Wasted an hour yesterday trying to access this bolt on A Class chain tensioner :(:(

[Submariner1]

I could use some fast help, As I have changed the oil, so would like to swop the chain tensioner that must be half full of dirty oil. With this nice new one. If I drive to an Indy, as it leaks the old crap will go in the engine.

the bolt at the rear is the problem in red. If anyone has done this, I would be interested to know what you used to access it i.e what connectors
I have these in 1/4” and 3/8” latter has wobble bars and a universal joint.



Above the tensioner is a junction on a coolant hose. So top access is difficult.
To the left is the screw body of a Jubilee clip.I am just about to loosen it off, and rotate the screw body out of the way. And then try with tiny 1/4” drive socket set.
To the right is this tube thing marked in yellow
What is this?

WIS says just unclip coolant tank and set aside with the hoses connected.
No special tools.

 

[umblecumbuz]

Just a thought ...
In their wisdom, MB now and then use five star torx. The industry standard is six star. That bolt in your photo looks to be five star, although hard to tell. Never done the job you're contemplating, so can't advise, but I have done one job that proved a real pig until I realised I was using six star bits on a virtually inaccessible five star bolt.

Some ring spanner sizes fit snugly on male torx bolts.

 

[Yugguy]

How much oil is likely to be in that tensioner? There's probably more left on the floor pan of the sump after an empty.

 

[area51]

The tube thing marked in yellow looks like the purge valve to me

 

[Submariner1]

Thanks for the replies.

Its a total pig, even if I managed to undo the back bolt, there is no way I can see to start the bolt manually when I replace it.

Sevan Motors can fit me in on Monday afternoon to change the tensioner and he will clean the air intake, MAF ? And the breather hoses .. that often clog up on low mileage short trip A Classes.

So I am sorted but thanks for all the replies ...appreciated.

Apparently the A160 Auto hoses are different and the certainly crowd that rear bolt.
So decided, it got to be worth him doing it, rather than me screwing up an £85 part and worse still a critical engine component.
Or be stuck half way having to drain the coolant to remove the hoses, to screw up the back bolt. with no contsiner to hold the coolant .. could be mareish.
Plus even if I started the bolt somehow, there is no way my set of torque wrenches would access that!

I did manage to change the air filter that was filthy.
And the oil and filter

2 very crucial things ... changing from Mobil1 0W 40 to Mobil 1 5W 50.
Wow what a difference ..
The top end tappetty noise dissappeared totallly.
And would you believe it, on initial start up the chain noise was almost impercievable.!!

I am still changing it as its bought, and if it makes a noise with 0W 40 then it has a problem.

The fact the noise goes away after 2 mins .. convinces me it leaks oil overnight, but is good enough to function once the oil pressure builds up.
The thicker oil seems to fill the tensioner to an acceptable level faster i.e. overcoming the leaking seal, so thats good.

But the dramatic improvement on the tappet rattle is ace.
Very scary for anyone buying one, that is run on 5W 50 or 10W 40 ... it would definitely disquise a fault on the chain tensioner (if it was a partial fault on the seal) and slightly noisy tappets.

She now sounds pretty decent.
Heres hoping once the new tensioner is fitted ... she will sound really sweet.

The second point is ... when draining it on the flat, once the dirty oil stopped and I left it 3 hours ( had other things to do ) I then jacked the drivers front up quite a bit.
And guess what 1/2 a coffee cup of dirty oil started to come out.
So drained on the flat or on a lift, it still leaves a fair bit of dirty oil in the engine, .....
Hmmm

 

[Submariner1]

Just a thought ...
In their wisdom, MB now and then use five star torx. The industry standard is six star. That bolt in your photo looks to be five star, although hard to tell. Never done the job you're contemplating, so can't advise, but I have done one job that proved a real pig until I realised I was using six star bits on a virtually inaccessible five star bolt.

Some ring spanner sizes fit snugly on male torx bolts.

Interesting you may well be right .. yes the new E8 socket did go on, but it sort of didnt feel super snug, if you know what I mean.
Does a 6 star actually physically fit on a 5 star E socket.?

 

[bembo449]

you need a decent 1/4 drive set pete , I have a Britool one and use it loads , you don't always need a torx to undo a torx bolt , more often than not I use an equivlant hex socket , 99% undoes most torx with ease

 

[LostKiwi]

you need a decent 1/4 drive set pete , I have a Britool one and use it loads , you don't always need a torx to undo a torx bolt , more often than not I use an equivlant hex socket , 99% undoes most torx with ease

But if you have the proper tool use it!

 

[Submariner1]

you need a decent 1/4 drive set pete , I have a Britool one and use it loads , you don't always need a torx to undo a torx bolt , more often than not I use an equivlant hex socket , 99% undoes most torx with ease

Thanks, I have a 1/4” E8 so sorted on that.
But it would need a 1/4” universal, and maybe a couple of wobble extensions to weave around two Hoses and that thing marked by a yellow arrow.

As tHe slight engine wobble at low tick-over, and the slightly slow tickover is sadly still there, but a bit better after changing the air filter, so its going to Sevan Motors , to clean the air intake tubes MAF, and crankcase and cylinder head breather tubes.

So faced with 2 obstacles ... mainly the possibility I may need to remove 2 coolant hoses, and no way can I get any of my 4 torque wrenches on the bolt head... I decided as its going there anyway ... let him do it.

 

[umblecumbuz]

... Try a small ring spanner that fits, if you can get access?
Sometimes you can access a bolt with a ring that is a pain to get to with a socket.

If Sevan Motors do the job for you it would be instructive to know how they get to the awkward bolt.

 

[Wighty]

... Try a small ring spanner that fits, if you can get access?
Sometimes you can access a bolt with a ring that is a pain to get to with a socket.

If Sevan Motors do the job for you it would be instructive to know how they get to the awkward bolt.

Polish up the old part without removing it , and throw the new part away . At least thats what "wighty motor services" would do !

 

[LostKiwi]

You've clearly never worked on a Smart thermostat. You can barely see the bolts on them and can't even touch them!
That doesn't look that awkward to me. E8 socket, very short extension and it looks pretty easy. Even easier if you remove the mountings for the yellow circled thing and push it out the way.
To get the back bolt started again fit the front bolt, fill the socket full of grease, insert the bolt in the socket and carefully start the bolt by hand using the extension on the socket.

 

[Submariner1]

... Try a small ring spanner that fits, if you can get access?
Sometimes you can access a bolt with a ring that is a pain to get to with a socket.

If Sevan Motors do the job for you it would be instructive to know how they get to the awkward bolt.

I will ask him.
I suspect he will clamp the hoses, undo them, then top up the coolant.
As all he does is A Classes he probably has exactly the right tools and knows the exact angle to do it.
I bought a few 3/8” drive universal joints and short wobble bars , only to find the bulge of 3/8s rods hit the yellow arrowed part.

 

[Submariner1]

You've clearly never worked on a Smart thermostat. You can barely see the bolts on them and can't even touch them!
That doesn't look that awkward to me. E8 socket, very short extension and it looks pretty easy. Even easier if you remove the mountings for the yellow circled thing and push it out the way.
To get the back bolt started again fit the front bolt, fill the socket full of grease, insert the bolt in the socket and carefully start the bolt by hand using the extension on the socket.

That was exactly my plan, other than use blutac to secure the bolt.
Once I got the 1/4” universal joint, I realised it had to be at almost 45 deg. to clear under the hose, and still turn. Pretty dificult to start a hand turn like that, and you cant get access from the top. Using the 50mm wobble bar is too long, and just using the socket .. then my fingers dont reach.
Adding 13mm of the bolt makes all extensions/universal joints impossible until the bolt is fully screwed down, but come to think of it might allow you to get hold of the socket initially as its raised 13mm.

Just didnt want to get caught with the bolt out and cant get a tool in to do it up.

That yellow marked item, is weird it looks like its moulded into a bracket, but that is aparently an engine stabiliser. And the back bolts have no top access.

If it wasnt going in to have the breather tubes cleaned, I would have persevered more.
But just took the easy option.

Appreciate your ideas though Alistair.

 

[LostKiwi]

These would be the answer. Shorter than a socket and extension.
https://www.machinemart.co.uk/p/8-p...BL0r_K14wq_6llCh4e-f-wlLfo5sRCp8aApgfEALw_wcB

 

[EmilysDad]

You've clearly never worked on a Smart thermostat. .....

I have .....

As I discovered when doing the starter, the 'stat is a lot easier to access when the engine is lowered .... still couldn't fit the original hose clips though fitted Jubliees instead.

 

[Uncle Benz]

Small bit of plastic bag placed between the Torx bolt and the correct Torx socket holds them in a treat.

 

[LostKiwi]

. still couldn't fit the original hose clips though fitted Jubliees instead.

Me too

 

[EmilysDad]

Me too

In stainless of course

 

[LostKiwi]

In stainless of course

Can you get them in anything else?