part # needed for small diameter main cooler o-ring

[ruedisrs6]

Dear RS6-enthusiasts,
after many hours of search in parts catalogs, I have not found any information about the part number or dimensions of the small diameter o-ring inside the left upper quick connect tube to the main coolant cooler. I have the part number and dimensions of the 3 larger o-rings (4E0121666, 38x4 mm), but no info about the single small diameter o-ring. Has someone recently replaced this o-ring and is able to help me on this?
Many thanks !
Best
Ruedi

[ruedisrs6]

Can anyone help me on this ? At least with the size of the o-ring ?
Any info is appreciated. Many thanks.
Ruedi

[Jim Haseltine]

My engine is coming out again in a couple of weeks so I might be able to measure the o-ring then. Judging from the parts lists it's not available as a spare part and the whole hose is something like GBP30, something close to 35Euro.

[ruedisrs6]

Many thanks Jim. I spend hours and did not find any information about this o-ring. And it bothers me somehow to buy the whole tube because of an o-ring.
Good luck for your upcoming engine-out job ! I am afraid, I have to do the same due to an increasing amount of oil in my spark plugs wells due to a leaking cam girdle seal.

[Jim Haseltine]

Looks like I'll be starting on Monday or Tuesday of next week. This time I'm working with the car under cover and with most of a garage in which I can work on the engine so I'll not be having to dodge rain storms. Main jobs - a pair of new turbos CHRAs together with a new starter motor and main cable as it's now got to the stage that once the car is hot the starter locks up.

[ATinOf]

Looks like I'll be starting on Monday or Tuesday of next week. This time I'm working with the car under cover and with most of a garage in which I can work on the engine so I'll not be having to dodge rain storms. Main jobs - a pair of new turbos CHRAs together with a new starter motor and main cable as it's now got to the stage that once the car is hot the starter locks up.

Are you sure its the starter locking up Jim, I have a starter on an old 3.1 essex V6 that refuses to work when its hot but I believe that to be an electrical breakdown either in the starter solenoid coil or the ignition feed to it, just need to get round to dropping the megger on the circuit to prove that, but that's a whole lot older system than yer 6

[Jim Haseltine]

The whole thing - starter, cable and plug for the exciter cable were all cooked. The main power terminal on the starter solenoid is loose and the power cable is missing 2" of insulation near the starter terminal. The exciter plug shattered into pieces when I removed it.
New starter, cable and plug fitted - along with some glass fibre and Mylar heat shielding.
CHRAs to be fitted over the next couple of days, as soon as I've been able to extract a broken stud from one of the manifolds. All studs are being replaced with A2 stainless.

[cammmy]

Have you looked at titanium for the studs? I had issues with turbo bolts on the Esprit and went titanium. They seem to have held up well.

[Jim Haseltine]

It crossed my mind but as Audi used A2 stainless for the head/manifold studs I thought I'd stick with it.

[cammmy]

Cool, bit of a thread hijack but what happened? I thought you had your turbos sorted?

[Jim Haseltine]

I'd hoped so but they were still dumping oil from both ends. I'd get a cloud of smoke on start up at irregular intervals varying between every day and once a fortnight with the most common being 3-4 days. I was draining a touch under half a litre of oil from the intercooler hoses every 3 weeks then I lucked across a pair of new CHRAs at an attractive price - pity I didn't find them a couple of years ago - just needed the excuse to fit them, which was provided by the starting issue. Car started OK(ish) from cold but once warm it was no go.
I took to carrying a full charged booster pack with me at all times and not a small one either, it was one I used to use to start tractors but sometimes even that wouldn't help. The day when I narrowly avoided an over-stay fine in a carpark was the last straw.

[cammmy]

Ah bummer. Are you turbos aftermarket?

[ATinOf]

The whole thing - starter, cable and plug for the exciter cable were all cooked. The main power terminal on the starter solenoid is loose and the power cable is missing 2" of insulation near the starter terminal. The exciter plug shattered into pieces when I removed it.
New starter, cable and plug fitted - along with some glass fibre and Mylar heat shielding.
CHRAs to be fitted over the next couple of days, as soon as I've been able to extract a broken stud from one of the manifolds. All studs are being replaced with A2 stainless.

Ouch, what was the root cause of the cooking Jim?

[Jim Haseltine]

Heat from the RH turbo. I had a moan about my starting woes to a RS specialist and his opinion was that it'd be either the starter solenoid or the cable and probably both as he'd done several cars with the same issue this year. He even sent me a video showing a loose terminal on a solenoid. Once I've got the car back on the road (engine goes back in tomorrow) and I've a few minutes free I'll post a pic of the cable.

[Jim Haseltine]

after many hours of search in parts catalogs, I have not found any information about the part number or dimensions of the small diameter o-ring inside the left upper quick connect tube to the main coolant cooler. I have the part number and dimensions of the 3 larger o-rings (4E0121666, 38x4 mm), but no info about the single small diameter o-ring. Has someone recently replaced this o-ring and is able to help me on this?

Sorry about the thread creep, but today I got the small o-ring out and measured it. Bearing in mind that it's nearly 14 years and some 116K miles old, I reckon that it's 22mm internal diameter and 3.5mm thick.