my disco problems, help!

[glenn82]

hi
i got 94 Es v8 diso.
finaly got it back from repairer today.
was there to fix possible bent push rod's or sticky lifter. put apperently this wasnt the cause for the knocking noise in the top end. meach said theres no knocking sound when tested

so therefor with the rear main seal being replaced.
you think the knocking noise would go ,app engine was low on oil from rear main leak)
well it hasent(stoped knocking) and murphy law it only started making the noise on way home from mech.

any one else heard of this prob. might have to get it checked over but it will be done by some one else.
i have a bad taste in my mouth afer the last lot of dealings with the mech

[WildOne]

hi
i got 94 Es v8 diso.
finaly got it back from repairer today.
was there to fix possible bent push rod's or sticky lifter. put apperently this wasnt the cause for the knocking noise in the top end. meach said theres no knocking sound when tested

so therefor with the rear main seal being replaced.
you think the knocking noise would go ,app engine was low on oil from rear main leak)
well it hasent(stoped knocking) and murphy law it only started making the noise on way home from mech.

any one else heard of this prob. might have to get it checked over but it will be done by some one else.
i have a bad taste in my mouth afer the last lot of dealings with the mech

Was it low on oil?

[Psimpson7]

If it was low on oil you could have some serious issues with the engines bottom end....

[glenn82]

had oil change this morning, noise is from the top end

[mcrover]

Could be low oil pressure caused by a blocked filter with a failed or sticky bypass valve.

It sounds strange I know but I have had 1 on a 302 clevo but not a rover where it was an intermittant problem.

I ended up swapping cars for a week with the freind who ownned the car before I could get to hear the noise which really didnt tell me much as when I stopped the car or gave it a rev it sometimes went away and sometimes didnt.

I would be checking the oil pressure before running it for too long to make sure your pump is working properly and Im assuming you changed the oil filter with the oil so that should eliminate that.

[glenn82]

well yes it does it on idle. and the disapears on acceleration. its going in again on sat. maybe it is a noisy lifter.

[mcrover]

well yes it does it on idle. and the disapears on acceleration. its going in again on sat. maybe it is a noisy lifter.

Just get them to whack a guage on to check the pressure as low pressure will make lifters noisey.:D

[glenn82]

what causes low presure? oil pump stuffed??

[PeterM]

Why did they change the rear main? Was it definitely leaking? Get a pressure test done as sometimes the heads do not mate well due to poor metal hardness. This leads to a blowing of the head gasket (subtely), often at the rear piston on the left of the vehicle. This pushes oil out and through the bell-housing, mimicking a rear main (not common).

Worth a quick check.

[glenn82]

OK OK I TELL THE WHOLE SAGA.
WHEN UP THE BEACH, GOT BOGGED BIG TIME (LIKE UP TO CHASSIS)
INTO LOW DIFF LOCK GOT IT OUT, THE MISSUS ACTUALY:(.

ONCE OUT, CAR WAS REVVING IT GUTS OUT, WITH NO FOOT ON ACCELRATOR.

I CHECKED THROTTLE BODY AND FOUND THAT CRUISE CONTROL CLIP HAD COME OF JAMMED THROTTEL ON. THERE FORE REV ANROUND 5-6000RPM.
NOT FOR LONGER THAN 4 SEC'S

THIS CAUSED INSTAND OIL LEAK FROM REAR OF ENGINE AND KNOCKING NOISE.
ALSO COOKED ALTERNATOR.

I TOPPED UP WITH OIL AND LIMPED IT BACK TO MY HOUSE (100KLMS AWAY)
TOOK TO MECH AND KNOCKING NOISE HAD STOPPED.
HE THOUGHT BENT PUSH RODS ETC ETC AS MENTIONED ABOVE.

BEEN 10 DAYS NOW AND NOW KNOCK IS BACK

I THINK I GOT A DUD MECH GOING ELSE WHERE NOW

[glenn82]

REAR MAIN WAS REPLACED COS DURING HIGH REVS THE CRANK HAD MOVED THE SEAL.. ETC ETC

[mcrover]

what causes low presure? oil pump stuffed??

Yes, oil pump could be on it's way out or bypass valve (if the rover oil pumps have them) may have been blown open and now is jammed bypassing oil back to the sump.

Or a blockage on the oil pick up or in the filter as I said before, you didnt happen to bend the sump or anything silly like that as if the sump is bent under the pickup it can cause cavitation and suck air which can cause a drop in oil pressure.

Without looking at it I couldnt tell you much more, take it to a Landrover speciallist, check the recomended repairers section on this forum for one near you.

[mcrover]

REAR MAIN WAS REPLACED COS DURING HIGH REVS THE CRANK HAD MOVED THE SEAL.. ETC ETC

That doesnt sound right, I used to have Datto engines running standard oil seals spinning at 10000 RPM and never spat one out.

I would suggest you have a look at the head gasket thing that PeterM I think it was suggested as that really doesnt sit right with me.

By the way, can you please turn you caps lock off.........Im going deaf with all the yelling :p

[glenn82]

OKOK every 1's telling me that, sorry.

yeah its booked in for a cheach on sat, a real LR mech is looking at it .

so nothing wrong with sump. had the sump seal replaced also, well so i was told.....

[Blknight.aus]

do you have brain 1 about mechanicing stuff? (thats not a go at you, so far you seem to be doing all the right things)

if you do...

take a rocker cover off and start it up if your getting good oil flow its not the pump,

take the supply lead to the coil off and crank it on the starter, if the oil pressure light goes out, its not the relief valve jammed wide open.

you could still have oil delivery problems from a blocked gallery but youd pick that by the no messing around crunching and grinding noises.

I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) but the over rev would have only been a contributing factor and not the cause.

with no other info my money is on a worn lifter/rod or a damaged cam along with the other general wear that will be in the valve train. if all of those have actually been checked and replaced then it may be a bearing on the rockers.

[mcrover]

do you have brain 1 about mechanicing stuff? (thats not a go at you, so far you seem to be doing all the right things)Your not having a go at him

if you do...

take a rocker cover off and start it up if your getting good oil flow its not the pump,

take the supply lead to the coil off and crank it on the starter, if the oil pressure light goes out, its not the relief valve jammed wide open.

you could still have oil delivery problems from a blocked gallery but youd pick that by the no messing around crunching and grinding noises.

But this makes me think you are at me over it

I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) but the over rev would have only been a contributing factor and not the cause.

with no other info my money is on a worn lifter/rod or a damaged cam along with the other general wear that will be in the valve train. if all of those have actually been checked and replaced then it may be a bearing on the rockers.

I just made a couple of suggestions and I suggested a dead easy way to check it......as did you but I have had oil pressure switches open circuit at 3psi so I dont rely on an oil pressure switch as a diagnostic tool when you have an engine knock that could be an oil feed problem.

Popping a rocker cover off will take longer and cost more than whacking a pressure guage into where the switch is and checking your getting pressure.

But your spot on, if it's getting to the top then it should have pressure.

It could also be a pumped up lifter which is geting stuck on a bit of gum from the over rev which may be coming loose as it heats up and then maybe getting stuck again intermittantly now that it has moved past that point.

This is comon in 253 and 308 V8s and I suppose anything with hydro lifters would be the same when they get old.

If it is a stuck lifter then it will chew out the cam before long so you do want to sort it asap.

Ive changed my mind since typing this, my money is deffinatly on the lifter.

[glenn82]

hi
i am 90% sure it is a lifter,
a i have spoken to many more knowledeable pppl than myself.
being a lifter is it a big job to rectify? i think i got qutoed around $6-7 each( + labour of course) with a total of 16??
i dont know if this is right. im so confuse;)

[mcrover]

Remove :

Rocker covers,
rockers,
Intake manifold,
Valley cover

Pick out 1 at a time (I use an O ring pick) either just removing the push rod for the lifter your working on or taking them out and keeping them all in order.

Take note of any imperfections in the pushrods or on the surface of the camshaft as you may need to replace them.

Again, that is general V8, Rover stuff may be a little different.

Imsure someone will pipe up If im wrong.

[Blknight.aus]

wasnt having a go or dig at you about the seal thing as theres no way just over revving an engine will cause the seal to fail. BUT..... With some other contributing factors an over-rev (ok revving beyond the normal range the engine runs at) can be the straw that breaks the camels back.

let say the engine normally only revs to say 3000 rpm just to pick a number because of the drivers driving style

lets also say that for some reason the guy who machined the crank goofed and the rear main seal section has a 10 thou eccentricity

Lets also say that theres been some very slight weapage of oil and its picked up some contamination which is sitting right next to the seals running surface

lets also say that at some point some idiots put some stop leak in to condition the seal and stop it from leaking just so it can be sold and then whoever bought it didnt put the stop leak back in on the next service.


the end effect is you wind up with a seal with a soft bit and a hard bit that runs fine with the slight eccentric of the crank and because its been running with seal softner the bit that does the flexing still flexes and the bit that just sits there gets harder... when you take the engine up past the normal rev range the seal stresses and fails.

OR

with the extra revs that little bit of crud that was happily running along side the seal shifts and picks itself up into the seal and with the slight eccentric of the crank it then works its way around the seal destroying it...

take any of the other caveats out of the picture and yep you could rev that puppy till the pistons made for the ISS and the seal would hold up right to the point that the crank decides to go somewhere else.

thats what I ment when i said


I can buy the rear seal failing from a sudden over rev providing some other conditions were present (some are in older engines in most cases) [color=blue]but the over rev would have only been a contributing factor and not the cause.

[glenn82]

its all good i do appreciate all your help.

[mumbo]

There is a common noise in the v8s where the liners have come loose. This happened to my less than 100,000 disco 2. If true it means engine out and machining of block for "top hat liners".
Hopefully this is not the issue though...

[glenn82]

ive driven the car nearly 1000klms now and some how the knock has gone, it had to much oil in the sump(so i drained some) and also the breather was slightly blocked so i cleaned it out, dont know what the noise was but havent heard it in a while.
she running great atm but using a little 2 much fuel.

last tank i worked out i was getting 6.1 klms to ltr does that sound right?
revs at 100k/hr was 2200-2300??

[PeterM]

So that's what, about 19L/100km. Not out of the question to get that although it depends on how you drive it, modifications etc.

[glenn82]

16.4 ltrs per 100 klm actually

[Ace]

I would say about 16L/100 is about right for a V8 Disco, well going from the numerous discussions about it on here. I have heard of 25L/100km around the city in heavy traffic, but as mentioned it all depends on how you drive it.