944 LUX Cooling system & hoses

[Outrun944]

Hi there!

My newly purchased 944 today decided to spring a leak near the clip around the main S-shaped hose going into the engine .... unfortunately it dumped a whole lot of coolant water everywhere ... I'm guessing probably 3 Litres worth. I've cut the end of the hose, remounted and clipped into place (feels sturdy and the hose isn't unduly stretched).

My question is ... am I ok just to top up with normal tap water for now? I have a journey I need to make later today (typical!).
I've seen articles where it tells you to completely empty/flush/bleed the system, and other articles stating to release the pressure using the top nut on the top hose going into the err top of the engine? Is this necessary? A whole lot of pressure and water was released when I opened the cap on the tank and coolant water gushed out everywhere (ooops) !

Thanks in advance for any help.
I'll be posting an introduction thread and photos shortly

 

[robwright]

You should really run a 50/50 coolant mix. Phosphate free antifreeze for aluminium blocks. I would advise that you top up just using antifreeze to guard against the coolant freezing. The consequences of which dont bear thinking about. If you have lost that much coolant then you should also bleed the system properly. There is a guide to do it at www.clarks-garage.com go to garage shop manual then cooling system draining, filling and venting. It's not that hard once you get into it.

 

[Outrun944]

Cheers Rob!

I'm going to bleed the system later today.

Just so I'm prepared, do the belly pans really need to be removed? I'm not worried about the mess as there's drainage channels in my underground car park.
Otherwise is the drain plug on the radiator going to be impossible to get to?

I guess I'll find out later anyway...... fun times!

 

[robwright]

Yes the belly pans will have to come off but only if you are drainiong the whole system. I usually don't bother with the radiator drain plug. I just remove the bottom pipe from the radiator. Be prepared to get wet if you are draining the whole system. If you are not draining and simply topping up then there is no need to do anything other than jack the car up and open the bleed screw on the top of the block. You need to make sure the bleed screw is high enough to be above the heater matrix though otherwise you will hear water sloshing round in the matrix when you brake hard or put your foot down due to air voids left in the system. Good luck you will be ok []

 

[Mike_Pollock]

Just top it up 50:50 water / Phosphate free anti freeze as Rob says.
No need to take the pans off, but MUST bleed the system, its only 1 screw on the top of the elbow at the front of the engine.
Put the heater to hot, no fan and do it at least twice running the engine in between and to get it warm.
I'd do it another 3 or 4 times over the next week or so, after a run, as they are notoriously hard to bleed fully. I think they have secret compartments to hold air []
Mike

 

[robwright]

Another thing make sure the ignition is on because the heater control valve which opens to allow hot coolant to the heater matrix won't work without electrickery. I think it won't work without vacuum in the resevoir but this be taken care of when you run the engine inbetween bleedings. Like Mike says they can be a little tricky to bleed properly but it's all quite simple stuff. If you are topping up I would suggest putting in neat antifreeze as you don't know what the concentration of the mixture is that's already in there.

 

[Outrun944]

Hi guys - thanks for the replies and advice
Sorry it's all a bit new to me really, I've only had to top up before in the past on my previous cars

So I've done it now, without too much heartache, the question is ... how do you know if you've bled it properly and all air pockets have gone?

I took it for a little run, came back and allowed it cool down for 10 minutes, took the cap off the expansion cap (very carefully) and some gushed out the top .... topped up to the maximum line and went for another 10 minute spin round the block. The temperature needle is sat nicely below the middle point. Is this job done then?

 

[Outrun944]

Phosphate free anti-freeze ....

Started out a real bugger to find any.

Halfords are useless they have no idea what's in their own brand stuff not even on the label, in the end on the phone I made the guy call up and find out then call me back - he told me that all their stuff is phosphate free and ethlyn glycole (sp?) based and will be fine. The 'Advanced' stuff is apparently better for the engine and will last 3 years more (5 years) but as it's an OTA if there's any copper in the system it will eat through this (I wasn't sure, I know the engine is a light alluminium).

In the end, to save faffing about I drove to the local Porsche dealership and just bought 3 litres of their stuff which works out at £9.47 (inc VAT) per litre! Ouch!

 

[944 man]

Phosphate free used to be an issue 20+ years ago when manufacturers strted to introduce aluminium cylinder heads. Surely youd struggle to find anti-freeze with phosphate in it now? []

 

[Outrun944]

ORIGINAL: 944 man

Phosphate free used to be an issue 20+ years ago when manufacturers strted to introduce aluminium cylinder heads. Surely youd struggle to find anti-freeze with phosphate in it now? []

Heh, yea that's what I found from reading up too! But its best to check, be safe rather than sorry ... just lots of puzzled looks and "eh?" from the Halfords et al places when I asked []

 

[Outrun944]

OK just to be sure, and feel safe and happy....

Here's what I did -

1) Filled the expansion tank up with normal water
2) Took out the bottom pipe from the radiator and let it all come out (I couldn't get to the radiator plug ... long story ... but mounting points look shot and probably will need some welding work underneath so couldn't get the belly pans off ... managed to get a trolley jack under one side OK to tilt up tho)
3) Pushed the heater slider to full, air con to full and turned key so electrics were on and air blowing
4) Loosened the release valve/nut on the top hose into the engine, enough so the small hole in the side of the screw threads was visible
5) Filled up with 50/50 coolant/distilled water mix litre by litre
6) I was expecting at least to have a good stream of coolant coming out the release valve but that didn't really happen, so errr very carefully blew into the expansion cap a few times and coolant came out fine from the release valve.
7) Close cap and valve and ran engine for a while, released cap and topped up a bit.
8) Took it for a 5min drive, temparature needle sat a little bit below the middle, came back and allowed to cool down for 10 mins ... undid expansion cap and allowed a bit to gush out, topped up again and went out for another 10 minute drive.

The temperature needle is sat nicely below the middle point. Is this job done then?

As I said above, how do you know if you've bled it properly and all air pockets have gone?

Thanks again! (Sorry for the waffle, best to provide as much detail as possible eh?)

 

[robwright]

Obvious signs can be poor cooling which sounds like you don't have. Heater will work better when you floor the accelerator and increase water pressure in the system or you can hear water sloshing around in the heater matrix when you brake or accelerate. All sounds good what you have done mate. As already posted I would do it a couple more times over the coming week just to make sure. Those air voids can be pesky little blighters!!! []

 

[Mike_Pollock]

Well done mate most of the way there - as we've said just do it a couple more times just to be save over the next week.
I'm only in Leicester, give us a call - no in the signature.
Mkie

 

[Outrun944]

Oh no. Not good.

Drove home today, all seemed fine last 2 days ... and pulled up and noticed that the temperature guage had shot up above the 3/4 mark ... it's never done that before.

So I vented and topped up .... temperature still rose up. Found a small patch of oil under the car. The oil gauge was at halfway, where after the full service on Saturday it was on full!
Left it to cool down, repeated the process but spent more time venting this time and made sure no bubbles at all could be found coming out the vent leaving it for extra time whilst topping up ... temperature was still slowly but steadily climbing towards that red zone Only a few spots of oil this time. First process took 10 minutes, second I took about 15-20minutes.

Very nervously I started driving it to my usual garage, expecting I'll need to stop every 10 minutes and wait half an hour for it to cool down ... except to my surprise driving along the temperature guage was around the 1/4 mark, only occasionally rising up to near the half mark before going back down again, plus the oil gauge was on the full mark! "Oh! It must have sorted itself!" I thought, but decided to drive it to the garage just in case and have them take a quick look over.

Now ... whilst pulled up handbrake on, engine still running ... the temperature gauge started to rise again!!!!!
We let it get just into the red zone before turning off One of two spots of oil under the car.

We had a quick look under the bonnet, and we found a couple of places where there was oil, but they're going to have a good look over it tomorrow.

Only had it a month and had fair amount of trouble so far


Has what I described sound familiar to anyone? Or anyone have any idea what this could be?

 

[Diver944]

Were the fans kicking in and out? They normally do once the gauge rises over half way. When stationary without fans they do get very hot very quickly

 

[FistsOfHam]

Sounds as if the cooling fan isn't working if it cooled down whilst driving and went up when stationary. Mine is dead and I think it's the relay that has died but not gotten around to ordering a new one yet.

I wouldn't expect the gauge to go down to 1/4 when driving but then I haven't driven mine on the road so not sure what the characteristics of the 944 temp gauge are.

 

[Outrun944]

Thanks guys - I tend to panic a bit, as I need the car for work and other commitments.

I'll pass the info onto my mechanics.

Could it be a head gasket has gone?

 

[FistsOfHam]

I'm no expert but I would've thought that if the headgasket had gone you'd be losing coolant and possibly have coolant in the oil.

If the headgasket is gone I don't think it's a big job on these. I've only ever done one and that was on a Volvo was was only really fiddly because of where and how the turbo was mounted.

Doesn't sound like the end of the world but if you really want peace of mind you could just have the headgasket changed anyway as they don't last forever.

 

[Outrun944]

Hi guys, just back from the garage and all sorted no major issue

You were exactly right about the fans ... I did forget to mention that when stationary, the temp above halfway point with engine/electrics on or off the fan at the front on the radiator wasn't kicking in. I remember reading that the fan should come on from battery power even after everything is shut off if the temperature is too high thinking about it.

My garage (Churchwalk in Stapleford just outside of Nottingham - highly recommended) bled the system properly this time with a proper pressure & tester kit. Now the fan kicks in when it should and temperature drops! Driving or stationary temperature control is behaving normally as it should

Nothing more needed to be done. I'm guessing then that there were still lots of air pockets in the actual block which I didn't drain properly and there must be somewhere a temperature sensor around there that wasn't picking up this temperature rise and not sending the signal to the fan relay to come on.

(In regards to the oil ... they've had the car all day but couldn't find any leak. On Friday the garage did fix an oil leak from I believe the cam shaft housing ... so our theory is, there must have been a small reservoir somewhere on the engine or in the engine bay where oil collected and with bleeding the system and having coolant come out the vent everywhere this of course flushed out this oil collection.)


Anyway, being a noobie to such things, I think this is a good lesson on how to bleed these cars properly (with possible dangers and side affects), and will be interesting reading to anyone new to these cars coming to these forums to stumble across. If I had been able to get under the car, remove the belly pans and dump the coolant and air from the valve under the block too, then maybe I would have avoided such issue. Either way, I think its best that you try and go the route of a pressure fill rather than a gravity fill. Or take it to your garage to do properly, my garage said next time bring it to us and we'll only charge a tenner or a twenty for labour and have it all sorted - I think it's worth losing a twenty note and save yourself worry and hassle ... but then there's no satisfaction and learning without doing yourself

 

[Mike_Pollock]

A 944 is not the easiest car to learn the art of bleeding an engine on! However they can be done with a bit of experience.
Glad to hear the problem is sorted.
I went to a dyno day organised through the forum a while ago, and when I got there after a good (quick!) trip my car was leaking water, I was rather worried but a new cap cured the problem!
Mike