Coolant Hose Burst - Potential Headgasket?

[Tommys86]

after some enthusiastic driving I returned to my sister-in-laws house to notice some coolant spray on my badge panel.... to great horror I lifted the hood and found a coolant hose had burst (not split around the clip or popped off - burst in the middle, almost looks like a cut?!)

Anyhow I drained the coolant (what was left) and inspected the pipe, looked reasonably new compare to others - clip definitely is newer compared to the rest.

I've questioned the headgasket previous when I found mayo in my header tank - in the end I went for the oil cooler seals after seeing 180psi across the board on compression test... 1,000 miles later this has happen and I'm thinking maybe I do still have an issue?

Coolant doesn't look bad in tank but at the hose looks horrific (picture attached for reference!)- I've had to do some flushing to clear the previous issue (oil cooler seals were poor condition - one wasn't actually the correct size).

Could what I'm seeing be residual oil? But then how have I burst a hose? Blocked up rad/relief valve maybe?

Compression tests show around 180 cylinders 1,2,4 but no.3 was down 160 mark but question whether I should do that again to gain confidence.

Cheers,

Tom

 

[jackois]

If you don't think the engine overheated, I'd replace the hose, re-fill the cooling system and give it a try, first on the drive to temperature & then gently on the road and see how it gets on.

As for how it happened... how new is the hose? ... did it get caught with a screwdriver last time the clip was tightened? You'll probably never find out.

 

[Tommys86]

Thanks, yeah luckily i had just caught it and checked oil pressure and coolant temp after the journey before i shut down and found the issue.

Is my water pump at any risk though if its been run dry for a short period?

Would you say the coolant doesnt look emulsified enough to worry?

 

[robwright]

I would tend to agree. If it didn't overheat more than likely fine. Replace pipe, refill and test it. If you are worried about the lower compression cylinder squirt some oil in it and see if it improves. If you are still worried you could get a garage to sniff test the coolant to see if there are any combustion gasses present in it.

 

[Tommys86]

Pipe on order! Thanks.

Might take the rad off and give it a good flush off first?

Plus rinse through the top port of the block?

 

[Cater_Racer]

Rinse the rad with Gunk can't do any harm, but the compression on #3 is suspicious........ Oli did his head gasket recently I'd see what he thinks.

 

[edh]

I would tend to agree. If it didn't overheat more than likely fine. Replace pipe, refill and test it. If you are worried about the lower compression cylinder squirt some oil in it and see if it improves. If you are still worried you could get a garage to sniff test the coolant to see if there are any combustion gasses present in it.

If you've had oil in your coolant then I guess it might take a fair bit of effort to flush it all out? I must say I'd be concerned if I took a hose off & saw that.

I suppose an exhaust gas test by a friendly MOT man (quick, easy & conclusive) only checks for issues with a coolant channel / cylinder breach, not coolant/oil mixing. In my experience of 944's it's the former that is the main mode of failure for HG's.

 

[robwright]

Good point Ed. I should have added the caveat that the sniff test is not 100% conclusive. HGs can have a number of different failure modes.

 

[zcacogp]

Tom,

That's a bit of a hairy one. As your dad said, I did indeed do my head recently but didn't check the compressions before (or after for that matter). The fact that #3 is now lower than it was before you did the oil cooler seals is suspicious but not conclusive. I'd be tempted to do as others have said; change the hose and refill it with coolant and see where that gets you. It's the logical first step and things that you need to do anyway, and it's not impossible that the pipe was damaged by a stray hoseclip or a numpty with a screwdriver. A trip to a friendly MOT man for a sniff if a good thing if things seem to be holding.

One last thought; have you checked the header tank cap to make sure there isn't anything amiss with the spring?


Oli.

 

[Tommys86]

thanks for the feedback guys - I assume the test requires to be taken whilst the engine is running directly from the coolant system? i.e I couldn't just bottle some coolant now for analysis?

Eitherway think I have a rough plan of action...
- Excessive cleaning job - all hoses off and rad
- Check header tank
- Fresh set of sparks
- Run / bleed system, check for leaks
- Sniff check @ MOT centre

Starting to think it does look a cut! But I've not been anywhere near it :S

 

[zcacogp]

Yes, that's a good plan. And yes, you need to take the car to the garage to have a sniff while it's running.

A cut would be a great thing as it would explain the problem and give a simple solution.


Oli.

 

[Tommys86]

Update: Didn't get very far.... inspected the rad and suspect I might need a new one before running it.

Done some flushing through the block (more nasty stuff into my lovely pink plastic container...) I stuck a hose and some cleaner in from the top port to the engine and from the header tank.

The rad appears to have a largish damp batch on it. Seen some new replacement ones going for 160 - 200 mark? Any recommendations?

 

[BenEngland]

Hi.

Just 'bumped' up a thread started earlier this year regarding radiators.

Look for thread titled '951 Radiator' there is some good information there, hope it helps.

 

[Tommys86]

So as per '951 radiator' thread (kindly bumped by Ben!) I've fitted one of these aftermarket aluminium rads...

Took me a while to fiddle it in - safe to say if i could go back i might have chucked another £100 at it and got a replica / more standard factory unit. Checked for leaks - all good!

Checked for fan - not so good! fan doesnt come on... which leads to think did my original problem (hose burst) happen because the fans werent working?

I gave the car a solid blast and drove into a housing estate which was 20mph max for a 4 mins before stopping (at her sisters house) and seeing the leak...(good news was their double garage was empty!)

Think that would cause a pipe leak? Probable.
Obvious first check is the fuse? both OK.
Second change the sensor?
Or is my new rad causing this only to happen now?

Cheers,
Tom

 

[jackois]

Hi Tom, not sure whether you've seen this at Clarks Garage but here's their troubleshooting guide for cooling & fans.

http://www.clarks-garage.com/shop-manual/cool-01.htm

worth running through rather than just changing stuff willy nilly....

 

[Tommys86]

Thanks!
After speaking to my Dad we came to the same test - jump the connector and see if the fan starts. It quotes electrical jumpers - i dont have these but was tempted to use a something as crud as a paperclip? its a 3 pin connector, any idea which points should i bridge?

 

[zcacogp]

Tom,

Your S2 will have two fans which will come on together, but either slow or fast depending upon the temperature. Bridging the connector wrongly won't do any harm so just bridge it to see what happens; one combination will do nothing, one will do low speed and one will do high speed.

However to answer an earlier question, I slightly doubt that a pipe leak would be caused by an inoperative fan (inoperative for whatever reason). I suspect that your hoses were simply a little past it and gave up the ghost.


Oli.

ETA: Peter's link (above) explains things much better than my post and gives a pin-out for the fan plug.

http://www.clarks-garage....1.htm#latefanoperation

 

[Tommys86]

Update! finally got round to working on my car - bridged the temp fan switch - fan fired up no problem.

So leads me to think either....

I need a new sensor?

The new radiator is having an affect? (not entirely sure how)

Or I didn't warm it up enough to switch on - but checked it again, oil pressure was at 3 bar and temp gauge was if anything a tad higher than normal? attached a photo for reference.

Currently have a butchers at sensors, see design911.co.uk do one £24.53 (£14.99 + vat + delivery) or can anyone recommend another site?

Cheers,

Tom