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[wombatcurry]

I can't see how the rad can cool too much - it was designed like that & other cars seem to work ok with the design.

[TheBoy]

I can't see how the rad can cool too much - it was designed like that & other cars seem to work ok with the design.

But with a locked visco fan.....

[wombatcurry]

Ahh :-/

[wombatcurry]

Having thought about it for a minute - if your visco fan is always on, then it's even more surprising that you've got overheating - a thermostat not opening would certainly lead to high pressures - the flow could only go thru the bypass - and that is not normally designed for higher revs & therefore higher flow rates. You might be onto something here.

[wombatcurry]

I thought I'd seen a new visco fan on ebay recently - just had a look & it's still there.

BUT it 284Euros & it's in Poland!!!

Is there any correlation between the time that your fan was locked & the time when the overpressurising started?

[Kevin Wood]

Seeing as the stat is on the coolant inlet, if the radiator was cooling too much, would that cause stat to close, hence hot engine?

I would be surprised but this type of setup can be temperamental. It's one of the contributors to the K series' appetite for head gaskets IMO.

What is critical with this type of setup is that the stat has plenty of bypass flow behind it so that it is responsive to the temperature of the coolant circulating in the engine NOT the coolant returning from the rad, which will be cold. This makes me start thinking about the fact that the heater makes a difference again. Can you see a bypass hose going to the engine side of the thermostat housing? I'm guessing it might be fed from the HBV or somewhere on the cylinder head? If this were blocked I'd expect wierd things to happen.

I think at speed the viscous fan will just be wasting fuel. I doubt it makes a big contribution to airflow once you're up to speed. Besides, they probably sell these in Norway too. The rad will be seeing MUCH colder air there.

Kevin

[TheBoy]

I thought I'd seen a new visco fan on ebay recently - just had a look & it's still there.

BUT it 284Euros & it's in Poland!!!

Is there any correlation between the time that your fan was locked & the time when the overpressurising started?

The fan when I got it had failed - seemed to spin slower the hotter it got.  So I acquired a seized one...


But, I think I'm barking up the wrong tree - I have tried the old (drilled) stat, no improvement....

[hotel21]

Just read through this thread.....

Thinking that any build up of limescale within the engine block may well act as an insulator and restrict the cooling effect.  Could well be worse towards the rear of the engine block if the circulation pressure is reduced a little.

If you are looking for something a tad more agressive to disolve limescale etc that may well be inhibiting cooling effect, how about some of that stuff that the always shouting Barry Scott is on about on the TV - Cillit Bang or whatever its called?  Certainly cleans pennies and limescale deposits and may be worth a punt prior to the next flush...  

[TheBoy]

Just read through this thread.....

Thinking that any build up of limescale within the engine block may well act as an insulator and restrict the cooling effect.  Could well be worse towards the rear of the engine block if the circulation pressure is reduced a little.

If you are looking for something a tad more agressive to disolve limescale etc that may well be inhibiting cooling effect, how about some of that stuff that the always shouting Barry Scott is on about on the TV - Cillit Bang or whatever its called?  Certainly cleans pennies and limescale deposits and may be worth a punt prior to the next flush...  

Had thought about it (or, truthfully, Mrs TheBoy had mentioned it), not sure if too harsh?

[Kevin Wood]

Had thought about it (or, truthfully, Mrs TheBoy had mentioned it), not sure if too harsh?

I don't think anything is too harsh to instantly kill an engine. As long as it's in there for long enough to do the job and  not left standing in the engine for ages you'll be OK.

Probably the most vulnerable part will be around the fire rings on the cylinder head gasket where you've got a couple of dissimilar metals together and you need a decent seal. However, with the amount of crud that must be in there for the cooling to suffer I don't think it's getting that far!

When I had my engine rebored they cleaned it in an acid bath. It took the (thick layer of) paint off the block. Granted it wasn't assembled with the water pump, head gasket, etc. but it does show what you can do! The water jacket in that was immaculate. Bare metal! Which reminds me. I must treat it to a coolant change!

Kevin

[smoothomega]

Hi TB.
 Been reading through this thread and just a couple of things to add. If you want to clear the lime scale etc from the engine then as i have mentioned in another thread there is nothing better in my mind than central heating cleaner (fernox) i have used this to great effect on other cars and you would not beleave the amount of crap it removes. Secondly it may be worth trying a product called "water wetter" which it claims to lower the temp in the cooling system by several degrees by chemically removing the heat. Buggered if i know how it works but it may be worth a try. I have seen it on ebay and if you type it into google it will find it for you. Hope this is of some help to you and i will keep an eye open for any results.
Cheers, Jez.

[TheBoy]

Hi TB.
 Been reading through this thread and just a couple of things to add. If you want to clear the lime scale etc from the engine then as i have mentioned in another thread there is nothing better in my mind than central heating cleaner (fernox) i have used this to great effect on other cars and you would not beleave the amount of crap it removes. Secondly it may be worth trying a product called "water wetter" which it claims to lower the temp in the cooling system by several degrees by chemically removing the heat. Buggered if i know how it works but it may be worth a try. I have seen it on ebay and if you type it into google it will find it for you. Hope this is of some help to you and i will keep an eye open for any results.
Cheers, Jez.

I now have some Forte stuff to try. Then may try fernox. How would I use fernox? - put some in (how much) and do a few miles (how many?). Or just flush with fernox?

[Taxi_Driver]

Hi TB.
 Been reading through this thread and just a couple of things to add. If you want to clear the lime scale etc from the engine then as i have mentioned in another thread there is nothing better in my mind than central heating cleaner (fernox) i have used this to great effect on other cars and you would not beleave the amount of crap it removes. Secondly it may be worth trying a product called "water wetter" which it claims to lower the temp in the cooling system by several degrees by chemically removing the heat. Buggered if i know how it works but it may be worth a try. I have seen it on ebay and if you type it into google it will find it for you. Hope this is of some help to you and i will keep an eye open for any results.
Cheers, Jez.

I now have some Forte stuff to try. Then may try fernox. How would I use fernox? - put some in (how much) and do a few miles (how many?). Or just flush with fernox?

I just had a look at the fernox website.....max strength 1kg to 10 litres (which is about the same as an omega) ....4 hours min / 12 hours max......tho you may want to reduce the quantity or how long you leave it in for as the temp is hotter with engine running

They do a neutraliser for the stuff as well.

Worth a go I guess if the Forte stuff doesnt work

Have a look here http://www.fernox.com/?cccpage=ds3&sub=6

[Kevin Wood]

Water wetter is essentially a detergent which breaks down the surface tension of the water apparently leading to better heat transfer to / from the surfaces it is in contact with. It also contains a corrosion inhibitor and is designed to be used where no antifreeze is used, IIRC.

Maybe it would help but there is a fundamental problem somewhere because the engine should cool itself happily without it.

Fernox is an interesting idea though.

Kevin

[Omegatoy]

Im still puzzling over this one the bit that doesent make sense is it can be left ticking over for hours or cruising as long as you like and it doesent over heat, as soon as you have been booting it for five mins it gets hot  then if you cruise agin it cools down, so to me headgasket doesent fit the bill, its more of a flow problem,either not enough flow or the heat exchange fromthe rad is not enough when boosting, the only thing that you havent done is improve the airflow through the rad by removing the aircon rad and there is no guarantee thats going to work!!! think as said the viscous isnt going to help when doing high speed but it will help cool the whole thing down at lower speeds,
what happend when you last swapped the drilled stat ? cos the only thing that seems to fit is the stat is causing a restriction in the flow? assuming you havent got a collapsed or seperated hose somewhere in the system,
having the heater on makes a difference againnpoints to a flow problem and the heater helps to improve the flow? does that make sense? the later ones have a hbv dont they? whereas the early ones dont, wwondr if its possible to get that out of the system and try it then?