Several problems, hopefully all the same cause.

[Junglist]

Hi everyone. It's getting embarrassing now so I need to sort it out. Problems include:

1. High idle - not immediately on starting, but after about a minute or so and then for the following 15 minutes. Then settling to around 1100rpm (but before this problem it would settle at 9500rpm once warmed up, after revving at 11-12 when cold)

2. Temp too high - high revs causing temp to rise to over three quarters, sometimes max.

3. Intermittent overrun - turn key off, engine revs and splutters but sounds nasty with it, not just a normal rev. Only happens sometimes.

4. No power from start - within first 5 mins of starting car in the morning, putting my foot down more than a gentle swell doesn't work! If anything, the car loses power as a result.

I hope all these problems are related - they all started at the same time. Can anyone help or advise me? Thanks in advance.

[Risocco]

I think your car is carb'd right mate? Is it weber too?

I'd check timing and get your carb set up properly on a rolling road. Problems 1,3 and 4 could be related to this. Mine were when I "expertly" set the timing on my car Although I didn't have any overrun problems.

As for overheating, naturally do the cheap stuff first. Flush the rad then thermostat and finally the water pump.

Alex

[Junglist]

It's a pierburg. Got the car tuned only 3000 miles ago and everything was perfect, so I'd be surprised if it's a timing problem. It was almost a year ago though. Only needed new plugs as the already new ones that were fitted at service were a bad batch.

I know hardly anything about mechanics though, so maybe you're completely right. Is the timing related to the camshaft too? I'm about to change that so I'll do both together if it is.

I think the overheating might be a result of the high idle, so sorting that could solve it. Maybe not?

The overrun tends to happen after I've switched the engine off and on a few times during high idle moments to avoid embarrassingly loud situations at traffic lights! Maybe if I stop doing that it won't happen.

[roccodave]

the overheating could be a dodgy fan or switch check that the fan is coming on when the temp goes just above halfway
i suspect it wont if it dosent bridge a spare bit of cable across the plug on the bottom of the radiator if it spins its the switch if it dosent its probly the fan
if you overheat it too much you may get a bill for a headgasket

[GT Matt]

Sounds like one thing has led to another here.

I feel that the overheating is the root cause of the problems that has effected other systems and has caused other problems. Temp gauge should always be no higher than vertical. Have you driven the car very far with the needle this high? Are you losing coolant (is the level going down)? Are you coolant hoses hard or soft when then engine is hot (MAKE SURE YOU WEAR A GLOVE OR SOMETHING WHEN YOU CHECK FOR THIS!)

This excessive operating temp will result in an increased combustion chamber temperature (resulting in a loss of power due to over vapourised fuel) and will also be the cause of the "running on" as the increased temperature will cause the air/fuel mixture to ignite (pre ignition) without the need of the spark plug. This is similar to pinking but does not necessarily mean your timing is out.

I suggest that:

1) Have your cooling system pressure tested to check for obvious coolant leaks
2) Have a 'block test' done on your cooling system which sniffs for CO in your coolant

If it does indicate head gasket failure, be aware that these can just fail but, sometimes, a leak elsewhere can often be the cause and the resulting excessive temp then causes the head gasket to fail.

I hope it isn't anything too serious for you but feel free to ask further questions.

GT Matt

[Junglist]

The overheating is the most recent problem to arise. Haven't driven particularly far with high needle - less than 5 miles (probably less than 2). Pretty sure I'm not losing coolant (I'll double check). Hoses are soft all the time, hot or cold.

So you think it might be a head gasket job? That's basically saying I may as well buy a new car isn't it? Or have I misunderstood?

Thanks for all this help - any advice/experience welcome.

I'm getting tonnes of different diagnoses: carb, radiator, inlet maniofold, thermostat, timing, etc. etc. and now possibly head gasket! Who's advice should I go with, or could they all be right?

[Risocco]

Nah mate, head gasket isnt game over anymore. With a free day and a Haynes book, the novice could take a head off for the first time. Basically drop it off at a garage and get the sniffer test done which Matt said, will put your mind at ease. If your not losing coolant, the gasket should be OK tho.

Alex

[Junglist]

The black plastic bit that distributes all the water from the rad with the 2 sensors plugged into the top of it has cracked! Also, 2 mechanics have had a look/listen and told me there's an inlet manifold issue as well. That's what the funny nasty noise in the overrun/running-on is all about apparrently. Pre-ignition (as previously cited by GT Matt).

I've filled the water up which seems to have temporarily fixed all obvious problems, but I need one of thase black plastic things. Don't know what it's called but I'm told the part number (stamped on it) is obsolete, but some other vehicles have the same part under a different part number which is not obsolete! Any help?

So it won't overheat or run-on any more, but apparently the inlet manifold needs sorting which could still cause high idle (so I'm glad this alerted me to it). More urgently, that black plastic water distribution thingy which I need a non-scirocco part number for needs replacing. So who knows another part number for it? Or even what it's called?

Thanks everyone for all your help so far and still to come! Gonna go and T-cut my bonnet now. Stupid tornado red.

[ianaudia4]

Jung,

Take a picture of the part you're after.
Shame you are not closer as I would love to help you out with your car and teach you more
about the mechanics.

[PeteGLi]

Sounds like the coolant flange on the front of the cylinder head that the radiator top hose goes to, is what you are after. When you get one, I suggest that you fit new sealing washers for the two senders that go in it.

Is the part number on it - 037121132B ?

[Junglist]

Jung,

Take a picture of the part you're after.
Shame you are not closer as I would love to help you out with your car and teach you more
about the mechanics.

I'll be up in richmond in a week! Which bit do you live in? Yeah, it is a shame - I really want to learn.

Sounds like the coolant flange on the front of the cylinder head that the radiator top hose goes to, is what you are after. When you get one, I suggest that you fit new sealing washers for the two senders that go in it.

Is the part number on it - 037121132B ?

Don't want to remove it to look in case it falls to bits. It was ages ago someone told me about the "obsolete part number but non-obsolete part" thing. I'll try to get a pic posted. It's got about 4 or 5 hoses of different sizes clipped on to it and it sits very centrally in the engine bay and it has 2 plugs in the top with wires coming off them. Does that help identification? I'll do a search for "coolant flange" to see if there are any pics. I'll know if it's the right description then.

Thanks lads. Much appreciated.

[ianaudia4]

Jung,

Get the picture up ASAP mate.

Richmond is about 35 minutes south of where I live. How long you gonna be there for, will you be in the Scirocco?

[Junglist]

Looked at tonnes of pics via google search and can't find any that take 2 sensors plugged into the top like on mine. Do I need to get a slightly different one to the original as it will work anyway? I'll try my best to get a pic posted this pm.

Ian - turns out I won't be in richmond after all - job was cancelled (I'm £150 out of pocket as a result!) but I'm up there now and again as my chick's folks live up there. Maybe we'll meet next time. I always bring the Sciroc!

[ianaudia4]

Looked at tonnes of pics via google search and can't find ant that take 2 sensors plugged into the top like on mine. Do I need to get a slightly different one to the original as it will work anyway? I'll try my best to get a pic posted this pm.

Ian - turns out I won't be in richmond after all - job was cancelled (I'm £150 out of pocket as a result!) but I'm up there now and again as my chick's folks live up there. Maybe we'll meet next time. I always bring the Sciroc!

No probs mate, give me a shout when you are up this way.

[Junglist]

Sounds like the coolant flange on the front of the cylinder head that the radiator top hose goes to, is what you are after. When you get one, I suggest that you fit new sealing washers for the two senders that go in it.

Is the part number on it - 037121132B ?

As far as I can tell, yes it is that part number. Mr P directed me to the vagcat site with an exploded diagram showing my flange and the injection one and mine APPEARS to be the one described under that part number. I'm pretty certain anyway, pics on google search I just did during writing this post show identical looking part.