Corsa C coolant hose mystery

Wig

Any Corsa C knowledgeable folk?
1.2 petrol Z12XE

There is a 15mm pipe from the top of the expansion bottle (along the back of the engine bay) to the throttle motor housing, and from the throttle motor housing to left hand side of the engine near the top pulley. This is the water pump housing. The pipe goes to the top of the water pump housing.

What are these pipes for? Why do they go through the throttle motor housing?

Mine has corroded right through at this small steel pipe at the top of the water pump housing and it has snapped off, I have plugged the tiny diameter hole in the water pump housing with a screw and it seems to be water tight, I have driven 40 miles like this now. Another screw was placed into the end of the pipe which broke away - but I don't think anything would come out of this pipe anyway as it would only happen if the expansion bottle overflowed.

The problem is I have to drive another 800 - 1000 miles before I can set about fixing it.

The bit that the pipe connects to on top of the water pump, has a 13mm Hex head on it like it was designed to be removeable..... it's the pipe connector right next to the temperature sensor.

Can I buy a replacement little pipe to fit without having to replace the whole water pump housing? Would 1st have to succesfully remove the broken bit from inside the water pump.

asbokid

Wig wrote: »

Any Corsa C knowledgeable folk?
1.2 petrol Z12XE

There is a 15mm pipe from the top of the expansion bottle (along the back of the engine bay) to the throttle motor housing, and from the throttle motor housing to left hand side of the engine near the top pulley. This is the water pump housing. The pipe goes to the top of the water pump housing.

What are these pipes for? Why do they go through the throttle motor housing?

I don't know that engine, but on Ford engines, it's common for there to be a Idle Air Control (IAC) Bypass Valve on the throttle body.

A secondary air inlet vent on the throttle body, controlled by the IAC valve, allows extra air into the manifold during cold engine conditions. The IAC valve is mechanically controlled by the temperature of the coolant that flows through it.

That probably explains why there are coolant pipes running through your throttle body. The IAC valve is probably called something else on the Vauxhall.

Mine has corroded right through at this small steel pipe at the top of the water pump housing and it has snapped off, I have plugged the tiny diameter hole in the water pump housing with a screw and it seems to be water tight, I have driven 40 miles like this now. Another screw was placed into the end of the pipe which broke away - but I don't think anything would come out of this pipe anyway as it would only happen if the expansion bottle overflowed.

Can't work that bit out.. But if it is the pipework for an IAC valve, it won't really matter except for rough idling during cold starts.

The problem is I have to drive another 800 - 1000 miles before I can set about fixing it.

The bit that the pipe connects to on top of the water pump, has a 13mm Hex head on it like it was designed to be removeable..... it's the pipe connector right next to the temperature sensor.

Can I buy a replacement little pipe to fit without having to replace the whole water pump housing? Would 1st have to succesfully remove the broken bit from inside the water pump.

That's the sort of question that a specialist Corsa forum would be better placed to answer..

vaio

Don't know about the repair but I'd guess the pipe is an air/water bleed which will also act as a bypass when the thermostat is closed. I guess it goes via the throttle body to help prevent icing

Wig

The diameter of the hole is about 2mm so I don't think it carries coolant - or not usually.

So I was thinking of some sort of overflow/breather pipe. The concept of a bleed sytem is a good one. And I just hadn't tought of it in that way.

And as it doesn't carry coolant that's why I find it hard to understand why it doesn't just go straight to the top of the expansion bottle, but instead goes in and out of the throttle motor.

There is another similar "bleed pipe" that goes to the front of the engine to the bottom hose also to the top of the expansion bottle.

I think the screw in the end of the coolant hose pipe was necessary afterall to keep the pressure up in the bottle.

It's probably not be a good idea to drive without the bleed pipe facility operating for the top of the engine....

Thanks for the ideas

Strider590

Coolant into the throttle body? it's to pre-heat the fuel.

burtons

I don't know what the pipe is for as i never looked at when mine when the plastic pipe snapped off. I had to replace the water pump on mine as vauxhall didn't sell a replacement part but i have just found this on ebay so i don't know if it will be any good as vauxhall have now changed the part from a plastic connector to a metal one.
http://cgi.ebay.co.uk/Corsa-Water-Pump-Repair-Pipe-Connector-M8-GENUINE-/330553692321?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4cf68910a1

asbokid

burtons wrote: »

I don't know what the pipe is for as i never looked at when mine when the plastic pipe snapped off. I had to replace the water pump on mine as vauxhall didn't sell a replacement part but i have just found this on ebay so i don't know if it will be any good as vauxhall have now changed the part from a plastic connector to a metal one.
http://cgi.ebay.co.uk/Corsa-Water-Pump-Repair-Pipe-Connector-M8-GENUINE-/330553692321?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4cf68910a1

That was a good find, burtons, if a bit of an ouch at £11!

The TIS2000 DVD would be useful to the OP as well...

http://motors-parts.shop.ebay.co.uk/i.html?_nkw=tis2000&_sacat=131090&LH_BIN=1&_sop=15&_dmpt=UK_CarParts_Vehicles_Manuals_Litterature_ET&_odkw=tis+2000&_osacat=131090&_trksid=p3286.c0.m270.l1313

Flying-High_2

From Vauxhalls P/N 90466779 About £3.50.

There maybe 2 variants of these with different threads as I'm sure they enlarged the diamter of the pipe on later ones.... Check first..

Wig

Update thanks for replies,

Story so far,

I went to work, left OH with instructions to phone vauxhalls to find out of there is a replacement pipe. At this point I am thinking the pipe that has broken is a corroded steel pipe.

Got email at work saying 1st dealer quoted £3.40 in stock, the the 2nd dealer -close to work- quoted £10.44 instock

sent email back for OH to find out what the discrepancy in price was for and to get a part number, only the part number was received by email.

After work, went to 2nd dealer with part number got part £3.40.
Parts dept guy says "Have you got the tap to tap it out with?"
to which I replied "isn't it the same thread?",
he shakes his head, so I'm thinking -Jeez! I haven't got time to tap it out, I had my hopes up for a straight swap-
Then he says something about the 'plastic pipe' breaking,
to which I say "plastic?, mines metal"
"metal?!!" he says "how did that snap"
"It was corroded and broke. Have you heard of these things snapping before"
"to the plastic ones, yes, but not metal ones"
"Ok maybe I'm mistaken, maybe it is plastic, I just assumed it was metal."

So I buy the bit and go home, on the way home I'm thinking -I wonder how the plastic bit is secured, is it threaded or a push fit, will it come out easily? How much is a full waterpump housing cover?

I decided best thing to do would be to go straight to the dealer by my house (dealer no.1) to ask those questions. It's easier to take something off when you know how it is fitted. There was a mechanic in the car park, so I asked him, he says he did one a few months ago, asked him how to get it out he says he used a screwdriver and it came out and then he just cleaned the rest that was left behind out of the threads. Asked him if he then had to tap a new thread, he said 'no the new one just screwed straight in' So I'm relieved a little and I go inside to find out how much the water pump housing costs. I'm at the desk with the bit in my hand, and he says straight away "they gave you the wrong one, there's two, a big one and a small one" I ask to see the small one. He brings it and it looks much more likely to fit, I say I'll buy it. He says £10.44. The observant among you will notice it was this dealer who initially said £3.40 and gave me the part number for the £3.40 part with the wrong thread, which led me to walk into dealer 2 (who initialy said £10.44) and gave me the part I had asked for which was the wrong part, but he didn't tell me there were 2 and there was now a better version costing £10!!!

Old part £3.40 wrong thread you have to tap a new one part number 90466779
New part (recently introduced by vauxhall) £10.44 allegedly correct thread straight swap £10.44 part number 55564351

Both identical except for the threads
Why on Earth did vauxhall not get it right in the first place or issue both sizes incase anyone damages the thread.
Why on Earth is the new one so much more expensive when they are otherwise identical?
Why design such a stupid plastic component where a metal one should have been used.

Going to have a go now at taking the plastic out, hope it goes well.

asbokid

glad you got it sorted, wig!

what is it for though?!

Wig

It is an air bleed pipe, it's not for coolant.
Don't know why it goes to the throttle motor.

It's not fitted yet.......

The good news is when I undid the screw coolant came out straight away, so there was no air-lock in the top of the engine as I was driving it yesterday.

The other good news is that this pipe is a replaceable item and I don't need to buy a whole pump housing costing £120 - edit I've since found them at £70 with temp sensor inc, and £28 without temp sensor