E51 E51 Cats (Newbie panics...)

Shelaz

Active Member
E51 Owner
#21
When I returned from work last night My wife reported that the Bus was making a rattling noise. As you do, I panicked and thought the cats had gone! In whatever little light there was left in the day I went to the bus to investigate. These where my findings.

1. I started the bus and the rattle had the likeness of a stone being rattled somewhere inside towards the O/S front lower side of the engine. It's fair to say where the O/S front cat is located.

2. I quickly checked the oil levels and the reading nearly gave me a heart attack. So I assumed maybe the engine had started consuming itself. All the same, I topped it up and ran the engine but the rattle was ever present.

3. I noticed that the rattle is only present when the bus is idling but completely disappears as soon as I apply any revs. She also reported that the rattle disappeares when driving and no apparent loss of power. Everything seems to be ticking over as usual.

4. I got a mobile mechanic guy to have a look at it whilst on the drive. The wife reported that he had suggested that indeed the front cat had started to disintegrate.

5. The rattle is always in the same location. Nothing seems to be coming out of the rear either (dust, debris etc)

I have had the coil pack replaced about a month ago, fluid levels where all in good order. The bus is now parked and booked into the garage for further investigation.

However, i am left with more questions than answers about the front cats. My rear cats where de-cored when I registered the bus. I was under the assumption that if the front cats started to go, the debris would be pushed to the rear where hopefully they get blown out. If that's the case surely the rattling core debris would be blown towards the rear. I suppose my questions are , Do the front cats have sif like gauze that may stop debris from escaping? Or indeed is there a chance of the rattle coming from a loose heat shield or anything similar? As said before, the rattle is only present whilst idling and at times not present at all.

Apologies for the long winded post but any help or suggestions would go a long way as always.

Thanks you.
 

Madfish

Administrator & Club Rep NE
Staff member
E50 Owner
Premium Member
E50 Expert
#23
I wouldn't panic too much, the rear cats have been decored so that saves engine failure..

Always hard to diagnose a fault online based on the description of a noise. It could be nothing but you're wise to get it checked regardless...

It's quite possibly something daft rattling away like a heat shield

Engine oil, some 3.5s like to consume a lot of oil and you really need to keep a check on levels on a regular basis. Top it up monitor closely
 

Alan Morgan

Here for life
Premium Member
E51 Owner
#24
As said by @Madfish, difficult to diagnose via a posting, but to add to the 'collective wisdom' - the clue may lay in the rattle only being apparent at low revs in that something like a pulley wheel on a keyed shaft may be loose. At low revs it'll rattle on the shaft but at higher revs the slack is taken up and the rattle ceases.

This has happened to me twice in my motoring life. On both occasions the 'professional' advice involved mega bucks but the simple solution was a spanner.
 

Brendan1969

Part of the furniture
Premium Member
E51 Owner
#25
Agreed on all of the above. Have everything that could come loose double checked FIRST and then move on to the more nitty gritty bits.

You could have a loose particle of a front cat broken away and that would indeed cause a rattle at low idle and once you apply power the pressure lodges it against the internals and the noise goes temp until you idle again.

Oil loss would be a worry if its a lot but it should be obvious as to where its leaking from unless its intercooler issues on an E50 diesel which I had on my old E50.

But lets hope its all ok for you and min expense.
 

MrRob_in

Part of the furniture (please de-cat your e51/2)
Premium Member
E51 Expert
E51 Owner
#26
High oil consumption in itself isn’t something to worry about These engines are designed to burn upto 1l per 1k miles. Most don’t but some do. It’s a pain to keep topping them up but upside is oil is always fresh.
A point to note is than often cars that don’t see the level drop are just contaminating the oil with the same amount of fuel as the amount of oil that is lost. Hence cars running on lpg appear to burn more oil. At least that’s my understanding and what I found.
 

Brendan1969

Part of the furniture
Premium Member
E51 Owner
#27
High oil consumption in itself isn’t something to worry about These engines are designed to burn upto 1l per 1k miles. Most don’t but some do. It’s a pain to keep topping them up but upside is oil is always fresh.
A point to note is than often cars that don’t see the level drop are just contaminating the oil with the same amount of fuel as the amount of oil that is lost. Hence cars running on lpg appear to burn more oil. At least that’s my understanding and what I found.
Just like the older Vauxhalls Rob, 1lt per 1000 miles normal.
 

Shelaz

Active Member
E51 Owner
#33
Not so high, any visable oil leaks on the floor?
No obvious oil leak anywhere, the bus has really never been bad on oil. As the wife has been using the it, I have been confined to the Punto so not certain if indeed the oil has been kept topped up. Nonetheless, it's a lesson I won't forget too soon. Will have a good nose about on Sat since the bus Is not at the garage till next week.
 

Brendan1969

Part of the furniture
Premium Member
E51 Owner
#34
No obvious oil leak anywhere, the bus has really never been bad on oil. As the wife has been using the it, I have been confined to the Punto so not certain if indeed the oil has been kept topped up. Nonetheless, it's a lesson I won't forget too soon. Will have a good nose about on Sat since the bus Is not at the garage till next week.
Take the lead matey and give her the Punto!!!!:p:p:p:p:p
 

Brendan1969

Part of the furniture
Premium Member
E51 Owner
#35
High mileage engines will burn oil through degraded piston rings, valve stem seals, or some other seal (crankshaft, etc) deteriorating over time.

@Shelaz, how many miles has your engine done?
I will 50/50 with you on this my friend. I owned a Mk 2 Ford Granada 2.8 injection which I used to commute to and from Germany in. She never used or dropped any oil spots in the 5 years I had her and I did 200000 miles in her all trouble free apart from routine servicing and maintenance. Ive been using the " slick 50 " oil additive in all my cars engines now for 30 years and NEVER had a failure.
 

Shelaz

Active Member
E51 Owner
#36
The bus is back now...and no more rattling. Apparently when the coil pack was done whatever dirt that had collected in system had formed into a cluster that found its way down the exhaust. This has had me worried as I've believed all along that my BP 95 RON was just fine. I have been advised to get a carbon cleaner on my next trip to the Petrol station but I have heard neumerous view point regarding carbon cleaners so really not sure if there are other alternatives. Does this mean I should now switch to Shell V Power or Bp Ultimate? The garage has worked on other JDM motors and recogns this is not altogether uncommon particularly after coil pack change? According to their calculations, I have been reassured that my oil reading skills could do with brushing up a bit, at the very least, to make sure that the engine is hot before l take a reading. Any merit in the diagnosis?
 

BMR

Moderator
E51 Expert
#37
Engine oil should be checked cold on level ground. Auto Trans fluid should be checked hot (with care) as the dip stick is towards the rear of the engine on the drivers side. Best to check the engine oil every Sunday morning takes a few seconds but make sure its parked on level ground.
 

Steve~Mk1

Here for life
E50 Owner
Premium Member
#39
Engine oil should be checked cold on level ground. Auto Trans fluid should be checked hot (with care) as the dip stick is towards the rear of the engine on the drivers side. Best to check the engine oil every Sunday morning takes a few seconds but make sure its parked on level ground.
Does the E51 auto trans fluid level need to be checked with the engine running and box in neutral after cycling the gears, like on the E50?
 
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