Strange coolant leak from engine block - help!

All the information you need on engine-problems is here. The engine includes the Turbo-charger, airco and everything else you'll find under the bonnet.

Moderators: jifflemon, coyote1980, Rachel

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Strange coolant leak from engine block - help!

Post by Macaroon » Thu Jul 31, 2008 4:06 pm

Oh Sh*t. Just when I had got Tonee back on the road, this happens:

Two days ago I saw steam coming from the bonnet after a 3 mile run and discovered I had been pissing coolant in a steady stream over the road as I parked. :(

A quick check under the bonnet revealed the following:

1. Coolant level was below the bottom of the expansion bottle but the radiator top pipe was hot and the radiator was not leaking.

2. The auxiliary water pump (electric pump found on 1.7 engines) was running but making a strange noise, as though the pipe was not full of water.
- This suggests steam bubbles in the system, i.e. a lack of pressure.

3. The steam was emerging from the back of the engine (looking from the front of the car) below the inlet manifold at the crankshaft end of the engine. It appeared to be emerging as water and turning to steam as it hit the hot exhaust manifold.

4. Squeezing the top hose when the engine was cold revealed it to be only partially filled with water, even with the expansion bottle full after having run the engine to temperature to pump coolant through the system. I also notice that with the engine running the coolant reached operating temperature quickly but levelled off at around 95 degrees.
- Could this mean the pump is not circulating coolant and it is boiling away through lack of pressure?

5. Squeezing the top hose with a cold or hot engine also produced a wheezing, gurgling noise as air and water escaped from a sizeable hole somewhere in the cylinder head. This is not good on many levels!
- First, the thermostat should be closed on a cold engine so I wonder how squeezing the top hose could force fluid backwards? I guess the thermostat needs replacing.
- Second, This hole is pretty worrying. :cry:

I don't believe the block is cracked and I can find no obvious signs of decompression or a gasket failure (milky oil, oily water, rising oil levels etc). The leak appears to be at the back of the cylinder head, above the level of the head gasket, somewhere below the inlet manifold. I can see the coolant squirt when I squeeze the pipe but cannot see or feel where it comes from.

Is there a coolant pipe / outlet round there to preheat the fuel/air mixture or could it be the mysterious coolant drain plug in the engine block mentioned here? :?

I will evidently have to remove the inlet manifold to investigate (unless I can lay my hands on an endoscope!) but that will be a drag as the car and manual are now at my mum's in south Bucks while I and my tools are in South London. Gnashhh!

Any advice or offers of help gratefully received (my mum makes a wicked cup of tea - or at least she will when she works out where the removal men hid her kettle!)
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
martinholmesuk
Friend of Club 480 Europe
Posts: 10049
Joined: Thu Sep 05, 2002 9:43 pm
Location: West Sussex

Post by martinholmesuk » Thu Jul 31, 2008 5:22 pm

Sounds like you have blown out your core plug on the engine block.

Image

See the discs being held in the engine? These are meant to pop out under pressure.

I think somewhere in Scotland sells them (search forum) it's not a easy job to do but do replace all of them mate.
Volvo 940 Turbo 19T (real Volvo :P)
Audi TT

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Thu Jul 31, 2008 6:28 pm

martinholmesuk wrote:Sounds like you have blown out your core plug on the engine block.

See the discs being held in the engine? These are meant to pop out under pressure.

I think somewhere in Scotland sells them (search forum) it's not a easy job to do but do replace all of them mate.
Cheers Mart, that sounds very much like it. Good to know, but a bugger to fix, by the sound of it.

I was considering a full garage service with cam belt renewal to celebrate passing 150,000 miles so I guess I'll let them do it, especially if the engine has to come out. It will be painfully expensive but worth it, I hope.

Now why might it pop? (apart from age and being a Volvo 480 of course)

I had a slight coolant loss (suspected both aux water pump and more recently the radiator) so I guess it's possible I added too little antifreeze on my regular top-ups (though I thought I didn't) leading to boiling and over-pressure in the block.

The engine has always run a little hot and I often saw the coolant temp rise to 101ºC before dropping to the low 90s, especially when entering town after a motorway run. The fan has always worked and still does but maybe the sensor is faulty..?

Mind you, the engine always smells hot ever since I left the oil filler cap off for 10 miles through London... Ironically, it seems I had earlier overfilled the oil because it didn't need topping up (nor has it ever since) even after spewing the stuff all around the engine bay (don't try this at home!).

When I did a short run home after the initial incident, I noticed the coolant temperature rising very quickly to 86º while the oil temp climbed at the normal rate.

Apart from running a bit rough lately I can't think of anything unusual, except that it stood for 4 months and was only turned over occasionally.

:?
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Thu Jul 31, 2008 6:32 pm

But on the other hand...

I am 99% sure the coolant is coming from the head not the block. It is coming from somewhere above the head gasket and dribbling down. Does the head also have core plugs???
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
martinholmesuk
Friend of Club 480 Europe
Posts: 10049
Joined: Thu Sep 05, 2002 9:43 pm
Location: West Sussex

Post by martinholmesuk » Thu Jul 31, 2008 10:37 pm

No core plugs in the head. Now you said about the high temps... Maybe and this would say more.

Have you blown the head gasket? That would cause a lot of heat and if blown then it might have leaked out the block/head
Volvo 940 Turbo 19T (real Volvo :P)
Audi TT

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Tue Aug 05, 2008 1:35 pm

I really don't think the head gasket is blown. I *really* hope the head gasket hasn't blown!

Next time I'm at my folks I'll try with mirrors to see where the coolant is coming from but failing that, the inlet manifold will have to come off when I can get my hands on a torque wrench and replacement gasket.

The pic you posted in the other thread is really useful. If I understand it correctly, is is looking to the front of the car with the inlet manifold removed.

Image

The coolant leak appears to come from somewhere around the orange oval but may be emerging from the head gasket and spraying upwards off the manifold. :(

I never knew about the air bleed screw you circled in red and that may be my downfall... I replaced the bottom hose clip a year ago but didn't know to bleed air from the head. :shock: (Mind you, the heater always worked so there must have been coolant up there?)
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
pol
480 Is my middle name
Posts: 2794
Joined: Wed Jan 22, 2003 10:48 pm
Location: Eastbourne

Post by pol » Tue Aug 05, 2008 1:49 pm

The red oval... I've had one of these pin holed with rust before if I remember correctly. Or i broke it somehow... That's all I can think of in that general area. Not sure what goes on near the orange oval.

You can buy the red oval part fairly cheap from volvo if needed.

pol

User avatar
martinholmesuk
Friend of Club 480 Europe
Posts: 10049
Joined: Thu Sep 05, 2002 9:43 pm
Location: West Sussex

Post by martinholmesuk » Tue Aug 05, 2008 2:37 pm

I'm 99% sure there is no water related bits there but there are petrol injectors.

i'll see if i got better pics
Volvo 940 Turbo 19T (real Volvo :P)
Audi TT

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Fri Aug 08, 2008 11:59 pm

I am pretty sure I have cracked it!

Not the engine - the problem...

I managed to locate a small round hole where Haynes says the cylinder head drain plug should be and it is right at the top of my orange oval in Mart's picture.

I took some pretty good pictures but cant upload them until I get back to civilisation ... and broadband. Anybody with photos of the plug, details of its size *or a spare* please let me know.

Rich
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
pol
480 Is my middle name
Posts: 2794
Joined: Wed Jan 22, 2003 10:48 pm
Location: Eastbourne

Post by pol » Sat Aug 09, 2008 7:59 am

Cylinder head drain plug? Didn't know there was one..

pol

User avatar
Yossarian
Knows an Aerodeck isn't a 480
Posts: 264
Joined: Thu Jul 17, 2008 11:14 am

Post by Yossarian » Sat Aug 09, 2008 8:41 am

Bubbles of air and a lack of pressure do suggest a blown head gasket, although I don't know if they could be caused by something else.

When my 825 inevitably blew it's head gasket I had more or less exactly the same symptoms up to a point.

In fact, one of the coolant hoses blew, which was caused by the build up of pressure caused by bubbles of gas, caused by the head gasket failing.

I didn't get any mayonnaise though. :D

User avatar
martinholmesuk
Friend of Club 480 Europe
Posts: 10049
Joined: Thu Sep 05, 2002 9:43 pm
Location: West Sussex

Post by martinholmesuk » Sat Aug 09, 2008 8:42 am

Well maybe the non turbo has a bleed screw? Never seen one.
Volvo 940 Turbo 19T (real Volvo :P)
Audi TT

User avatar
lee
480 Is my middle name
Posts: 1680
Joined: Thu Jan 23, 2003 8:24 pm
Location: Sheffield, uk

Post by lee » Sat Aug 09, 2008 9:57 am

i would go for the red circle. As in the heater pipe from the head. If this was leaking it would drip on to the exhaust hence steam, this would also not be localised. If this pipe has gone you can refit with chemical metal however i would recommend a new one even though a new one is tough to fit.

This pipe has failed on many a 480 i have dealt with. it would be my first port of call
hmmmmmmmmmmmmmmm

User avatar
pol
480 Is my middle name
Posts: 2794
Joined: Wed Jan 22, 2003 10:48 pm
Location: Eastbourne

Post by pol » Sat Aug 09, 2008 10:15 am

I didn't even need chemical metal to replace that part. Its a tapered fit which i hammered in. Might have used some instant gasket.. Probably...Can't remember.

pol

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Sat Aug 09, 2008 6:31 pm

Macaroon wrote:I managed to locate a small round hole where Haynes says the cylinder head drain plug should be and it is right at the top of my orange oval in Mart's picture.
Er, I think I was talking bølløcks. Sorry!

No bleed screw where I said it was.

There is a coolant leak from the round hole where I describe it but I now realise this is not the infamous cylinder head drain plug. Just a mysterious round hole about 5mm deep.

(It would help if I knew where the "oil pressure switch" was (as Haynes describes it) - perhaps they mean the engine temp sensor located near the distributor, just below the red circled item. In which case they just mean the coolant bleed point thingy.)

Anyway, my coolant is definitely coming from this shallow round hole hidden in the shadow at the top of the orange oval. I don't know what it is for but there is another one more easily visible behind the left hand stud for mounting the manifold (in Mart's picture). Needless to say that one doesn't have a bolt in it either but coolant doesn't leak from it.

I am thinking these holes are an unused feature of the engine block and a blown gasket has allowed coolant to get into one somehow.


Does anybody have a picture where these are visible or a diassembled engine they could look at?
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

User avatar
martinholmesuk
Friend of Club 480 Europe
Posts: 10049
Joined: Thu Sep 05, 2002 9:43 pm
Location: West Sussex

Post by martinholmesuk » Sat Aug 09, 2008 10:53 pm

post a new picture as your confusing the issue. cheers
Volvo 940 Turbo 19T (real Volvo :P)
Audi TT

shimon340
Knows where Volvo is from
Posts: 179
Joined: Wed Jul 21, 2004 10:40 am
Location: Manchester
Contact:

Post by shimon340 » Sat Aug 09, 2008 11:53 pm

hi there

Im following this post with interest but at the moment cant suggest anything as where the leak is from as I wasnt aware of a cylinder head drain plug

however, what engine do you have? Ive got a new unused 1.7 head I could post some pics of if that helps?

also, do you know the torque setting for the upper section of the inlet manifold (the part you removed in the pic above which links the lower section of the inlet manifold to the throttle body

thanks

shimon

User avatar
glasgowjim
480 Is my middle name
Posts: 4830
Joined: Sun Oct 01, 2006 5:28 pm
Location: GLASGOW SCOTLAND

Post by glasgowjim » Sun Aug 10, 2008 10:17 pm

on later models 2.0 ltr 94 for example there is a red "dial" oh the drivers side water pipe leading down to the heater matrix this is this the bleed valve ! you cant miss it will try to load a photo

jim

User avatar
glasgowjim
480 Is my middle name
Posts: 4830
Joined: Sun Oct 01, 2006 5:28 pm
Location: GLASGOW SCOTLAND

Post by glasgowjim » Sun Aug 10, 2008 10:26 pm

heres the photo

Image

:D

bleed valve arrowed

User avatar
Macaroon
Advanced 480 rookie
Posts: 532
Joined: Tue Mar 21, 2006 2:43 am
Location: Sunny Brixton, Sarf London

Post by Macaroon » Tue Aug 12, 2008 3:18 am

Yeah I was confusing the issue with this talk of coolant drain plugs. Basically, I was grasping at straws in the hope of finding a simple solution.
(In my defence I was massively sleep-deprive, suffering from big time back pain and doped out on codeine. 8) )

Anyhoo.

Thanks for your help so far but please forget the drain plugs and coolant bleed screws (or post further info in the thread here) - that was a red herring.

And this is a real mystery. Here is where the coolant comes out:
Image
As you can see, it is a machined hole, about 5-7mm diameter and maybe 3mm deep.

Apparently the picture shows more than I realised. It looks like coolant is bubbling through at the bottom - which suggests a cracked head..? But the engine was cold when these were taken so it could be an illusion.

Here's a close-up. There is no sign of any crack that coolant could escape from. When the water pump is running it just flows out gently.
Image

The hole is located just to one side of the injector in a recess behind the stud mounting at the cam belt end of the head. Its hard to locate with the manifold on, but in the picture below the long screwdriver is pointing right at it and the tip is in the hole.
Image

It's really inaccessible but I managed to get my finger over it - which stops the air/coolant leak when I squeeze the top hose.

There is an identical hole that is easy to see near the injector at the distributor end of the engine so I suppose there is one behind every stud but I realised this too late to take any pics.

Here are the two known locations:
Image

I got it wrong before with the orange oval on Mart's picture with the manifold off. The leaking one is hidden but indicated by the orange arrow in this picture and the more visible one is in the shadow that the red arrow points to. You can clearly see the stud mounting I mentioned.
Image

@ Shimon: I don't know the torque settings but they should all be in Haynes. Martin may know as he took that picture with the manifold removed. I'd be grateful if you could post a photo of the holes which should be clearly visible on the new head - and any other information would be great.

Of course I'm kicking myself for scrapping Sheba with the head in situ. (Shimon I don't suppose you'd consider selling it if mine is cracked...?)


So what to make of it??? :dunno:

The lack of any visible crack at the bottom of the hole and the fact that air / coolant comes out easily when I squeeze the top hose is confusing but suggests a fairly open connection to the coolant channels. So not a crack then - after all there is no loss of compression and no mixing of fluids.

Does anybody know what these holes are? In this thread Lee and Gaz state that 1.7ES and 1.7 Turbo heads are the same except "there are a few extra studs on the rear of the turbo head that you don't need for the ES" ... is that what they are for?

Unfortunately I am 30 miles from my Haynes & my 480 so I can't investigate further for a few days but it would be great if both a turbo owner and a non-turbo owner could check for these holes. And if you find them, investigate with thin wire whether they are just blank holes or if they connect to something else sideways.

My best hope (and this is a real shot in the dark) is that these holes are for a separate set of coolant channels that aren't used in the B18FP engine (but are used in the Turbo?) and so are normally open to the air on an ES. I have no idea how realistic that is but it is just possible a blown gasket or corroded blanking plate could allow coolant to get from the proper coolant channels to these other ones and so leak out the open hole.

Its a shot in the dark and based on insufficient knowledge but otherwise I'm looking at a new cylinder head. :(

:help:
Tonee: '93 Two Tone. High mileage but nice 'n' tidy.
Sheba: '91 ES Paris Special. Love that leather, baby. Scrapped and used as a spares car.

Image

Post Reply