while it is idling with ATF only...In other words if it sounds odd, should I let it run its course? lol

Thanks for the advice, and also for some other posts I have read on board from you regarding similar procedures.

John

 

Thanks for the help on this. The flush Mike suggested worked great and if there was any build up in there it deffinetly cleaned things up nicely and engine seemed fine with running on ATF alone for 20 mins.

Update:

Well, I drained the oil and checked it and no metal in it at all. Also did the flush as suggested by mike and then pulled the oil pan off and there was no metal and no sludge either. Pickup tube was completely clean and clear.

The bottom half of engine looked very good, with just a light orange brown color to it. The cylinders all looked good from what we could see underneath with very little wear showing and cylinder sleeves appeared ok. Rods and pistons looked normal.

We aslo pulled off the rod bearing caps to take a look at bearing wear, and they looked practiaclly brand new, with no copper at all showing and barely even any wear at all showing, and it pretty much looks like everywhere was getting very good oil flow, so probbably not an oil starvation issue.

However, while we had the pan off timing chain looked a bit slack and so we checking it with a long screwdriver there and was significant slack in it. Say a 1/2 inch play in and out from center in each direction on both sides.

Do you think that possibly the chain is so stretched that at certain RPMs it is throwing timing off enough to be causing the valves to be getting slapped a bit by pistons or possibly causing any of the missfires and fuel trim issues? and mostly, could I be hearing the chain slapping the front cover being so slack at times or that it could be off enough to slip or make it pretty much off by a few teeth on the gear Causing things to make the noize I am hearing?

Also. It is deffinetly happening at slower and slower speeds and with almost any mong uphill grade. Thinking if chain is stretching more now, or slipping more with use this could account for that? Seemes if RPS can be kept under 2k it really wont do it unless it has already started to do it for a few and then RPMs fall below 2k it will do it as well, till I stop for a minute. Trying not to drive it right now, but needed friends garrage and help for this one.

Thanks for the help on this. Mike's advice on flushing with ATF is deffinetly worth doing as a semi-regular maintanance for anyone with some miles adding up. or before taking off the pan to do work.

John

 

Hey John,
Sorry I didn't get back to you a little faster, glad you like the results from the ATF, some people also do that with diesel fuel, I just prefer the ATF.

With 128K on the engine and some slack showing up, I would probably suggest you replace it sooner then later.

Have you considered doing a oil pressure test using a mechanical guage hooked up to the engine at the oil pump, might tell you something?

The only other thing I can think of would be a failing lifter, may be time to pull the intake and v/c's and inspect from the top side. Wouldn't be the first time a rocker or lifter failed on a Rover.
Mike

 

Thanks Mike,

Yeh, flush worked great and things looked very good in there.

If I can find some more time coming up I can try looking in the top. Might be hard though. Where I live I am in a parking garrge, and they frown on such things, lol. I have a friend that is pretty good with engines and we used his garrage to do other work. it is about 40 miles though and last time back and forth thing started happening at lower and lower speed so I am a bit worried about driving it. Been trying to figure it out for 3 weeks now including a trip to indy mech that thought it was Flax plate and Rover tech that thought it was engine, but could not give difinitive diagnosis. Part of why I was wondering if chain might be the culprit. Causing other things to happen that are had to pinpoint as one thing.

I wanted to try to check the oil pressure, but couldn't find a guage anywhere around here in time for the weekend for some reason.

It did look like everything had been getting good flow though. Would oil pressure give me some insight to the top end and lifters and such?

Thanks for the help.

 

Won't give you much insight as to top end problems but if it is low when hot, you are going to need to determine if it is the pump or a bad set of bearings.
I just had a friend that went thru a long bought of oil problems, end results was the low pressure on his engine was from a cam bearing that slipped out leaving him with little or no pressure.
Mike