Throwing a rod! What are the symptoms??

[Liddo]

IF my car had thrown a rod, what would I expect???

There is a LOUD tapping noise from the alternator area, this after having a blast down the motorway, with sum stuttering overboost. It rises and falls with the engine noise, BUT, the car is still sounding and running perfect, apart from this tapping.


Any idea's chaps?? Does this sound familiar to anyone???

PS, the cars only done 70k and has never tapped in its life :)

[Tiff_T5]

loud tapping from the alternator area could be a timing belt tensioner,happened to mine,whip the cover off quick!

Good guide is the speed of the noise,remember camshafts/top end turns at half crank speed.

My stethoscope is my favorite tool in my box-get one! or use a screwdriver..

[Goof]

If it's thrown a rod you could expect a con-rod to be visible sticking out the side of your block! ~ and a whole mess of oil. Oh, and it wouldn't run!

How loud is the tapping?
Have you checked oil?
Does it tickover smooth? - not lumpy?

[S60D5]

loud tapping from the alternator area could be a timing belt tensioner,happened to mine,whip the cover off quick!

.

The tensioner (one of the?) on my uncles XK8 went pete tong the other week and he had to fork out £7,000 on a new engine from Jaguar. Whoops.

[Tiff_T5]

Yup,happens more often than you may think.On mine the front idler bearing had seperated,so the pulley had detatched itself from the engine.The belt was slack,and had worn half way through the pulley.The car ran perfectly,only clue was a slight noise-which sounded like a slipping alternator belt,so I ignored it for 2 days!!!

I'll have to get round to changing the belt :slap:

One of the guys from work once had the company Vw LT over to Edinburgh,after I had spent a few days fitting a recon engine..(which goes in through the passengers door) Upon changing down for the climb up the M90,he got 1st instead of 3rd...and hung a leg out of bed....boy was I pleased...

These old 2.4 diesel engines were indestructable..unless your name is Stevie-he killed 3 of 'em!

[Redbrick]

IF my car had thrown a rod, what would I expect???

There is a LOUD tapping noise from the alternator area, this after having a blast down the motorway, with sum stuttering overboost. It rises and falls with the engine noise, BUT, the car is still sounding and running perfect, apart from this tapping.


Any idea's chaps?? Does this sound familiar to anyone???

PS, the cars only done 70k and has never tapped in its life :)

I've got a video clip of a US T5 with a bent rod, I'll find it and post it. Meanwhile...

Yes it sounds familiar, I bent 3 rods after a slight stutter. Trouble is I said I wonder if it will do it again and got a monster cough- that properly stuffed it.

there will be no confusion in your mind that there is something seriously wrong, your engine will sound f*ucked!

Its a loud ticking, that is related to engine speed (obviously) :slap:, car will run OK though. Sound will slightly decrease in volume as the rod is worn away.

If I was being brutal and didn't care if I did more damage as I was trading it in (lol) I'd run it till the noise quietened down and then get shot of it.

[volvotuning]

The easiest way to find out if it's a bent rod is to take the sump off on a ramp, then look up into the engine up the length of the rods, you will spot a very very slight bend in them if they are indeed bent.

If they are bent, then you have to find out what has caused it. Main culprits are overboost caused by -

1. Actuator hose split and therefore working like a bleed valve.
2. Boost control solenoid faulty.
3. Actuator fault.

A sticky lifter can also sound like a bent rod so you need to check that too. A bent rod sounds like a metallic knock, as if you were tapping a hammer on the block, but so does a sticky lifter!

Adam.

[racer]

Speaking from bitter experience, you could be losing a big end bearing. This does generate the loud noise you describe. Trouble is there’s no quick and easy way to check. You need to either get the sump off and have a look for play in the big ends, or measure the max height that the pistons reach as you turn the engine. First method is best, second needs a good reference plane and involves poking dial gauge probes down the plug holes (also subject to inaccuracy due to different amounts of carbon on the piston tops).
If you have access to one, an endoscope down the plug holes and look for impact marks on the tops of the pistons. If the big end bearing has play in it the piston can impact the head and you’ll see the marks in the carbon deposits. Get this soon enough and that's all you'll see. If the piston is hitting the head with any force, the crown compresses and jams the top ring. You're looking at bits of metal getting away at this point. Worth dropping the oil and filtering it to see if you have any bits of metal in it. If you don't you've probably caught it in time.
This is probably worst case stuff, but if it looks like a bearing issue don’t run the engine anymore. You can damage the crank real fast. An oval bearing surface would mean you have to get the crank re-ground. Major engine out and rebuild time.

And everything Adam said too. I've got much less experience with turbocharged engines than these guys!!

[volvotuning]

Normally if a bearing goes it's often caused by an oil issue, such as poor grade, low pressure, or simply not enough of it. As mentioned above, worth checking. If you take the sump off you can check the bearings and the rods at the same time.

Adam.

[Liddo]

OMFG! :jaw: Thanks for all the replies guys. All very technical and all sound probable :( It sounds as though Im looking at a new engine! Im suprised though, as its only done 70k, and I wasnt giving any stick at all really) I'll take it to a guy who used to look after my BMW's, cos he is a VERY decent bloke. FWIW, how much would I get a replacement engine for?????

PS, the car was "serviced" by the supplying dealer about 4 months ago! 90 day warranty has since passed :(

[fireclown]

get your oil presseure check. and do not run the car. if it pokes a hole in the block it'll cost you more. louds taps aint good news. sorry to hear about it m8.

[Liddo]

If it's thrown a rod you could expect a con-rod to be visible sticking out the side of your block! ~ and a whole mess of oil. Oh, and it wouldn't run!

How loud is the tapping?
Have you checked oil?
Does it tickover smooth? - not lumpy?

Quite loud!
Oil seems at least half way and is allegedly 4 months old
Ticks over as smooth as silk! If it wasnt for the tapping, Id say nothing was wrong

[volvotuning]

Is the sound the same volume at say 3000 rpm? If it gets quiteter with increased rpm, then I think it's a lifter.

Did you change the oil when you got the car?

Adam.

[Liddo]

Hi Adam,

You can hardly hear in at speed. It deffo goes quieter the faster you go. I too think/hope its a lifter! Whats involved getting that sorted???
Also, the car was "serviced" just before i picked it up from the dealer. 90 days warranty has now passed im afraid :(

[Andrew]

I had a con rod problem in my s-type. Bent several - grind - puff of smoke and a big bang!! - car stops...

Thankfully it was under warrenty so new engine for me :)

Ac.

[Liddo]

Update! Listened to the engine via a large screwdriver to my ear, and it does sound like a lifter issue! Hope its not a too expensive job. Also along with the tapping, is a slight metallic releaseing noise every 10 seconds near the cambelt area!!!! Mad!!

Oh well, of to my local garage next week

[racer]

Big relief ! Lifter issue is a lot cheaper. Mind you they are bloody pricey from a main dealer. You could try running Wynns engine flush in the oil for half an hour (that's twice what they reccommend BTW) and seeing if the lifter frees up. Worth trying first as it costs you a tin of engine flush, some new oil and a filter. Much less than taking it to someone to have the head off.

[fireclown]

you can get proper engine flush a gallon at a time. its a lot better than an additive. give this a go 1st. worth a try. cheers

[madness]

mine sounded like a tappet had gone which increased with engine speed.

second reaction- how the hell am i gonna pay for this :slap:

[mat562be]

One of the guys from work once had the company Vw LT over to Edinburgh,after I had spent a few days fitting a recon engine..(which goes in through the passengers door) Upon changing down for the climb up the M90,he got 1st instead of 3rd...and hung a leg out of bed....boy was I pleased...


A certain colleague, who shall remain nameless, did a similar thing on his advanced driving course - the last hurdle before he became a fully-fledged traffic man - which caused much mirth...

Picture this.. 850 full of 3 plods and an ADC instructor. Approach, at 100+ to an A road roundabout. Start braking. Select third gear at about 60, seeing that the roundabout is clear.. Oops!! Dammit, that'll be first gear then...

Engine survived. As did gearbox. One occupant later retired on ill-health grounds a while later, citing the "driving school incident" as the primary cause of his career-ending neck complaint.

Never, ever, will that be lived down.

[Liddo]

mine sounded like a tappet had gone which increased with engine speed.

second reaction- how the hell am i gonna pay for this :slap:

Mine gets quieter with engine speed!!!!! Ya cant hear it on the motorway! Not that Im driving it anymore :o(

[madness]

strange !

best not to continue driving though. Mine made it home for me :brokenhea

[Liddo]

Im not! She's on the drive. Gotta drive her the 5 miles to the garage tonight! Its gonna be hard to keep the rev's as low as poss! Did about 20 miles on Saturday as she is, and all was ok, well, apart from the tapping! Fingers crossed I dont get a big bill for Christmas :(

[madness]

here's hoping you dont.
I bought a new engine as it didnt cost much more than repairing properly and i got it at cost

[Liddo]

Update! The mechanic has phoned me, saying one of the lifters had failed, and this has now put a flat spot on the cam! He's going to try and get me a replacement cam tomorrow from a slavage yard and then replace the lifter!!!! Looks like a few hundred quid bill JUST before Christmas!! :slap: :(

[pault5]

hi,
don't you think it makes more sense to replace all the lifters? more costly i know but might save the same thing happening again IMHO.

[Liddo]

I know, thats what I thought!!! I'll speak to him tomorrow when he lets me know about the cam!!