Major coolant leak

[jonrb 0]

Hi guys

 

I've got a major coolant leak at the moment to the extent that I'm putting over a litre of coolant mix into the header tank a day to keep the car running (which I know is less than ideal).

 

When I was in my local VW dealer recently buying yet another couple of bottles of G12+ I got chatting to the guy on the parts desk who was really helpful and called up Ekta and pointed out a complicated looking plastic assembly that looks like it bolts to the engine block on the same side as the header tank and told me that was a common failure point.

 

I checked the car when hot and sure enough I have wetness / steam / slight spitting in that area so he could well be right. The area has several coolant hoses and seems to be the point of entry into the engine to my untrained eye.

 

The question is, how difficult is that to change? I'm no mechanic, but I'm competent enough to have changed the ISV in the past and also the engine speed sensor, although I acknowledge that neither of those are difficult jobs.

 

Thanks in advance for any help anyone can give

Jon

[Supercharged 2]

Thats the temp sender housing I think...

 

If you buy it make sure you get all new clips, seals, bolts etc with it...

[dr_mat 0]

Note that the first point of failure, in 90% of VR6 engines, from my own evidence and from this forum is the hose that runs from the heater matrix to the rear of the cylinder head. It develops a split right near the head, under the plastic cable guides so you can't see it. Check this spot first.

Then fork out another £40 at VW for a replacement.

Then check your engine mounts ...

[jonrb 0]

Check my engine mounts? How come? (confused)

 

Could you expand on the hose you're referring to Matt? Sounds like something I might conceivably be able to handle but I'm not sure I know which bit you're referring to.

[dr_mat 0]

Flexi engine mounts -> more strain on hoses. Gearbox mount seems to go first. It's oil filled, you'll see sticky black mess all over that part of the subframe if it's gone.

"The" hose goes from the bulkhead wall (i.e. the back of the engine bay) to the *rear* of the cylinder head. There's only one hose that does that. It's directly on top of the exhaust manifold. Go have a shufty.

[jonrb 0]

My Corrado is 9 years old and to my knowledge has never had any of its mounts changed. I have noticed lots of oil around the place, but I put that down to the fact that I know my mechanic who looks after both my Corrado and Chimaera is into Waxoyl in a big way and regularly Waxoyls the Chimaera. I just assumed he'd Waxoyled the Corrado too.

I guess it was maybe a bad assumption in the light of what you're saying. ;)

 

I've just popped out and checked the hose that you mention. There are two hoses that pass through the bulkhead. One goes to the top rear of the engine under the plastic guard that routes the HT leads. I'm guessing that this is the one you mean? This one appears sound.

The other one has a ribbed aluminium sleeve on it and it goes down to the lower part of the engine and then up into a metal cylinder marked Bosch, near the coil pack. This is heavily crusted in white evaporation products and is down near all the other hoses I mentioned, so looks like a prime candidate. There is a plastic collar that secures the hose to the Bosch cylinder and this looks quite loose. I didn't want to disturb it too much as the car has to get me home tonight. Incidentally the header tank is completely dry, despite me putting about 1.5L of solution before leaving the house this morning. Looks like it has been leaking sat in the car park. Fortunately I have about 3 litres of made-up coolant with me so I'll refill it before I journey home tonight.

[dr_mat 0]

It "appears sound" - but the bit where it normally goes is right up under the plastic cable guides. Honestly, you can't see it without removing the cable guides (12 point spline key required!).

The "metal cylinder" sounds like the aux water pump. This, too, is a possible cause. With the ignition on it should make a very subtle whirring noise.

[jonrb 0]

12 point spline key required!

Or a #6 Allen key, if I remember correctly. :D

 

I'll have to limp the car home and check that tonight, though, as I have neither with me.

 

Incidentally, when I wrote 'appears sound' I meant no obvious evaporation products, unlike on the aux water pump. However, I accept what you're saying and will have a proper look tonight.

 

Cheers!

Jon

[jonrb 0]

I think I may have the same problem as the poster on this thread - my aux water pump and hose are heavily crusted with coolant evaporation products.

[dr_mat 0]

Is it wet there, or just crusty .. (ahem!)?

[jonrb 0]

You beat me to it Matt - I was just writing a reply when yours came in. :)

 

When I got home this evening I removed the plastic HT-lead guards and had a good look at the upper hose. It is indeed sound, and by that I mean it looks fresh, firm, black and remarkably new-looking for its age. There is no crusting, deposits or signs of wear or leakage.

 

The hose leading into the aux water pump, on the other hand, looks pretty tired and ropey. The hose clip is crusted and possibly corroded (hard to say). It is indeed wet and there are wisps of steam coming off it even with the engine having been off for 30-odd minutes. [pic here]

 

What I think I may do is take the Chimaera to work tomorrow (shame :)) and then tomorrow evening, when everything is nice and cold, I'll remove the hose clip, bind the end of the hose up with self-amalgamating tape and hose repair tape and then put a proper jubilee clip on it and see if that helps. If it doesn't then I'll replace the hose obviously.

 

(Edit: Having said that, looking at the pic I've just posted does make me now wonder if binding it up will do anything).

 

The aux pump itself seems fine. With the ignition on and the engine off it whirrs away quite noisily, but it is definitely doing something. When I start the engine up the coolant in the header tank starts bubbling so there is air getting into the system and coolant getting out.

[dr_mat 0]

The original hose clips are specially designed to maintain the right amount of pressure on the joint, iirc. You shouldn't need to swap them, despite all appearances they're reusable.

Yeah - if it's steaming there I'd say that's your problem. Judging by the pic I'd be straight off to buy a new aux pump!!

(Note that the aux pump will run on after the ignition goes off with the fans so that might explain why it's still steaming ten minutes later ..)

[jonrb 0]

The original hose clips are specially designed to maintain the right amount of pressure on the joint, iirc. You shouldn't need to swap them, despite all appearances they're reusable.

Oh. I completely buggered the ones on the ISV when I changed it and used jubiliee clips instead. :oops:

 

You think it's the pump and not the hoses / connector then?

[dr_mat 0]

It looks like the plastic housing around the pump that's leaking to me, don't you think? My old one was pretty knacked when it came off too, but it wasn't leaking much.

Jubilee clips are fine, but the main reason VW used those spring clips is so it's not possible to over-tighten them.

[jonrb 0]

You may be right. I just couldn't work out if the cause of leakage was part of the pump assembly or the hose assembly. Kind of makes a difference which you replace really. ;)

 

Or, to put it another way, I wasn't sure if the plastic housing the hoses are attached to was part of the pump or the hose kit. If it is the former then, yes, I appear to need a new pump.

 

Is this one of those parts you should buy genuine VW on or is it a GSF / ECP / GPC purchase?

 

Dou you reckon I can do it myself given I managed to replace an ISV myself?

[dr_mat 0]

I think Haynes would call this a three-spanner repair... ;)

 

(The whole plastics there are part of the pump. The hoses bolt onto the pump inlet/outlet itself.)

[jonrb 0]

I think Haynes would call this a three-spanner repair...

 

"Haynes: Three spanner rating (intermediate).

Translation: Make sure you won’t need your car for a couple of days and that your AA cover includes Home Start."

 

Seriously though, it looks like a case removing the HT-guide panels, clamping off the hoses to minimise coolant loss and reduce airlocks, removing the hoses and electrical connector, removing the aux pump, replacing with the new pump and re-assembly. Or am I missing half a world of pain and suffering there? :)

[dr_mat 0]

No idea, mine got replaced at the garage... Just go for it. If you louse it up, fine, tow it to a garage!

[jonrb 0]

Matt, if you got yours done at a garage then that's good enough for me - I won't even try to do it myself. :)

[dr_mat 0]

Hey, I'm no spanner monkey! I do at least have a full set now (of spanners!), which is a start, but frankly I do very little myself.. At the time the car was in for a service anyway and I had them replace it out of convenience more than anything else...

I get nervous about the coolant system in general though, cos I can't drive anywhere to pick up new bits if I break something .. !

[jonrb 0]

Ah, I see. Fortunately I have the luxury of one or two other cars to use if I render the Corrado undriveable, although it is a total pain in the arse to get it to a garage if the car is undriveable and unfixable by myself, as I found with that non-starting engine problem I had last year that you helped me out with if you recall.

 

I feel quite confident about disconnecting & reconnecting hoses, especially if they can be clamped off first (assuming the hoses can take being clamped without splitting) and it looks fairly straightforward but it would be good to hear from someone who had done it.

[corozin 0]

Jon,

It is possible to do this yourself, but it largely depends on how mechanically skilled you are, and how attached you are to the skin on your knuckles.

 

The part can be obtained from German & Swedish, but getting to all the bolts around the back to remove the pump is a complete bu99er, and from recollection one of the bolts has to be removed by feel alone.

 

Like the man said above, it's a 3/5 spanner job. I'd recommend you put the car into a local specialist, as it's less than an hours work.

 

HTH,

John (soon to be united with my third Corrado)

[jonrb 0]

I'd recommend you put the car into a local specialist, as it's less than an hours work.

 

True, but most local specialists I know have a 2-3 week lead time in their calenders and I could do with having the car back on the road quicker than that.

 

So what we're saying is that apart from the hassle of getting it off, it all boils down (no pun intended) to disconnect hoses & connectors, get the old one off, put new one on, reconnected hoses & connectors, top up coolant, run aux pump for a while to bubble out any air and then watch for airlocks for a while.

 

Sounds like an afternoon's work on the basis that a pro can do it in an hour or so. ;)

[Roger Blassberg 0]

Jonrb, make sure that the new pump has the same electrical connector as the original - there are at least 2 different shapes of socket around and its a pain to get home only to discover that you have the wrong one.........Can you guess how I know this?? Yes, it's a fiddly job but not too bad.

 

Best wishes

 

 

RB

[jonrb 0]

Jonrb, make sure that the new pump has the same electrical connector as the original - there are at least 2 different shapes of socket around and its a pain to get home only to discover that you have the wrong one.........Can you guess how I know this??

 

Cheers Roger. I'm pretty sure I've ordered the right one as I got the part number from Etka for the model year of my car and ordered from GPC by part number. Charlie has also confirmed that he only has one part number for the 1995 VR6 and that's what he's ordered for me. So fingers crossed, eh? :)